Circulatory System Chapters

Anatomy 201 Exam III OBJECTIVES GUIDE____________ Chapter 16: The Brain and Cranial Nerves Sections :16.1 through 16-19 .I highlighted anatomy and selected topics of some areas (see lectures). 1. Identify the major regions of the brain and explain their functions. Have a general idea of the functions of various regions of the brain, : the limbic system, the basal ganglia, the cerebral cortex, the cerebellum, brain stem and mid 2. How does the brain develop in the early embryo? 3. What is a fissure? What is a sulcus? What is the central sulcus and longitudinal fissure? 4. Cerebrum: cerebral hemispheres, longitudinal fissure, gyri, sulci, lobes (basic function of each one), superficial gray layer-cortex, ventricles, (how are they organized), pre-central and post-central gyrus ( What are these two strips of cortex all about? how are they organized? 5. Name and be able to recognize the lobes of the cerebral cortex. 6. Cranial Meninges: Organization: pia, arachnoid, dura (give specifics of each layer). Give the basic anatomy of each layer. How does the Tentorium cerebelli, falx cerebelli, falx cerebri-come into play here? Arachnoid sinus ? 7. Where does CFS enter the venous system for recycling? 8. What is an Epidural hematoma? 9. What ventricles of the brain? How are they situated? 10. Choroid Plexuses: Where are they found? Histology? Function? 11. Medulla Oblongata: Location, basic function(s); 12. Pons: Locations function. 13. Mesencephalon- Structures found here, Corpora Quadrigemina 14. Fornix, Corpus Collosum, optic chiasm. 15. What is the pineal gland? Secretion? 16. What is meant by “lateralization” of the cerebral cortex. What is contralateral? ( cerebrum) What is ipsilateral? ( Cerebellum) 17. Diencephalon: Thalamus: Location, structure, and function ( be familiar with figure 16.11 in text) and in presentation ( the families of nuclei- note the sensory) 18. Diencephalon: Hypothalamus: Location, structure, and functions: ( figure on page 419) 19. Cerebellum: Location and structurally organization ( Folia, arbor vitae, lobes, peduncles) functions. 20. White matter brain: Types of fibers: commissural, association, and projection. How are they the same? How are they different? ( Compare) 21. What are the basal nuclei? Be familiar with their names. We focused on the Substantia Nigra. 22. What is the Limbic system? Be familiar with included structures. Location? Basic function. 23. Cranial Nerves: Know each by name and number. What is the Reticular Formation? How is it situated in the brain? General Functions? 24. What is the Reticular Formation? How is it situated in the brain? General Functions? 25. Be familiar with the Homunculus or “little man”. Why the differences in size of body structure that is represented on the sensory or motor cortex? The are located on pre and post CENTRAL SULCUS. 26. Epithalamus, structure, and function Chapter 17: The Autonomic Nervous System We covered sections 17.1 -17.4 (some sections modified)- pay close attention to modified PowerPoint I posted and presented in class!! 1. Compare and contrast the roles of somatic and autonomic nervous systems. 2. How is the autonomic nervous system subdivided? 3. The somatic nervous system innervates skeletal muscle. What does the autonomic NS innervate?( Know all effectors) 4. Differences between the somatic NS and autonomic NS are not only the EFFECTORs but also the number of EFFERENT NEURONS. How do they differ?? ( notice the first and second neuron of the efferent neurons. The preganglionic : is it myelinated? The postganglionic: Is it myelinated? 5. Distinguish between the sympathetic and parasympathetic divisions of the nervous systems. Explain this in terms of thoracolumbar and craniosacral. Also, what is the third division of the ANS, the enteric nervous system? 6. Describe the preganglionic fibers and neurons and postganglionic fibers and neurons 7. Name the neurotransmitter released by most postganglionic sympathetic fibers. 8. Be familiar with neurotransmitter releases at each preganglionic and postganglionic synapse for both sympathetic and parasympathetic . 9. Know terms “Cholinergic” and Adrenergic 10. What does the communicating rami have to do with the connection between the spinal cord and the autonomic pathway of innervation? 11. Where on the spinal cord (gray matter) do we find nuclei for autonomic tissue? 12. What is meant by “fight or flight” and “rest or digest” with respect to the autonomic nervous system? 13. Which cranial nerves carry parasympathetic fibers? (There are four) 14. Explain what happens when a preganglionic fiber synapses on modified neurons of the Adrenal Medulla. Which neurotransmitter is released? 15. What do we mean by “dual innervation” with respect to the sympathetic and parasympathetic nervous systems? 17.4. 16. Compare the Sympathetic and Parasympathetic Division of the ANS (Table 17.1) 17. What is the organization of the Sympathetic NS with respect to sympathetic chain ganglionic neurons and target organs? 18. What is the organization of the Parasympathetic division of the ANS? 19. What is a visceral reflex? Know general.. Circulatory System Chapters ( 20-BLOOD, 21-HEART, and 22)-VESSELS & CIRCULATION 1. Know the structure of the heart. Be able to identify all of the chambers and the distinguishing anatomical characteristics of each region. Include the septa, papillary muscle, valves, chordae tendineae, trabeculae carinae, and pectinate muscle. 2. Be able to describe in detail the endocardium, myocardium, epicardium, and pericardium. a) KEY POINT: The wall of the heart is composed of three layers: from superficial to deep: the epicardium, myocardium, and endocardium. i. Visceral layer of the serous pericardium (EPICARDIUM) - covers the surface of the heart. 1. The epicardium has two layers: a mesothelium and an underlying, supporting layer of areolar tissue. 2. The parietal layer of the serous pericardium consists of an outer dense fibrous layer and an inner mesothelium. ii. MYOCARDIUM - is cardiac muscle tissue that forms the atria and ventricles. 1. Associated with the myocardium are the cardiac muscle cells, connective tissues, blood vessels, and nerves. 2. The atrial myocardium is thin and is organized into layers forming figure eights as they pass from one atrium to the other. 3. The ventricular myocardium is thicker, and its muscle orientation changes from layer to layer. a) The most superficial ventricular muscles wrap around both ventricles. b) Deeper layers spiral around and between the individual ventricles. iii. ENDOCARDIUM - covers the inner surfaces of the heart, including those of the heart valves. 1. This simple squamous epithelium is continuous with the endothelium of the attached great vessels. 3. Know the pathway of the blood through the heart. a) Heart is a small organ—roughly the size of your fist, has four muscular chambers: the right and left atria and right and left ventricles. i. These four chambers work together, pumping blood through a network of blood vessels that connect the heart to peripheral tissues. b) The network of vessels is divided into two circuits: the pulmonary circuit and the systemic circuit. i. Pulmonary Circuit - carries carbon dioxide–rich blood from the heart to the gas exchange surfaces of the lungs and returns oxygen-rich blood to the heart. ii. Sytematic Circuit - transports oxygen–rich blood from the heart to the rest of the body’s cells and returns carbon dioxide-rich blood back to the heart. iii. Right atrium - receives blood from the systemic circuit iv. Right ventricle - pumps blood into the pulmonary circuit. v. Left atrium - receives blood from the pulmonary circuit vi. Left ventricle - pumps blood into the systemic circuit. vii. With each heartbeat, the atria contract first, followed by the ventricles. viii. The two ventricles contract at the same time and eject equal volumes of blood into the pulmonary and systemic circuits. c) Each circuit begins and ends at the heart, and blood flows through these circuits in sequence. i. Blood returning to the heart from the systemic circuit must complete the pulmonary circuit before re-entering the systemic circuit. ii. The blood vessels of both circuits are arteries, veins, and capillaries. 1. Arteries transport blood away from the heart 2. Veins return blood to the heart. 3. Capillaries are small, thin-walled vessels connecting the smallest arteries and veins. a) Capillaries are called exchange vessels because their thin walls permit exchange of nutrients, dissolved gases, and wastes between the blood and surrounding tissues. >Blood enters to: SVC & IVC -->Right Atrium --> Right Ventricle --> Pulmonary Artery --> LUNGS (Pulmonary Circuit) --> Pulmonary Veins ---> Left Atrium --> Left Ventricle --> Aorta --> Systematic Circuit 4. Be able to identify all of the major vessels of the coronary circulation. 21.6 a) KEY POINT: The coronary circulation supplies blood to the muscle tissue of the heart. The right and left coronary arteries are the first vessels to branch from the ascending aorta. b) The left and right coronary arteries originate at the base of the ascending aorta, within the aortic sinus. They are the first branches from this vessel. Blood pressure here is the highest found anywhere in the systemic circuit, and this pressure guarantees a continuous flow of blood to meet the demands of active cardiac muscle tissue. c) KEYPOINT: The right coronary artery circles the heart to the right (when viewed from above) within the coronary sulcus. In addition to the atrial branches, the right coronary artery gives off two major branches: the right marginal branch and the right posterior interventricular branch. d) Right coronary artery (RCA) - branches off the aorta and extends laterally around the posterior side of the heart; delivers blood to the right marginal area e) Left Coronary Artery (LCA) - branches off the aorta and extends inferiorly towards the left ventricle; branches to form the circumflex and anterior interventricular arteries f) Anterior Interventricular Artery - branch from the left coronary artery; sits in the anterior interventricular sulcus; supplies blood to the anterior sides of both ventricles g) Circumflex Artery - Major branch of the Left Coronary Artery; extends laterally around the left side of the heart to supply blood to the left atrium and posterior side of the left ventricle h) Posterior interventricular Artery - Branch from the right coronary artery; sits in the posterior interventricular sulcus; supplies blood to the posterior, middle and right side of the myocardium i) Right Marginal Artery - Branches off the right coronary artery; supplies blood to the right lateral side of the heart j) Left Marginal Artery - Branches off the circumflex artery; supplies blood to the left lateral side of the heart k) Anterior Cardiac Veins - Small veins that drain the anterior surface of the right atrium; empties blood directly into the right atrium l) Small Cardiac Vein - Drains the left lateral side of the heart; empties ito the coronary sinus m) Great Cardiac Vein - runs parallel to the interventricular artery; drains blood from the anterior surface of the heart; travels superiorly before following the coronary sulcus laterally around the heart; empties into the coronary sinus n) Posterior Cardiac Vein - drains the right lateral side of the heart; empties into the coronary sinus o) Middle Cardiac Vein - runs parallel to the postprior interventricular artery; drains blood from the posterior surface of the heart; empties into the coronary sinus p) Coronary Sinus - Large horizontal vessel on the posterior side of the heart ; collects blood from several cardiac veins; drains to the right atrium 5. What is the electrical conduction system of the heart? Be able to identify all of the associated structures. a) Cardiac Muscle Tissue contracts on its own; has the ability to generate and conduct impulses on its own called AUTOMATICITY OR AUTORHYMICITY. b) Conducting System of the Heart - is a network of specialized cardiac muscle cells responsible for initiating and distributing the stimulus to contract. i. SA Node (cardiac pacemaker) - contains pacemaker cells, establish rate of contraction: initiate electrical impulse that results in a heartbeat ii. Internodal Pathways - conducting fibers in the atrial wall that conduct the impulse to the AV node while simultaneously stimulating cardiac muscle cells of both atria iii. AV Node - slows electrical impulse when it arrives from the internodal pathways iv. AV Bundle - conducts the impulse from the AV node to the bundle branches v. Left Bundle Branch - extends toward the apex of the heart and then radiates across the inner surface of the left ventricle vi. Right Bundle Branch - extends toward the apex of the heart and then radiates across the inner surface of the right ventricle vii. Moderator Band - relays the stimulus through the ventricle to the papilalry muscles, which tense the chordae tendinae before the ventricles contract viii. Purkinje Fibers - convey the impulses very rapidly to the contractile cells of the ventricular myocardium 6. Compare and contrast the structure of the fetal heart with the heart of an adult. SEE #12 FOR ALL FETAL RELATED QUESTIONS. 7. Distinguish between systemic and pulmonary circulation. a) The systemic circulation is a circuit loop that delivers oxygenated blood from the left heart to the rest of the body, and returns deoxygenated blood back to the right heart via large veins known as the venae cavae. b) The pulmonary circulation is a circuit for blood flow to and from the lungs that provides oxygenation of the venous blood. 8. Compare and contrast the anatomical structure of arteries, arterioles, veins, capillaries, venules. Know Tunics. Be able to identify the major blood vessels of the body. a) Artery - carries blood away from the heart i. Resistance vessels ii. High pressure iii. Smaller diameter than veins iv. Thick tunica media v. Lots of elastin vi. Function: carry blood away from the heart; not always oxygenated b) Vein - carries blood back to the heart i. Capacitance vessels ii. Low pressure lines iii. Carry blood to the heart c) Capillary - are permeable and for exchange i. Exchange vessels d) Venules - smallest veins, collect blood from capillaries. e) Arterioles - smaller than muscular arteries; have very thin adventitia and the media consists of scattered smooth muscle cells that my not form a complete layer 9. What is so important about the tunica media? How does it vary? How in which vessels? In which vessels do we have vasodilation and vasoconstriction? Explain which tissue and nervous system accounts for this. a) Outer Adventitia (tunica externa) - forms a connective tissue sheath around the vessel. i. This layer is very thick and is composed chiefly of collagen fibers, with scattered bands of elastic fibers. ii. In veins, this layer is usually thicker than the media. iii. The fibers of the adventitia blend into those of adjacent tissues, stabilizing and anchoring the blood vessel. b) The media (tunica media) - the middle layer, contains concentric layers of smooth muscle tissue supported by a framework of loose connective tissue. i. The smooth muscle cells of the media encircle the lumen of the blood vessel. ii. When stimulated by the sympathetic branch of the autonomic nervous system, these smooth muscles contract, reducing the luminal diameter of the blood vessel called VASOCONTRICTION. iii. Relaxation of the smooth muscles increases the diameter of the lumen is called VASODILATION. In addition to responding to the autonomic nervous system, these smooth muscles contract or relax in response to local stimuli, such as changes in pH, pCO2, or pO2. Any change in vessel diameter affects both blood pressure and blood flow. Collagen fibers bind the media to both the intima and adventitia. Arteries have a thin band of elastic fibers, called the external elastic membrane, located between the media and adventitia. c) The intima (tunica intima) - is the innermost layer of a blood vessel. i. It is composed of the endothelial lining of the vessel and an underlying layer of connective tissue containing variable amounts of elastic fibers. ii. In arteries, the outer margin of the intima contains a thick layer of elastic fibers called the internal elastic membrane. iii. In the largest arteries, the connective tissue within this layer is extensive, and the intima is thicker than in smaller arteries. 10. what is an anastomosis? Be familiar with some of the examples. What is a metarteriole and sphincter system? How does it regulate blood flow? Purpose? a) ANASTOMOSIS- direct connections between arterioles and venules (found in the capillaries) i. EX: Arteriovenous Anastomosis b) Metarteriole (also called Precapillary Sphincters) - guard the entrances to capillaries in mesentries i. Metarterioles represent thoroughfare channels within the mesentries (not outside) ii. Passageways known as thoroughfare channels connect arterioles with venules 1. Lined with smooth muscle, their contraction and relaxations constrict or dilate, thus narrowing or widening the diameter of the vessel and regulating blood flow. 11. Be able to identify the major vessels of the hepatic portal system. a) The hepatic portal system - begins in the capillaries of the digestive organs and ends in the liver sinusoids. i. The liver is the only digestive organ draining directly into the inferior vena cava. ii. Blood leaving the capillary beds supplied by the celiac, superior mesenteric, and inferior mesenteric arteries flows into the veins of the hepatic portal system instead of traveling directly to the inferior vena cava. iii. a blood vessel connecting two capillary beds is called a portal vessel, and the network is a portal system. iv. Blood flowing in the hepatic portal system is quite different from blood in other systemic veins because it contains substances absorbed from the stomach and intestines. 1. EX: levels of blood glucose and amino acids in the hepatic portal vein often exceed those found anywhere else in the cardiovascular system. 2. The hepatic portal system delivers these and other absorbed compounds directly to the liver for storage, metabolic conversion, or excretion 12. Describe fetal circulation in detail. Know the shunts, blood pathway and vessels. Compare and contrast the structure of the fetal heart with the heart of an adult. a) Key Point: During development, the fetus receives its nutrients and oxygen, and excretes its wastes and carbon dioxide, by diffusion through the placenta. With a newborn’s first breath, lung function, gastrointestinal activity, and circulatory patterns change. b) During fetal development, the umbilical arteries carry blood to the placenta. It returns via the umbilical vein and enters a network of vascular sinuses in the liver. The ductus venosus collects this blood and returns it to the inferior vena cava. c) Ductus Arteriosus - A Vessel that shunts blood from the pulmonary trunk, away from the pulmonary circuit, into tha aortic arch d) Foramen Ovale - an opening in the interatrial septum that permits some blood to flow directly into the left atrium e) Ductus Venosus - A shunt that permits most blood to bypass the fetal liver so it directly enters the inferior vena cava and then the right atrium f) Umbilical Vein - transports oxygen-rich, nutrient-rich blood from placenta to fetal liver g) Difference between fetal heart and adult heart: CRITERIA ADULT CIRCULATION FETAL CIRCULATION Artery Carries oxygenated blood away Carries Non-Oxygenated blood away from the heart from the fetal heart Veins Carries Non-oxygenated blood Carries oxygenated blood back to the towards the heart heart Gas Takes place in the lungs Takes place in the placenta Exchange Pressure Increase pressure on the left side of Increase pressure on the right side of the the heart heart 13. What is the composition of blood? 20.1 What are the types formed element including specifics about leucocytes ( If stated, know its special characteristic). 20.2 Which are granulocytes? Stem cell pathway for all blood cells. Page 535 “The following mnemonic will help you remember the various white blood cell populations: “Never Let Monkeys Eat Bananas.” Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils” a) Blood is a fluid connective tissue distributing nutrients, oxygen, and hormones to each of the roughly 75 trillion cells in the human body. Blood also carries metabolic wastes to the kidneys for excretion and transports specialized cells that defend peripheral tissues from infection and disease. b) Blood consists of the following two components: i. Plasma is the liquid component of blood. It has a density only slightly greater than water. Plasma contains dissolved proteins and other solutes (nutrients, electrolytes, and wastes). 1. Plasma Proteins has 3 major classes a) Albumins - major contributors to osmotic pressure; transports fatty acids, thryoid hormones, steroid hormones and other substances. b) Globulins - 2nd most abundant proteins. Includes: i. Immunoglobulins (Antibodies) - aid in the body’s defense ii. Transport Globulins - bind small ions, hormones, or compounds that either are insoluble or will be filtered out of the blood by the kidneys ii. iii. iv. v. vi. c) Fibrinogen - largest of the plasma proteins; essential for normal blood clotting i. Fibrin - basic framework of blood clot. Formed elements are blood cells (red blood cells and white blood cells) and cell fragments (platelets) suspended in the plasma. RBCs transport oxygen and carbon dioxide. WBCs are components of the immune system and are less numerous than RBCs. Platelets are small, membrane-enclosed packets of cytoplasm containing enzymes and clotting factors, proteins that play a role in blood clotting. 1. RBCs (erthythrocytes) - less than 1/2 of total blood volume a) Hematocrit - is the percentage of whole blood containing formed elements (VPRC or PCV) b) RBCs transport oxygen and CO2 within the bloodstream c) Each RBCs are biconcave disc with a thin central region and thick outer margin d) RBCs unusual biconcave shape gives each RBC a very large surface area which permits rapid diffusion between the RBC cytoplasm and the surrounding plasma e) As blood circulates from the capillaries of the lungs to the capillaries in the peripheral tissues and then back to the lungs, RBCs absorb and release respiratory gases. f) The biconcave shape gives RBCs a large surface area allowing for rapid diffusion of gases and the ability to form stacks (called ROULEAX) that can pass easily through small vessels. g) Because RBCs lack mitochondria, ribosomes, and nuclei, they are unable to perform normal maintenance operations, so they usually degenerate after about 120 days in the circulation. h) Damaged or dead RBCs are recycled by phagocytes. Whole blood - is a mixture of plasma and formed elements Hypovolemic - low blood volumes Normovolemic - normal blood volumes Hypervolemic - excessive blood volumes 2. WBC (Leukoctyes) - defend the body against invasion by pathogens and remove toxins, wastes, and abnormal or damaged cells. a) When body cells are infected or damaged, they release chemicals into the interstitial CHEMOTAXIS b) WBCs are transported in the bloodstream to the invading pathogens, damaged tissues, and white blood cells already in the damaged tissues. They then cross the endothelial lining of a capillary by squeezing between adjacent endothelial cells in a process called DIAPEDESIS, or emigration. c) Has two groups: i. Granular Leukocytes (Granulocytes) 1. Neutrophils - is packed with pale, neutral-staining granules containing lysosomal enzymes and bactericidal (bacteria-killing) compounds a) Neutrophils are highly mobile and are usually the first WBCs to arrive at an injury site. b) They are active phagocytes, specializing in attacking and digesting bacteria. c) Neutrophils have a short life span, surviving in the bloodstream for only 10 hours. d) A neutrophil dies after actively engulfing one to two dozen bacteria, but its death and breakdown release chemicals that attract other neutrophils to the site. 2. Eosinophils - similar in size to neutrophils but have deep red cytoplasmic granules and a bilobed (two-lobed) nucleus a) Eosinophils attack objects that are coated with antibodies. i. The number of eosinophils increases dramatically during an allergic reaction or parasitic infection. ii. These WBCs release enzymes that reduce inflammation produced by mast cells and neutrophils, which controls the spread of inflammation to adjacent tissues. 3. Basophils - are, accounting for less than 1 percent of the circulating WBC population. a) They migrate to sites of injury and cross the capillary endothelium into the damaged or infected tissues. i. There they release their granules into the interstitial fluids. The granules contain histamine and heparin. ii. Histamine dilates blood vessels, and heparin prevents blood clotting. iii. Stimulated basophils release these chemicals into the interstitial fluids to enhance the local inflammation initiated by mast cells. ii. Agranular Leukocytes (Agranulocytes) 1. Monocytes - are the largest white blood cells, with a diameter two to three times larger than an RBC. Each monocyte has a large oval or kidney bean–shaped nucleus a) Monocytes circulate for just a few days before entering peripheral tissues. Outside the bloodstream, monocytes are called free macrophages and are very different from the immobile fixed macrophages found in connective tissues. Free macrophages are highly mobile, phagocytic cells. They usually arrive at an injury site shortly after the first neutrophils. While phagocytizing, free and fixed macrophages release chemicals that attract and stimulate other monocytes and other phagocytic cells. 2. Lymphocytes - have very little cytoplasm, forming a thin halo around a large, round, purple-staining nucleus. a) Lymphocytes are the primary cells of the lymphatic system, a network of special vessels and organs distinct from, but connected to, those of the cardiovascular system. b) Lymphocytes are responsible for specific immunity - the ability of the body to attack invading pathogens or foreign proteins on an individual basis. c) The circulating blood contains three functional classes of lymphocytes: i. T Cells (T lymphocytes) enter peripheral tissues and attack foreign cells directly. ii. B Cells (B lymphocytes) differentiate into plasma cells (plasmocytes). Plasma cells secrete antibodies that attack foreign cells or proteins. iii. Natural Killer Cells (NK) are responsible for immune surveillance and the destruction of abnormal cells. These cells, sometimes known as large granular lymphocytes, are important in preventing cancer. iii. Platelets - re small, membrane-bound, anucleate cytoplasmic fragments that play an important role in blood clotting. They are formed from cells called Megakaryocytes 1. Thrombocytopenia - abnormally low platelet count 2. 3. 4. Thrombocytosis - abnormally high platelet count - indicates accelerated platelet formation in response to infection, inflammation, or cancer Hemostasis - prevents the loss of blood through the walls of damaged vessels which restricts blood loss and establishes a framework for tissue repairs FUNCTIONS OF PLATELETS: a) Initiating and controlling the clotting process by releasing enzymes and other factors at the appropriate times. b) Clumping together at an injury site to form a platelet plug that slows the rate of blood loss while clotting occurs. c) Containing actin and myosin filaments that interact and shorten during the clotting process. After a blood clot has formed, the contraction of platelets shrinks the clot and pulls together the cut edges of the vessel wall. 14. What is the basic structure and function of hemoglobin. Compare and contrast with myoglobin. What is hematocrit? How much blood do we have? Page 533 a) Hemoglobin - make up more than 95% of RBCs proteins. i. Hemoglobin is responsible for the cell’s ability to carry and transport oxygen and carbon dioxide. It is a globular protein that contains a nonprotein red pigment. Oxygenated hemoglobin has a bright red color, while deoxygenated hemoglobin has a deep red color.(FUNCTION) ii. STRUCTURE: Hemoglobin consists of four globular protein subunits. Each subunit contains a single molecule of heme, a porphyrin ring surrounding a single ion of iron. It is the iron ion that reversibly binds to an oxygen molecule. b) Difference between Hgb and Myoglobin: i. difference between hemoglobin and myoglobin gives rise to their different functions; hemoglobin is found in the blood stream, transporting oxygen from lungs to the rest of the body while myoglobin is found in the muscle, releasing oxygen needed. ii. Since myoglobin stores oxygen, it has a higher affinity for oxygen. Hemoglobin's lower affinity for oxygen allows hemoglobin to release oxygen to the tissues at a lower blood pH. Hemoglobin transports oxygen and myoglobin stores oxygen. c) Hematocrit value indicates the percentage of whole blood occupied by cellular elements. i. Average Hct in Adult male is 45 (40-54) ii. Average Hct in Adult female is 42 (37-47) iii. Whole blood contains 1000x more RBCs than WBCs 15. Relative Difference in blood pressure found in arteries and veins? How do veins facilitate transfer blood back to the heart? a) The pressure is higher in arteries due to their proximity to the heart and increased muscle tissue which is able to cause contractions. Whereas veins have a lower pressure as blood moving through veins often comes from low-pressure capillary beds. Flow is the movement of the blood around the circulatory system. b) A thin layer of smooth muscle in the veins helps squeeze blood back towards the heart. When muscles contract and relax during the inspiration and expiration process, pressure changes occur in the thoracic and abdominal cavities. These pressure changes compress the nearby veins and assist blood return to the heart. c) Most veins carry deoxygenated blood from bodily tissue back to the heart, where it receives fresh oxygen. Veins must work against gravity to return blood the heart. The muscles of the leg help that process, and valves within the veins usually keep the moving blood from flowing back down toward the feet. 16. How do capillaries differ? a) Capillaries transport blood between arteries and veins. Arteries are the largest blood vessels with the thickest walls, and capillaries are the smallest. Arteries are only located deep inside your muscles, but capillaries are inside tissues all over your body. b) Capillaries are the smallest blood vessels and the only blood vessels whose walls permit exchange between blood and interstitial fluid. c) Capillaries maybe continuous (the endothelium is a complete lining) or fenestrated (the endothelium contains “windows”). d) Sinusoids are specialized fenetrated capillaries found in selected tissues (such as the lvier) that allow very slow blood flow. 17. What is endothelium? Where do we find it? Which vessels are made of only endothelium? a) Endothelium - lines the heart and blood vessels b) Found in blood vessels and lymphatic vessels 18. What is a Vasa Vasorum? a) Vasa Vasorum - small blood vessels that supply or drain the walls of the larger arteries and veins and connect with a branch of the same vessel or a neighboring vessel. b) The walls of large vessels contain small arteries and veins that supply the smooth muscle cells, fibroblasts, and fibrocytes of the media and adventitia called the VASO VASORUM (VESSELS OF VESSELS) 19. Know major arteries and veins of the body. a) The Aorta i. The ascending aorta gives rise to the coronary circulation. ii. The aortic arch continues as the descending aorta. Three large arteries arise from the aortic arch to collectively supply the head, neck, shoulder, and upper limbs: the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. iii. The brachiocephalic trunk gives rise to the right subclavian artery and the right common carotid artery. These arteries supply the right upper limb and portions of the right shoulder, neck, and head. iv. Each subclavian artery exits the thoracic cavity to become the axillary artery, which enters the arm to become the brachial artery. The brachial arteries and their branches supply blood to the upper limbs. v. Each common carotid artery divides into an external carotid artery and an internal carotid artery. The external carotids and their branches supply blood to structures in the neck and face. The internal carotids and their branches enter the skull to supply blood to the brain and eyes. The brain also receives blood from the vertebral arteries. The vertebral arteries and the internal carotids form the cerebral arterial circle (or circle of Willis), which ensures the blood supply to the brain. b) The Descending Aorta i. The descending aorta superior to the diaphragm is termed the thoracic aorta and that inferior to it the abdominal aorta. The thoracic aorta and its branches supply blood to the thorax and thoracic viscera. The abdominal aorta and its branches supply blood to the abdominal wall, abdominal viscera, pelvic structures, and lower limbs. The three unpaired arteries are the celiac trunk, the superior mesenteric artery, and the inferior mesenteric artery. The celiac trunk divides into the left gastric artery, the common hepatic artery, and the splenic artery. Paired arteries include the adrenal arteries, the renal arteries, the lumbar arteries, and the gonadal arteries. ii. Arteries in the neck and limbs are deep beneath the skin; in contrast, there are usually two sets of peripheral veins—one superficial and one deep. This dual venous drainage is important for controlling body temperature. iii. Arteries of the pelvis and lower limbs include the right and left common iliac arteries, which branch to form the external and internal iliac arteries. The femoral and deep femoral arteries supply the lower limb. c) Superior Vena Cava (VEIN) - The superior vena cava receives blood from the head, neck, chest, shoulders, and upper limbs. d) Inferior Vena Cava (VEIN) - collects most of the venous blood from organs and structures inferior to the diaphragm that are not drained by the hepatic portal vein. i. Any blood vessel connecting two capillary beds is called a portal vessel, and the network of blood vessels comprises a portal system. Blood leaving the capillaries supplied by the celiac trunk, superior, and inferior mesenteric arteries flows into the hepatic portal system. Blood in the hepatic portal system is unique compared to that of the other systemic veins because portal blood contains high concentrations of nutrients. These substances are collected from the digestive organs through the vessels of the portal system and are transported directly to the liver for processing. Respiratory System ( Chapter 24) Sections: 24.1 though 24.8 STOP (not covered 24.9) 1. Which structures are in the Respiratory System? Divide the RS into the Upper RS. a) The Respiratory system includes all structures from the nose to the alveoli. i. Upper Respiratory System consists of: 1. Paranasal sinuses 2. Nasal conchae 3. Nasal cavity 4. Nasopharynx ii. Lower Respiratory System consists of: 1. Larynx 2. Trachea 3. Bronchi 4. Lungs 5. Bronchioles 6. Alveoli of the lungs b) These passageways “condition the air” by filtering, warming, and humidifying it, thereby protecting the delicate conduction and exchange surfaces of the lower respiratory system from debris, pathogens, and environmental extremes c) The respiratory tract consists of a conducting portion, which extends from the entrance to the nasal cavity to the bronchioles, and a respiratory portion, which includes the respiratory bronchioles and the alveoli. d) The process of filtering, warming, and humidifying inhaled air begins at the entrance to the upper respiratory system and continues through the rest of the conducting portion. e) By the time the air reaches the alveoli of the lungs, most foreign particles and pathogens have been removed, and its humidity and temperature are within acceptable limits. f) The success of this conditioning process is due to the properties of the respiratory epithelium. 2. What are the basic functions of the Respiratory System? a) Providing an extensive area for gas exchange between air and circulating blood b) Moving air to and from the exchange surfaces of the lungs c) Protecting respiratory surfaces from dehydration, temperature changes, and other environmental variations d) Defending the respiratory system and other tissues from pathogens e) Producing sounds involved in speaking, singing, or nonverbal communication f) Helping regulate blood volume, blood pressure, and body fluid pH The respiratory system performs these functions in conjunction with the cardiovascular and lymphatic system, selected skeletal muscles, and the nervous system. KEY POINT: Functions of the respiratory system include conducting air, providing an area for gas exchange, protecting respiratory surfaces, producing sounds, and helping regulate blood pressure and body fluid pH. 3. What is the most common respiratory epithelium? Know the common one and the 3 others and where each is found. a) The respiratory epithelium is a pseudostratrified ciliated columnar epithelium with numerous mucous cells i. The respiratory epithelium lines the entire respiratory tract except for the inferior portions of the pharynx, the smalles conducting passages, and the alveoli. (It lines the conducting portions of the respiratory system down to the level of the terminal bronchioles) b) c) d) e) f) g) ii. PCCE to simple cuboidal non-ciliated in parts of trachea, to bronchioles - simple columnar to simple squamous in alveoli. (gradual transition of respiratory epithelium of mucosa) A stratified squamous epithelium lines the inferior portion of the pharynx, protecting it from abrasion and chemicals. i. This portion of the pharynx conducts air to the larynx and also conveys food to the esophagus ii. The epithelium changes from pseudostratified ciliated columnar epithelium to a nonkeratinized (mucosal type) stratified squamous epithelium at the boundary between the nasopharynx and oropharynx. Mucous cells in the epithelium and mucous glands in the lamina propria produce a sticky mucus that bathes the exposed surfaces. (the respiratory epithelium produces mucus that traps incoming particles. Underneath is the lamina propria; the combined respiratory epithelium and lamina propria form a mucosa (mucous membrane). In the nasal cavity, cilia sweep that mucus and any trapped debris or microorganisms toward the pharynx, where it is swallowed and exposed to the acids and enzymes in the stomach. In the lower respiratory system, the cilia beat toward the pharynx, moving a carpet of mucus in that direction and cleaning the respiratory surfaces - mechanism is the MUCOCILIARY ESCALATOR. Lines respiratory tract except pharynx and alveoli CLARA CELLS (in some small bronchial tube - have simple cuboid non-ciliated) 4. What are the nasal conchae? How do they function? a) The superior, middle, and inferior nasal conchaie, or turbinated bones, project toward the nasal septum from the lateral walls of the nasal cavity. b) Air flows between the adjacent conchae and through the superior, middle, or inferior meatuses as it passes from the nasal vestibule to the narrow posterior nasal apertures (or choanae) c) The incoming air bounces of the conchae and churns around like water flowing over rapids d) This air turbulence brings small airborne particles into contact with the mucus lining the nasal cavity e) The turbulence allows extra time for warming and humidifying incoming air and creating air currents that bring olfactory stimuli to the olfactory receptors. 5. Respiratory Defense System? Vibrissae? Mucous? a) Contamination of the inspired air by pathogens or debris will damage the delicate surfaces of the respiratory system. However, the air entering the respiratory system is filtered to remove contaminants. The respiratory filtration mechanisms form the RESPIRATORY DEFENSE SYSTEM b) In the nasal cavity, almost all particles larger than 10um are removed from the inspired air c) Vibrissae - Stiff hairs within the nasal cavity remove larger particles d) The mucous of the nasopharynx or secretions of the pharynx trap smaller particles before they enter smaller passageways of the conducting portion. e) The respiratory defense system includes: i. Mucous glands ii. Mucus produced (which washes particles toward the stomach) iii. Alveolar macrophages iv. Hairs v. Cilia f) Mucus is secreted by nasopharynx g) Odors are detected by sensory smells h) The Lamina Propria - is populated by lymphocytes! Kills! 6. Going from the NASAL CAVITY TO THE PHARYNXWhat is another name for pharynx??( a common passageway) Where does it start? a) b) c) d) The NOSE is the primary passageway for air entering the respiratory system. Air enters the nose through the paired nostrils, or nares. These open into the NASAL VESTIBULE and the NASAL CAVITY. The nasal vestibule is the portion of the nasal cavity enclosed by the flexible tissues of the nose i. It is supported by thin paired lateral and alar cartilages e) The epithelium of the nasal vestibule contains coarse hairs that extend across the external nares i. Large airborne particles such as sand, sawdust and even insects are trapped in these hairs and are prvented from entering the nasal cavity f) The nasal septum separates the right and left portions of the nasal cavity i. The fusion of the perpendicluar plate of the ethmoid and vomer forms the bony portion of the nasal septum g) The anterior portion of the nasal septum is formed of hyaline cartilage i. The cartilaginous plate supports the dorsum (bridge) of the nose and the apex (tip of the nose. h) The maxillae, nasal and frontal bones, ethmoid, and sphenoid form the lateral and superior walls of the nasal cavity. i) Mucus produced in the paranasal sinuses, aided by tears draining through the nasolacrimal ducts, keep the surface of the nasal cavity moist and clean. j) The superior portion, or olfactory region, of the nasal cavity consists of the areas lined by olfactory epithelium i. The inferior surface of the cribriform plate ii. The superior nasal conchae of the ethmoid iii. The superior portion of the nasal septum k) A bony hard palate, formed by the maxillae and palatine bones, forms the floor of the nasal cavity and separates the oral and nasal cavities l) A fleshy soft palate extends posteiror to the hard palate which marks the boundary between the superior nasopharnyx and the rest of the pharynx m) The nasal cavity opens into the nasopharynx at the posterior nasal apertures. 7. What are the subdivisions of the pharynx? (Naso, Oro and Laryngo) a) KEY POINT: The pharynx, a common passageway shared by the digestive and respiratory systems, is subdivided into the nasopharynx, oropharynx, and laryngopharynx. b) Pharynx - connects the nose, mouth, and throat i. The digestive and respiratory systems share the pharynx ii. It extends between the posterior nasal apertures and the entrances to the trachea and esophagus iii. The curving superior and posterior walls are attached to the axial skeleton, but the lateral walls are flexible and muscular c) Nasopharynx- is the superior portion of the pharynx i. It is connected to the posterior portion of the nasal cavity by the posterior nasal apertures ii. The soft palate separates it from the oral cavity iii. Produces your voice iv. Control pressure between your nasopharynx and middle ear d) Oropharynx - is the middle region behind the mouth i. extends between the soft palate and the base of the tongue at the level of the hyoid bone e) Like the posterior and inferior portions of the nasopharynx, the posterior portion of the oral cavity communicates directly with the oropharynx f) Laryngopharynx - is the inferior region attached to larynx i. (narrow) includes the region of the pharynx lying between the hyoid bone and the entrance to the esophagus g) The oropharynx and laryngopharynx are common passageways for air and food 8. The nasopharynx is connected to middle ears by eustachian tube. Consequence? a) Your eustachian tubes connect from your middle ears to your nasopharynx, draining fluid and balancing pressure. Conditions that affect your nasopharynx include the common cold and enlarged adenoids. 9. What epithelial tissues are found in nasopharynx? Oropharynx? Laryngopharynx? Hint: PCCE only is nasopharynx. a) Nasopharynx is lined with Pseudostratified ciliated columnar epithelium b) Like the oropharynx, the laryngopharynx is lined with a stratified squamous epithelium that resists abrasion, chemicals, and pathogens. 10. What is the larynx? Describe the cartilages of the larynx. What is the function of the epiglottis? Be familiar with the different types of cartilage found in these regions and structures? a) Larynx - inhaled air passes through the glottis en route to the lungs; the larynx surrounds and protects the glottis i. Contain the the true vocal folds and false vocal folds ii. Begins between the level of vertebra C3 to C5 and ends at the level of C6 to C7 11. What is the mucocillary escalator? Where do we find this? a) In the lower respiratory system, the cilia beat toward the pharynx, moving a carpet of mucus in that direction and cleaning the respiratory surfaces - mechanism is the MUCOCILIARY ESCALATOR. 12. What are the parasinal cavities? From which bones? (Text talks about meatuses- Go with sinuses as we discussed the actual bones) a) The maxillae, nasal and frontal bones, ethmoid, and sphenoid form the lateral and superior walls of the nasal cavity. b) Mucus produced in the paranasal sinuses, aided by tears draining through the nasolacrimal ducts, keep the surface of the nasal cavity moist and clean. c) The superior portion, or olfactory region, of the nasal cavity consists of the areas lined by olfactory epithelium i. The inferior surface of the cribriform plate ii. The superior nasal conchae of the ethmoid iii. The superior portion of the nasal septum d) A bony hard palate, formed by the maxillae and palatine bones, forms the floor of the nasal cavity and separates the oral and nasal cavities e) A fleshy soft palate extends posteiror to the hard palate which marks the boundary between the superior nasopharnyx and the rest of the pharynx f) The nasal cavity opens into the nasopharynx at the posterior nasal apertures. 13. What does the acronym MALT stand for? a) Mucosa-associated lymphoid tissue (MALT) - the extensive collection of lymphoid (lymphatic) tissues linked within the epithelia of the digestive, respiratory, urinary, and reproductive tracts. 14. What is another name for the larynx? What happens here? What can be found here? a) Another name for the larynx - VOICE BOX. b) Sound Production - air passing through the glottis vibrates the vocal folds and produces sound waves i. The pitch of the sound produced depends on the diameter, length, and tension of the vocal folds ii. Tension is controlled by the contraction of the skeletal muscles iii. This changes the positions of the thyroid and arytenoid cartilages. iv. When the distance between the thyroid and arytenoid cartilages increases, the vocal folds tense and the pitch rises v. When the distances decreases, the vocal folds relax and pitch falls vi. Then entire larynx is involved in sound production because its walls vibrate, creating a composite sound vii. Amplification and echoing of the sound occur within the pharynx, oral cavity, nasal cavity, and paranasal sinuses. viii. The final production of distinct sounds depends on voluntary movements of the tongue, lips and cheeks. 15. Which types of cartilages do we find covering larynx and trachea? Names? Functions? a) Cartilages of the Larynx i. The Thyroid Cartilage - largest laryngeal cartilage; forms most of the anterior & lateral walls of the larynx 1. Laryngeal Prominence or Adam’s Apple is located on the anterior surface of this cartilage; easily seen and felt. 2. Inferior surface of thyroid cartilage articulates with the cricoid cartilage 3. The superior surface of the thyroid cartilage has ligamentous attachments to the epiglottis and smaller laryneal cartilages ii. Cricoid Cartilage - forms a complete circle. 1. Its posterior portion is greatly expanded and supports the posterior surface of the larynx 2. Cricoid and larynx cartilages protect the glottis and the entrance to the trachea 3. Broad surfaces are sites for the attachment of important laryngeal muscles and ligaments 4. Ligaments attach the inferior surface of the cricoid cartilage to the first cartialge of the trachea 5. The superior surface of the cricoid cartialge articulates with the small paired arytenoid cartilages iii. Epiglottis - shoehorn-shaped; protects superior to the glottis 1. During swallowing, the larynx is elevated, and the epiglottis folds bac over the glottis, which prevents both liquids and solid food from entering the respiratory passageways iv. Paired Laryngeal Cartilages - contains three pairs of smaller cartilages: arytenoid, corniculate, and cuneiform cartilages. 1. Paired Arytenoid Cartilages - hyaline cartilage; articulate with the posterior, superior border of the cricoid cartilage 2. Small Corniculate Cartilages - hyaline cartilage; articulate with arytenoid cartilages; corniculate & arytenoid are important in opening and closing the glottis and producing sound 3. Cuneiform Cartilages - elastic cartilage; lie within the ary-epiglottic fold, tissue that extends between the lateral aspect of each arytenoid cartilage and the epiglottis 16. The basics of how vocal cords work what is involved. See slide. a) b) 17. Laryngeal Muscles: Intrinsic muscles/ Extrinsic a) Intrinsic Laryngeal Muscles - contained within larynx and have 2 functions i. One group regulates tension in the vocal folds ii. The second set opens and closes the glottis 1. Those regulating vocal fold tension insert upon the thyroid, arytenoid, and corniculate cartilages 2. Those opening or closing the glottis insert onto the arytenoid cartilages b) Extrinsic Laryngeal Muscles - connect the larynx to neighboring structures and move it up and down during swallowing and speaking. c) The extrinsic and Intrinsic muscles cooperate to prevent food and liquids from entering the glottis during swallowing. d) Before you swallow, food is crushed and chewed, forming a pasty mass known as bolus. e) Extrinsic muscles elevate the larynx, bending the epiglottis over the entrance to the glottis which causes the bolus to glide across the epiglottis, rather than falling into the larynx f) While this movement is under way, intrinsic muscles close the glottis. g) If particles or liquids touch the surface of the vestibular or vocal folds, the coughing reflex is triggered. Coughing prevents the material from entering the glottis. 18. Trachea: mucosal epithelium a) Trachea - WINDPIPE - is a tough, flexible tube with a diameter of about 2.5cm and length of 11cm i. Trachea begins anterior to vertebra C6, attached to the cricoid cartilage by connective tissue. ii. It ends within the mediastinum at T5, where it branches to form the right and left main bronchi. iii. The lining of the trachea is a pseudostratified ciliated columnar epithelium with mucous cells, sits on a layer of loose connective tissue called the lamina propria. iv. Lamina Propria separates the respiratory epithelium from the deeper hyaline cartilages. v. The combination of epithelium and lamina propria is an example of Mucosa or Mucous Membrane vi. Submucosa (layer of connective tissue, deep to the lamina propria) - contains tracheal glands that secrete mucus onto the epithelial surface through secretory ducts 19. Bronchial Tree-Primary/Secondary/Tertiary- (At T-3 The Trachea branches into Bronchial tree) -24.5 a) T5 - trachea branches within the mediastinum, giving rise to the right and left main bronchi b) An internal ridge, the carina of trachea, lies between the entrances to the two main bronchi. c) Histology of the main bronchi is the same as the trachea i. Right Main Bronchus - supplies the right lung; shorter, has a larger diameter, and descends toward the lung at a steeper angle than the left. For these reasons, most foreign objects that enter the trachea find their way into the right bronchus rather than the left ii. Left Main Bronchus - supplies the left lung iii. Each main bronchus travels to and through the hilum of the lung before branching further. iv. Hilum - is a groove on the mediastinal surface of the lung and, in addition to the entrance of the main bronchi, is the site for the entry and exit of pulmonary vessels and nerves. v. Root - a meshwork of dense connective tissue anchors all of these structures to the lung; it is attached to the mediastinum and holds the major nerves, vessels, and lymphatics in place The Main Bronchi d) KEYPOINT: After each main bronchus enters the lung, it divides into smaller and smaller lobar and segmental bronchi. e) The main bronchi and their branches form the bronchial tree. As the main bronchi enter the lungs, they divide to form smaller passageways f) After entering the lung, each main bronchus divides, forming lobar bronchi, also known as secondary bronchi. Lobar bronchi then divide, forming segmental, or tertiary, bronchi. The branching pattern differs in the right and left lungs. Each segmental bronchus supplies air to a single bronchopulmonary segment. There are 10 segmental bronchi and 10 bronchopulmonary segments in the right lung. In the developing fetus, the left lung also starts out with 10 bronchopulmonary segments. However, one or more of these segments fuse, resulting in eight or nine bronchopulmonary segments in the adult. g) The walls of the main, lobar, and segmental bronchi have a typical respiratory epithelium but contain less and less cartilage with each division. The walls of lobar and segmental bronchi contain cartilage plates arranged around the lumen. These cartilages serve the same purpose as the rings of cartilage in the trachea and main bronchi. Branches of the Right Main Bronchus h) The right lung has three lobes. The right main bronchus divides into three lobar bronchi: a superior lobar bronchus, a middle lobar bronchus, and an inferior lobar bronchus. Each lobar bronchus delivers air to one of the lobes of the right lung Branches of the Left Main Bronchus i) The left lung has two lobes. The left main bronchus divides into two branches: a superior lobar bronchus and an inferior lobar bronchus Branches of the Lobar Bronchi j) The lobar bronchi in each lung divide, forming segmental bronchi. In the right lung there are 10 segmental bronchi. Three supply the superior lobe, two supply the middle lobe, and five supply the inferior lobe. The left lung usually has nine segmental bronchi. Four supply the superior lobe and five supply the inferior lobe. The segmental bronchi deliver air to the bronchopulmonary segments of the lungs. The Bronchopulmonary Segments k) Each lobe of the lung can be divided into smaller units called bronchopulmonary segments. Each segment consists of the lung tissue associated with a single segmental bronchus. The bronchopulmonary segments have names that correspond to those of the associated segmental bronchi 20. How do terminal bronchioles differ from primary bronchioles? (these lack cartilage-no PCCE) See slide and/or page 635 a) Terminal bronchioles are confusingly named, as they are not the final branches but rather the distal bronchioles that do not bear alveoli. b) KEY POINT: Each segmental bronchus branches several times, ultimately ending in terminal bronchioles. The walls of terminal bronchioles lack cartilage, and their epithelium is not the typical respiratory epithelium c) Terminal bronchioles lack cartilage and mucous cells. d) e) f) g) The proximal segments are lined by pseudostratified, ciliated columnar epithelium The more distal segments are lined with simple columnar ciliated epithelium Terminal bronchiole walls contain smooth muscle The autonomic nervous system regulates the activity of the smooth muscle layer in the terminal bronchioles h) Sympathetic activation and the release of epinephrine by the adrenal medullae cause bronchodilation, which increases the luminar diameter of airways, reducing resistance to airflow i) Parasympathetic stimulation causes bronchoconstriction, a reduction in the luminal diameter of the airways, increasing resistance to airflow. i. Excessive parasympathetic stimulation (asthma) can almost completely prevent airflow along the terminal bronchioles j) Each bronchiole delivers air to a single pulmonary lobule k) Within the lobule, the terminal bronchiole branches into several respiratory bronchioles - thinnest and most delicate branches of the bronchial tree; walls are incomplete and lined by a simple cuboidal epithelium that lacks cilia l) Terminal bronchioles deliver air to the exchange surfaces of the lungs. 21. The lungs: Know about the right and left lobe organization and fissures. What is the hilum? Basically, know the how the right and left lungs differ. What is the pleural cavity? The mediastinum? (The two pleural cavities are separated by the mediastinum. a) Hilum - is a groove on the mediastinal surface of the lung and, in addition to the entrance of the main bronchi, is the site for the entry and exit of pulmonary vessels and nerves. b) The left and right lungs are situated in the left & right PLEURAL CAVITIES c) Each lung is cone-shaped. Its APEX extends superior to the attachment of the first rib to the sternum & its BASE sits on the diaphragm d) The right lung is divided into THREE lobes (superior, middle, inferior) and the left lung is divided into TWO lobes (superior & inferior). e) Each lobe is separated by a fissure: i. Horizontal Fissure - separates the superior and middle lobes ii. Oblique Fissure - separates the superior and inferior lobes f) Right lung - shorter, broader, and heavier than the left. i. The right lung is shorter because the right half of the diaphragm rises higher than the left half to accommodate the liver within the abdominal cavity g) The difference in width and weight is due to the heart and great vessels projecting into the left pleural cavity. Lung Surfaces: h) KEYPOINT: The surfaces of the lungs are named for the structures that come into contact with the lungs. Connective tissue from the root of the lung travels inward, forming trabeculae and septa that partition the lobes into smaller compartments. i) The curving anterior costal surface of the lungs contacts the inner contours of the rib cage. The mediastinal surface contains the hilum of the lung. The mediastinal surface of both lungs have grooves marking the positions of the great vessels and the heart. The left lung has a larger cardiac impression because most of the heart is located to the left of midline. The medial margin of the right lung forms a vertical line when viewed anteriorly. The left, however, has an indentation, the cardiac notch, when viewed anteriorly. j) The connective tissues of the root of each lung extend inward, forming fibrous partitions, or trabeculae. These trabeculae, which branch repeatedly, contain elastic fibers, smooth muscle, and lymphatic vessels. The branching of the trabeculae divides the lobes into smaller and smaller compartments. The branches of the conducting passageways, pulmonary vessels, and nerves of the lungs follow these trabeculae to their peripheral destinations. k) The terminal connective tissue partitions are called interlobular septa. These septa divide the lung into pulmonary lobules. Each lobule is supplied by branches of the pulmonary arteries, pulmonary veins, and respiratory passageways. The connective tissues of the septa are continuous with those of the visceral pleura. l) KEYPOINT: The pleural membrane consists of two layers: the parietal pleura and the visceral pleura. m) The thoracic cavity has the shape of a broad cone. Its walls are the rib cage, and the muscular diaphragm forms the floor. The two pleural cavities are separated by the mediastinum (Figures 24.10a and 24.15). Each lung occupies a single pleural cavity, lined by a serous membrane, or pleura (PLOO-ruh; plural, pleurae). The pleural membrane consists of two continuous layers. The parietal pleura covers the inner surface of the thoracic wall, the superior surface of the diaphragm, and the surfaces of the mediastinum. The visceral pleura covers the outer surfaces of the lungs and extends into the fissures between the lobes. The space between the parietal and visceral pleurae is called the pleural cavity. pp. 19 - 20 Each pleural cavity is actually a “potential space” rather than an open chamber because the parietal and visceral layers are in close contact. Both pleural membranes secrete a small amount of pleural fluid, a moist, slippery coating that lubricates. It reduces friction between the parietal and visceral surfaces as you breathe. n) Inflammation of the pleurae, a condition called pleurisy, may (1) cause the membranes to produce and secrete excess pleural fluid or (2) cause the inflamed pleurae to adhere to one another, limiting movement. In either case, breathing becomes difficult, and prompt medical attention is required. 22. What are mast cells? How do they affect bronchial tubes? Histamine? a) Mast Cells - Antigen-antibody complexes b) Trigger release of Histamine causes vasocontriction = Asthma c) 23. Describe what happens at the alveoli? How many cell types are there? What does each one do? What type of epithelial tissue? What is a surfactant? Why here? See presentation for details. a) KEYPOINT: Alveolar ducts are respiratory pathways with incomplete walls and alveoli at their most distal segment. Gas exchange occurs across the respiratory membrane. b) Respiratory bronchioles are connected to individual alveoli and to multiple alveoli along regions called alveolar ducts. i. Alveolar ducts end at alveolar sacs, common chambers connected to multiple alveoli. ii. Alveolar ducts are lined with simple squamous epithelium. iii. Isolated smooth muscle cells are found in the interalveolar septa of these alveolar ducts, and an extensive network of capillaries surrounds each alveolus. iv. The capillaries are surrounded by a network of elastic fibers, which maintains the positions of the alveoli, alveolar ducts, and respiratory bronchioles. v. During inspiration these elastic fibers stretch. During expiration they recoil, reducing the size of the alveoli and assisting the process of expiration. The Alveolus and the Blood Air Barrier c) The alveolar cell layer consists mainly of simple squamous epithelium. i. type I alveolar cells (squamous epithelial cells) - are unusually thin and are the sites of gas diffusion. 1. Roaming alveolar macrophages patrol the epithelial surface. 2. They engulf any particles that have eluded other defenses. ii. Large type II alveolar cells are scattered among the squamous cells. 1. Type II alveolar cells produce SURFACTANT - an oily secretion containing phospholipids and proteins. 2. Surfactant plays a key role in keeping the alveoli open. 3. Surfactant interacts with water molecules, reducing surface tension and preventing the collapse of the alveoli. d) Gas exchange occurs across the three-layered blood air barrier of the alveoli. This barrier is made up of: i. the alveolar cell layer ii. the capillary endothelial layer iii. the fused basement membrane between them e) Gas exchange can take place quickly and efficiently at the blood air barrier, as only a very short distance separates alveolar air from blood. i. Diffusion proceeds very rapidly because the distance is short and both oxygen and carbon dioxide are small, lipid-soluble molecules. ii. the surface area of the blood air barrier is very large. The Blood Supply to the Lungs f) KEY POINT: The lungs receive blood from two sources: the pulmonary circuit and the bronchial arteries of the systemic circuit. g) The respiratory exchange surfaces receive blood from arteries of the pulmonary circuit. i. The pulmonary arteries enter the lungs at the hilum and branch with the bronchi as they approach the lobules. ii. Each lobule receives an arteriole, and a venule and a network of capillaries surround each alveolus as part of the blood air barrier. iii. Blood from the alveolar capillaries passes through the pulmonary venules and then enters the pulmonary veins, which deliver the blood to the left atrium. 24. Inspiration/Expiration: Which muscles are the primary muscles using in inspiration? expiration? The accessory muscles? We covered the origin/insertion/action of primary muscle and nerve of the diaphragm. (phrenic nerve). a) KEY POINT: Pulmonary ventilation (breathing) moves air into and out of the alveoli. b) Pulmonary ventilation or breathing, physically moves air into and out of the lungs. i. FUNCTION: to maintain adequate alveolar ventilation, the movement of air into and out of the alveoli. ii. Alveolar ventilation prevents the buildup of carbon dioxide in the alveoli and ensures a continual supply of oxygen that keeps pace with absorption by the bloodstream. c) KEY POINT: The diaphragm and external intercostal muscles are the primary muscles of respiration. Respiratory movements are classified as eupnea or hyperpnea. d) The most important muscles involved in breathing are the diaphragm and the external intercostals. Respiratory muscles are classified as primary respiratory muscles and the accessory respiratory muscles e) During eupnea, expansion of the lungs stretches their elastic fibers i. elevation of the rib cage stretches skeletal muscles and elastic fibers in the connective tissues of the body wall. ii. When the inspiratory muscles relax, these elastic structures recoil, returning the diaphragm and rib cage to their original positions. f) Eupnea may involve diaphragmatic breathing or costal breathing. i. During diaphragmatic breathing, or deep breathing, contraction of the diaphragm provides the necessary change in thoracic volume. 1. Air is drawn into the lungs as the diaphragm contracts, and exhalation occurs when the diaphragm relaxes. ii. In costal breathing, or shallow breathing, the thoracic volume changes because the rib cage changes shape. 1. Inhalation occurs when contraction of the external intercostal muscles elevates the ribs and enlarges the thoracic cavity. 2. Exhalation occurs when these muscles relax. 3. During pregnancy women increasingly rely on costal breathing as the uterus enlarges and pushes the abdominal viscera against the diaphragm. g) During hyperpnea, accessory muscles assist with inspiration, and expiration involves contraction of the transversus thoracis and internal intercostal muscles. i. When we breathe at maximum levels, such as during vigorous exercise, we also use our abdominal muscles in exhalation. ii. Their contraction compresses the abdominal contents, pushing them up against the diaphragm, reducing the volume of the thoracic cavity. h) Phrenic Nerve - provides sensory information from, and motor innervation to, the diaphragm i. Originates from C4, with minor contributions from C3 and C5.