Biology Body Systems

SBI3U Grade 11 Biology Body Systems Review Questions Unit One: Animal Structures and Functions, Answers to Review Questions Respiratory System 1. Indicate the importance of gas exchange in all living organisms. Respiration is gas exchange (Oxygen and Carbon Dioxide) with the external environment. All living things respire. Gas exchange is important so that cellular respiration can take place and energy can be made for the cells. 2. Distinguish among the terms cellular respiration, external respiration and internal respiration. Cellular respiration is cells using oxygen in the reaction where glucose is converted into a chemical known as ATP (adenosine triphosphate). ATP is used to provide energy to the cell and carbon dioxide is a byproduct of cellular respiration. External respiration is air moving in through the nose or mouth and into the lungs, and oxygen diffusing out of the alveoli and into the capillaries. The alveoli wall is only one cell thick and the alveoli have a greater concentration of oxygen then the blood. The oxygen is bound on to the blood cells by the protein hemoglobin. Carbon dioxide diffuses from the blood and into the alveoli. Internal respiration is when oxygen is transported to the cells by the blood in the circulatory system. Oxygen is released from the red blood cells and diffuses into the body cells. Carbon dioxide diffuses into the blood from the cells. 3. Indicate the importance of external and internal respiration(and the respiratory system) to the process of cellular respiration. External respiration brings in air through the external environment and diffuses oxygen into the blood cells. Internal respiration diffuses oxygen into the body cells. Cells use the oxygen in cellular respiration to make energy. 4. Identify the Structures of the human respiratory system and identify their functions. Nasal cavity conducts air into hollow nasal passages, oral cavity conducts air into hollow nasal passages. The Nasal passages contain thin hanging bones called turbinates that increase the surface area of the nasal passages and clean the air. The mucous covering the turbinates moisten the air and the capillaries within the epithelial lining warm and moisten the air. The Pharynx connects the mouth and nasal cavity to the larynx and the esophagus. The Epiglottis prevents food from falling into the trachea and protects the opening of the glottis. The Larynx houses the vocal cords and when speaking, muscles around larynx contract which close the gap between the chords and different sounds are made from the vibration of the chords. The trachea transports air down the trachea and into the lungs. The Bronchi transports air through the trachea to the bronchioles. The Bronchioles transports air and the ciliated mucous membrane moistens air passing through it. The Alveoli site of gas exchange and most of gases are exchanged by simple diffusion. The Diaphragm separates the region of lungs and stomach and it contracts during inhalation and relaxes during exhalation. 6. The right lung has 3 lobes and left has 2 lobes and is enveloped in layers of tissue called pleura, where gas exchange occurs, has alveoli in it, located deep within body. 7. External Respiration is alveoli have greater concentration of oxygen then the blood and internal respiration is oxygen transported to cells by blood and is released from red blood cells and diffuses into body cells, carbon dioxide diffuse into blood from the cells. 8. Oxygen is bound to the blood cells by the protein hemoglobin and carbon dioxide diffuses from the blood into the alveoli. 9. Inhaling is thoracic cavity increases volume and to achieve equilibrium the air pressure decreases and cavity pressure decreases and the outside pressure is higher then inside, so the air is taken in. Exhaling is when the diaphragm relaxes and thoracic cavity decreases volume and to achieve equilibrium the air pressure increases and air goes out of body. 10. Tidal volume is the volume of air inhaled and exhaled in normal breathing. Inspiratory reserve volume is the extra amount of air that can be taken in past regular volume. Expiratory reserve volume is the extra amount of air that can be forced out from the lungs past regular volume. Vital capacity is the total amount of gas that can be moved in or out from lungs and the calculation is tidal volume plus inspiratory reserve volume plus respiratory reserve volume. Residual volume is the amount of gas left in lungs and the whole respiratory system after a full exhalation. Respiratory efficiency is the rate at which oxygen can be transferred into the blood system for transport to the body. Circulatory System 1. List and explain the functions of the circulatory system. Five major functions: -transports oxygen received from lungs to our cells for energy production – removes waste products from our cells, such as carbon dioxide – transports nutrients absorbed by our digestive system to our cells for energy – temperature regulation – transports disease fighting agents and hormones throughout the body 2. Indicate the relationship of the circulatory system to cellular respiration. Circulatory system brings oxygen to the cells(mitochondria) and prepares it for cellular respiration so it can produce energy, it also removes waste products from cellular respiration which is mainly carbon dioxide 4. Trace the pathway of blood through the heart. Inferior and Superior Vena Cava-right atrium-tricuspid valve-right ventricle-pulmonary semilunar valve- left and right pulmonary arteries- lungs- left and right pulmonary veins- left atrium-bicuspid valve-left ventricle-aortic semilunar valve-aorta-to the body 5. Atrioventricular valves are on each side of the heart, atrium and ventricle are separated, prevents backflow of blood from ventricle to atrium when ventricle contracts. The heart’s right side is tricuspid valve and left side is bicuspid valve. Semilunar valves are the gateway to the pulmonary arteries on right side and aorta on left. The right side is the pulmonary semilunar valve which prevents backflow from right ventricle from pulmonary artery while left side is aortic semilunar valve which prevents backflow into left ventricle from aorta. 6. Coronary circulation is blood within heart itself, pulmonary circulation is between heart and lungs, and systemic circulation is blood from the heart to the rest of the body. 7. Arteries carry oxygenated blood away from the heart. It has thick strong muscular walls and elastics and tissues to handle the high blood pressure. Veins carry deoxygenated blood to the heart. It has thin smooth muscular walls which support low blood pressure and contain one way valves to prevent backflow of blood. Capillaries exchange gasses and nutrients with cells by diffusion. It is the smallest blood vessel in the body which allows for gas exchange all around the body. 8. Diastole is 0.4 seconds and is the heart relaxing. The blood flows into the atria by the two venae cavae. Systole is 0.4 seconds and is the contraction of the heart. In the first 0.1 seconds, the atria contracts and pumps blood to ventricles. In the next 0.3 seconds, the ventricles contract and push blood out of the heart. The right ventricle contracts and blood is pumped to the lungs, left ventricle contracts and blood is pumped to the rest of the body. The cardiac cycle is one complete sequence of pumping and filling . 9. The SA node is located in the right atrium and the rate of heart contraction is controlled by the sinoatrial node, or the pacemaker. The cells in the SA node can contract without any signal from the nervous system. The SA node sends electrical signals across to the left atrium so both atria contract at the same time. SA node can be influenced by hormones, body temperature amd exercise. Internodal Pathway is the pathway where electrical impulses travel through to go from SA node to AV node. AV node is located between the right and right ventricle. Once impulse is received, a delay of 0.1 secs occurs before the message is sent to the ventricles to contract, this delay ensures the atria contracts first and empty into ventricle completely and that both ventricles contract at the same time. Bundle of HIS is AV node sends signal to Bundle of His, which are specialized muscle fibers. Purkinje fibers is located in the walls of the ventricles and the signal is sned from Bundle of His to the Purkinje Fibers(the Nerve Fibers) where it triggers powerful contractions of both ventricles driving blood into the arteries.