A Patient is Brought to the Emergency Department

1 A patient was brought to the Emergency Department by ambulance with two arrow wounds. One arrow is still in the patient on the left side; entering anteriorly between the 7th and 8th ribs in a 15-degree angle, the arrow head protruding posteriorly. The second wound is located in the posterior cervical triangle. Question 1 What serosal cavities have been penetrated by the 1 st arrow? The first arrow penetrated the pleural cavity which is located in between the parietal serosa (outermost part) and the visceral serosa (innermost part). These cavities surround each of the lungs and are sheltered by a pleural membrane. Explain the location, the microscopic characteristics of the serous membrane, and the purpose of the serous membrane. The serous membrane, also called as serosa, is altered by simple squamous epithelial cells which envelops the organs present in the serous cavity. This so-called serosal fluid are made up of blood filtrate along with discharges from the membrane, and these fluids help in reducing friction between the organs through lubrication thereby preventing internal tears (Sugarbaker, 2007). In this case, the serosal fluid lubricates the surface which allows the lungs to have easier movement in the thoracic cavity. The simple squamous epithelial cell which modifies the serous membrane is composed of a single layer of flattened epithelial cells. As previously mentioned, the serosa has two layers; the parietal layer which provides wall lining of the serous cavity, and the visceral layer which surrounds the organs. The locations of the serosa include in the peritoneal cavity (in the abdominal and pelvic cavities), pleural cavity, pericardial cavity 2 (thoracic cavity), and in the vaginal tunics (Reymond, 2016; Adeyinka, 2020; Van der Wal, 2007). Question 2 Describe the Autonomic Nervous System and explain how the patient’s ANS reacts to the arrow attack and how it will affect the patient’s vital signs (P, BP, R, T). The Autonomic Nervous System (ANS) oversees most involuntary processes and routinely adjustments within the body. It maintains our body temperature, while also works with other systems such as respiratory, digestive, and excretory (Bankenahally, 2016). The ANS is always “turned on” since it always operates, whether through the inhibition of organs, release of neurotransmitters, or through short-term fluctuations within its scope. In addition, there are four primary regions in which the ANS is dependent, namely, the (1) thalamus, (2) hypothalamus, (3) limbic system, and the (4) cerebral cortex. Moreover, the ANS, in combination with both Sympathetic and Parasympathetic Nervous System, also helps in controlling the various vital signs such as heart rate, blood pressure, respiratory rate, and temperature. In this particular case study, the blunt and penetrative injury that the patient suffered would have tremendous impacts on his/her vital signs. Heart rate will increase in order to offset the trauma, while blood pressure will become lower because of the internal bleeding and/or other shock symptoms. The arrow in the pleural cavity may cause irregular respiratory pattern (fast going to slow) while difficulty in breathing and shortness of breath may also manifest. Hypoxia may also be experience due to lack of oxygen because of blood loss and blood in lungs. Lastly, the body temperature of the patient may also drop due to less blood supply in the vital organs. Question 3 3 Describe the trajectory of the first arrow using directional terms and anatomical planes. The first arrow landed on the superior portion of the body (transverse plane), anterior and posterior (coronal plane), and on lateral left (sagittal plane). In addition, the trajectory of the arrow is located in the left upper quadrant of the body (i.e. left hypochondriac). Identify and describe the organs and any other membranes that may have been affected by the first arrow. Obviously, the arrow was able to penetrate all layers of the skin (from epidermis to dermis), followed by the muscles (from external oblique to serratus anterior muscle). Injury to the organs located in the left hypochondriac region (i.e. stomach, diaphragm, and lungs) followed. The arrow will probably puncture the serous membrane of the stomach, followed by the gastric mucosa and posterior serous membrane. Then it will go through the diaphragm and into the serous membrane of the lungs, and into the lungs itself. After puncturing the lungs, the arrow will traverse the intercostal space of the 7th and 8th rib, before puncturing the muscles and skin of the opposite portion. Question 4 Describe the cardiovascular system and explain how both the pulmonary and systemic circuits will be affected by both arrows. The cardiovascular system’s role is to transport numerous hosts of substances across the whole body. Its main constituents include the heart, blood vessels, and the blood. The heart is utilized as a pump which allows the blood to move across the blood vessels thus giving much needed oxygen and other nutrients in our body (Gordan, 2015). It is located in mediastinum, is 4 encircled by the pericardium and contains the cardiac muscle. It is composed of two atriums (left and right), and two ventricles (left and right) which is its chambers. The two atriums are each divided by valves and these are located superior to the ventricle. The purpose of the valves is to avert backflow of blood from atrium into the ventricle. Another component of the cardiovascular system is the arteries, which carry blood away from heart, and veins, which carries blood into the heart. The first arrow which pierced the serosal cavity affects the pulmonary circulation since it protrudes across the inferior lobe of lungs, thereby injuring the lobular and tertiary branches that hold both the alveoli and alveoli sacs. These sacs are storage area of oxygen which is used directly by the lungs for gas exchange. Since this body parts are damaged, gas exchange will be harder or almost impossible. This means that there will be inadequate oxygenated blood that circulates to the heart, slowing the entire process and eventually breaking both the pulmonary and systemic circulation. On the other hand, the second arrow that pierced the posterior cervical triangle has dire effects on both pulmonary and systemic circulations since the deep penetration reached the area which houses important nerve (Cranial Nerve XI), arteries (subclavian, transverse cervical, and suprascapular), and vein (external jugular). Include the effect on the Hematocrit and Hemoglobin values. The systemic circuit will be affected directly via the ANS, along with the sympathetic and parasympathetic nervous system, thus disturbing the vital signs and lowering both hematocrit and hemoglobin values due to blood loss in these sites. Question 5 Identify the possible neuromuscular effects of the second arrow and explain your reasoning. 5 As previously discussed, the second arrow that pierced the posterior cervical triangle may have damaged some nerves in the area, and one of which is the Cranial Nerve XI. This accessory nerve is critical in moving both the sternocleidomastoid and trapezius muscles. If this was injured, then the patient won’t be able to move their neck and shoulders. The patient won’t be able to shrug his/her shoulders nor raise his/her arms above the head. Another possible damage would be in the cervical plexus which could paralyze the face and neck. Since these neurotransmitters are damaged, loss of muscle functions on the neck, shoulder, and arms may happen to the patient. Describe the components of a neuromuscular junction including key organelles. The neuromuscular junction is composed of the neurons coming from the spinal cord which stimulates the skeletal muscles, as well as the neurons which facilitate coordinated muscle contraction. Signals from the brain in the form of electrical waves travel across the spinal cord via axon of the motor neuron. These axons then connect to the muscles and muscle fibers at each neuromuscular junction causing it to move (Hughes, 2006). Question 6 Identify and describe the three labeled tissue types found in the tracheal slide (Slide 2) below. Include the subcategories and cellular components for each tissue type. 1. Connective tissue (subcategory: hyaline cartilage). The hyaline cartilage is characterized as a translucent, white-blue, firm in consistency, and contains collagen (Chang, 2018). Different from other connective tissues, the hyaline cartilage does not have nerves or blood vessels, and it is covered with a fibrous membrane. It is usually located in the trachea, ribs, nose, and larynx. The main function of this cartilage is to provide flexibility and support. 6 2. Epithelial tissue (subcategory: ciliated pseudostratified columnar epithelium). This tissue consists of cilia and mucus-producing goblet cells, which are approximately one cell layer thick (Kia’i, 2019). This ciliated pseudostratified columnar epithelium is located in the surface linings of the upper respiratory tract and trachea. Their cilia and mucous discharges are critical in moistening and protecting the airways, and the collected foreign materials could be released via coughing or sneezing. 3. Loose connective tissue (subcategory: lamina propria). The lamina propia is a thin layer of loose connective tissue which can be found in the linings of the respiratory tract (Herbert, 2018). The lamina propia, in conjunction with the epithelium, makes up the mucous membrane. Moreover, the lamina propia contains a lot of elastic fibers and immune cells (lymphocytes). This particular tissue is critical in the healing of wounds and inflammations. How will the injuries affect this area? Any blunt trauma to the neck or abdomen area could cause a number of debilitating effects on the patient particularly on the obstruction of air passages which may directly lead to death. The broken tracheal fragments may potentially splint causing problems in respiration. The patient may potentially suffer from hoarseness, stridor, and crepitus due to position of the second arrow in the trachea. Moreover, excessive bleeding may also manifest for the patient because of the puncture. Bleeding of the pleural spaces can potentially happen due to the position of the first arrow in the chest area.