A&P EXAM 4 REVIEW GUIDE. 2023

PN 103 ANATOMY and PHYSIOLOGY FALL 2023/SCHMITT Exam #4 STUDY GUIDE CHAPTER 16: Vascular System Define arteries, vein, and capillaries Arteries: Blood vessels that carry blood away from the heart Veins: Blood vessels that return blood to the heart; called capacitance vessels because of their capacity for storing blood Capillary: Microscopic vessels that link arterioles to venules; site where nutrients, wastes, and hormones are exchanged between blood and tissue Describe capillary exchange At the beginning of each capillary bed is a precapillary sphincter that regulates the flow of blood into the network. During exercise, when skeletal muscles require more oxygen, the precapillary sphincters open, blood fills the capillary network, and the exchange of oxygen, nutrients, and wastes occurs with the tissue fluid. During a time of rest, the precapillary sphincters close. Blood bypasses the capillary bed and flows directly into a venule to begin its journey back to the heart and lungs. Capillaries release chemicals to be used by surrounding tissues. Then take up waste, such as carbon dioxide and ammonia. They also take up substances that need to be transported to other parts of the body. These include glucose (released by the liver), calcium (released from bone), antibodies (released from immune cells), and hormones (released from endocrine glands). Water moves into and out of capillaries. The mechanisms used to move substances into and out of capillaries are diffusion, filtration, and osmosis. In diffusion—the most important mechanism of capillary exchange—substances move from areas of greater to lesser concentration. What occurs is this: Blood flows into the capillaries from the arterial system, carrying a supply of oxygen. Therefore, the concentration of oxygen inside capillaries is greater than that in surrounding tissue fluid. As a result, oxygen diffuses out of capillaries and into the surrounding fluid. At the same time, carbon dioxide, which is more concentrated in the fluid of the surrounding tissue, diffuses into the capillary. Blood enters the capillary through the metarteriole. The pressure here is about 30 to 35 mm Hg, while the pressure of the fluid in surrounding tissues is about 2 mm Hg. The higher pressure in the capillary pushes plasma and dissolved nutrients (such as glucose and amino acids) through the capillary wall and into the fluid in the surrounding tissues. This is filtration. Meanwhile, as blood continues to move toward the venous end of the capillary, blood pressure inside the capillary drops to about 10 mm Hg. The lower pressure allows proteins in the blood, such as albumin, to exert what’s known as colloid osmotic pressure. In this mechanism, the albumin in the blood pulls tissue fluid, along with the cells’ waste products, into the capillaries. Differentiate between systemic, hepatic and pulmonary circulation Pulmonary circulation begins at the right ventricle and involves the circulation of blood through the lungs. Systemic circulation begins at the left ventricle and involves the circulation of blood through the body. Specialized circulatory systems include hepatic portal circulation (which routes blood from the digestive organs to the liver), circulation to the brain, and fetal circulation. Pulmonary circulation routes blood to and from the lungs to exchange carbon dioxide for oxygen. It doesn’t supply the lung tissue itself with oxygen. Those needs are met through systemic circulation.

In the systemic circulation, arteries carry oxygen-rich blood and veins carry deoxygenated blood. In the pulmonary circulation, the opposite is true. Arteries still carry blood away from the heart. (Remember: Arteries: Away.) However, in this circulatory route, pulmonary arteries carry oxygen-poor blood to the lungs. Once oxygenated, pulmonary veins carry oxygen-rich blood back to the heart for distribution to the body. Systemic circulation supplies oxygen and nutrients to organs and removes wastes. This, of course, involves both arteries and veins. All systemic arteries arise, either directly or indirectly, from the aorta. The aorta, which originates in the left ventricle, is divided into three regions: (1) the ascending aorta, (2) the aortic arch, and (3) the descending aorta. It branches into several major arteries. Locate and discuss the importance of the major vessels of the body Branching off the aortic arch is the: Subclavian artery, which supplies blood to the arm; Axillary artery, which is the continuation of the subclavian artery in the axillary region; Brachial artery, which is the continuation of the axillary artery and the artery most often used for routine blood pressure measurement; Radial artery, which is often palpated to measure a pulse The thoracic aorta and its branches supply the chest wall and the organs within the thoracic cavity. The abdominal aorta gives rise to the: Celiac trunk, which divides into the gastric artery (which supplies the stomach), the splenic artery (which supplies the spleen), and the hepatic artery (which supplies the liver); Renal arteries, which supply the kidneys; Superior mesenteric artery, which supplies most of the small intestine and part of the large intestine; Inferior mesenteric artery, which supplies the other part of the large intestine The distal end of the abdominal aorta splits into the right and left common iliac arteries, which supply the pelvic organs, thigh, and lower extremities. Major arteries branching off the iliac arteries include the: Internal iliac artery, Dorsalis pedis artery, External iliac artery, Femoral artery, Popliteal artery, Anterior tibial artery, Posterior tibial artery The vertebral arteries arise from the right and left subclavian arteries. Each extends up the neck, through the cervical vertebrae, and enters the cranium. The right common carotid artery arises from the brachiocephalic artery. The left common carotid arises from the aortic arch. At about the level of the Adam’s apple, each common carotid branches into the external carotid artery (which supplies most of the external head structures) and the internal carotid artery (which enters the cranial cavity and supplies the orbits and 80% of the cerebrum). The complete circle of Willis consists of: A single anterior communicating artery, two anterior cerebral arteries, two posterior communicating arteries, two posterior cerebral arteries The vena cava is the body’s main vein. It’s divided into two branches: Superior vena cava (SVC), which receives blood from the head, shoulders, and arms. Inferior vena cava (IVC), which receives blood from the lower part of the body The internal jugular vein drains most of the blood from the brain. In right-sided heart failure, blood backs up from the heart and causes jugular vein distension. The cephalic vein, at its distal end, is a common site for the administration of intravenous fluids. The median cubital vein is the most common site for drawing blood. The hepatic veins drain the liver. Because of its proximity to the heart, right-sided heart failure can cause congestion in the liver. The great saphenous vein is the longest vein in the body; it’s often harvested for use as grafts in coronary artery bypass surgery. The popliteal vein runs behind the knee. The internal jugular vein receives most of the blood from the brain as well as from the face. The

↑CO = ↑BP ↓CO = ↓BP Blood volume: When blood volume declines, such as from dehydration or a hemorrhage, blood pressure falls. To try and preserve blood pressure, the kidneys reduce urine output, which helps boost blood volume and raise blood pressure. ↓Volume = ↓BP ↑Volume = ↑BP Resistance: Also called peripheral resistance, this is the opposition to flow resulting from the friction of moving blood against the vessel walls. The greater the resistance, the slower the flow and the higher the pressure. The lower the resistance, the faster the flow and the lower the pressure. ↑Resistance = ↓Flow and ↑Pressure ↓Resistance = ↑Flow and ↓Pressure CHAPTER 18: Respiratory System Describe the structure and function the upper respiratory system The upper respiratory tract consists of structures located outside the thoracic cavity; this includes the nose, nasopharynx, oropharynx, laryngopharynx, and larynx. These structures warm and humidify inspired air. They are also responsible for the senses of smell and taste, as well as chewing and swallowing. The structures of the upper respiratory tract—consisting of the nose, nasopharynx, oropharynx, laryngopharynx, and larynx—warm and humidify inspired air. They’re also responsible for the senses of smell and taste as well as swallowing food. Air enters and leaves the respiratory system through the nose. Just inside the nostrils are small hairs called cilia that filter out dust and large foreign particles. The nasal cavity is separated from the mouth by a bony structure called the palate. A vertical plate of bone and cartilage (the septum) separates the nasal cavity into two halves. The cavity is lined with epithelium rich in goblet cells that produce mucus. Projecting from the lateral wall of each cavity are three bones called conchae. The conchae warm and moisten air as it flows past. At the same time, dust sticks to the mucus, which is then swallowed. Branches of the olfactory nerve (responsible for the sense of smell) penetrate the upper nasal cavity and lead to the brain. The sphenoid sinus (shown here) and the other paranasal sinuses (including the frontal, maxillary, and ethmoidal sinuses) drain mucus into the nasal cavity. Just behind the nasal and oral cavities is a muscular tube called the pharynx. Commonly called the throat, the pharynx has three regions: The nasopharynx lies just behind the soft palate. It contains openings for the right and left auditory (eustachian) tubes. The oropharynx is a space between the soft palate and the base of the tongue. It contains the palatine tonsils (the ones most commonly removed by tonsillectomy) and the lingual tonsils, found at the base of the tongue. The laryngopharynx passes dorsal to the larynx and connects to the esophagus. Only air passes through the nasopharynx, whereas both food and air pass through the oropharynx and laryngopharynx. THE LARYNX: Lying between the root of the tongue and the upper end of the trachea, the larynx is a chamber formed by walls of cartilage and muscle. Because it contains the vocal cords, it’s often called the voice box; however, it actually has three

functions: It prevents food and liquids from entering the trachea. It acts as an air passageway between the pharynx and trachea. It produces sound. The larynx is formed by 9 pieces of cartilage that keep it from collapsing. A group of ligaments bind the pieces of cartilage together and to adjacent structures in the neck. The Epiglottis- is the uppermost cartilage- which closes over the top of the larynx during swallowing to direct food and fluids to enter the esophagus instead of entering the trachea and lungs. The thyroid cartilage is the largest piece of cartilage. Also known as the Adam's apple. The cricoid cartilage - a ring like cartilage links the larynx to the trachea. Air passing between the vocal cords during exhalation produces sound. Loudness depends on the force of the air: the more forceful the air, the louder the sound. Only the vocal cords produce sound; however, the pharynx, oral cavity, tongue, and lips shape the sounds to form words. High-pitched sounds result when the cords are relatively taut; more relaxed cords produce lower- pitched sounds. The vocal cords in men are usually longer and thicker and vibrate more slowly, producing lower- pitched sounds than in women. Describe the structure and function the lower respiratory system The lower respiratory tract consists of the trachea, bronchi, and lungs. The trachea and the bronchi distribute air to the interior of the lungs; deep within the lungs is where gas exchange occurs. The trachea and two bronchi with their many branches, resemble an inverted tree; that’s why it’s often called the bronchial tree. The trachea lies in front of the esophagus; it is a rigid tube about 4.5 inches (12 cm) long and 1 inch (2.5 cm) wide. C-shaped rings of cartilage encircle the trachea to reinforce it and keep it from collapsing. The open part of the “C” faces posteriorly, giving the esophagus room to expand during swallowing. At the carina, the trachea branches into two primary bronchi, which are also supported by C-shaped rings of cartilage. The right bronchus is slightly wider and more vertical than the left, making this the most likely location for aspirated food particles and small objects to lodge. (Primary bronchi is shaded green in right lung.) Immediately after entering the lungs, the primary bronchi branch into secondary bronchi: one for each of the lung’s lobe (two on the left and three on the right). (These are shaded yellow in right lung.) Secondary bronchi branch into smaller tertiary bronchi (shaded in orange in right lung) The cartilaginous rings surrounding the bronchi become irregular and disappear in the smaller bronchioles. Tertiary bronchi continue to branch, resulting in very small airways called bronchioles (shaded purple in right lung). Bronchioles divide further to form thin-walled passages called alveolar ducts. Alveolar ducts throughout the lungs terminate in clusters of alveoli called alveolar sacs, these are the primary structures for gas exchange. A layer of protective mucus coats the lining of the bronchial tree, which helps purify air entering the respiratory tract. This cleansing mucus moves up from the lower bronchial tree toward the pharynx, propelled by millions of hair-like cilia that line the respiratory mucosa. The cilia beat in one direction— upward—so that mucus will move toward the pharynx. Cigarette smoke paralyzes these cilia. As a result, mucus accumulates in the lower bronchial tree, causing the typical “smoker’s cough” as the lungs attempt to clear excess mucus. The lung passages all exist to serve the alveoli, because it’s within the alveoli that gas exchange occurs. Keep in mind that deoxygenated blood flows into alveoli through pulmonary arterioles, and oxygenated blood leaves alveoli via pulmonary venules.

pressing the abdominal organs downward and enlarging the thoracic cavity. Air rushes in to equalize pressure. Expiration: The internal intercostal muscles relax; the diaphragm relaxes, bulging upward and pressing against the base of the lungs, reducing the size of the thoracic cavity; and air is pushed out of the lungs. During times of forced or labored breathing, accessory muscles of respiration assist with breathing. During deep inspiration, muscles of the neck (the sternocleidomastoids and scalenes) and the chest (the pectoralis minor) contract to help elevate the chest. During forced expiration, the rectus abdominis and external abdominal obliques contract to pull down the ribs and sternum as the internal intercostals pull the other ribs downward. This further reduces chest size to expel air more rapidly. People having difficulty breathing may depend heavily on accessory muscles to breathe. For example, in emphysema, lungs lose elasticity and exhaling is no longer a passive process. Patients must use accessory muscles to exhale, making exhaling an active, exhausting process. In other patients, the use of accessory muscles can indicate acute respiratory distress, signaling a medical emergency. Describe the neural control of breathing The muscles used for breathing are skeletal muscles, which require nervous stimulation to contract. Unconscious breathing resides in the medulla and pons (parts of the brainstem). The medulla contains two interconnected centers that control breathing: the inspiratory center and the expiratory center. The inspiratory center (in medulla) is the primary respiratory center. It controls inspiration and, indirectly, expiration. The inspiratory center sends impulses to the intercostal muscles (via the intercostal nerves) and to the diaphragm (via the phrenic nerves). The inspiratory muscles contract, causing inhalation. Nerve output then ceases abruptly, causing the inspiratory muscles to relax. The elastic recoil of the thoracic cage produces exhalation. The apneustic center stimulates the inspiratory center to increase the length and depth of inspiration. The pneumotaxic center inhibits both the apneustic and inspiratory center and contributes to normal breathing and prevents over inflation of the lung. The expiratory center sends impulses to the abdominal and accessory muscles. The cerebral cortex allows you to voluntarily change your breathing rate or rhythm, such as to sing or blow out a candle, or even to hold your breath. However, when you hold your breath, CO2 isn’t expelled through breathing and the CO2 level in the blood rises. CO2 is a powerful respiratory stimulant. When CO2 rises to a certain level, the respiratory centers override your voluntary action and breathing resumes. Identify normal versus abnormal inhalation and expiration Inspiration: The intercostal muscles contract, pulling the ribs up and out; the diaphragm contracts and moves downward. This enlarges the chest cavity in all directions. The lungs expand along with the chest because of the two layers of the pleura. The parietal pleura is attached to the ribs; the visceral pleura covers the lungs. A thin film of fluid between the two pleura causes them to cling together like two pieces of wet paper. Also, the potential space between the two pleura maintains a pressure slightly less than atmospheric pressure (negative pressure). This is the intrapleural pressure. When the ribs expand and the parietal pleura pulls away, intrapleural pressure becomes even more negative. This has a suction-like effect, causing the visceral pleura to cling even tighter to the parietal pleura.

The visceral pleura follows the parietal pleura, pulling the lung along with it. When the lungs expand, the volume of air in the lungs spreads throughout the enlarging space. This causes the pressure within the bronchi and alveoli (the intrapulmonic pressure) to drop. When the intrapulmonic pressure drops lower than the atmospheric pressure, air flows down the pressure gradient into the lungs. Expiration: Normal expiration is a passive process. The diaphragm and external intercostal muscles relax and the thoracic cage springs back to its original size. The lungs are compressed by the thoracic cage and intrapulmonary pressure rises. Air flows down the pressure gradient and out of the lungs. Besides being affected by pressure, airflow in the lungs is also determined by resistance. Just as in blood flow, the greater the resistance, the slower the flow. Diameter of bronchioles: Bronchioles readily change diameter to control resistance. Bronchodilation: An increase in diameter of bronchiole Bronchoconstriction: A reduction in diameter of bronchiole Epinephrine and sympathetic nerves trigger bronchodilation, which increases airflow. Parasympathetic nerves as well as histamine, cold air, and chemical irritants stimulate bronchoconstriction, which restricts airflow. Pulmonary compliance: This refers to the elasticity of lung tissue. Ventilation cannot occur unless the lungs and thorax can stretch and recoil. Diseases that cause scarring (such as tuberculosis or black lung disease) make the lungs stiff and less compliant. The lungs have difficulty expanding and ventilation is impaired. Alveolar surface tension: The inner surface of each alveoli is covered with a thin film of water, which is necessary for gas exchange. However, water molecules are electrically attracted to each other; left alone, the water molecules will move toward each other and collapse the alveoli. (If the alveoli collapse, gas exchange cannot occur.) To avoid this problem, alveolar cells secrete surfactant, a lipoprotein that disrupts the electrical attraction between the water molecules. This lowers surface tension and prevents alveolar collapse. Infants born before 28 weeks’ gestation commonly lack surfactant. Without surfactant, surface tension created by the strong attraction between water molecules draws the walls of alveoli inward. This restricts alveolar expansion during inspiration and during expiration, alveoli collapse. That’s why neonates often develop respiratory distress syndrome and require administration of artificial surfactant. Describe the variations in respiratory rhythm Apnea: Temporary cessation of breathing Biot’s respirations: Abrupt, irregular breathing pattern in which periods of apnea alternate with periods of breathing that are consistent in rate and depth; often results from increased intracranial pressure Bradypnea: Abnormally slow breathing Cheyne-Stokes respirations: Cyclical breathing pattern that begins with an increase in rate and depth of respirations (crescendo effect) followed by a gradual decrease in rate and depth of respirations (decrescendo effect), culminating in a short period of apnea before repeating; often seen in terminally ill or brain-damaged adults Dyspnea: Labored or difficult breathing Eupnea: Relaxed, quiet breathing Hyperpnea: Increased rate of breathing; may be physiological (such as during exercise) or may be

that causes the cell to die and break apart Inflammation : Tissue injury, whether from trauma, ischemia, or infection, produces inflammation. Inflammation stimulates the body’s defense system to begin fighting the infection while instigating measures to contain the pathogen. Furthermore, the inflammatory response includes processes that clean up and repair the damaged tissue. Fever : Also known as pyrexia, fever is an abnormal elevation of body temperature. (A person with a fever is said to be febrile.) Experts now believe that fever is beneficial during an illness. Besides promoting the activity of interferon, an elevated body temperature inhibits the reproduction of bacteria and viruses. Differentiate antibodies from antigens Antibodies (also known as immunoglobulins [Ig]) are gamma-globulin proteins formed by B cells; they’re found in plasma and body secretions. Consist of chains of protein joined in a way that resembles a capital letter “Y” or “T.” The end of each arm of the Y is uniquely shaped, allowing each antibody to combine with a specific antigen. An antigen is any molecule that triggers an immune response. Any foreign substance is said to be antigenic. Describe the development of hypersensitivity When someone with a genetic predisposition to an allergy (such as ragweed) is first exposed to the allergen, the body produces large amounts of the antibody IgE specific to ragweed. These antibodies bind to mast cells. Although this response doesn’t produce an allergic reaction, the person is now sensitized to ragweed. When the person encounters ragweed at a later date, the allergen binds to the antibodies already in the body. If the allergen links two or more antibodies, the mast cells release histamine and other inflammatory chemicals. Histamine causes inflammatory responses that produce the symptoms of an allergy, such as runny nose, watery eyes, congestion, and hives. A severe, immediate allergic reaction that affects the whole body is anaphylaxis. Anaphylactic shock occurs when symptoms worsen to the point of circulatory shock; sudden death can occur. Explain the differences between active and passive immunity Natural active immunity: When the body produces antibodies or T cells after being exposed to a particular antigen. (Such as follows having an infection, such as the measles.) Artificial active immunity: Results when the body makes T cells and antibodies against a disease as a result of a vaccination containing dead or weakened pathogens. In response, the body produces an immune response without developing the illness. Natural passive immunity: Results when a fetus acquires antibodies from the mother through the placenta, or when a baby acquires them through breastfeeding. Artificial passive immunity: Involves obtaining serum from a person or animal that has produced antibodies against a certain pathogen and then injecting it into someone else. This is typically used in emergencies for the treatment of rabies and botulism. Discuss selected immune system disorders In immunodeficiency diseases, the immune system fails to adequately protect the body against pathogens. Rarely, the deficiency may be present at birth, such as in severe combined immunodeficiency disease

(SCID), in which children have few or no T and B cells. As a result, their bodies can’t fight off pathogens, forcing them to live in a protective environment. More common is acquired immunodeficiency syndrome (AIDS), which results from infection with the human immunodeficiency virus (HIV). The virus invades helper T cells, eventually destroying them. Because helper T cells are key players in both humoral and cellular immunity, their loss places the host at risk for infections and cancers that a healthy immune system easily rebuffs. For example, a protozoal infection called Pneumocystis jirovecii pneumonia and a type of cancer called Kaposi sarcoma rarely occur in healthy people but occur frequently in persons with AIDS. Hypersensitivity: Hypersensitivity involves an inappropriate or excessive response of the immune system. The most common type of hypersensitivity is called an allergy, a condition in which the immune system reacts to environmental substances (called allergens) that most people can tolerate. Autoimmune Diseases: Sometimes the body’s immune system fails to differentiate between self- antigens—the molecules native to a person’s body—and foreign antigens. When this occurs, the body produces antibodies that attack its own tissues, resulting in an autoimmune disease. Immunodeficiency Diseases: In immunodeficiency diseases, the immune system fails to adequately protect the body against pathogens. FOCUS TIPS: P. 329 Hepatic Portal Circulation-what is its purpose Liver filters blood and blood from digestive organs flows through liver before returning to IVC This circulatory pathway allows the liver to modify the blood returning to the heart. For example, after a meal, blood glucose levels rise dramatically. This circulatory pathway allows the liver to remove excess glucose, which it then stores as glycogen. Toxins, such as bacteria or alcohol, can also be partially removed before the blood is distributed to the rest of the body P. 327.first paragraph. Know these arteries. Carotid arteries provide most of the blood supply to the brain. At about the level of the Adam’s apple, each common carotid branches into the external carotid artery (which supplies most of the external head structures) and the internal carotid artery (which enters the cranial cavity and supplies the orbits and 80% of the cerebrum). How is oxygen transported in the blood Bonded to hemoglobin in the RBCs Capillaries, arterioles, veins, venules. Know the differences. What are exchange vessels? Capillaries: Microscopic vessels that link arterioles to venules; site where nutrients, wastes, and hormones are exchanged between blood and tissue Arteriole: The smallest arteries; also called resistance vessels Veins: Blood vessels that return blood to the heart; called capacitance vessels because of their capacity for storing blood Venule: The smallest veins; serve to collect blood from the capillaries Exchange vessels: Capillaries P351 The body’s first line of defense Skin and mucous membranes

(called expiration). Both actions depend on the function of respiratory muscles and a difference between the air pressure within the lungs and the air pressure outside the body. One inspiration and one expiration comprise one respiratory cycle. The lungs depend on the skeletal muscles of the trunk (especially the diaphragm and the intercostal muscles) to expand and contract to create airflow. The main muscle responsible for pulmonary ventilation is the diaphragm. Inspiration: The external intercostal muscles pull the ribs upward and outward, widening the thoracic cavity; the internal intercostals help elevate the ribs; the diaphragm contracts, flattens, and drops, pressing the abdominal organs downward and enlarging the thoracic cavity. Air rushes in to equalize pressure. Expiration: The internal intercostal muscles relax; the diaphragm relaxes, bulging upward and pressing against the base of the lungs, reducing the size of the thoracic cavity; and air is pushed out of the lungs. During times of forced or labored breathing, accessory muscles of respiration assist with breathing. During deep inspiration, muscles of the neck (the sternocleidomastoids and scalenes) and the chest (the pectoralis minor) contract to help elevate the chest. During forced expiration, the rectus abdominis and external abdominal obliques contract to pull down the ribs and sternum as the internal intercostals pull the other ribs downward. This further reduces chest size to expel air more rapidly. People having difficulty breathing may depend heavily on accessory muscles to breathe. For example, in emphysema, lungs lose elasticity and exhaling is no longer a passive process. Patients must use accessory muscles to exhale, making exhaling an active, exhausting process. In other patients, the use of accessory muscles can indicate acute respiratory distress, signaling a medical emergency. Up during exhalation Breathing response to hypoxia- - Increases to bring in more O2 Low blood levels of oxygen cause peripheral chemoreceptors to send impulses to the medulla to increase the rate and depth of respirations. This brings more air, and therefore oxygen, into the lungs. P.355 Elevated body temp Fever inhibits reproduction of virus /bacteria Besides promoting the activity of interferon, an elevated body temperature inhibits the reproduction of bacteria and viruses Vaccines take the place of helper T cells/macrophage Why is a person without a spleen at risk for infections. p. 350 purple box Immunity: Lymphocytes and macrophages in the white pulp screen passing blood for foreign antigens while phagocytic cells in the sinuses ingest and destroy any microorganisms. Throughout life, the spleen provides a location for monocytes and lymphocytes to mature. The spleen’s location makes it vulnerable to injury from trauma. Because it is highly vascular, a severe injury or rupture can produce a fatal hemorrhage. The spleen is also difficult to repair, which is why it is usually removed surgically when injured. A person can live without a spleen but may be more vulnerable to infection P. 332 Blood vessels constrict and dilate as needed to maintain blood pressure The muscular layer of arterioles allows them to constrict or dilate, changing the amount of resistance to blood flow. Because blood viscosity remains stable in healthy individuals, adjusting the diameter of vessels is the body’s chief way of controlling peripheral resistance, and therefore blood pressure. Adjusting the diameter of blood vessels is called vasomotion. A reduction of the diameter of a vessel—called vasoconstriction—increases the resistance to blood flow. Because blood is being squeezed into a smaller space, pressure rises. Also, because the amount of blood allowed to enter

the vessel is reduced, blood flow into tissues decreases. An increase in vessel diameter caused by the relaxation of vascular muscles—called vasodilation— decreases resistance to blood flow. Blood pressure declines and blood flow into tissues increases. Trachea branches to Left and right; what next structure- p 370 At the carina, the trachea branches into two primary bronchi Location of spleen - first paragraph p 350 It resides in the upper left quadrant of the abdomen, just inferior to the diaphragm, where it’s protected by the lower ribs. Carbon Dioxide role in regulating respirations Central chemoreceptors monitor the pH of cerebrospinal fluid (CSF), which mirrors the level of carbon dioxide in the blood. Falling pH levels indicate an excess of carbon dioxide. When this occurs, central chemoreceptors signal the respiratory centers to increase the rate and depth of breathing. This helps the body “blow off “excess carbon dioxide, raising the pH. Location of lower respiratory tract where aspirated object most likely to get stuck.p 370 green box The right bronchus is slightly wider and more vertical than the left, making this the most likely location for aspirated (inhaled) food particles and small objects to lodge. Diaphragm, where is it, what does it do. The main muscle responsible for pulmonary ventilation is the diaphragm: the dome-shaped muscle separating the thoracic and abdominal cavities. Inspiration: The diaphragm contracts, flattens, and drops, pressing the abdominal organs downward and enlarging the thoracic cavity. Expiration: The diaphragm relaxes, bulging upward and pressing against the base of the lungs, reducing the size of the thoracic cavity. Arteries p. 319- first paragraph. Carry blood biggest to smallest- Aorta, arteries, arterioles The arteries closest to the heart are the largest. As they travel farther away from the heart, the arteries branch and divide, becoming ever smaller. Finally, they become arterioles, which are the smallest arteries. Arteries can be divided into conducting arteries, distributing arteries, and arterioles. Larynx-blue box . 369 Cartilage keeps it from collapsing The larynx is formed by nine pieces of cartilage that keep it from collapsing; a group of ligaments bind the pieces of cartilage together and to adjacent structures in the neck. The epiglottis—which closes over the top of the larynx during swallowing to direct food and liquids into the esophagus—is the uppermost cartilage. The largest piece of cartilage is the thyroid cartilage, which is also known as the Adam’s apple. The ring-like cricoid cartilage links the larynx to the trachea. Trachea- purple box p 370 Cartilage important. Lying just in front of the esophagus, the trachea is a rigid tube about 4.5 inches (11 cm) long and 1 inch (2.5 cm) wide. C-shaped rings of cartilage encircle the trachea to reinforce it and keep it from collapsing during inhalation. The open part of the “C” faces posteriorly, giving the esophagus room to expand during swallowing. Know differences- Natural passive immunity/natural active immunity, etc… p, 356 body at work -Flash cards for

system. Tunica externa, the outer layer, is made of strong, flexible, fibrous connective tissue. This layer supports and protects the blood vessel. In veins, this is the thickest of the three layers. In arteries, it’s usually a little thinner than the middle layer. P. 331 3 factors that affect BP--- Blood volume , involvement of kidney, effect on BP Cardiac output: When the heart beats harder, such as during exercise, cardiac output increases. When cardiac output increases, blood pressure increases. When cardiac output falls, such as when exercise ends or the heart is weak, blood pressure falls. ↑CO = ↑BP ↓CO = ↓BP Blood volume: When blood volume declines, such as from dehydration or a hemorrhage, blood pressure falls. To try and preserve blood pressure, the kidneys reduce urine output, which helps boost blood volume and raise blood pressure. ↓Volume = ↓BP ↑Volume = ↑BP Resistance: Also called peripheral resistance, this is the opposition to flow resulting from the friction of moving blood against the vessel walls. The greater the resistance, the slower the flow and the higher the pressure. The lower the resistance, the faster the flow and the lower the pressure. ↑Resistance = ↓Flow and ↑Pressure ↓Resistance = ↑Flow and ↓Pressure What is normally in the pleural cavity The space between the visceral and parietal pleurae is called the pleural cavity. The pleural cavity is only a potential space; the two membranes are normally separated only by a film of slippery pleural fluid. The fluid in the pleural cavity serves two purposes: It lubricates the pleural surfaces, allowing the two surfaces to glide painlessly against each other as the lungs expand and contract. Because pressure in the pleural cavity is lower than atmospheric pressure, it creates a pressure gradient that assists in lung inflation. Primary function of lymph nodes As lymph flows along its course, it passes through multiple lymph nodes. When it reaches a node, the fluid slows to a trickle as the lymph node removes pathogens and other foreign material. Besides cleansing lymph, lymph nodes also serve as sites for final maturation of some types of lymphocytes and monocytes. T cells-what are they what do they do The immune process begins when a phagocyte (such as a macrophage, reticular cell, or B cell) ingests an antigen. The phagocyte, called an antigen-presenting cell (APC), displays fragments of the antigen on its surface—a process called antigen presentation—which alerts the immune system to the presence of a foreign antigen. When a T cell spots the foreign antigen, it binds to it. This activates (or sensitizes) the T cell, which begins dividing repeatedly to form clones: identical T cells already sensitized to the antigen. Some of these T cells become effector cells (such as cytotoxic T cells and helper T cells), which will carry out the attack, while others become memory T cells. The cytotoxic T cell binds to the surface of the antigen and delivers a toxic dose of chemicals that will kill it. Helper T cells support the attack by secreting the chemical interleukin, which attracts neutrophils, natural killer cells, and macrophages. It also stimulates the production of T and B cells. After the attack, some of the cytotoxic T cells and helper T cells become memory T cells. These numerous, long- lived cells retain a memory of this particular pathogen. If re-exposure to the same antigen occurs, these cells can launch a quick attack.

How much % O2 is in room air? 21% Oxygen constitutes approximately 21% of atmospheric air Location/ purpose of valves in lymph system Valves prevent backflow, ensuring that lymph moves steadily away from the tissues and toward the heart. The cells forming lymphatic vessel walls overlap loosely, allowing gaps to exist between the cells Inspiratory reserve volume, what is it, what does it mean After taking a normal breath, it’s still possible to inhale even more air. This amount of air—inhaled using maximum effort after a normal inspiration—is called the inspiratory reserve volume. Transport of CO2 p 386 #3 bicarb ions. The vast majority—about 70%—is carried in the form of bicarbonate ions (HCO3-). This occurs because when CO2 dissolves in plasma, it reacts with the water in the plasma to form carbonic acid. Carbonic acid then dissociates into bicarbonate and hydrogen ions. Know the diagrams we did in assignment #4 Factors that increase or decrease BP- P 331-333 The maintenance of a proper blood pressure—the force exerted by the blood against a vessel wall—is crucial for proper body functioning. Blood pressure is determined by three factors: cardiac output, blood volume, and resistance. Baroreceptors in the carotid sinus and aortic arch detect changes in blood pressure and transmit signals along the glossopharyngeal and vagus nerves to the cardiac control center and the vasomotor center in the medulla. The vasomotor center (an area of the medulla in the brain) sends impulses via the autonomic nervous system to alter blood vessel diameter and, therefore, blood pressure. If pressure is too HIGH: The medulla increases its output of parasympathetic impulses. Vasodilation occurs; heart rate and stroke volume decrease. Blood pressure drops. If pressure is too LOW: The medulla increases its output of sympathetic impulses. Vasoconstriction occurs; heart rate and stroke volume increase. Blood pressure rises. Hormones Renin, angiotensin I, and angiotensin II: Cause vasoconstriction and water retention through an interactive mechanism. Aldosterone: Secreted by the adrenal medulla when blood pressure falls. Stimulates the kidneys to retain sodium. Water follows sodium, increasing blood volume Antidiuretic hormone (ADH): Secreted by the posterior pituitary gland when the water content of the body falls. Promotes vasoconstriction and water retention Epinephrine and norepinephrine: Secreted by the adrenal medulla when the body is under stress. Cause vasoconstriction. Increases heart rate and force of contraction (epinephrine only) Atrial natriuretic peptide (ANP): Released by the heart’s atria when elevated blood pressure stretches the walls of the heart. Causes vasodilation. Stimulates the kidneys to excrete sodium (and, therefore, water), reducing blood volume Three Factors That Affect Blood Pressure How Factors Affect Blood Pressure Cardiac output: When the heart beats harder, such as during exercise, cardiac output increases. When cardiac output increases, blood pressure increases. When cardiac output falls, such as when exercise ends or the heart is weak, blood pressure falls. ↑CO = ↑BP ↓CO = ↓BP Blood volume: When blood volume declines, such as from dehydration or a hemorrhage, blood pressure falls. To

Veins : Blood vessels that return blood to the heart; called capacitance vessels because of their capacity for storing blood Vena cava : The body’s chief vein, which serves to return blood to the heart Venule : The smallest veins; serve to collect blood from the capillaries Active immunity : Immunity that results when the body manufactures its own antibodies or T cells against a pathogen Afferent lymphatic vessels : Lymphatic vessels that channel lymphatic fluid into a lymph node Allergen : Environmental substance that triggers an allergic response Anaphylaxis : Severe, immediate hypersensitivity reaction affecting the entire body Antibody : Substance produced by B lymphocytes in response to a specific antigen Antigen : Any molecule that triggers an immune response Antigen-presenting cell : Phagocyte that displays fragments of an antigen on its surface to alert the immune system to the presence of a foreign antigen Appendix : A narrow pouch that projects off the lower end of the large intestine, where it is thought to serve as a reservoir for beneficial gut bacteria Artificial active immunity : Results when the body makes T cells and antibodies against a disease as a result of a vaccination Artificial passive immunity : Immunity that results following an injection of serum obtained from a person or animal that has produced antibodies against a pathogen B lymphocytes : White blood cell that makes antibodies Cellular immunity : Immune response that targets foreign cells or host cells that have become infected with a pathogen Chemotaxis : The movement of white blood cells to an area of inflammation in response to the release of chemicals from the injured cells Complement : A group of proteins in the blood that, through a cascade of chemical reactions, participate in nonspecific immunity Cortical nodules : Compartments within lymph nodes filled with lymphocytes Diapedesis : Process in which neutrophils enzymatically digest a portion of the capillary basement membrane, allowing them to leave the vessel and enter inflamed tissue Efferent lymphatic vessels : Lymphatic vessels through which lymphatic fluid leaves a lymph node Germinal centers : Less dense area at the center of cortical nodules that form and release lymphocytes Gut-associated lymphatic tissue (GALT) : Diffuse system of small concentrations of lymphoid tissue in the small intestine; consists of Peyer’s patches and the appendix Histamine : Substance secreted by injured or irritated cells that produces local vasodilation, among other effects Humoral immunity : Immune response that uses antibodies to target pathogens outside the host cells Hyperemia : Increased blood flow to an area Immunoglobulins : Antibodies Inflammation : An immunological response to injury, infection, or allergy, marked by increases in regional blood flow, immigration of white blood cells, and release of chemical toxins Interferon : Protein released from virus-infected cells that helps protect nearby cells from invasion Interleukin : Chemical secreted by helper T cells that attracts neutrophils Lymph nodes : Kidney-shaped masses of lymphatic tissue that lie along lymphatic vessels Lymph : Clear, colorless fluid filling lymphatic capillaries Lysozyme : Enzyme in mucus, tears, and saliva that destroys bacteria Macrophage : Important phagocyte that remains fixed in strategic areas Mucosa-associated lymphatic tissue (MALT) : Diffuse system of small concentrations of lymphoid tissue throughout the body Natural active immunity : Occurs when the body produces antibodies or T cells after being exposed to an antigen Natural killer cells : Unique group of lymphocytes that continually roam the body seeking out pathogens or diseased cells

Natural passive immunity : Immunity that results when a fetus acquires antibodies from the mother through the placenta or from breastfeeding Neutrophils : Phagocytes that accumulate rapidly at sites of acute injury Nonspecific immunity : First and second lines of defense; immune response aimed at a broad range of pathogens Passive immunity : Immunity that results when someone receives antibodies from another person or animal Peyer’s patches : Small masses of lymphatic tissue scattered throughout the small intestine Phagocytosis : Process by which phagocytes engulf and destroy microorganisms Primary lymphatic organs : Organs that provide a location for stem cells to mature into T and B lymphocytes; consists of the thymus and red bone marrow Pyrexia : Fever Pyrogen : A fever-producing substance secreted by neutrophils and macrophages Secondary lymphatic organs : Where mature lymphocytes become activated; consists of lymph nodes and the spleen Specific immunity : The third line of defense; immune response targeted at a specific pathogen Spleen : The body’s largest lymphatic organ; contains masses of lymphocytes T lymphocytes : Lymphocytes that participate in both cellular and humoral immunity; also called T cells Thymus gland : Lymphoid organ where T cells mature; located in the mediastinal cavity Tonsils : Masses of lymphoid tissue that form a protective circle at the back of the throat Trabeculae : Connective tissue that divides a lymph node into compartments Alveolar sacs : Clusters of alveoli residing at the termination of alveolar ducts Alveolus : Air sac in the lungs Anatomical dead space : Air that normally remains in conducting airways during respiration Bronchi : The two main branches leading from the trachea to the lungs that serve as passageways for air Bronchioles : One of the smaller subdivisions of the bronchial tubes Carbaminohemoglobin : Combination of hemoglobin with carbon dioxide Carina : Cartilaginous ridge situated where the trachea divides into two bronchi Epiglottis : The uppermost cartilage of the larynx; closes during swallowing to direct food and liquids into the esophagus Expiratory reserve volume : The amount of air that can be exhaled after normal expiration using maximum effort Glottis : The opening between the vocal cords Gut-lung axis : Link between the microbiota of the gut and that of the lung that influences health Hilum : Opening on the lung’s medial surface through which primary bronchi and pulmonary blood vessels pass Inspiratory reserve volume : The amount of air inhaled using maximum effort after a normal inspiration Intrapleural pressure : The pressure between the visceral and parietal pleurae, which assists with lung expansion Laryngopharynx : Part of the pharynx that passes dorsal to the larynx and connects to the esophagus Larynx : Structure made of cartilage and muscle at the upper end of the trachea; part of the airway and the vocal apparatus Nasopharynx : Upper part of the pharynx, extending from the posterior nares to the soft palate Oropharynx : Part of the pharynx residing between the soft palate and the base of the tongue Oxygen saturation : The number of oxygen molecules bound to hemoglobin at any one time Oxyhemoglobin : Combination of hemoglobin with oxygen Palate : Bony structure separating the mouth from the nasal cavity Partial pressure : The contribution of a single gas in a mixture of gases toward the total pressure of the gas mixture Pharynx : Muscular tube behind the oral and nasal cavities; commonly called the throat