BIO 202 Heart, Blood Pressure, and Respiration Practice Questions Answers PDF

BIO 202 Heart, blood pressure, and respiration practice question ANSWERS Heart: 1. The heart is approximately the size of a closed fist and has a conical shape. It is located in the middle mediastinum, slightly to the left side of the thorax. The base of the heart is directed towards the right shoul...

BIO 202 Heart, blood pressure, and respiration practice question ANSWERS Heart: 1. The heart is approximately the size of a closed fist and has a conical shape. It is located in the middle mediastinum, slightly to the left side of the thorax. The base of the heart is directed towards the right shoulder, while the apex points downward and slightly to the left. 2. The coverings of the heart include: - Pericardium: The pericardium is a double-layered sac that surrounds and protects the heart. It consists of an outer fibrous pericardium and an inner serous pericardium. - Epicardium: Also known as the visceral layer of serous pericardium, it covers the surface of the heart. - Myocardium: This thick muscular layer is responsible for contracting and pumping blood. - Endocardium: This smooth inner lining covers the chambers and valves of the heart. 3. The three layers of the heart wall are: - Epicardium: It is composed primarily of connective tissue with some adipose tissue. Its main function is to protect and lubricate the outer surface of the heart. - Myocardium: This middle layer consists mainly of cardiac muscle cells that contract to pump blood throughout the body. It also contains blood vessels, nerves, and connective tissues that support its structure. - Endocardium: A thin layer composed of endothelial cells that line the inside of all four chambers and valves. It provides a smooth surface for blood flow and prevents abnormal clotting. 4. The four heart chambers are: - Right atrium: Receives deoxygenated blood from systemic circulation through the superior and inferior vena cavae. Associated great vessel(s): Superior vena cava, inferior vena cava - Right ventricle: Receives deoxygenated blood from the right atrium and pumps it to the lungs for oxygenation. Associated great vessel(s): Pulmonary artery - Left atrium: Receives oxygenated blood from the lungs through the pulmonary veins. Associated great vessel(s): Four pulmonary veins - Left ventricle: Receives oxygenated blood from the left atrium and pumps it to the systemic circulation. Associated great vessel(s): Aorta 5. The heart valves include: - Tricuspid valve: Located between the right atrium and right ventricle, it prevents backflow of blood when the ventricle contracts. - Pulmonary valve: Positioned between the right ventricle and the pulmonary artery, it controls blood flow from the heart to the lungs. - Mitral (bicuspid) valve: Found between the left atrium and left ventricle, it prevents backflow of blood when the ventricle contracts. - Aortic valve: Situated between the left ventricle and aorta, it regulates blood flow from the heart to the systemic circulation. 6. Pathway of blood through the heart and lungs: Right atrium -> tricuspid valve -> right ventricle -> pulmonary valve -> pulmonary artery -> lungs -> pulmonary veins -> left atrium -> mitral valve -> left ventricle -> aortic valve -> aorta -> systemic circulation 7. The pulmonary circuit carries deoxygenated blood from the heart to the lungs for gas exchange, while the systemic circuit carries oxygenated blood from the heart to all body tissues. The coronary circuit supplies oxygenated blood to the myocardium itself. Gas exchange occurs in capillaries within alveoli in the lungs during respiration. 8. The major branches of coronary arteries are: - Right coronary artery (RCA): Supplies blood to portions of both ventricles, interventricular septum, and sinoatrial (SA) node. - Left main coronary artery (LMCA): Divides into two main branches - left anterior descending (LAD) artery and circumflex artery. - Left anterior descending (LAD) artery: Supplies blood to the anterior portion of the interventricular septum and parts of the left and right ventricles. - Circumflex artery: Supplies blood to the left atrium, lateral walls of the left ventricle, and posterior walls of both ventricles. 9. Cardiac muscle is striated like skeletal muscle but has branching fibers interconnected by intercalated discs. It contains more mitochondria for aerobic respiration due to its continuous contraction. Unlike skeletal muscle, cardiac muscle contracts involuntarily, synchronously, and continuously without fatiguing. 10. Cardiac muscle cell contraction involves a series of events: 1. Depolarization: Sodium ions rapidly enter the cell through voltage-gated sodium channels, causing depolarization. 2. Plateau phase: Calcium ions enter the cell through slow calcium channels, maintaining prolonged depolarization. 3. Repolarization: Potassium ions exit the cell through voltage-gated potassium channels, leading to repolarization. 11. The components of the conduction system include: - Sinoatrial (SA) node: Located in the right atrial wall near the opening of superior vena cava, it initiates each heartbeat and acts as the natural pacemaker. - Atrioventricular (AV) node: Found at the base of the right atrium near the interatrial septum, it receives electrical signals from the SA node and delays them before transmitting them to the ventricles. - Bundle of His (atrioventricular bundle): Divides into two branches called bundle branches that carry electrical impulses down the interventricular septum. - Purkinje fibers: Branches off from bundle branches and transmit electrical signals throughout both ventricles. 12. Autorythmicity means that certain cardiac cells can generate spontaneous electrical impulses without external stimulation. 13. The SA node works by spontaneously generating an electrical impulse that initiates each heartbeat. It is called the pacemaker because it sets the rhythm and rate of the heart's contractions. 14. The AV node functions as a delay system, allowing the atria to contract fully before sending the electrical signals to the ventricles. The pause at the AV node allows time for blood to flow from the atria into the ventricles before ventricular contraction begins. 15. A normal electrocardiogram (ECG) tracing includes waves and intervals: - P wave: Represents atrial depolarization. - QRS complex: Depicts ventricular depolarization. - T wave: Signifies ventricular repolarization. - PR interval: Measures from the beginning of the P wave to the beginning of the QRS complex, representing time taken for electrical conduction through atria and AV node. - QT interval: Measures from beginning of QRS complex to end of T wave, indicating total time for ventricular depolarization and repolarization. 16. Some abnormalities that can be detected on an ECG tracing include: - Arrhythmias: Irregular heart rhythms such as atrial fibrillation, ventricular tachycardia, or bradycardia. - Myocardial infarction: This is indicated by ST-segment elevation or depression and Q waves. - Conduction abnormalities: These can manifest as prolonged PR intervals, bundle branch blocks, or other conduction delays. - Ventricular hypertrophy: Enlargement of the ventricles may be seen as increased amplitude of QRS complexes. - Ischemia: Reduced blood flow to the heart muscle can be indicated by T-wave inversion or ST-segment depression. 17. Heart sounds are the sounds produced by the closing of the heart valves during the cardiac cycle. The first heart sound (S1) is caused by the closure of the atrioventricular valves (mitral and tricuspid), while the second heart sound (S2) is caused by the closure of the semilunar valves (aortic and pulmonary). A murmur is an abnormal sound caused by turbulent blood flow through a valve that may indicate a valve disorder. Stenosis refers to a narrowing or obstruction of a valve, impairing its ability to open fully, while prolapse refers to when a valve leaflet bulges back into the previous chamber during systole. 18. The cardiac cycle consists of several events: - Atrial systole: Contraction of the atria forces blood into the ventricles. - Isovolumetric contraction: Ventricular contraction begins, but all valves are closed, so no blood leaves yet. - Ventricular ejection: Once pressure in the ventricles exceeds arterial pressure, semilunar valves open and blood is ejected into circulation. - Isovolumetric relaxation: All valves close again briefly before diastole begins. - Ventricular filling: Blood flows from the atria into the ventricles due to pressure differences. 19. Systole refers to the phase of the cardiac cycle when the heart chambers contract, while diastole refers to the phase when the heart chambers relax and fill with blood. Isovolumetric contraction is a brief period during systole when all valves are closed, preventing any change in volume. 20. Cardiac output is the amount of blood pumped by the heart per minute and is calculated by multiplying stroke volume (the amount of blood ejected with each heartbeat) by heart rate. It represents how effectively the heart is delivering oxygenated blood to tissues. 21. Stroke volume (SV) is the amount of blood ejected from the left ventricle with each beat. End-systolic volume (ESV) is the amount of blood remaining in the left ventricle after contraction, while end-diastolic volume (EDV) is the amount of blood in the left ventricle at the end of diastole before contraction. These values can change based on factors such as preload, afterload, and contractility. 22. Heart rate refers to the number of times the heart beats per minute. It can be influenced by factors such as physical activity, stress, or hormonal changes. 23. The contractility of the heart can be changed through various mechanisms such as sympathetic stimulation or certain medications. Preload refers to the degree of stretch on cardiac muscle fibers before contraction, while afterload refers to resistance against which the ventricles must pump blood. 24. Various factors regulate stroke volume and heart rate: - Preload: Increased preload leads to increased stroke volume. - Afterload: Increased afterload decreases stroke volume. - Contractility: Increased contractility increases stroke volume. - Autonomic nervous system: Sympathetic stimulation increases heart rate and contractility, while parasympathetic stimulation decreases heart rate. 25. Tachycardia refers to a rapid heart rate, while bradycardia refers to a slow heart rate. Angina is chest pain caused by reduced blood flow to the heart muscle. Fibrillation refers to chaotic and irregular contractions of the heart muscles. Myocardial infarction is commonly known as a heart attack and occurs when blood flow to the heart muscle is blocked. 26. The autonomic nervous system plays a significant role in regulating cardiac output. Sympathetic stimulation increases heart rate, contractility, and vasoconstriction, leading to increased cardiac output. Parasympathetic stimulation decreases heart rate and contractility. 27. If someone scared you, your body would likely exhibit a stress response, causing an increase in sympathetic activity. This would lead to an increase in cardiac output (CO), heart rate (HR), stroke volume (SV), and contractility due to sympathetic stimulation. 28. The cardioacceleratory center and cardioinhibitory center are regions within the medulla oblongata of the brainstem that regulate cardiovascular function. The cardioacceleratory center stimulates sympathetic activity, increasing heart rate and contractility, while the cardioinhibitory center inhibits parasympathetic activity, reducing heart rate. 29. During development, the heart begins as a simple tube that gradually forms into four chambers: two atria and two ventricles with associated valves. In fetal circulation, there are temporary structures like the foramen ovale and ductus arteriosus that allow blood to bypass certain parts of the immature lungs since oxygenation occurs through the placenta instead of breathing air. 30. Age-related changes in heart function can include decreased elasticity of blood vessels, reduced efficiency of electrical conduction in the heart, thickening or stiffening of heart valves or vessels, and decreased maximum achievable heart rate during exercise. 31. Some common fetal heart defects include atrial septal defect, ventricular septal defect, tetralogy of Fallot, coarctation of the aorta, and transposition of the great arteries. These defects involve abnormalities in the structure or function of the heart during fetal development. Blood Pressure: 1. Blood flow refers to the movement of blood through the circulatory system, delivering oxygen and nutrients to tissues and removing waste products. 2. Blood pressure is the force exerted by circulating blood against the walls of blood vessels. It is generated by the pumping action of the heart, as it pushes blood into the arteries during systole. A pulse is a rhythmic expansion and contraction of arterial walls caused by the ejection of blood from the heart. 3. Systolic pressure is the maximum pressure in the arteries during ventricular contraction, while diastolic pressure is the minimum pressure in the arteries during ventricular relaxation. Mean Arterial Pressure (MAP) represents an average blood pressure throughout one cardiac cycle and is calculated using a formula: MAP = [(2 x diastolic) + systolic] / 3. 4. Peripheral resistance refers to the opposition encountered by blood flow in peripheral arteries. It depends on factors such as vessel diameter, vessel length, blood viscosity, and vessel elasticity. Increased peripheral resistance can be caused by vasoconstriction or narrowing of blood vessels, while decreased resistance can result from vasodilation or widening of blood vessels. 5. Cardiac output (CO), which is the amount of blood pumped by the heart per minute, is determined by heart rate (HR) and stroke volume (SV). Resistance plays a role in determining systemic vascular resistance (SVR), which affects blood pressure. An increase in CO, HR, SV, or resistance can lead to an increase in blood pressure. 6. Blood pressure is highest in arteries due to their proximity to the pumping action of the heart and gradually decreases as it moves through capillaries and veins back towards the heart. 7. Short-term neural controls of BP include baroreceptor reflexes, chemoreceptor reflexes, and hormonal regulation. 8. Baroreceptors are specialized sensory receptors located in certain areas such as carotid sinuses and aortic arch. They monitor changes in blood pressure and transmit signals to the cardiovascular center in the brainstem. Chemoreceptors located in carotid bodies and aortic bodies detect changes in oxygen, carbon dioxide, and pH levels in the blood. If either receptors are stimulated by changes outside normal ranges, they send signals to adjust heart rate, stroke volume, and peripheral resistance. 9. The hypothalamus plays a role in regulating blood pressure through its control of the autonomic nervous system. It integrates inputs from various receptors and sends appropriate signals to maintain homeostasis. 10. Norepinephrine causes vasoconstriction and increases heart rate, atrial natriuretic peptide promotes vasodilation and sodium excretion, aldosterone increases sodium reabsorption leading to water retention, anti-diuretic hormone (ADH) promotes water reabsorption by kidneys, Angiotensin II is a potent vasoconstrictor that also stimulates aldosterone release, and nitric oxide causes vasodilation. 11. Long-term regulation of blood pressure involves the kidneys via direct mechanisms (regulating blood volume) or indirect mechanisms (renin-angiotensin-aldosterone system). The kidneys can increase or decrease urine output based on body fluid needs to help maintain optimal blood pressure. 12. Hypertension is defined as persistently high blood pressure above 130/80 mmHg. It often has no noticeable symptoms but can lead to serious complications such as heart disease, stroke, kidney damage, or vision loss if left untreated. 13. Hypotension refers to abnormally low blood pressure below 90/60 mmHg. It can cause dizziness, fainting, blurred vision, fatigue, or confusion. 14. Circulatory shock is a life-threatening condition characterized by inadequate perfusion of tissues due to low blood volume or impaired cardiac function. Causes can include severe bleeding, heart failure, septicemia, or anaphylaxis. Respiration: 1. Cellular respiration refers to the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water, while mechanical respiration refers to the physical act of breathing. We need both processes because cellular respiration provides our cells with the energy they need to function properly, while mechanical respiration ensures that oxygen is brought into the body and carbon dioxide is removed. 2. Internal respiration refers to the exchange of gases (oxygen and carbon dioxide) between the blood and tissues within the body, while external respiration refers to the exchange of gases between the lungs and the external environment. 3. In addition to its primary function of gas exchange, the respiratory system also plays other important roles. It contributes to speech production by regulating airflow through the vocal cords. The olfactory receptors in our nasal cavity allow us to detect smells. The respiratory muscles act as a pump to facilitate breathing. The Valsalva maneuver is a process where breath-holding helps increase pressure in certain parts of the body, such as during childbirth or lifting heavy objects. Lastly, the respiratory system helps regulate pH levels in the body by controlling levels of carbon dioxide. 4. The conducting zone of the respiratory system includes structures like the nose, pharynx, larynx, trachea, bronchi, and bronchioles. Its main function is to warm, humidify, and cleanse incoming air before it reaches the delicate structures of the lungs. 5. Nasal conchae are scroll-like bones located inside each nasal cavity. They help increase surface area within the nasal cavity, which aids in warming, humidifying, and filtering incoming air. 6. The uvula is a small flap of tissue at the back of your throat that prevents food and liquid from entering your nasal cavity when you swallow. The epiglottis is a leaf-shaped cartilage that covers the glottis (opening into the larynx) during swallowing to prevent food from entering the airway. The glottis is the opening between the vocal cords in the larynx. The true vocal folds are responsible for producing sound, while the false vocal folds help protect the true vocal folds and assist in producing a deeper voice. 7. The three different tonsils are the pharyngeal tonsil (adenoids), located in the back of the throat; the palatine tonsils, located on either side of the back of your throat; and the lingual tonsils, located at the base of the tongue. Their function is to help fight off infections by trapping bacteria and viruses that enter through the mouth and nose. 8. The trachea, also known as the windpipe, is a tube made up of C-shaped cartilage rings that provide structural support and prevent collapse while allowing flexibility during breathing. The respiratory zone refers to structures within the lungs where gas exchange occurs, specifically in tiny air sacs called alveoli. Gas exchange occurs across thin walls composed mainly of Type I cells, which are responsible for gas diffusion, and Type II cells, which secrete surfactant to reduce surface tension and prevent alveolar collapse. 9. Type I cells are extremely thin cells that make up most of the alveolar wall and are directly involved in gas exchange. Type II cells secrete pulmonary surfactant, a substance that helps reduce surface tension in alveoli and prevents them from collapsing during exhalation. 10. Oxygen is carried in the blood primarily by binding to hemoglobin molecules within red blood cells. Carbon dioxide is transported in three forms: dissolved in plasma, bound to hemoglobin, or converted into bicarbonate ions. 11. Hyperventilation refers to rapid or deep breathing, while hyperventilation refers to slow or shallow breathing. Dyspnea is difficulty or discomfort in breathing, and apnea is the temporary cessation of breathing. 12. The respiratory center of the brain is located in the medulla oblongata and pons. The pons helps regulate the rate and depth of breathing, while the medulla controls the basic rhythm of respiration. The hypothalamus can influence breathing through emotional responses. 13. Mechanical breathing involves the contraction and relaxation of muscles involved in respiration, such as the diaphragm and intercostal muscles. Nerves like the phrenic nerve and intercostal nerves control these muscles. Breathing does require energy expenditure. 14. Tidal volume is the amount of air inhaled or exhaled during normal breathing at rest. Inspiratory reserve volume is the additional air that can be forcefully inhaled after a tidal breath. Expiratory reserve volume is the additional air that can be forcefully exhaled after a tidal breath. Vital capacity is the total amount of air that can be forcibly exhaled after maximal inhalation. Residual volume is the air remaining in the lungs after maximal exhalation. 15. COPD (Chronic Obstructive Pulmonary Disease) encompasses chronic bronchitis and emphysema, characterized by airflow limitation and difficulty breathing. Asthma involves chronic inflammation and narrowing of airways leading to wheezing and shortness of breath. Tuberculosis (TB) is a bacterial infection that primarily affects the lungs. Lung cancer refers to the uncontrolled growth of abnormal cells in the lung tissue. 16. Smoking damages the respiratory system by causing inflammation, mucous production, and destruction of lung tissues. However, some damage can be reversed when a person quits smoking, such as improved lung function and decreased risk of certain diseases. 17. Lifespan changes in the respiratory system include decreased cilia function, leading to reduced ability to remove mucus and debris from the airways. Mucus becomes thicker, cough and gag reflexes weaken, macrophage activity decreases, and alveoli lose elasticity and may become distended. Negative Feedback in relation to blood pressure: Baroreflex works to maintain blood pressure the same, ideally 120/80 mm Hg. It is a negative feedback loop because an increase in pressure in the sinus caroticus leads to vasodilation and reduced heart rate, which reduces the blood pressure back to normal. The reversed effect also applies, where a drop in pressure in sinus caroticus leads to vasoconstriction and increased heart rate, which brings the blood pressure to normal. The baroreflex provides a negative feedback loop for controlling blood pressure, such that heart rate falls when blood pressure rises, and vice-versa when blood pressure falls, thus modulating blood pressure fluctuations.