A&P II Unit 2: Cardiovascular System Study Flashcards

Comprehensive practice question-and-answer flashcards covering Chapters 19 and 20 (Cardiovascular System: Heart and Blood Vessels) for BIO1414 Anatomy & Physiology II.

What are the primary functions of the epicardium, myocardium, and endocardium?

The epicardium is the outermost muscle layer that provides protection under the pericardium with thick adipose in some areas; the myocardium is the middle layer that spirals around the heart to produce a wringing motion during contraction and provides electrical insulation between the atria and ventricles; the endocardium is the smooth innermost lining covering valve surfaces and is continuous with blood vessel endothelium.

What anatomical structures are shown in this internal view diagram of the human heart?

This internal view shows structures including the fossa ovalis, pectinate muscles, tricuspid (right AV) valve, bicuspid (left AV) valve, tendinous cords (chordae tendineae), trabeculae carneae, papillary muscles, interventricular septum, endocardium, myocardium, and epicardium.

What function do the chordae tendineae and papillary muscles serve during ventricular contraction?

The chordae tendineae are cords connecting the AV valves to the papillary muscles on the floor of the ventricles. Papillary muscles serve as anchors for the valve flaps, preventing them from flipping or inverting into the atria when the ventricles contract.

What is the complete sequence of blood flow through the heart starting from the vena cavas?

1. Superior and inferior vena cava → 2. Right atrium → 3. Tricuspid valve → 4. Right ventricle → 5. Pulmonary semilunar valve → 6. Pulmonary trunk and pulmonary arteries → 7. Lungs (gas exchange) → 8. Pulmonary veins → 9. Left atrium → 10. Bicuspid (mitral) valve → 11. Left ventricle → 12. Aortic semilunar valve → 13. Aorta → 14. Rest of the body.

How do Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), and Patent Ductus Arteriosus differ?

ASD is a hole between the two upper chambers (atria); VSD is a hole between the two lower chambers (ventricles); Patent Ductus Arteriosus is an opening between the aorta and pulmonary artery that allows oxygen-rich blood from the aorta to mix with deoxygenated blood in the pulmonary artery.

What four congenital defects make up Tetralogy of Fallot?

1. Pulmonary valve stenosis, 2. Ventricular septal defect (VSD), 3. An aorta shifted to the right lying above the VSD, and 4. Right ventricular hypertrophy.

What is the exact pathway of electrical impulse propagation through the cardiac conduction system?

1. Sinuatrial (SA) node fires in the right atrium → 2. Excitation spreads through the atrial myocardium → 3. Atrioventricular (AV) node fires → 4. Excitation travels down the AV bundle (Bundle of His) and bundle branches → 5. Subendocardial conducting network (Purkinje fibers) distributes excitation through the ventricular myocardium.

What electrical event in the heart is represented by each wave and interval of a normal Lead II ECG?

P wave represents SA node firing and atrial depolarization; PR interval represents signal conduction through the AV node before activating ventricles; QRS complex represents ventricular depolarization; QT interval represents the duration of ventricular depolarization; ST segment represents ventricular systole (plateau phase); T wave represents ventricular repolarization.

What are the four phases of the cardiac cycle and their key mechanical events?

1. Ventricular filling (diastole): AV valves open, blood fills ventricles (rapid filling, diastasis, atrial systole). 2. Isovolumetric contraction (systole): AV valves close (S1 sound), all valves closed, no volume change. 3. Ventricular ejection (systole): Semilunar valves open, blood ejected. 4. Isovolumetric relaxation (diastole): Semilunar valves close (S2 sound, dicrotic notch), all valves closed.

What are the normal durations for the components of a single cardiac cycle in a heart beating at 75\n,bpm?

Atrial systole lasts about $0.1\,second$; ventricular systole lasts about $0.3\,second$; the quiescent period (all four chambers in diastole) lasts about $0.4\,second$; total cardiac cycle duration is $0.8\,second$.

What are the clinical definitions and conditions associated with bradycardia and tachycardia?

Bradycardia is a resting adult heart rate below $60\,bpm$ (normal during sleep, low body temperature, or in endurance-trained athletes). Tachycardia is a resting adult heart rate above $100\,bpm$ (caused by stress, anxiety, drugs, fever, heart disease, blood loss, or myocardial damage).

What causes the chest pain in angina pectoris?

Partial obstruction of coronary blood flow causes ischemia of the cardiac muscle. The oxygen-deprived myocardium shifts to anaerobic fermentation, producing lactate, which stimulates pain receptors.

What are the main causes and consequences of coronary thrombosis and myocardial infarction?

Coronary thrombosis is a complete occlusion of coronary arteries typically caused by atherosclerosis. Myocardial infarction is the sudden death of a patch of myocardium due to long-term obstruction; downstream cardiac muscle dies, causing heavy squeezing chest pain radiating to the left arm or sudden cardiac arrest.

What are the normal resting numerical ranges for blood pressure, blood volume, stroke volume, heart rate, and cardiac output?

Blood pressure: lower than $120/80\,mm\,Hg$; Blood volume: approximately $5\,L$ ($4-6\,L$); Stroke volume: about $70\,mL$ ($50-100\,mL$); Heart rate: $60-100\,bpm$; Cardiac output: $4-6\,L/min$ at rest.

How are preload, afterload, contractility, EDV, and ESV defined?

EDV (end-diastolic volume) is blood volume in ventricles before contraction; ESV (end-systolic volume) is blood volume remaining after contraction; Preload is myocardium tension from volume before contraction; Afterload is the force required to eject blood during contraction; Contractility is muscle fiber strength needed to shorten.

What is the Frank-Starling Law of the Heart?

The Frank-Starling Law states that stroke volume is proportional to end-diastolic volume ($SV \propto EDV$). The ventricles eject almost as much blood as they receive; the more cardiac muscle fibers are stretched, the harder they contract.

What three structural layers make up the walls of blood vessels and what are their features?

1. Tunica interna (intima): Simple squamous endothelium, selectively permeable barrier, produces cell-adhesion molecules during inflammation. 2. Tunica media: Middle layer of smooth muscle, collagen, and elastic tissue that controls vessel diameter. 3. Tunica externa (adventitia): Outermost loose connective tissue layer containing vasa vasorum that anchors vessels.

How does the skeletal muscle venous pump work and how do damaged valves lead to varicose veins?

When skeletal muscles contract around a vein, they compress it and force blood toward the heart while venous valves prevent backflow. If valves become damaged, blood flows backward and pools, which in superficial veins causes swelling known as varicose veins.

What is the primary function of the hepatic portal system?

To deliver deoxygenated, nutrient-rich blood from the digestive tract, spleen, and stomach to the liver to be detoxified before returning to the heart via the inferior vena cava.

What are collateral circulation and vascular anastomoses?

Collateral circulation is a network of tiny blood vessels that open and enlarge when primary arteries narrow, routing blood around blockages. Vascular anastomoses are junctions between blood vessels that provide backup pathways for blood flow.

What is edema and what are its three primary causes?

Edema is the accumulation of excess fluid in tissues when fluid filters out faster than it is absorbed. Three primary causes: 1. Increased capillary filtration (e.g., kidney failure, histamine, old age), 2. Reduced capillary reabsorption (e.g., hypoproteinemia, liver disease), 3. Obstructed lymphatic drainage (e.g., surgical removal of lymph nodes).

How do ADH, epinephrine, and blood viscosity affect blood pressure?

ADH (antidiuretic hormone) promotes water retention and raises blood pressure; Epinephrine causes vasoconstriction, which increases resistance and raises blood pressure; Higher blood viscosity (thicker blood) increases flow resistance and raises blood pressure.

How does the baroreflex regulate blood pressure?

Carotid sinuses detect elevated blood pressure and send signals via the glossopharyngeal nerve to the brainstem. This inhibits sympathetic cardiac and vasomotor neurons and excites vagal fibers, slowing the heart rate and inducing vasodilation to reduce blood pressure.

How do chemoreflexes respond to changes in blood chemistry?

Chemoreceptors in aortic and carotid bodies detect hypoxemia, hypercapnia, or acidosis and signal the vasomotor center to induce widespread vasoconstriction. This increases blood pressure, lung perfusion, and gas exchange while stimulating breathing.

What triggers the medullary ischemic reflex and what is the body's response?

A drop in brain perfusion (ischemia) triggers the medulla oblongata to send sympathetic signals to the heart and blood vessels. This increases heart rate, contraction force, and widespread vasoconstriction to elevate blood pressure and restore cerebral perfusion.

What is an aneurysm and what causes a dissecting aneurysm?

An aneurysm is a weak point forming a thin-walled bulging sac in an artery or heart wall. A dissecting aneurysm occurs when blood accumulates between vessel tunics and separates them due to degeneration of the tunica media.

How do hypovolemic, neurogenic, septic, and anaphylactic shock differ in origin?

Hypovolemic shock results from loss of blood volume (trauma, burns, dehydration); Neurogenic shock is caused by loss of vasomotor tone and widespread vasodilation (emotional shock, brainstem injury); Septic shock is triggered by bacterial toxins causing vasodilation and high capillary permeability; Anaphylactic shock is a severe allergic reaction releasing histamine that causes widespread vasodilation.