Hole's Anatomy and Physiology- Ch 15- Cardiovascular System

Explain why the atria are passive chambers, while the ventricles are active.

Atria are passive bc they receive blood from the veins. The ventricles are active because they pump blood from the heart into arteries.

Define the term cardiac output.

CO = Volume of blood pumped by each ventricle in one minute. Is equal to heart rate X stroke volume.

Track a drop of blood through the body.

1) Aorta through the semi-lunar valve to the 2) arteries, to the 3) arterioles, to the 4) capillaries in the body tissues to the 5) venules, then to the 6) veins, next to the 7) vena cavae, and finally to the 8) right atrium.

Branches of the aortic arch

1) Brachiocephalic (right side of head and right arm) a) right subclavian (right arm) o Verterbral (cervical vertebrae/skull) 1. basilar (brain) Circle of Willis (brain) o axillary (armpit) 1) brachial (upper arm) a- radial b- ulnar * pulmar arches (palm) 1) digital (fingers) b) right common carotid (right side of head) o external carotid (scalp) o internal carotid (brain) 2) left common carotid artery (left side of head) 3) left subclavian artery

Compare and contrast continuous, fenestrated, and sinusoidal capillaries in terms of structure and location.

1) Continuous capillaries = plasma membranes form a continuous, uninterrupted ring around the lumen. Found in skeletal, smooth muscle, CT, and lungs. 2) Fenestrated capillary = endothelial plasma membranes contain pores. Found in glomeruli of kidneys and villi of small intestine. 3) Sinusoids= contain spaces between the endothelial cells with basement membranes being incomplete or absent. Found in liver and spleen.

Branches of the thoracic aorta

1) Intercoastals (intercoastal/chest muscles) 2) Superior phrenics (superior diaphragm) 3) Bronchial arteries (bronchi of lungs) 4) Esophageal arteries (esophagus)

Track a drop of blood through the following circulation- myocardium.

1) Oxygenated blood from the ascending aorta through the semi-lunar valve to the 2) left and right coronary arteries, to the 3) capillaries of the myocardium (gas exchange), through the 4) cardiac veins (deoxygenated blood, veins include great and middle cardiac vein), to the 5) coronary sinus, then to the 6) right atrium.

Outline the phases of the cardiac cycle in terms of what is happening in the ECG trace, mechanical events, atrial pressure, ventricular pressure, ventricular volume, aortic pressure, and timing.

1) Relaxation period, 2) ventricular filling, 3) ventricular systole.

Track a drop of blood through the following circulation- heart/lung/heart.

1) Right atrium (deoxygenated blood), through the tricuspid valve, to the 2) right ventricle, through the pulmonary semi-lunar valve, to the 3) pulmonary trunk, 4) the pulmonary arteries, then 5) the capillaries (alveoli) in lungs, then 6) the pulmonary veins, then 7) the left atrium and through the bicuspid or mitral valve to the 8) left ventricle, through the aortic semi-lunar valve to the ascending 9) ascending aorta.

Name the functions of heart valves.

2 functions, actually: 1) To open correctly so that blood can empty from the chamber, and 2) to close properly so that blood cannot flow the wrong way

Describe the structure of the heart in terms of its blood vessels.

2 types. 1) Arteries, which carry blood away from the heart. They a) carry bood that is high in O2 and low in CO2, except pulmonary arteries, which are low in O2 and high in CO2. Aorta carries blood from the left ventricle to the body. Pulmonary arteries carry blood from the right ventricle to the lungs (via the pulmonary trunk). Coronary arteries carry blood to the myocardium. 2) Veins, which carry blood toward the heart. Veins carry blood that is high in CO2 and low in O2, except for the pulmonary veins, which are high in O2 and low in CO2. Superior vena cava brings blood from the head and upper limbs. Inferior vena cava brings blood from the trunk and lower limbs. The coronary sinus (posterior surface) brings blood from the myocardium. All of the above deposit blood into the right atrium. The pulmonary veins bring blood from the lungs to the left atrium (2 from right lung, 2 from left lung). Note the ligamentum arteriosum, which is a remnant of the fetal ductus arteriosus.

Discuss factors that regulate heart rate.

A) autonomic nervous system (located n medulla of brainstem), includes parasympathetic and sympathetic systems. B) Chemicals (hormones, ions (includes calcium, potassium, and sodium). C) Age (decreases). D) Sex (females increased, males decreased). E) Temperature. F) Emotion. G) Disease.

Distinguish between AV and SL valves in terms of location, structure, and when they close.

AV valves- between atrium and ventricles, associated with the chordae tendineae, and papillary muscle. Close during each pump of the heart. SL valves lie within the pulmonary trunk or the aorta- close when ventricles are relaxed.

Describe the structure of the heart in terms of its valves.

Atrioventricular valves (aka AV valves): tricuspid valve is between RIGHT atrium and ventricle, bicuspid (the mitral valve) is between LEFT atrium and ventricle. Structures associated with the AV valves are chordae tendineae, which are tendon-like, fibrous cords that connect the cusps of AV valves to the papillary muscle (inner surface) of ventrices- this prevents cuss from swinging back into atria. The papillar muscle is the muscular columns that are located on the inner surface of the ventricles. Semilunar valves (aka SL valves): pulmonary SL valve lies within the pulmonary trunk, and the aortic SL valve lies within the aorta.

QRS complex

Begins as a downward deflection, continues as a large, upright, triangular wave, ends as a downward wave. Represents onset of ventricular depolarization (spreads throughout ventricles). Shortly after QRS begins, ventricles start to contract.

Define the term blood pressure, name the type of blood vessels where blood pressure is significant, and name the normal (average) value in a resting adult.

Blood pressure = pressure exerted by blood on the wall of a blood vessel. Pulse= pressure wave that travels through arteries following left ventricular systole. Strongest in arteries closest to heart. Most commonly referred to is arterial blood pressure (blood pressure in veins is essentially insignificant). Arterial blood pressure rises to maximum during systole (contraction) and falls to its lowest during diastole (relaxation). In a normal adult at rest, the BP = 120 mm Hg / 80 mm Hg.

Discuss the factors that affect cardiac output.

CO is affected by stroke volume and heart rate.

Locate the neural cardiovascular center on a mid-sagittal diagram of the brain, explain where impulses sent to it are first detected, and explain where its outgoing impulses are directed and what happens when they get there.

CV center is located in the medulla of the brainstem. Input to centers nerve impulses are sent from higher brain centers, baroreceptors, and chemoreceptors. Output: Nerve impulses are sent from the cv center to the SA node of heart- nerve impulses are sent from the vasomotor center to the smooth muscle of peripheral blood vessels (arterioles). Negative feedback and regulation: If BP is too high- BP increase detected by baroreceptors in aorta or carotid artery; they send impulse to CV and vasomotor centers, which interpret this and send a message to the SA node to decrease heart rate, then lower CO and bp. Vasomotor center sends an impulse to the peripheral arterioles causing vasodilation, which lowers bp.

Discuss the major event that occurs at capillaries.

Capillaries permit the exchange of gases, nutrients, and wastes between blood and tissues. Connects arterioles to venules.

Name the term referring to all of the events associated with one heartbeat.

Cardiac cycle. A complete cardiac cycle includes systole and diastole of both atria, and systole and diastole of both ventricles.

Explain what is meant by the human cardiovascular system being a closed system.

Circular system. Tubes carry blood away from the heart, transport it to all of the body tissues, then returns it to the heart.

Define anastosmosis.

Connection between 2 or more branches of arteries that supply the same region with blood.

Describe the structure of the heart in terms of its coverings.

Coverings: three membranes, 1) serous pericardium, composed of a) visceral pericardium, the innermost delicate epithelium and connective tissue covering surrounding the heart muscle, and b) parietal pericardium- inner lining of fibrous pericardium. Remember: the pericardial cavity between a and b is filled with serous fluid for lubrication. 2) fibrous pericardium, the outermost, tough, fibrous protective CT layer that prevents overstretching of the heart.

T wave

Dome-shaped, upward deflection. Represents ventricular repolarization. Occurs just before ventricles start to relax. Shape indicates slow process.

Specific Phases of the Cardiac Cycle: 1) Relaxation (Quiescent) Period (early ventricular diastole)

Follows T-wave. Ventricular pressure drops, SL valves close, isovolumetric relaxation for brief time. When ventricular pressure drops below atrial pressure, AV valves open. 0.4 seconds.

Capillary Exchange

Gases, nutrients, and wastes are exchanged between blood in capillaries and tissues in three ways. 1) Diffusion (most common), 2) vesticular transport, 3) bulk flow (filtration and absorption)

List organs of the cardiovascular system and discuss the general functions of the system.

Heart and blood vessels, and blood, a connective tissue, is circulated through the heart and vessels. The major function of the cardiovascular system is to circulate substances throughout the body- supply cells and tissues with oxygen and nutrients and to remove wastes (CO2 and urea) from cells and tissues.

List the hormones involved in regulation of blood pressure and blood flow.

Hormones that increase BP: Epinephrine and norephinephrine, antiduretic hormone, angeiotensin II, and aldosterone. Hormones that decrease BP: Atrial natriuretic peptide (ANP) and Histamine (causes vasodilation of arterioles, plays a key role in inflammation)

Specific Phases of the Cardiac Cycle: 3) Ventricular Systole

Impulse passes through AV node and then through ventricles. Ventricles contract, ventricular pressure increases rapidly; AV valve close: Isovolumetric contraction phase (constant volume) = start of contraction to opening of SL valves (0.05 seconds). Ventricular ejection phase = open of SL valves to closing of SL valves. End-systolic volume reached when ventricle finishes emptying. Total: 0.3 seconds.

Describe the structure and function of the interventricular septum.

Interventricular septum is a muscular wall that separates right and left ventricles. It prevents the mixing of oxygenated and deoxygenated blood.

Describe the term traveculae carneae.

Irregular inner surface (ridges and folds) of the ventricles.

Define the terms ischemia and hypoxia, and explain how they are related to the pathologic conditions of angina pectoris and myocardial infarction.

Ischemia: Reduction of blood flow. Hypoxia: reduced oxygen supply due to ischemia. Angina pectoris: "strangled chest" - severe pain that accompanies myocardial ischemia. Angina pectoris notes: a) crushing chest pain radiating down left arm, b) labored breathing, weakness, dizziness, perspiration, c) occurs during exertion, fades with rest, d) relieved by nitroglycerin. Myocardial infarction 0 heart attack- death portion of myocardium, usually caused by a thrombus or embolus (moving blood clot) in a coronary artery.

Component of CCS: 5) Purkinje Fibers (Conduction Myofibers)

Large diameter conduction myofibers located within the papillary muscles of the ventricles. Conducts impulse to the mass of ventricular muscle tissue. Causes ventricles to contract which forces blood out.

Component of CCS: 4) Right and left bundle branches

Lead downward through interventricular septum toward apex, and finally impulse reaches...

Component of CCS: 2) Atrioventricular Node (AV Node)

Located in interatrial septum. Serves as a delay signal that allows for ventricular filling. Cardiac impulse then moves to the...

Component of Cardiac Conduction System: 1) Sinoatrial Node (SA Node)

Located in the uppermost atrial wall. It is the pacemaker component. Impulses travel throughout the atrial fibers via gap junctions in intercalated discs to the...

Describe the location, size, and orientation of the human heart.

Location - within mediastinum. Size- closed fist, approx. 300 g for an adult. Base - wide superior border. Apex- inferior point.

Discuss heart sounds in terms of what they represent, how they sound, how they are detected, and their significance.

Lub= closing of AV valves (ventricular systole) - loud and long. Dup = closing of SL valves (ventricular diastole) - short and sharp. Heard with stethoscope. If the closing of the valve cusps is incomplete, some blood may leak back (this is a heart murmur).

Name the function of serous fluid around the heart.

Lubrication between visceral and parietal pericardium in serous pericardium membrane.

Describe the term papillary muscle.

Muscular columns that are located on the inner surface of the ventricles.

Define the term heart rate.

Number of heartbeats per unit time

Discuss what causes reperfusion damage.

Occurs when an oxygen deprived tissue's blood supply is reestablished. Due to the formation of oxygen free radicals, there is damage to enzymes, neurotransmitters, nucleic acids, and phospholipids. Implicated in a variety of diseases including heart disease, Alzheimer's, Parkinson's, etc. Anti-oxidants defend body against this damage.

Component of CCS: 3) Atrioventricular bundle (Bundle of His)

Only electrical connection between atria and ventricles. Located in the superior interventricular septum. Impulses enters both....

Name the common term for the sinoatrial (SA) node.

Pacemaker

Define the term blood resistance and discuss the three major factors that determine it.

Peripheral resistance primarily due to friction. Depends on blood viscosity (normally constant, direct relationship), total blood vessel length (normally constant, direct relationship), and blood vessel radius (inverse relationship- if radius increases, bp drops, and visa versa- most significant factor in determining blood pressure).

Define systole.

Phase of contraction

Define diastole.

Phase of relaxation

Distinguish between pulmonary, coronary, and systemic circulation.

Pulmonary - lungs. Coronary - heart itself. Systemic - whole body.

Distinguish between the pulmonary and systemic circuits (circulatory routes).

Pulmonary circuit: vessels that carry blood from the right ventricle to the lungs, and the vessels that return the blood to left atrium. Steps: 1) pulmonary trunk, 2) right and left pulmonary arteries (deoxygenated blood), 3) capillaries in lungs, 4) right and left pulmonary veins (oxygenated blood). Systemic circuit: vessels that carry blood from the heart to body cells and back to the heart.

Specific Phases of the Cardiac Cycle: 2) Ventricular Filling (mid to late ventricular diastole)

Rapid ventricular filling occurs just after AV valves open (remember atria had filled during ventricular contraction). SA node fires (P wave), atria contract, and remainder of ventricular filling occurs. Ventricles have completed filling = end diastolic volume. Atria relax, ventricles depolarize (QRS complex). 0.1. seconds.

ECG

Recording of electrical charges that occur in the myocardium during cardiac cycle. Recorded using an electrocardiograph. Used to determine if a) conduction pathway is normal, b) heart is enlarged, c) certain regions are damaged. Two rules to remember: 1) depolarization precedes contraction, and 2) repolarization precedes relaxation. 3 waves per heartbeat (P, QRS complex, and T).

Explain why a refractory period between cardiac muscle contractions is so long.

Refractory period = time following a contraction when a second contraction cannot be triggered. It is longer than the contraction itself because it is necessary for ventricles to relax and fill with blood before again contracting to eject the blood.

Branches of the ascending aorta

Right coronary artery (myocardium) Left coronary artery (myocardium)

P wave

Small upward wave. Represents atrial depolarization, spreads from SA node throughout both atria. 0.1 seconds after P wave begins, atria contract.

Define Cardiac Conduction System

Specialized areas of cardiac muscle tissue in the heart that are autorhythmic (self-exciting). These cells compose the CCS and are responsible for initiating and distributing cardiac (electrical) impulses throughout the heart muscle which causes the heart to beat. These specialized areas together coordinate the events of the cardiac cycle, which makes the heart an effective pump.

Define the term stroke volume.

Stoke volume = end-diastolic volume minus end-systolic volume.

Define the term hemodynamics.

Study of the forces involved in carrying blood away from the heart, transporting it to all of the body tissues, then returning it to the heart.

Define cardiology.

Study of the heart and diseases associated with it.

Name and locate the veins that deposit their blood into the atria of the heart- specify which atria, and deox- or oxygenated blood.

Superior vena cava brings deoxygenated blood from the head and upper limbs into the right atrium. Inferior vena cava brings deoxygenated blood from the trunk and lower limbs into the right atrium. The coronary sinus brings deoxygenated blood from the myocardium into the right atrium. The pulmonary veins bring oxygenated blood into the left atrium- there are two from the right lung and two from the left lung.

Define the terms tachycardia and bradycardia.

Tachycardia = pulse higher than 100 bpm. Bradycardia = pulse lower than 60 bpm.

Describe the term chordae tendineae.

Tendon-like, fibrous cords that connect the cusps of AV valves to the inner surface of the papillary muscle.

Explain what happens to the aorta at the brim of the pelvis.

The abdominal aorta terminates at the brim of the pelvis and branches into each leg (common iliac arteries).

Name and locate the arteries that take blood away from the heart- specify which ventricle, deox- or oxygenated blood.

The aorta carries oxygenated blood away from the left ventricle to the body. The coronary arteries carry oxygenated blood to the myocardium. The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs via the pulmonary trunk.

Describe the skeleton of the heart.

The skeleton of the heart has three components. 1) rings of dense connective tissue around the four valves, 2) mass of dense connective tissue in the interventricular septum, 3) provide attachment sites for valves and cardiac muscle fibers.

Type of blood vessel: Capillaries

Thinnest, smallest blood vessels. Capillaries permit the exchange of gases, nutrients, and wastes between blood and tissues. Connects arterioles to venules. Are composed of only a single layer of endothelium and a basement membrane. Three types, based on structure and permeability.

Describe the structure of the heart in terms of its chambers.

Upper chambers: atria. Right and left atrium are separated by the interatrial septum. Atria receive blood from veins, are thin walled chambers. Ear like flaps over the atria are called auricles, and note the fossa ovalis, the remnant of the fetal foramen ovale. The lower chambers: ventricles. Right and left ventricles are separated by the interventricular septum. Ventricles pump blood from the heart into arteries, are thick walled chambers. Note the trabeculae carnea, the irregular inner surface (ridges and folds) of the ventricles.

Spygmomanometer

Used to measure blood pressure. Typically brachial artery is used.

Describe how arterioles play a major role in regulating blood flow to capillaries.

Vasoconstriction and Vasodilation

Type of blood vessel: Venules and veins

Venules and veins carry blood toward the heart. Venules extend from capillaries and merge together to form veins. They are thin-walled vessels with 3 tunics (tunica intima, tunica media -much thinner than artery, and tuna externa - elastic and collage fibers. They carry blood under low pressure. They contain valves, carry blood that is high in CO2 and low in O2 except the pulmonary veins. Veins are large and serve as a blood reservoir, esp.in skin.

Type of blood vessel: Arterioles

Very small arteries. Deliver blood to capillaries in tissues. Play a major role in regulating blood flow to capillaries and therefore regulate blood pressure. Vasoconstriction = decreased vessel volume, decreased blood flow, and increased blood pressure. Vasodilation = increased vessel volume, increased blood flow, and decreased blood pressure.

Give another name for epicardium.

Visceral pericardium

Describe the structure of the heart in terms of its layers.

Walls of the heart are composed of three layers. 1) epicardium (aka visceral pericardium), 2) myocardium, the cardiac muscle tissue, which composes the bulk of the heart, and 3) endocardium, the smooth inner lining of the heart chambers and valves.

Although the venous circuit is essentially parallel to the arterial circuit, list the differences between the two.

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Branches of Common Iliac Arteries

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Branches of the abdominal aorta

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Compare and contrast the three types of blood vessels in terms of the following: a) Direction of blood flow in terms of the heart, b) wall structure (# of layers and components of those layers), c) gas concentrations, and d) pressure.

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Define the term anastomosis.

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Define the terms blood flow and circulation time and give the value of the normal circulation time in a resting adult.

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Discuss hypertension.

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Discuss the physiological stages of cardiac muscle contraction and trace how they appear on a graph plotting mV vs. time.

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Explain the process by which materials are exchanged through a capillary.

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Name the longest vein in the body and the venipuncture site.

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Venous System

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Frank-Starling Law of the Heart

strength (and therefore stroke volume) increases as venous return (preload) increases. Essentially, as blood flows into the heart, it must be pumped out.