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A&P Ch. 11
Cardiovascular System
109
Anatomy
Undergraduate 3
03/15/2014

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Term
Orientation: Apex and Base
Definition
-apex: pointed; directed toward the left hip and rests on the diaphragm
-base: broad posterosuperior aspect from which the great vessels of the body emerge; points toward the right shoulder
Term
Pericardium
Definition
-double-walled sac that encloses the heart
Term
Fibrous pericardium
Definition
-loosely fitting superficial part of the sac
-helps protect the heart and anchors it to surrounding structures (diaphragm and sternum)
Term
Serous pericardium
Definition
-parietal layer: lines the interior of the fibrous pericardium
-visceral layer (epicardium): actually part of the heard wall
*both produce serous fluid that allows the heart to beat easily in a relatively frictionless environment
Term
Pericarditis
Definition
-inflammation of the pericardium
-often results in decrease of serous fluid
-causes layers to bind and stick to each other, adhesions
Term
Heart Wall: 3 layers
Definition
-outer epicardium (visceral pericardium)
-myocardium
-endocardium
Term
Epicardium
Definition
-outer layer of heart wall
-visceral pericardium
-produces serous fluid
Term
Myocardium
Definition
-thick bundles of cardiac muscle twisted and whorled into ringlike arrangements
-layer that actually contracts
-cells: tight junctions (bind mobile cardiac cells together) and gap junctions (allows ions to flow carrying wave of excitement)
Term
Endocardium
Definition
-thin, glistening sheet of endothelium that lines heart chambers
-continuous with linings of blood vessels leaving and entering the heart
Term
Chambers of Heart
Definition
-2 atria (receiving chambers)
-2 ventricles (discharging chambers; actual pumps)
*each lined with endocardium
Term
Double Pump
Definition
-right side: pulmonary circuit pump (pumps deoxygenated blood to lungs)
-left side: pumps oxygenated blood to body
Term
Pulmonary Circulation
Definition
-right side of heart receives relatively oxygen-poor blood from veins of body through sup. and inf. venae cavae
-pumps it out through the pulmonary trunk
-trunk splits into the right and left pulmonary arteries
-arteries carry blood to the lungs, where oxygen is picked up and carbon dioxide is unloaded
-oxygen-rich blood drains from the lungs and is returned to the left side of the heart through the four pulmonary veins
**function: carry blood to lungs for gas exchange and then return it to the heart
Term
Systemic Cirulation
Definition
-blood returned to left side of heart is pumped out into the aorta
-systemic arteries branch to supply essentially all body tissues
-oxygen-poor blood circulates from the tissues back to the right atrium via the systemic veins
-empty cargo into sup. or inf. vena cava
**function: supply oxygen- and nutrient-rich blood to all body organs
-left ventricle: thicker walls and more powerful pump than right
Term
Valves
Definition
-four
-prevent backflow
-only allow blood to flow from atria to ventricles
Term
Arteries
Definition
-carry blood away from the heart
Term
Veins
Definition
-carry blood to the heart
Term
Atrioventricular (AV) Valves
Definition
located between the atrial and ventricular chambers on each side
-prevent backflow into atria when ventricles contract
-left AV valve = bicuspid/mitral
-right AV valve = tricuspid
Term
Bicuspid/Mitral Valve
Definition
-left AV valve
-consists of 2 flaps or endocardium
Term
Tricuspid Valve
Definition
-right AV valve
-has 3 flaps
Term
Chordae Tendineae
Definition
tiny white cords that anchor the flaps to the walls of the ventricles
Term
Semilunar Valves
Definition
-guards the bases of the 2 large arteries leaving the ventricular chambers
-pulmonary and aortic
-each has 3 leaflets that fit tightly together when the valves are closed
Term
Timing of Valves
Definition
-AV open: during heart relaxation
-AV closed: when ventricles are contracting
-semilunar open: when ventricles are contracting
-semilunar closed: during heart relaxation
Term
Coronary Ateries
Definition
-branch from the base of the aorta and encircle the heart in the coronary sulcus at the junction of the atria and ventricles
-provides the functional blood supply that oxygenates and nourishes the heart
-drained by cardiac veins which empty into coronary sinus on posterior side of heart--> coronary sinus empties into right atrium
Term
Valves
Definition
-four
-prevent backflow
-only allow blood to flow from atria to ventricles
Term
Arteries
Definition
-carry blood away from the heart
Term
Veins
Definition
-carry blood to the heart
Term
Atrioventricular (AV) Valves
Definition
located between the atrial and ventricular chambers on each side
-prevent backflow into atria when ventricles contract
-left AV valve = bicuspid/mitral
-right AV valve = tricuspid
Term
Bicuspid/Mitral Valve
Definition
-left AV valve
-consists of 2 flaps or endocardium
Term
Tricuspid Valve
Definition
-right AV valve
-has 3 flaps
Term
Chordae Tendineae
Definition
tiny white cords that anchor the flaps to the walls of the ventricles
Term
Semilunar Valves
Definition
-guards the bases of the 2 large arteries leaving the ventricular chambers
-pulmonary and aortic
-each has 3 leaflets that fit tightly together when the valves are closed
Term
Timing of Valves
Definition
-AV open: during heart relaxation
-AV closed: when ventricles are contracting
-semilunar open: when ventricles are contracting
-semilunar closed: during heart relaxation
Term
Coronary Ateries
Definition
-branch from the base of the aorta and encircle the heart in the coronary sulcus at the junction of the atria and ventricles
-provides the functional blood supply that oxygenates and nourishes the heart
Term
Valves
Definition
-four
-prevent backflow
-only allow blood to flow from atria to ventricles
Term
Arteries
Definition
-carry blood away from the heart
Term
Veins
Definition
-carry blood to the heart
Term
Atrioventricular (AV) Valves
Definition
located between the atrial and ventricular chambers on each side
-prevent backflow into atria when ventricles contract
-left AV valve = bicuspid/mitral
-right AV valve = tricuspid
Term
Bicuspid/Mitral Valve
Definition
-left AV valve
-consists of 2 flaps or endocardium
Term
Tricuspid Valve
Definition
-right AV valve
-has 3 flaps
Term
Chordae Tendineae
Definition
tiny white cords that anchor the flaps to the walls of the ventricles
Term
Semilunar Valves
Definition
-guards the bases of the 2 large arteries leaving the ventricular chambers
-pulmonary and aortic
-each has 3 leaflets that fit tightly together when the valves are closed
Term
Timing of Valves
Definition
-AV open: during heart relaxation
-AV closed: when ventricles are contracting
-semilunar open: when ventricles are contracting
-semilunar closed: during heart relaxation
Term
Coronary Ateries
Definition
-4
-branch from the base of the aorta and encircle the heart in the coronary sulcus at the junction of the atria and ventricles
-provides the functional blood supply that oxygenates and nourishes the heart
-compressed when ventricles are contracting and fill when the heart is relaxed
Term
Cardiac Veins
Definition
drain myocardium
-empty into coronary sinus (enlarged vessel on the posterior of the heart)
Term
Superior and Inferior Venae Cavae
Definition
-veins through which the right atrium receives relatively oxygen-poor blood from the body
-blood is then pumped out thorough the pulmonary trunk to be oxygenated
Term
Left Ventricle
Definition
systemic pump
-pumps over longer pathway-->more powerful
-walls much thicker
Term
Pulmonary Trunk
Definition
-splits into the right and left pulmonary arteries to bring blood to the lungs
Term
Pulmonary Arteries
Definition
-created from the pulmonary trunk
-brings blood to lungs
Term
Pulmonary Veins
Definition
-returns oxygenated blood to the left side of the heart
Term
Capillary Beds
Definition
-of lungs
-of body tissues
-where gas exchange occurs
Term
Aorta
Definition
-blood pumped to aorta from left ventricle
-all systemic arteries branch from aorta to supply all body tissues
Term
Systemic Veins
Definition
-brings oxygen-poor blood to sup. and inf. venae cavae from body tissues
-sup. and inf. vena cava empty into right atrium
Term
Cardiac Muscle
Definition
-striated
-intercalated discs
-figure 8-shaped bundles
-muscle cells beat independently but beat at different rates in different areas of heart
Term
Rate of Atrial Beat
Definition
60 times/min
Term
Rate of Ventricular Beat
Definition
20-40 times/min
Term
2 Systems that Regulate Heart Activity
Definition
1)autonomic nervous system
2)intrinsic conduction system (nodal)
Term
Intrinsic Conduction System
Definition
-sets heart's basic rhythm
-tissue is cross between muscle and nervous
-causes heart muscle depolarization in the direction from atria to ventricles
-enforces contraction rate or approx. 75 beats/min
Term
Components of Intrinsic Conduction System
Definition
1)sinoatrial (SA) node
2)atrioventricular node (AV)
3)AV bundle
4)right and left bundle branches
5)Purkinje fibers
Term
Desmosomes of Cardiac Muscle Cells
Definition
for adherence
Term
Gap Junctions of Cardiac Muscle Cells
Definition
allow action potentials to pass from cell to cell quickly
Term
Sinoatrial (SA) Node
Definition
-located in right atrium
-composition: neurons that fire regularly without input
-function: starts each heartbeat..so-called pacemaker
-impulse spreads via the cardiac muscle cells through the atria on both sides to AV node--> atria contract
Term
Atrioventricular (AV) Node
Definition
-located at junction of atria and ventricles
-receives input from SA node
-impulse delayed shortly to give the atria time to finish contracting--> passes through the AV bundle, bundle branches, and Purkinje fibers resulting in a wringing contraction of the ventricles that begins at the apex and moves upward
Term
Atrioventricular (AV) Bundle
Definition
-bundle of His
-splits into bundle branches
-carry impulses to ventricles
Term
Bundle Branches
Definition
-right and left
-located in the interventricular septum
-carry electrical impulses to the Purkinje fibers
Term
Purkinje Fibers
Definition
-fibers spread within the muscle of the ventricle walls
-function: impulses reach cardiac cells--> cause spiral-like contraction of heart muscle cells that start at the apex and move upward to the atria
Term
Systole
Definition
-heart contraction
Term
Diastole
Definition
-heart relaxation
Term
Cardiac Cycle
Definition
-events of one complete heartbeat
-usually 0.8 seconds
-avg heart beats 75 times per minute
Term
Cardiac Cycle: Sequence of Events
Definition
1.Relaxation
2.Atria Contract
3.Ventricles Contract
4.Ventricles Relax
Term
1.Relaxation
Definition
*mid-to-late diastole
-blood flowing passively into atria and to ventricles
-AV valves are open
-semilunar valves are closed
-next: atria contract
Term
2.Atria Contract
Definition
*atrial systole
-only small fraction of blood pumped from atrium to ventricles
-most moves passively
Term
3.Ventricles Contract
Definition
*ventricular systole
-AV valves close as pressure increases in ventricles due to contractions
-semilunar valves are pushed open when pressure in ventricles is higher than in the aorta
-blood rushes into aorta
-->during this time: atria are relaxed and their chambers are filling with blood
Term
4.Ventricles Relax
Definition
*early diastole
-Semilunar valves snap shut (to prevent backflow)
-pressure drops below that of the atria-->AV valves open
Term
Cardiac Output (CO)
Definition
amount of blood pumped out by each side of the heart (each ventricle) in 1 minute
-product of the heart rate and stroke volume
Term
Stroke Volume (SV)
Definition
-the volume of blood pumped out by a ventricle with each heartbeat
-avg of 70 mL per beat (60% of blood in ventricles)
Term
Starling's Law of the Heart
Definition
-critical factor controlling stroke volume = how much the cardiac cells are stretched just before they contract (positive correlation)
-amount of blood returned from veins controls stretch
Term
3 Factors that Modify Heart Rate
Definition
1)Neural (ANS) Controls
2)Hormones and Ions
3)Physical Factors
Term
Neural (ANS) Controls
Definition
-sympathetic division
-fright-or-flight increases heart rate
-stimulates SA and AV nodes as well as cardiac muscle
-parasympathetic: mainly vagus nerves, slow and steady heart
-gives heart chance to rest
Term
Hormones and Ions
Definition
-epinephrine (mimics effect of sympathetic nerves) and thyroxine increase heart rate
-low calcium depress heart
-low potassium causes heart to beat feebly
-high sodium: kidney or heart disease--> elevated blood pressure = increased heart rate
Term
Physical Factors
Definition
gender, age, exercise, body temp
-fastest in fetus: 140-160 bpm
-faster in females: 72-80 bpm
-slower in males: 64-72 bpm
-heat increase heart rate
Term
Blood Vessels
Definition
heart--> arteries--> smaller arteries--> arterioles--> feed capillary beds--> drained by venules--> empty into veins--> empty into sup. and inf. vena cava--> back to heart
Term
Tunics of Blood Vessels
Definition
1)Tunica intima
2)Tunica media
3)Tunica externa
Term
1)Tunica intima
Definition
-location: lines the lumen/interior
-composition: thin layer of endothelium (squamous epithelial cells) resting on basement membrane
-function: decreases friction as blood flows through the vessel lumen
Term
2)Tunica media
Definition
-location: bulky middle coat
-composition: smooth muscle and elastic fibers (some larger ones have elastic laminae, sheets of elastic tissue)
-function: smooth muscle controlled by sympathetic NS changes diameter of vessel,
Term
3)Tunica externa
Definition
-location: outermost tunic
-composition: fibrous connective tissue
-function: support and protect the vessels
Term
Structure of Arteries
Definition
-thick (b/c higher pressure), stretchy walls
-able to expand and contract
Term
Structure of Veins
Definition
-thinner walls (lower pressure)
-lumens much larger
-large veins have valves to prevent backflow b/c pressure so low
-venous return enhanced by musculature and valves
Term
Structure of Capillaries
Definition
-wall is one cell layer thick, just the tunica intima
-capillary beds in body tissues
Term
2 Types of Capillary Bed Vessels
Definition
1)Vascular Shunt: directly connects the terminal arteriole with the post-capillary venule at opposite ends of the bed
2)True Capillaries: actual exchange vessels
Term
Precapillary Sphincter
Definition
-cuff of smooth muscle
-surrounds the root of each true capillary
-acts as a valve to regulate the flow of blood into capillary
-blood flows through true caps when sphincters are relaxed
-sphincters contracted--> blood flows through shunts (bypasses tissue cells)
Term
Capillary Bed
Definition
-structure: 10-100 caps per bed
-microcirculation: flow of blood through cap bed
-extensive beds throughout tissues so substances do not have to move very far from blood to cells
-interstitial fluid: bathes tissues and capillaries
Term
4 Ways of Capillary Exchange
Definition
1)direct diffusion through membrane (lipid-soluble substances)
2)diffusion through intracellular clefts (gaps by tight junctions)
3)diffusion through pores (in “fenestrated capillaries”; free passage of small solutes and fluids)
4)transport via vesicles (endocytosis or exocytosis)
Term
2 Forces Creating Fluid Movement in Capillary Beds
Definition
1.blood pressure: higher than osmotic pressure at arterial end of capillary bed so fluid moves into tissues
2.osmotic pressure: higher than blood pressure at venous end so fluid moves into blood (proteins in plasma increase osmotic pressure)
Term
Incompetent Valve
Definition
-valve does not close properly--> blood backflows--> heart has to re-pump same blood
-heart workload increases--> heart weakens and may fail
-valves can be replaced with synthetic valve, cryopreserved human valve or chemically-treated valve from a pig
Term
Valvular Stenosis
Definition
-valve flaps become stiff, often because of repeated bacterial infection of the endocardium (endocarditis)
-heart workload increases--> heart weakens and may fail
-valves can be replaced with synthetic valve, cryopreserved human valve or chemically-treated valve from a pig
Term
Heart Attack
Definition
-heart deprived of oxygen--> leads to severe pain called angina pectoris
-oxygen-deprived cells may die, forming an infarct or myocardial infarction
Term
Pericarditis
Definition
-inflammation of pericardium
-can result in decrease in serous fluid--> two layers adhere forming adhesions that interfere with heart movements
Term
Heart Block
Definition
-damage to AV node can fully or partially release the ventricles from the control of the SA node
-ventricles start to beat at their own rate which is much slower
Term
Damage to SA node
Definition
-can result in slower heart rate
-usually treated with implanted pacemaker
Term
Fibrillation
Definition
-rapid, uncoordinated shuddering of the heart muscle
-useless as a pump
-major cause of heart attacks in adults
-can result from ischemia or lack of adequate oxygen
-“Defibrillators” can be life-saving
Term
Tachycardia
Definition
-rapid heartbeat over 100 beats per minute
-prolonged tachycardia may progress to fibrillation
Term
Bradycardia
Definition
heart rate substantially slower than normal (less than 60 beats per minute)
Term
Heart murmurs
Definition
-abnormal or unusual heart sounds
-can be common in young children or elderly with no heart problems
-walls are relatively thin and vibrate with rushing blood
-most often indicate valve problems
-If valve doesn't close properly, will hear swishing AFTER valve closes as blood flows back through partially closed valve or through narrowed valves.
Term
Congestive heart failure
Definition
-pumping efficiency of heart is depressed so circulation is inadequate to meet tissue needs
-reflects weakening of heart
-Causes: coronary artherosclerosis, persistent high blood pressure; multiple myocardial infarctions (scar tissue does not contract)
Term
Pulmonary congestion
Definition
-left heart fails
-right side continues to pump blood to lungs but left side is unable to pump all of the returning blood to the body--> So blood vessels in the lungs swell--> fluid leaks into the lung tissue--> pulmonary edema results
-person suffocates if not treated
Term
Peripheral congestion
Definition
-right side of heart fails--> blood backs up in systemic circulation--> leading to edema in the peripheral parts of the body (ankles, feet, hands, etc.)
-puts strain on whole heart, which eventually fails
Term
Varicose veins
Definition
-veins are twisted and dilated--> valves give way
-results from pooling of blood in feet and legs and inefficient venous return resulting from inactivity or pressure on the veins
Term
Thrombophlebitis
Definition
-inflammation of vein resulting from formation of clot
-can be dangerous because clot can move to the lungs and cause a pulmonary embolism
Term
Pericarditis
Definition
-inflammation of pericardium
-can result in decrease in serous fluid--> two layers adhere, forming adhesions that interfere with heart movements
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