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
|
Definition
| -double-walled sac that encloses the heart |
|
|
Term
|
Definition
-loosely fitting superficial part of the sac
-helps protect the heart and anchors it to surrounding structures (diaphragm and sternum) |
|
|
Term
|
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
|
Definition
-inflammation of the pericardium
-often results in decrease of serous fluid
-causes layers to bind and stick to each other, adhesions |
|
|
Term
|
Definition
-outer epicardium (visceral pericardium)
-myocardium
-endocardium |
|
|
Term
|
Definition
-outer layer of heart wall
-visceral pericardium
-produces serous fluid |
|
|
Term
|
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
|
Definition
-thin, glistening sheet of endothelium that lines heart chambers
-continuous with linings of blood vessels leaving and entering the heart |
|
|
Term
|
Definition
-2 atria (receiving chambers)
-2 ventricles (discharging chambers; actual pumps)
*each lined with endocardium |
|
|
Term
|
Definition
-right side: pulmonary circuit pump (pumps deoxygenated blood to lungs)
-left side: pumps oxygenated blood to body |
|
|
Term
|
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
|
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
|
Definition
-four
-prevent backflow
-only allow blood to flow from atria to ventricles |
|
|
Term
|
Definition
| -carry blood away from the heart |
|
|
Term
|
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
|
Definition
-left AV valve
-consists of 2 flaps or endocardium |
|
|
Term
|
Definition
-right AV valve
-has 3 flaps |
|
|
Term
|
Definition
| tiny white cords that anchor the flaps to the walls of the ventricles |
|
|
Term
|
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
|
Definition
-AV open: during heart relaxation
-AV closed: when ventricles are contracting
-semilunar open: when ventricles are contracting
-semilunar closed: during heart relaxation |
|
|
Term
|
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
|
Definition
-four
-prevent backflow
-only allow blood to flow from atria to ventricles |
|
|
Term
|
Definition
| -carry blood away from the heart |
|
|
Term
|
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
|
Definition
-left AV valve
-consists of 2 flaps or endocardium |
|
|
Term
|
Definition
-right AV valve
-has 3 flaps |
|
|
Term
|
Definition
| tiny white cords that anchor the flaps to the walls of the ventricles |
|
|
Term
|
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
|
Definition
-AV open: during heart relaxation
-AV closed: when ventricles are contracting
-semilunar open: when ventricles are contracting
-semilunar closed: during heart relaxation |
|
|
Term
|
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
|
Definition
-four
-prevent backflow
-only allow blood to flow from atria to ventricles |
|
|
Term
|
Definition
| -carry blood away from the heart |
|
|
Term
|
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
|
Definition
-left AV valve
-consists of 2 flaps or endocardium |
|
|
Term
|
Definition
-right AV valve
-has 3 flaps |
|
|
Term
|
Definition
| tiny white cords that anchor the flaps to the walls of the ventricles |
|
|
Term
|
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
|
Definition
-AV open: during heart relaxation
-AV closed: when ventricles are contracting
-semilunar open: when ventricles are contracting
-semilunar closed: during heart relaxation |
|
|
Term
|
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
|
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
|
Definition
systemic pump
-pumps over longer pathway-->more powerful
-walls much thicker |
|
|
Term
|
Definition
| -splits into the right and left pulmonary arteries to bring blood to the lungs |
|
|
Term
|
Definition
-created from the pulmonary trunk
-brings blood to lungs |
|
|
Term
|
Definition
| -returns oxygenated blood to the left side of the heart |
|
|
Term
|
Definition
-of lungs
-of body tissues
-where gas exchange occurs |
|
|
Term
|
Definition
-blood pumped to aorta from left ventricle
-all systemic arteries branch from aorta to supply all body tissues |
|
|
Term
|
Definition
-brings oxygen-poor blood to sup. and inf. venae cavae from body tissues
-sup. and inf. vena cava empty into right atrium |
|
|
Term
|
Definition
-striated
-intercalated discs
-figure 8-shaped bundles
-muscle cells beat independently but beat at different rates in different areas of heart |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
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
|
|
Term
| Gap Junctions of Cardiac Muscle Cells |
|
Definition
| allow action potentials to pass from cell to cell quickly |
|
|
Term
|
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
|
Definition
-right and left
-located in the interventricular septum
-carry electrical impulses to the Purkinje fibers |
|
|
Term
|
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
|
Definition
|
|
Term
|
Definition
|
|
Term
|
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
|
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
|
Definition
*atrial systole
-only small fraction of blood pumped from atrium to ventricles
-most moves passively |
|
|
Term
|
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
|
Definition
*early diastole
-Semilunar valves snap shut (to prevent backflow)
-pressure drops below that of the atria-->AV valves open |
|
|
Term
|
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
|
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
|
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
|
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
|
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
|
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
|
Definition
1)Tunica intima
2)Tunica media
3)Tunica externa |
|
|
Term
|
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
|
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
|
Definition
-location: outermost tunic
-composition: fibrous connective tissue
-function: support and protect the vessels |
|
|
Term
|
Definition
-thick (b/c higher pressure), stretchy walls
-able to expand and contract |
|
|
Term
|
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
|
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
|
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
|
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
|
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
|
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
|
Definition
-heart deprived of oxygen--> leads to severe pain called angina pectoris
-oxygen-deprived cells may die, forming an infarct or myocardial infarction |
|
|
Term
|
Definition
-inflammation of pericardium
-can result in decrease in serous fluid--> two layers adhere forming adhesions that interfere with heart movements |
|
|
Term
|
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
|
Definition
-can result in slower heart rate
-usually treated with implanted pacemaker |
|
|
Term
|
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
|
Definition
-rapid heartbeat over 100 beats per minute
-prolonged tachycardia may progress to fibrillation |
|
|
Term
|
Definition
| heart rate substantially slower than normal (less than 60 beats per minute) |
|
|
Term
|
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
|
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
|
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
|
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
|
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
|
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
|
Definition
-inflammation of pericardium
-can result in decrease in serous fluid--> two layers adhere, forming adhesions that interfere with heart movements |
|
|
