Test 1 Flashcards
(150 cards)
1
Q
3 Layers of the Heart Wall
A
epicardium (outer most), myocardium (middle/muscle), endocardium (inner most)
2
Q
epicardium
A
same as visceral pericardium. simple squamous on top of areolar connective tissue
3
Q
myocardium
A
muscular wall of the heart that lines the ventricles and atria. Composed of cardiac muscle, blood vessels, and nerves. has a nesting layer of tissue (stacked like an onion)
4
Q
endocardium
A
inner most layer, very thin, continuous with blood vessels
5
Q
Cardiac Muscle tissue
A
striated the same as skeletal, made of myofibrils with sarcomeres. It has cardiocytes (heart muscle cell)
6
Q
Cardiocyte
A
very small, uninucleate, many more mitochondria and those mitochondria are HUGE (25% of volume). tons of myoglobin. more vascular than skeletal. Help make our heart aerobic, great stamina, and efficiency. branched instead of long cylinders.
7
Q
Cardiac T-tubules
A
extensions of the sarcolemma (wider and shorter than in a skeletal muscle) Muscles get triggered from calcium in the SR but also Calcium ions from the wide t-tubules.
8
Q
Intercalated discs
A
connect the cardiocytes, located at the end of each cell. has a bumpy edge known as an interdigitating fold which increases the surface area. connected via desmosomes and gap junctions
9
Q
desmosomes
A
resist stretching and help to transfer the force of a contraction
10
Q
gap junctions
A
allow molecules and ions to flow from cell to cell (communication) Action Potentials flow from cell-to-cell which make the cardio cites act as 1 big cell.
11
Q
autorhythmic
A
the tissue contracts w/o neural stimulation. connected by pacemaker cells. motor neurons do influence the force and speed of contractions. heart is almost a totally aerobic metabolism which is why we need HUGE mitochondria
12
Q
Path of Blood Through the Heart
A
Right Atrium, tricuspid, Right Ventricle, pulmonary semilunar valve, Left Atrium, bicuspid, Left Ventricle, aorta semilunar valve.
13
Q
Right Atrium
A
receives blood from the systemic circuit through the superior(Upper body) and inferior(Lower body) vena cava. Blood then leaks into atria and ventricle due to the very low pressure (end of the systemic system)
14
Q
Interarterial Septum
A
thin wall that separates the right and left atria. We have a foramen ovale that lets blood flow from right to left atria while we are in the womb. It seals up and becomes the fossa ovalis, a small depression in the interarterial septum
15
Q
Right Ventricle
A
blood flows from right atria to right AV valve(tricuspid) into right ventricle. 3 fibrous flaps called cusps, each is connected to connective tissue called “chordae tendinae” which originate at papillary muscles on inner surface of right ventricle.
16
Q
Pulmonary Circuit
A
when right ventricle contracts blood flows through the pulmonary semilunar valve and enters the pulmonary trunk. Purpose of the valve is to prevent back flow into the right ventricle during RELAXATION.
17
Q
Pulmonary trunk
A
divides into R and L pulmonary arteries and carries deoxygenated blood into the lungs to get oxygen. Blood then flows through the pulmonary veins to the L atrium.
18
Q
Left atrium
A
also has an auricle (flap that looks like an ear when not full of blood). Gets oxygenated blood from the lungs. Sends blood through the bicuspid valve (Mitral) into the left ventricle
19
Q
Left Ventricle
A
MUSCULAR ridges called trabeculae carnae. interventricular septum is the thick wall separating the R and L ventricles. When the L ventricle CONTRACTS, bicuspid valve closes and prevents back flow into the atrium.
20
Q
Aorta
A
Left Ventricle pumps blood throughout the aortic semilunar valve into the ascending aorta. ASV prevents back flow during RELXATION. after blood moves thru ascending aorta it enters the aortic arch where it moves to the descending aorta, through your diaphragm, and then your abs.
21
Q
Similarities of Ventricles
A
hold same amount of blood
22
Q
Differences of Ventricles
A
L ventricle is much thicker/stronger because it needs more pressure to pump blood through the entire body. R ventricle acts as a bellow and squeezes blood out. L ventricle contracts all at once with tons of force (5x’s) L is shorter and wider (round). Atria contract simultaneously as do ventricles. Pulmonary and Systemic circuits get same amounts of blood.
23
Q
Heart Valves
A
permit blood to flow in only 1 direction. REGURGITATION is the back flow of blood.
24
Q
Atrioventricular valves
A
1) prevent blood from being forced back into the atria during ventricular CONTRACTION. 2) When ventricles relax the papillary muscles/chordae tendinae are also relaxed. (AV valves have no control of blood flowing from atrium to ventricles. 3) upon CONTRACTION, blood pushes the cusps closed and the chord tendinae keep the cusps from swinging into the atria.
25
Semiluanr valves
1) prevent regurgitation into the ventricles during relaxation. 2) unlike AV valves, no need for muscular braces because the pressure is so weak since ventricles are relaxed, 3 cusps that brace each other.
26
Valvular Heart Disease
VHD - occurs if the heart valves malfunction so the heart cannot pump efficiently. 1) sometimes the calves are faulty from birth. 2) sometimes develop after carditis - inflammation of the heart.
27
Cardiac Skeleton of the Heart (fibrous)
1) has 4 dense bands of tough elastic tissue that encircles the heart valves as well as base of aorta and pulmonary trunk. 2) bands stabilize the heart valves and bases of great vessels. 3) also electrically insulate the cardiac cells of ventricles from atria (otherwise the ventricles would contract too quickly)
28
Connective tissue of the Heart
1) lots of collagen and elastic fibers to support the heart, each cardiocyte is wrapped in an elastic sheath, neighbors hooked together by cross links. 2) CT supports the muscle, nerve, and vessels of the heart. prevent over expansion, help the heart spring back after contraction, and help distribute the force of contraction throughout the heart.
29
The Hearts Own Blood Supply
Coronary Circulation - blood supply to the heart (5% of entire blood of body) heart is always working so we need constant o2, nutrients, glucose, amino acids...
30
Coronary Arteries
R and L both emerge from the base of the aorta, close to the aortic semiluanr valve. When L ventricle contracts it forces blood up the aorta and valves close the coronary arteries, then upon relaxation the valves close and the coronary arteries are now open, can get blood flow to supply the heart. Blood moves due to the distensible aorta which relaxes and recoils to "pump" blood.
31
Specific Coronary Arteries
most variable aspect of anatomy. RCA supplies the right atrium and ventricle - Posterior Interventricular (descending) branch of RCA supplies blood to both ventricles. LCA runs along margin of left atrium and splits into 2 paths
32
2 Paths of the LCA
1) circumflex - branch of LCA that supplies the left atrium and posterior ventricle. 2) Anterior Interventricular (descending) supplies both ventricles and known as the LAD
33
anastomosis
convergence of two vessels, seen in the LAD and Posterior Interventricular. Liver has a portal system - 2 capillary beds.
34
Arteriovenous anastomosis
shunt - is a short cut where there are no capillaries
35
Cardiac Veins
1) Great Cardiac Vein, 2) Middle Cardiac Vein, 3) Coronary Sinus
36
Great cardiac vein
drains blood from anterior great and runs alongside the LAD
37
Middle cardiac vein
drains blood from posterior heart, runs alongside the posterior inter ventricular branch of the RCA
38
coronary sinus
all cardiac veins empty into the sinus which in turn empties into the right atrium. Its a large thin walled vein on the posterior of the heart.
39
Heart Attack
Myocardium infarctions (MIs) account for 25% of deaths, caused by long term insufficient supply of blood to one or more parts of the heart. 1) poor blood supply is usually due to a blood clot, 2) atherosclerosis - build up of deposit in arteries, 3) is damage is small you can recover from it
40
Angina Pectorosis
chest pain - sense of heaviness or pain in chest and L shoulder. insufficient blood supply for a short time which causes anaerobic fermentation to occur. Elevates lactic acid and causes pain.
41
Conducting System of the Heart
specialized cardiac muscle cells initiate and distribute electrical impulses thru the heart. 2 types of cells contractile and conducting. Contraction lags behind electrical signal because it must spread thru entire cardiocyte and calcium must enter, bind to troponin...same as skeletal.
42
contractile cells
muscle cells that contract to help move blood
43
conducting cells
specialized to coordinate contraction, make sure contractile cells push blood in correct direction at correct time. normally smaller than contractile cells and have fewer myofibrils.
44
Components of the Conducting System
1) Sinoatrial node (SA) - pacemaker. 2) Internodal pathways (connect 2 nodes and both atria) 3) Atrioventricular node (AV) 4) AV Bundle (Bundle of His) 5) Bundle branches 6) Purkinje fibers
45
Prepotential
pacemaker potential (in both nodes), gradual depolarization (constantly gets more positive), no stable resting stage (moving to ~40mV), move up due to ions flowing thru
46
Rate of Depolarization
differs depending on which node were in, fastest is the SA node @ 80 bpm, slower is AV node @ 50 bpm. Normal heart beat isn't 80 bpm because of parasympathetic NS. If SA gets damaged, AV steps up and keeps heart beating but beat is slowed.
47
Sinoatrial Node
located in superior and posterior wall of R atrium, near entrance of the superior vena cava. contains the pacemaker cells
48
Internodal pathways
CONDUCTING CELLS in atrial walls that connect SA node to AV node, they relay signal to contractile cells of both atria, as APs spread we get contraction across all cells from intercalated discs and gap junctions. AP doesn't reach ventricles due to fibrous skeleton which isolates atrial myocardium and ventricular myocardium
49
Atrioventricular Node
located on the floor of the R atrium, signal is delayed by 1/10th of a second because conducting cells are smaller and have fewer gap junctions. This allows the ventricles to fill completely with blood before contracting
50
Bundle of His
bundle of conducting cells that run from AV node to interventricular septum and then they split.
51
Bundle Branches
located in interventricular septum, extend toward the apex and then branch out. L is larger than R because L ventricle is bigger and needs more blood. They conduct impulses to 2 places: purkinje fibers and papillary muscles (to make chordae tendinae contract
52
purkinje fibers
spread from apex to base of the heart. ventricles start contracting @ apex and spread like a wave to ensure that blood moves in the right direction. Different than other conducting cells because very large so APs move quickly., makes it appear that entire ventricle contracts at once.
53
Conducting Cell Physiology
exhibit pre potentials - no resting membrane so always drifting up and more positive. Spontaeneous depolarization, membrane of conducting cells has "leaky" Sodium channels but not "leaky" Calcium channels...Na flows out and resting potential creeps up.
54
Pattern of Charges
begins at -60mV but climbs because Na leaves (positive charge creeps up) reaches threshold of -40mV so voltage gated channels open up. Calcium gets in and spikes above +0, now K channels open and Ca channels close so membrane repolarizes.
55
Electrocardiograms
ECG or EKG - records electrical activity, detected by electrodes on body, doesn't measure contractions but pulses. Spikes tell us about rates.
56
P wave
atrial depolarization
57
QRS complex
ventricular depolarization - strongest because ventricles are stronger
58
T wave
ventricular depolarization (No wave for atrial depolarization because it gets covered by QRS complex
59
EKGs
used to diagnose cardiac arrythmias - abnormal pattern of beating.
60
Serious arrythmias reduce efficiency and could indicate.....
damage to myocardium, injuries to pacemaker and conducting pathways, drug exposure, electrolyte imbalances
61
Analyzing EKG
voltage changes on the y-axis and duration of waves on x-axis. P-R interval, Q-T interval
62
P-R interval
period from start of atrial depolarization to start of QRS complex, tells us how long it takes for the signal to go from SA to AV node.
63
Q-T interval
period from start of ventricular depolarization to end of ventricular repolariation
64
5 Classes of Blood Vessels
1) arteries 2) arterioles 3) capillaries 4) venule 5) veins
65
3 layers of arteries and veins
tunica externa, tunica media, tunica intima
66
tunica externa
outer most wall, connective tissue sheath that blends into surrounding tissue and anchors the vessel
67
tunica media
concentric layer of smooth muscle, can relax or contract to change the diameter, controlled by autonomic NS. Helps move blood through the body. in ARTERIES the outer margin contains a band of elastic fibers called the external elastic membrane (They see biggest change in pressure)
68
tunica intima
inner most, in contact with the blood. composed of endothelium = simple squamous. in arteries (high pressure) contains a layer of elastic fibers called the internal elastic membrane.
69
5 Difference in Arteries and Veins: 1
walls of arteries are thicker than veins, mainly due to tunica media of artery w/ smooth muscle and elastic fibers. Arteries are big and circular, veins are not circular because their walls aren't as thick
70
5 Differences in Arteries and Veins: 2
arteries keep circular shape but veins look flat and distorted because they are less muscular
71
5 Differences in Arteries and Veins: 3
endothelial lining of artery looks ripples when artery is constricted
72
5 Differences in Arteries and Veins: 4
veins are much more expandable (distensible) than arteries, could expand by 8x more. Veins are like balloons and arteries are like tires.
73
5 Differences in Arteries and Veins: 5
only veins have valves, veins have most blood in the whole body.
74
Arteries
muscular walls that make them elastic and contractile. Sometime pressure is too great and arteries form aneurysms.
75
Elasticity in Arteries
helps vessels absorb the pressure changes from pumping of ventricles
76
Contractility in Arteries
enables the vessels to change in diameter and alter blood flow and blood pressure
77
Aneurysms
bulge of a weakend wall of an artery, could burst and become very dangerous if in aorta or brain.
78
Blood flow from heart to capillaries
Elastic arteries then to muscular arteries and finally to arterioles
79
Elastic Arteries
BIG, up 2.5 cm. largest arteries (aorta, pulmonary trunk, subclavian artery) tunica media has high density of elastic fibers (highly elastic and can withstand great pressure changes that happen close to the heart) exhibit elastic rebound to a)push the blood forward and b) dampens the pressure, peaks and valleys such that blood flow is more continuous.
80
Muscular Arteries
4mm, medium sized arteries, distribute blood to skeletal muscles and internal organs. Walls of tunica media are less elastic, and more muscular than elastic arteries. Don't need to be as elastic because not as close to the heart (place to check pulse)
81
Arterioles
30 micrometers, tiny compared to muscular arteries, transport blood from small muscular arteries to capillaries (no obvious tunica enterna) and tunica media is very small...Arterioles vasodialate when O2 is low and vasoconstrict if stimulated by sympathetic NS.
82
Capillaries
walls can exchange substances btwn blood and interstitial fluid. Substances diffuse across walls and blood slows down to give extra time for exchange to occur.
83
Structure of Capillary
single layer of endothelium over a thin basement membrane, no tunica media or externa, diameter of 8 micrometers (similar to a single blood cell)
84
Types of Capillaries (3)
Continuous, Fenestrated, and Sinusoids
85
Continuous Capillaries
most common type, endothelium is complete. found in all tissues except avascular. allow water, small solutes, and hydrophobic substances to diffuse into interstitial fluid but prevent blood loss of plasma proteins (seen in blood brain barrier)
86
Fenestrated Capillaries
"window" endothelium lining has small pores, allow for exchange of water and solutes as big as peptides, common in blood vessels and endocrine organs (hypothalamus, pituitary, pineal, thyroid)
87
Sinusoids Capillaries
resemble fenestrated capillaries that are flattened and irregularly shaped but have large gaps btwn endothelial cells. Allow solutes as large as plasma proteins to pass thru. Occur in liver, bone marrow, spleen, and endocrine organs.
88
Capillary beds
capillaries function as interconnected networks or webs called beds. entrance to capillary is regulated by the pre capillary sphincter which is a ring of smooth muscle. When the pre capillary sphincter constricts, blood flow is slowed or stopped so blood must go elsewhere.
89
perfusion
good blood flow and good nutrition
90
Veins
larger diameters than arteries and thin walled, carry blood back to the heart. tunica extern is now the thickest layer (not media like artery) walls are thin, smooth muscle in media and veins are much more expandable. Have valves
91
Valves in veins
prevent venous back flow into capillary beds, gravity could cause back flow but valves keep that from happening. Don't need it in arteries because pressure is so great. Often sandwiched btwn muscles which help squeeze veins and promote blood flow. If valves get weak blood starts pooling and veins could get swollen (varicose)
92
Distribution of Blood
total volume (5 liters) is unevenly distributed (2/3 is in veins). hold so much in veins because they expand so easily. if blood volume suddenly drops then sympathetic NS constricts the veins.
93
Reasons for Sympathetic Activity
vasoconstriction - occurs when theres low blood in veins, high in arteries. Venous Reserve - mvmnt of large volumes of water into and out of skin and liver.
94
Cardiovascular Physiology
Blood flowing through capillary beds depends on pressure and resistance.
95
Cardiovascular Pressure
measure of force exerted by blood on vessel walls (3 types) Arterial Blood Pressure, Capillary Hydrostatic Pressure, and Venous Pressure
96
Blood Pressure
arterial pressure measured in mm of Hg, biggest change from aorta to capillaries (100-35).
97
Systolic pressure
pressure when left ventricle is in systole (contraction) of about 120 mm of Hg
98
Diastolic pressure
pressure when left ventricle is in diastole (relaxation) about 80 mm of Hg
99
Capillary Hydrostatic Pressure
pressure within a capillary bed, declines the whole way across bed from 35 mm of Hg to 18 mm of Hg.
100
Venous Pressure
very low from 18-2 mm of Hg in vena cava. Hypertension is 140/90 which damages blood vessels. Increased workload on heart, tougher for ventricles to work.
101
Types of Peripheral Resistance
1) Vascular (length and diameter) 2) viscosity 3) turbulence
102
Vascular Resistance
Resistance from the blood vessels (most common form) due to friction btwn the blood and the walls. due to 2 things: length and diameter
103
Lengths effect on Vascular Resistance
longer = more resistance due to surface area in contact with blood. length is fairly consistent in adults, could change slightly by gaining or losing weight because adipose and muscle are both extremely vascular
104
Diameters effect on Vascular Resistance
smaller = more friction, greatest near vessel walls and so high resistance in small vessels. diameter (factor of 16) has a much larger effect on resistance than length (factor of 2). Arterioles see the highest resistance but they are muscular, small changes in diameter have big effect on resistance...also known as resistance vessels.
105
Viscosity's effect on Vascular Resistance
thickness of a liquid, blood is about 5x that of water, mainly due to the presence of RBC and plasma proteins
106
Turbulences effect on Vascular Resistance
occurs when blood flows in eddies and whirls due to a high flow rate, irregular surfaces on vessel walls, and sudden changes in diameter (valves) increases resistance, occurs btwn atria and ventricles, at semilunar valves, and rare unless walls are damaged
107
Heart Sounds
listening to sounds is called auscultation, don't position stethoscope directly above spot you want to listen to because sound gets distorted.
108
3 Sounds of the Heart
S1 (lubb) loudest, associated with closing of left AV valve and start of ventricular contraction, S2 (dubb) shorter, softer and associated with closing of semilunar valves/ventricular filing, S3 - very faint, associated with blood flowing into ventricles (children)
109
heart murmur
gurgling, rushing sound heard when a valve malfunctions and allows reguritation
110
Possible Short Answer 1, Relationships among vessel diameter
greatest closest to the heart and smallest at capillary beds. due to divergence (branching of arteries). from capillaries to vena cave (convergence) into larger and larger diameters
111
Possible Short Answer 2, Cross Sectional Area
much greater at capillaries due to the extremely high number of them
112
Possible Short Answer 3, Blood Pressure
drops steadily from aorta thru CV system, due to resistance, and due to total cross sectional area of capillaries
113
Possible Short Answer 4, Velocity of Blood Flow
decreases rapidly from aorta to capillaries, lowest in capillary beds, speeds us some in venous system - due to convergence of smaller veins into bigger ones, larger veins are small in total cross-section area and less resistance, also helped along by muscular contractions.
114
Similarities of Cardiac and Skeletal muscle
both are striated, both have myofibrils with sarcomeres
115
Differences of Cardiac and Skeletal muscle
Cardiac is: small, uninucleate, HUGE mitochondria, more vascular, branched, doesn't fatigue. Skeletal is: bigger, multinucleate, and made of cylindrical stacks
116
Arteries vs Veins: Arteries characteristics
carry blood away from the heart, thicker walls (tuncia media) circular shape, endothelium is rippled, no valves
117
Arteries vs Veins: Veins characteristics
carry blood to the heart, thinner walls (not as much pressure), flat shape, more distensible (8x), contain valves
118
To get from right atrium to right ventricle, blood flows through
tricuspid (Right atrioventricular valve)
119
How many pulmonary veins empty into the right atrium?
None, superior and inferior vena cava empty into the right atrium
120
The coronary blood vessels are part of the ___________ circuit of the circulatory system?
systemic
121
Cardiac muscles do not exhibit tetanus because it has____________
a long, absolute, refraction period
122
The contraction of ay heart chamber is called ________ and its relaxation is called ____________
systole, and diastole
123
How do electrical signals pass from one caridocyte to another quickly?
gap junctions
124
another name for heart attack is__________
myocardial infarction
125
blood from the heart chambers is separated from the myocardium by a thin membrane called the ___________
endocardium
126
Coronary circulation is part of the __________circuit of blood flow?
systemic
127
Are there valves when venous blood flows into the atria?
No
128
how much blood is moved during atrial contraction? How does the rest get there?
1/3, the rest leaks in
129
what do nerves affect in the heart?
speed and force of the contraction
130
ischema
deficiency of blood flow to cardiac muscle
131
atheroma
blood clot of fatty deposit that leads to a myocardial infarction
132
Are tendinae chord part of the conduction system of the heart?
no
133
A heart rate of 45 bpm and an absence of P waves indicates __________
damage to the SA node
134
During what segment of the ECG do the atria contract ?
PQ segment
135
Repolarization of the ventricles on an ECG produces what?
T wave
136
The _______ nerves innervate the heart and tend to reduce heart rate.
vagus
137
A high blood CO2 and low blood pH stimulate a __________ in heart rate?
increase
138
Where do plasma solutes enter the tissue fluid most easily?
fenestrated capillaries
139
A blood vessel thats adapted to withstand a high blood pressure would most like have_________
an elastic tunica media
140
Why does blood flow faster in a venule than in a capillary?
venues have larger diameters than capillaries
141
Capillaries of skeletal muscles are ___________.
continuous capillaries
142
What are pressure receptors near major arteries called?
barorecptors
143
What is the bodies longest blood vessel?
the great saphanous vein
144
How many time does the average heart beat a day?
100,000, maybe more like 160,000 in an athlete or toddler
145
Where is the heart located?
anterior mediastinum - space btwn two lungs and is tilted about 3 inches from the left of the middle of your body.
146
pericardium
fibrous sac that surrounds your heart and has two layers: parietal and visceral
147
parietal pericardium
the outer layer, consists of dense irregular and aerolar connective tissue with an inner lining of simple squamous
148
visceral pericardium
"epicardium" - inner layer that clings to the heart
149
pericardial cavity
potential space btwn parietal and visceral pericardium. Contains pericardial fluid which reduces friction
150
pericarditis
inflammation on the pericardium due to infection or trauma
