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cardiovascular system Flashcards

1
Q

what does the cardiovascular system consists of

A

blood vessels, blood, and the heart

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2
Q

the heart generates pressure

A

to propel blood through the vessels continuously

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3
Q

blood picks up oxygen in the lungs and nutrients in the intestine delivering…

A

them to body cells

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4
Q

the system removes cellular wastes and heat for excretion…. also it plays a role in

A

cell to cell communication and defending against foreign invaders

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5
Q

what is the cardiovascular system’s primary function?

A

is to transport materials throughout the body, including nutrients, water, gases, cell to cell materials and cellular wastes

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6
Q

how does oxygen enter the body?

A

through the lungs, and nutrients and water are absorbed via the intestinal epithelium. these materials are then distributed by the cardiovascular system.

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7
Q

oxygen is crucial for

A

cell survival, especially for brain neurons, which have high oxygen consumption and cannot rely on anaerobic pathways for ATP production. lack of oxygen to the brain for 5-10 seconds causes unconsciousness, and 5-10 minutes can result in permanent brain damage.

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8
Q

homeostatic controls prioritize maintaining

A

cerebral blood flow due to the brain’s sensitivity to hypoxia

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9
Q

the cardiovascular system facilitates cell-to-cell communication by

A

transporting hormones from endocrine glands to their targets and delivering nutrients like glucose and fatty acids to active cells.

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10
Q

white blood cells and antibodies in the blood help

A

defend against foreign invaders

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11
Q

the system also removes carbon dioxide and metabolic wastes from cells, transporting them to the

A

lungs and kidneys from excretion, and some wastes are processed by the liver before excretion.

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12
Q

heat is circulated through

A

the blood, moving from the body core to the surface to dissipate

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13
Q

the cardiovascular system includes the

A

heart, blood vessels (arteries and veins), and blood (cells and plasma)

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14
Q

arteries carry blood away from the heart,

A

while veins return blood to the heart

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15
Q

valves in the heart and veins ensure

A

unidirectional blood flow

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16
Q

the right atrium receives deoxygenated blood from the body and sends it to the lungs via

A

right ventricle and pulmonary arteries for oxygenation

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17
Q

oxygenated blood returns from the lungs to the left atrium via pulmonary veins, then is pumped by the left ventricle into the

A

aorta and systemic circulation

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18
Q

the systemic circulation includes arteries branching from the aorta (main artery taking blood from the left ventricle to the body)

A

capillaries where oxygen is exchanged with tissues, and veins returning deoxygenated blood to the right atrium via the superior and inferior vena cava

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19
Q

the coronary arteries (branching from the aorta)

A

supply the heart muscle with blood, which returns to the right atrium through coronary veins

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20
Q

the hepatic portal system connects

A

the digestive tract and liver, allowing nutrient processing and detoxification before blood enters general circulation

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21
Q

the kidneys have a

A

portal system with two capillary beds connected in series

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22
Q

the atrium is the upper chamber of the heart that receives blood,

A

while the ventricle is the lower chamber that pumps blood out of the heart

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23
Q

inferior vena cava

A

great vein that returns blood from the lower body to the right atrium

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24
Q

blood flows through the cardiovascular system due to

A

pressure gradients, moving from regions of higher pressure to regions of lower pressure

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25
Q

the heart generates high pressure when it contracts,

A

pushing blood into the blood vessels where pressure is lower

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26
Q

as blood travels through vessels, pressure decreases due to

A

friction between the blood and the vessel walls

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27
Q

the highest pressure and the lowest pressure is found where

A

highest found in the aorta and lowest found in the venae cavae before they empty into the right atrium

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28
Q

the principles of pressure volume, flow, and resistance that govern blood flow also apply

A

to other fluids and gases, such as air in the respiratory system

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29
Q

pressure in a fluid is the

A

force exerted by the fluids on its container, commonly measured in millimeters of mercury mmHg, torr, or centimeters of water

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30
Q

1mmHg is the pressure

A

exerted by a 1mm high column of mercury on an area of 1cm^2

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31
Q

1 torr is equivalent to

A

1mmHg and 1 m H2O is equivalent to 0.74mmHg

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32
Q

hydrostatic pressure is the

A

exerted by non-moving fluid, acting equally in all directions

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33
Q

in a flowing fluid system

A

pressure decreases over distance due to energy loss from friction

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34
Q

the pressure of moving fluid has two components:

A

dynamic (kinetic energy) and lateral (hydrostatic pressure or potential energy)

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35
Q

in a cardiovascular system, pressure is often referred to as

A

hydrostatic pressure, even though the fluid is in motion

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36
Q

when the walls of a fluid-filled container contract,

A

the pressure on the fluid increases. (driving pressure)

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37
Q

when the walls of a fluid-filled container expand,

A

the pressure on the fluid decreases

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38
Q

blood pressure changes can also occur in the blood vessels

A

dilation of blood vessels leads to a decrease in blood pressure, while contraction of blood vessels results in an increase in blood pressure

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39
Q

volume changes in the heart and blood vessels are

A

major factors influencing blood pressure in the cardiovascular system

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40
Q

flow is directly proportional to

A

pressure gradient (delta P)

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41
Q

the pressure gradient is defines as

A

delta P= P1-P2 (where P1 and P2 are the pressures at two ends of the tube)

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42
Q

a higher pressure gradient results in

A

greater fluid flow

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43
Q

the pressure gradient is different from absolute pressure

A

even if the absolute pressure is high at both ends of a tube, without a gradient, there is no flow

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44
Q

identical tubes can have different absolute pressures but

A

the same flow if their pressure gradients are equal

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45
Q

in an system, friction opposes

A

motion, includng blood flow in the cardiovascular system, which encounters resistance from vessel walls and blood cells

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46
Q

resistance (R) in the cardiovascular system opposes

A

blood flow, and blood takes the path of least resistance

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47
Q

flow is inversely proportional to resistance

A

flow proportional 1/R

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48
Q

resistance in a tube is influenced by

A

the tube’s radius, length and the fluid’s viscosity (poiseuille’s law)

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49
Q

resistance increases with

A

tube length, fluid viscosity

50
Q

resistance decreases with

A

an increase in tube radius

51
Q

in the cardiovascular system, tube length and blood viscosity are

A

relatively constant, making vessel radius the primary variable affecting resistance

52
Q

the relationship between resistance and radius is

A

R proportional to 1/r^4 (doubling the radius of a tube decreases resistance by a factor of 16, significantly increasing flow.

53
Q

vasoconstriction (decrease in vessel diameter) reduces

A

blood flow, while vasodilation (increase in vessel diameter) increases blood flow

54
Q

blood flow in the cardiovascular system is directly proportional to the pressure gradient (delta P) and inversely proportional to

A

resistance

55
Q

flow rate refers to the

A

volume of blood passing a point per unit time, typically measure in (L/min)

56
Q

velocity of flow is

A

the distance a fixed volume of blood travels in a given period of time, indicating how fast blood moves past a point

57
Q

the relationship between velocity of flow (v), flow rate (Q), and cross sectional area (A) is given by

A

v = Q/A (this means that velocity is directly related to low rate in a tube of fixed diameter and inversely related to the cross-sectional area in a tube of variable diameter

58
Q

in a vessel with variable width, if the flow rate is constant

A

velocity is faster in narrow sections and slower in wider sections

59
Q

the heart generates pressure during contraction,

A

pumping blood into arterial side of circulation

60
Q

arteries act as a

A

pressure reservoir during the heart’s relaxation phase, maintaining mean arterial pressure (MAP)

61
Q

mean arterial pressure is influenced by

A

cardiac output (the volume of blood the heart pumps per minute) and the peripheral resistance (the resistance of blood vessels to blood flow)

62
Q

the heart is a muscular organ located in the center of

A

the thoracic cavity with its apex pointing down to the left and its base behind the sternum

63
Q

the heart is encased in the pericardium,

A

a tough membranous sac containing pericardial fluid that lubricates the heart’s surface

64
Q

pericarditis

A

is inflammation of the pericardium, can cause a friction rub due to reduced lubrication

65
Q

the heart is primarily composed of cardiac muscle (myocardium)

A

and has thick muscular walls in the ventricles and thinner walls in the atria

66
Q

major blood vessels, including the aorta and pulmonary trunk, emerge from the base of the heart,

A

directing blood to tissues, while the venae cavae and pulmonary veins return blood to the heart

67
Q

the heart’s left and right sides are separated by a

A

septum, preventing the mixing of blood between the two sides

68
Q

the atria contraction together first, followed by the ventricles, with blood flowing from veins to atria,

A

through one way valves into ventricles and then out via the pulmonary trunk and aorta

69
Q

the heart’s development involved a twisting of the embryonic heart,

A

positioning the arteries at the top of the ventricles, necessitating a bottom-up contraction for efficient blood ejection

70
Q

four fibrous connective tissue rings surround the heart valves

A

providing structural support and acting as electrical insulators to ensure proper signal conduction and coordinated contraction

71
Q

the heart has its own blood supply called

A

coronary circulation, with vessels encircling the heart near its base

72
Q

major coronary arteries run across the heart’s surface in shallow grooves,

A

branching into smaller arteries and arterioles that penetrate the heart muscle

73
Q

the two primary coronary arteries originate at the

A

aorta’s root. just above the aortic valve

74
Q

the right coronary artery (RCA)

A

runs around the right side of the heart, supplying the right atrium, most of the right ventricle, part of the left ventricle, and the posterior interventricular septum

75
Q

the left coronary artery LCA)

A

divides into the circumflex branch and the anterior interventricular branch (LAD), supplying the left atrium, most of the left ventricle, the interventricular septum, and part of the right ventricle

76
Q

venous blood from the coronary circulation returns to the heart mainly through cardiac veins that empty into the coronary sinus,

A

which then empties into the right atrium.

77
Q

smaller blood channels within the heart muscle and

A

small veins on the anterior right ventricle also drain directly into the right atrium

78
Q

venous blood in the coronary circulation has much lower oxygen content

A

compared to blood returning through the venae cavae, as cardiac muscle consumes 70-80% of the oxygen delivered to it

79
Q

during increased activity, the heart uses almost all the oxygen brought by the coronary arteries,

A

necessitating increased blood flow to meet oxygen demands

80
Q

the heart is primarily composed of cardiac muscle cells (known as myocardium)

A

with about 1% being auto rhythmic cells that generate action potentials spontaneously

81
Q

autorhythmic cells or pacemakers enable the

A

heart to contract without external signals, a property known as myogenic contraction

82
Q

autorhythmic cells are smaller, have fewer contractile fibers, and lack organized sarcomeres,

A

thus they do not contribute to the heart’s contractile force

83
Q

cardiac muscle fibers are smaller than skeleton muscle fibers

A

typically with a single nucleus, and they branch and join end-to-end forming a complex network

84
Q

intercalated disks, consisting on desmosomes and gap junction, connection cardiac muscle cells

A

desmosomes provide strong connections for force transfer, while gap junctions allow rapid electrical communication fro synchronized contraction

85
Q

cardiac muscles share some properties with

A

smooth muscles, such as reliance on extracellular Ca2+ for contraction and having a smaller sarcoplasmic reticulum

86
Q

myocardial cells have larger t-tubules that branch within the cells and a high mitochondrial content,

A

occupying about one-third of the cell volume, reflecting their high energy demand

87
Q

in skeletal muscle, acetylcholine from a somatic motor neuron

A

initiates excitation-contraction coupling (EC coupling), while in cardiac muscle, the action potential originates spontaneously through gap junctions

88
Q

the action potential in cardiac muscles moves across the

A

sarcolemma and into the t-tubules, opening voltage-gated L type Ca2+ channels, allowing Ca2+ to enter the cell

89
Q

calcium triggers the opening of ryanodine receptor Ca2+ release channels (RyR) in the sacroplasmic reticulum,

A

a process known as calcium-induced calcium release (CICR)

90
Q

Released Ca2+ from the sarcoplasmic reticulum creates a

A

Ca2+ spark, which sums to create a Ca2+ signal

91
Q

Approximately 90% of the Ca2+ needed for muscle contraction comes from

A

the sarcoplasmic reticulum, with the remaining 10% entering from the extracellular fluid

92
Q

calcium binds to troponin, initiating the cycle of

A

crossbridge information and movement, leading to contraction via the sliding filament mechanism

93
Q

relaxation occurs as cytoplasmic Ca2+ concentrations decrease,

A

Ca2+ unbind from troponin, myosin releases actin, and the filaments slide back to their relaxed position

94
Q

Ca2+ is transported back into the sarcoplasmic reticulum by Ca2+ - ATPase and is also removed from the cell

A

via the Na +- Ca2+ exchanger (NCX)

95
Q

The NCX exchanger moves one Ca2+ out of the cell in exchange for

A

three NA+ entering the cell, which are then removed by the Na+-K+- ATPase

96
Q

cardiac muscle cells can execute graded contractions,

A

varying the force generated by a single muscle fiber

97
Q

the force generated by cardiac muscle

A

is proportional to the number of active crossbridges

98
Q

the number of active crossbridges is determined by

A

the amount of Ca2+ bound to troponin

99
Q

Low cytosolic Ca2+ concentrations result in

A

fewer active crossbridges and smaller contraction force

100
Q

additional Ca2+ from extracellular fluid and sarcoplasmic reticulum increases the number of

A

active crossbridges, enhancing contraction force

101
Q

the sarcomere length at the beginning of contraction

A

also affects the force of contraction

102
Q

in the heart, the stretch on individual fibers, influenced by the blood volume in the chambers, impacts

A

the force of contraction

103
Q

the relationship between force and ventricular volume is crucial

A

for cardiac function

104
Q

Cardiac EC coupling involves different receptors and channels compared to skeletal muscle EC coupling. In cardiac muscle, the L-type calcium channels and

A

ryanodine receptors (RyR2) play a crucial role, while in skeletal muscle, the dihydropyridine receptors (DHPR) and ryanodine receptors (RyR1) are key.

105
Q

cardiac muscle is an excitable tissue capable of generating

A

action potentials, similar to skeletal muscle and neurons

106
Q

There are two types of cardiac muscle cells, each with distinctive action potentials

A

that vary in shape depending on their location in the heart

107
Q

In both auto-rhythmic and contractile myocardium,

A

Ca2+ plays a crucial role in the action potential, unlike skeletal muscle and neurons, which rely solely on Na+ and K+ movement

108
Q

A single ion channel, such as Ca2+ or K+ channel, can have multiple

A

roles due to existence of families of ion channels with various members

109
Q

there are at least 10 different types of K+ channels involved in

A

myocardial action potentials, each with unique properties

110
Q

Myocardial contractile cells have action potentials similar to neurons and skeletal muscle, with rapid

A

depolarization due to Na+ entry and steep repolarization due to K+ exit

111
Q

the key difference is longer action potential in

A

myocardial cells, caused by Ca2+ entry.

112
Q

phases of myocardial action potential

A

Phase 4: resting membrane potential (-90mV)
Phase 0: depolarization occurs as Na+ enters the cell, raising the membrane potential to about +20mV
Phase 1: initial repolarization begins as Na+ channels close and K+ leaves the cell
Phase 2: plateau phase where Ca2+ enters the cell and K+ efflux decreases, flattening the action potential
Phase 3: Rapid repolarization as Ca2+ channels close and K+ permeability increases, returning the cell to resting potential

113
Q

the longer action potential in myocardial cells, prevents

A

tetanus, allowing the heart to relax between contraction for proper venticular filling

114
Q

the refractory period in cardiac muscle overlaps with the contraction period,

A

preventing summation and tetanus, unlike in skeletal muscle where summation can occur due to the timing of action potentials and refractory periods

115
Q

myocardial autorhythmic cells can generate action potentials due to their unstable

A

membrane potential, known as the pacemaker potential, which starts at -60mV and drifts upward toward the threshold

116
Q

the instability of the membrane potential is due to unique channels

A

in autorhythmic cells, specifically If channels, which are permeable to both K+ and Na+

117
Q

The heart’s coordinated contraction is essential for

A

effective blood circulation, similar to how a group effort is needed to push a stalled car

118
Q

electrical communication in the heart starts with an action potential an autorhythmic cell,

A

spreading through gap junctions in intercalated disks

119
Q

depolarization begins in the sinoatrial (SA) node,

A

the heart’s main pacemaker, located in the right atrium

120
Q

The depolarization wave spreads through a specialized conducting system, including the internodal pathway

A

connecting the SA node to the atrioventricular (AV) node

121
Q
A

physio (6 decks)

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