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PE - anatomy and physiology > cardiovascular system > Flashcards

cardiovascular system Flashcards

(80 cards)

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1
Q

myogenic

A

the capacity of the heart to generate its own impulses

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2
Q

systole

A

when the heart contracts

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3
Q

how the cardiac conduction system

A
  1. an electrical impulse signal begins in the SA node
  2. this impulse spreads through the walls of the atria, causing them to contract, forcing blood into the ventricles (atrial systole)
  3. this impulse passes through the AV node found in the atrioventricular system. the AVN delays the impulse for 0.1 secs to enable the atria to fully contract before ventricular systole begins
  4. impulse passes through the specialised fibres which form the bindle of his
  5. it then passes through the 2 bundle branches and then into the purkinje fibres which spread throughout the ventricles causing them to contract
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4
Q

what 2 systems control heart rate?

A

. sympathetic nervous system
. parasympathetic nervous system

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5
Q

sympathetic nervous system

A

. prepares body for exercise
. stimulates the heart to beat

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6
Q

parasympathetic nervous system

A

. calming yourself
. relaxes the body and slow down many high energy functions
. returns heart to its resting level

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7
Q

purpose of chemoreceptors

A

detect chemical changes, in exercise they detect increases in CO2

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8
Q

location of chemoreceptors

A

carotid arteries and aortic arch (neck and heart)

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9
Q

purpose of baroreceptors

A

contain nerve endings that respond to the stretching of the arterial wall caused by changes in blood pressure, during exercise they set point increases

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10
Q

location of baroreceptors

A

arterial wall

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11
Q

what does an increase in arterial pressure cause?

A

causes an increase in the stretch of the baroreceptor sensors and causes a decrease in heart rate

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12
Q

purpose of proprioceptors

A

provide information on movement and body position and detect changes in movement. in exercise, they detect increases in muscle movement so then increases the heart rate by sending impulses to the medulla, which sends impulse through the sympathetic nervous system to the SAN.

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13
Q

location of proprioceptors

A

sensory nerve endings in muscles, tendons and joints

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14
Q

adrenaline

A

stress hormone that is released by sympathetic nerves and cardiac nerves during exercise . stimulates SAN which causes an increase in speed and force of contraction which causes an increase in cardiac output

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15
Q

stroke volume

A

volume of blood pumped out by the heart ventricles in each contraction

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16
Q

cardiac output equation

A

stroke volume x heart rate

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17
Q

cardiac output

A

volume of blood pumped out by the heart ventricles per minute

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18
Q

heart rate

A

number of times the heart beats per minute

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19
Q

max heart rate equation

A

220 - age

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20
Q

cardiac hypertrophy

A

thickening of the muscular wall of the heart so it becomes bigger and stronger. this causes increase in stroke volume and increase in resting HR

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21
Q

bradycardia

A

decrease in resting HR to below 60bpm. oxygen delivery to the muscles improvises there is less oxygen needed for contraction of the heart

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22
Q

cardiac output during exercise

A

. cardiac output increases as the intensity of exercise increases
. once maximum intensity is reached, cardiac output then plateaus

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23
Q

ejection fraction

A

% of blood pumped out by left ventricle per beat

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24
Q

impact of exercise on stroke volume

A

. SV increases as exercise intensity increases but this is only the case up to 40-60% of maximum effort
. at this point, stroke volume plateaus

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25
factors that influence stroke volume
. venous return . elasticity of elastic fibres . contractivity of cardiac tissue
26
how does venous return influence stroke volume?
an increase in venous return causes an increase in stroke volume. if more blood is retuning to heart, more can go out
27
how does elasticity of elastic fibres influence stroke volume?
the more cardiac fibres can stretch, the greater the force of contraction will be. greater force of contraction increases ejection fraction (starlings law)
28
how does contractivity of cardiac tissue influence stroke volume
the greater the contractivity of cardiac tissue, the greater the force of contraction. this causes an increase stroke volume
29
starlings law
1. venous return increases 2. more blood fills the ventricles in the diastolic phase as more is retuning 3. cardiac muscles if the ventricles is stretched 4. this stretch means that there us more force in the contraction 5. this increases ejection fraction 6. and therefore stroke volume increases
30
cardiovascular drift
when the HR slowly climbs, rather than staying the same. at the same time there is a progressive decrease in stroke volume and BP
31
when does cardiovascular drift happen?
. in pro-longed submaximal exercise (10 mins after) . often in a warm environment . the intensity of the exercise remains the same
32
why does cardiovascular drift happen?
. decrease in plasma volume caused by loss in fluid volume due to sweat . reduces venous return, and due to starlings law, stroke volume. HR increases to maintain a higher cardiac output for exercise, and for more energy to cool the body down
33
order of the vascular system
heart -> arteries -> arterioles -> capillaries -> venules -> veins -> heart
34
features of arteries
. small lumen . thicker elastic tissue . highest blood pressure
35
features of veins
. large lumen . have valves . thinner muscle/elastic tissue layers . lower blood pressure
36
key feature of capillaries
narrow (1 red blood cell can pass through)
37
blood pressure
the force exerted by the blood against the blood vessel wall
38
blood pressure equation
blood flow x resistance
39
systolic pressure
the pressure in arteries when the ventricles are contracting
40
diastolic pressure
the pressure in arteries when the ventricles are relaxing
41
venous return
the return of blood to the right side of the heart to the vena cava
42
what happens to venous return when there's an increase or decrease in systolic pressure
. increase = increase in venous return . decrease = decrease in venous return
43
venous pressure
the blood pressure in the veins (this reflects the amount of blood returning to the heart)
44
right atrial pressure
the blood pressure in the right atrium
45
Venus vascular pressure
the resistance that must be overcome to push blood through the circulatory system and create flow, e.g vessel diameter
46
3 main venous return mechanisms
. skeletal muscle pump . respiratory pump . pocket valves
47
skeletal muscle pump
when the muscles press on the nearby veins and cause a pumping effect that squeezes blood back to the heart
48
respiratory pump
the changes in pressure compresses the nearby veins to help pump blood back to the heart when we breathe in and out . pressure changes occur in the thoracic and abdominal cavities
49
pocket valves
. presence of valves ensures that blood in the veins only flows in one direction . they open to let blood through and immediately close after
50
other factors that aid venous return
. a very thin layer of smooth muscle in the walls if the veins to squeeze blood back to the heart . gravity helps the blood return to the heart from the upper body . the suction pump action of the heart
51
venous rerun equation
venous pressure - right atrial pressure / venous vascular resistance
52
venous return will increase if there is
. an increase in venous pressure . a decrease in right atrial pressure . a decrease in venous resistance
53
venous return will decrease if there is
. an increase in right atrial pressure
54
vasodilation
the widening of the blood vessels to increase the flow of the blood into the capillaries
55
vasodilation during exercise
occur in the arterioles supplying these muscles to increase blood flow and brining in much needed oxygen
56
vasoconstriction
the narrowing of the blood vessels to reduce blood flow into the capillaries
57
vasoconstriction during exercise
occur in the arterioles supplying non-essential organs
58
sympathetic nerves
located in the walls of the blood vessel, also redirect blood flow
59
sympathetic nerves during exercise
sympathetic stimulation increases
60
sympathetic nerves after exercise
sympathetic stimulation decreases
61
pre-capillary sphincters
tiny rings of muscle located at the opening of capillaries
62
pre-capillary sphincters during exercise
capillary networks for skeletal muscles will relax them and then blood flow increases
63
importance of redistribution of blood flow
. increase the supply of oxygen to the working muscles . remove waste products from the muscles . ensure more blood goes to the skin and during exercise to regulate body temperature and get rid of heat through radiation, evaporation and sweating . direct more blood to the heart as it is a muscle and required more oxygen during exercise
64
plasma
the fluid part of blood that surrounds blood cells and transports them
65
haemoglobin
an iron containing pigment found in red blood cells which combines with oxygen to form oxyhaemoglobin
66
myoglobin
an iron containing pigment in slow twitch muscle fibres which has a higher affinity for oxygen than haemoglobin. it stores the oxygen in the muscle fibres which can be used quickly when exercise begins
67
mitochondria
often referred to as the powerhouse of the cell as respiration and energy production occurs there
68
oxygen dissociation curve
. in the slow twitch muscle fibres, oxygen is stored for myoglobin . this has a higher affinity for oxygen and will store the oxygen for the mitochondria until it's used by the muscles
69
Bohr shift
additional oxygen released from haemoglobin at lower pH (high CO2 concetration)
70
oxyhemoglobin dissociation curve
the partial pressure of oxygen in the lungs is high so haemoglobin is almost completely saturated with oxygen. in the tissues, the partial pressure of oxygen is lower, therefore, the haemoglobin gives up some of its oxygen to the tissues
71
why does the bohr shift happen?
In the tissues there's a low partial pressure pf oxygen and high partial pressure of carbon dioxide, so haemoglobin unloads at this point. this means that even more oxygen is available to the tissues
72
bohr shift during exercise
the S-shaped curve shifts to the right because when muscles require more oxygen, the dissociation of oxygen from haemoglobin in the blood capillaries to the muscle tissue occurs more readily. this shift to the right is known as the bohr shift
73
what is the bohr shift caused by?
. decrease in blood pH . increase in blood temperature . partial pressure of CO2 increases
74
why does a decrease in blood pH cause the bohr shift?
. during exercise, more CO2 is produced in the muscles . more CO2 lowers the pH in the blood . this drop in pH causes oxygen to dissociate more quickly
75
why does an increase in blood temperature cause the bohr shift?
. heat is a by product of aerobic respiration which occurs more frequently during exercise . therefore muscle temperature increases during exercise . oxygen will dissociate more quickly when there is an increase in blood and muscle temperature
76
why does increased partial pressure of CO2 cause the bohr shift?
. during exercise, more CO2 is produced in muscles . as the level of blood CO2 increases during exercise oxygen will dissociate faster from haemoglobin
77
arterio-venous difference at rest
low at rest as not much oxygen is required by the muscles
77
arterio-venous difference
the difference between the oxygen content of the arterial blood arriving at the muscle and the venous blood leaving the muscles
78
impact of increase in artery-venous difference during exercise
affects gaseous exchange at the alveoli so more oxygen taken in and more CO2 is removed
78
arterio-venous difference during exercise
high during exercise more oxygen is extracted by the working muscles and therefore venous blood has less oxygen returned to the heart

PE - anatomy and physiology (3 decks)

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