Cardiovascular Physiology Flashcards
(134 cards)
1
Q
why is the heart important ?
A
transport and temperature regulation
2
Q
describe the organization of the CV system:
A
-arteries become arterioles then capillaries
- capillaries reunite to form venues and then veins
- rest of the body
3
Q
where do arteries carry blood ?
A
away from the heart
4
Q
where do veins carry blood ?
A
towards the heart
5
Q
between arteries and veins which have more pressure and musculature ?
A
arteries
6
Q
what are the two circuits of the body ?
A
pulmonary and systematic
7
Q
what is the pulmonary circuit responsible for?
A
lungs / upper body
8
Q
what is the systemic circuit responsible for ?
A
rest of the body circulation
9
Q
what carries oxygen-rich and CO2 poor blood ?
A
veins
10
Q
what carries oxygen-poor and CO-rich blood ?
A
arteries
11
Q
how much % of the body is pulmonary circuit ?
A
15%
12
Q
how much % of the body is systemic circuit ?
A
85%
13
Q
within the systemic circuit what % is arteries, veins and capilaries ?
A
- arteries = 10%
- capillaries = 5%
- veins = 70%
14
Q
how does blood travel through the heart ?
A
- blood from upper body goes through the superior vena cava and blood from the lower body goes through the inferior vena cava into the right atrium
- blood does into the right ventricle (through the tricuspid valve/right AV valve)
- blood goes through the pulmonary valve
- blood exists through the pulmonary artery to the lungs
- blood returns oxygenated into the left atrium
- blood goes through the bicuspid valve into the left ventricle
- blood goes to the aorta
- blood then gets distributed throughout the body
15
Q
what are the two types of myocardial cells ?
A
contractile and nodal & conducting
16
Q
name some differences between skeletal and cardiomyocytes ?
A
- skeletal = motor neuron action potential while cardiomyocyetes = electrically connected
- skeletal have mitochondria whole cadiomyocytes have a LOT of mitochondria
17
Q
describe nodal and conducting cells:
A
minimal actin and myosin but self-excitable
18
Q
what are some examples of nodal & conducting cells :
A
SA node (pacemaker), AV node, purkinje fibers and bundle of his
19
Q
what does the AV node do ?
A
controls messages and creates desired heart rate (slows down from SA node)
20
Q
what is depolarization ?
A
cell becomes more positive than RMP
21
Q
what is repolarization ?
A
positive cell returns to RMP
22
Q
what is the RMP of a neuron vs nodal cell ?
A
-70 mV and -60mV
23
Q
what is the threshold of a neuron vs nodal cell ?
A
-55mv and -40mV
24
Q
what are two differences between neurons and nodal cells ?
A
- RMP and threshold
- calcium presence in nodal cells
25
describe the SA nodal action potential :
- always fluctuating
- RMP, goes to threshold,
- depolarizes then depolarizes back to RMP
26
within the conducting system which AP propagation ?
SA node
27
what dos the AV do ?
regulate heart rate after the SA node
28
in order for muscle to contract what do you need ?
need an action potential first
29
what does a electrocardiogram do ?
- records the electrical activity of the heart
30
in an ECG what are the four letters ?
P, QRS, and T
31
what does P, QRS and T represent ?
P =atrial depolarization
QRS = ventricular depolarization
T = ventricular repolarization
32
what 5 things can an ECG tell us ?
- heart rate
- heart damage
- conduction issues
- rhythm disturbance
- effects of drugs
33
what is the resting heart rate of the average person ?
70 beats/min
34
how does heart rate change ?
sympathetic & parasympathetic stimulation
35
what is parasympathetic ?
rest and digest
36
what is sympathetic ?
fight and flight
37
what are 4 characteristics of parasympathetic innervation ?
- slower heart rate
- increase K permability
- decease Na permeability
- decrease Ca permeability
38
what are 3 characteristics of sympathetic innervation ?
- faster heart rate
- increase Na permability
- increase Ca permability
39
what does permability mean in the sense of "increase Ca permability" ?
more calcium coming in
40
between the sympathetic and parasympathetic innervation which has a faster/slower heart rate ?
sympathetic = faster
parasympathetic = slower
41
between ACh and NE, which is associated with parasympathetic and sympathetic ?
ACh = prasympathtic
NE = sympathetic
42
what does systole mean ?
contraction
43
what does diastole mean ?
relaxation
44
when do ECG events occur in regards to a heart muscle contraction ?
the ECG events occur before heart muscle contraction
45
what are the five cardiac cycle heartbeat events ?
1. atrial systole
2. iso-volumetric ventricular systole
3. ventricular systole
4. isovolumeetric ventricular diastole
5. late ventricular diastole
46
how does blood move (in regards to pressure gradient) ?
blood moves down a pressure gradient
47
what does systole mean ?
contraction
48
what is phase 1 of the ECG ?
atrial systole
49
what does diastole mean ?
relaxed (isn't changing)
50
when does systole occur ?
when the heart contracts to pump blood out
51
when does diastole occur ?
when the heart relaxes after contraction
52
what is atrial systole ?
contraction of the atrial
53
what happens to pressure in atrial systole ?
pressure increases
54
what happens to volume in atrial systole ?
volume increases
55
what do you need in order to have a contraction in the heart ?
action potential
56
what is phase 2 of ECG ?
isovolumetric ventricular systole
57
what happens to pressure in isovolumetric ventricular systole ?
pressure increases
58
what happens to volume in isovolumetric ventricular systole ?
no change
59
what are the valves doing during isovvolumetric ventricular systole ?
all valves closed
60
if a phase begins with "isovolum" what does this mean ?
volume stays the same
61
what is phase 3 of the ECG ?
ventricular systole
62
what happens to pressure in ventricular systole ?
pressure increases
63
what happens to volume in ventricular systole ?
volume decreases
64
what are the valves doing during ventricular systole ?
aortic valve open
65
if pressure is high in the ventricles what does that mean for the aorta ?
aortic pressure is lower
66
what is phase 4 of the ECG ?
isovolumetric ventricular diastole
67
what happens to pressure in isovolumetric ventricular diastole ?
pressure decreases
68
what happens to volume in isovolumetric ventricular diastole ?
no change
69
what are the valves doing during iso-volumetric ventricular diastole ?
all valves closed
70
what is phase 5 of the ECG ?
late ventricular diastole
71
what happens to pressure in late ventricular diastole ?
pressure decreases
72
what happens to volume in late ventricular diastole ?
volume increases
73
what are the valves doing during late ventricular diastole ?
AV valve opens
74
what is the term for during ONE ventricular systole (contractions) ?
stroke volume
75
what is cardiac output ?
per min of ventricular contractions
76
what is the formula for cardiac output ?
heart rate x stroke volume
77
what two things control stroke volume ?
1. autonomic nervous system innervation
2. preload on the heart
78
what does "preload" mean ?
how much blood we can get into ventricle before contraction occurs
79
what do muscles need more of to better function ?
more blood
80
what is EDV ?
amount of blood in the ventricle after atrial systole
81
what is the formula for stroke volume ?
EDV - ESV
82
what is ESV ?
amount of blood in the ventricle after ventricular systole
83
what are two major rules regarding the heart ?
1. blood will only move down pressure gradient
2. blood should never be going in the wrong direction
84
the more calcium what does this mean for the heart ?
more contractions
85
when discussing the "load" on the heart prior to contraction what is this "load" ?
the EDV
86
what happens if muscles are over stretched ?
heart will fail
87
what is frank-starling's law ?
"an increase in EDV will cause an increase in stroke volume"
88
what is MAP (mean arterial pressure) ?
difference between systolic pressure and diastolic pressure
89
what is the average blood pressure for the healthy individual ?
120/80
90
in what way does blood move ?
from high to low blood will flow
91
what is the anatomy of a blood vessel ?
- tunica externa
- tunica media
- tunica interna
92
what is thicker ? arteries or veins ?
arteries are thicker in order to produce contractions
93
what is the tunica external made of ?
fibrous connective tissue
94
what is the tunica media made of ?
smooth muscle and elastic fiber
95
what is the tunica interna made of ?
endothelial cells
96
describe the structure of arteries ?
- large diameter
- thin walls compared to diameter
- lost of elastic
97
describe blood characteristics of arteries ?
- very high blood pressure
- high blood flow
- low resistance, small drop in pressure
98
what is the main function of arteries ?
distribution vessels
99
what is the main function of arterioles ?
resistance vessels
100
describe the structure of arterioles ?
- small diameter
- thick walls compared to diameter
- lots of smooth muscle
- smooth muscle innervated by SNS
101
describe the blood characteristics of arterioles ?
large drop in pressure and slower blood pressure
102
what is the purpose of arterioles ?
controls blood flow (vasoconstrictor and vasodilatation)
103
what does resistance do ?
decreases blood flow
104
what are the two formulas for blood flow ?
- blood flow = pressure gradient / resistance
and
- blood flow = (P1 - P2) x r^4
105
what is the formula for resistance ?
Lη / r^4
106
what is the main function of capillaries ?
exchange vessels
107
describe the structure of capillaries ?
- one endothelial cell thick
- very thin walls
108
describe the blood characteristics of capillaries ?
- low blood pressure, small drop in pressure
- very low blood velocity
- huge total cross-sectional area for diffusion
- blood flow is very slow
109
what is the purpose of capillaries ?
to exchange gasses, nutrients, etc.
110
what does more cross-sectional area = ?
slower flow
111
what does slower flow =
maximize exchange
112
between mean blood velocity and total cross sectional area which is highest / lowest for capillaries ?
capillaries highest = for total cross sectional area
and
capillaries lowest = mean velocity
113
what is filtration ?
movement of fluid OUT of a capillary
114
what is reabsorption ?
movement of fluid INTO a capillary
115
what are the four starling forces ?
1. capillaries hydrostatic pressure
2. interstitial fluid hydrostatic pressure
3. capillary plasma osmotic pressure
4. interstitial fluid osmotic pressure
116
which two of the four starling forces go IN to the capillary ?
capillary plasma osmotic pressure and interstitial fluid hydrostatic pressure
117
which two of the four starling forces go OUT of the capillary ?
capillaries hydrostatic pressure and interstitial fluid osmotic pressure
118
if the net filtration pressure is a positive number, what does this mean ?
filtration
119
if the net filtration pressure is a negative number, what does this mean ?
rebsorption
120
what is the formula for net filtration pressure ?
(out + out) - (in + in)
121
describe the structure of veins ?
- valves
- large diameter
- very thin walls compared to diameter
- some elastic fibers and smooth muscles
- SNS innervates smooth muscles
122
describe the blood characteristics of veins ?
- very low blood pressure
- medium blood velocity
123
why do we regulate blood flow
- increase blood supply to active tissues and decrease it to inactive tissues
- maintain blood supply to vital organs (heart and brain at all times)
- maintain blood pressure (MAP)
- increase/decrease heat loss from the body by redistributing blood
124
between vasoconstriction and vasodilation, which has less/more flow ?
vasoconstriction = less flow
vasodilation = more flow
125
what are the three mechanics used to regulate blood flow ?
1. local (intrinsic)
2. humoral (extrinsic)
3. neural (extrinsic)
126
what is local (intrinsic) ?
tissue environment (temp, gasses and pressure)
127
what is humoral (extrinsic) ?
substances in blood
128
what is neural (extrinsic) ?
nervous system
129
what are the two autoregulatory mechanisms of local (intrinsic) ?
1. myogenic theory (muscle stretch)
2. metabolic. theory (metabolic needs)
130
what is the 5 steps of myogenic theory ?
- sudden increase in blood pressure
- this stretches walls of arterioles
- smooth muscle in arteriole walls contracts (reflex)
- vasoconstriction
- decrease blood flow and pressure AFTER constriction
131
what does the metabolic theory do to CO2 and O2 ?
increases CO2 and decreases O2
132
what does vasoconstriction and vasodilation do to blood pressure ?
vasoconstriction = will RAISE blood pressure
vasodilation = will LOWER blood pressure
133
the neural (extrinsic) mechanism is further divided into ...
the autonomic nervous system which is ; the sympathetic and parasympathetic nervous system
134
what are baroreceptors ?
- they monitor blood pressure
- located in walls of aortic arch, carotid sinuses
- send action potentials back to CV central in medulla of brainstem
