Module 1: cardiovascular system Flashcards
1
Q
what are the 3 functions of the Cardiovascular system?
A
- transport
- homeostasis
- protection
2
Q
what are the 3 functions of the transport system in the CVS?
A
- oxygen and nutrients to cells
- wastes incluing CO2
- hormones (endocrine)
3
Q
how does the CVS achieve homeostasis?
A
- body termperature by redistributing blood
- pH levels in blood and interstitial fluid (fluid between cells)
- blood volume/pressue
4
Q
how does the CVS protect?
A
white blood cells create an immune response
5
Q
what are the 3 major structures of the CVS?
A
- Blood
- Heart
- Blood Vessels
6
Q
what are the 5 blood vessels of the CVS?
A
- arteries (blood away from the heart)
- capillaries ( exchange between blood and tissue)
- Veins (blood towards the heart)
- Arterioles
- Ventrioles
7
Q
what do the capillaries exchange between blood and tissue?
A
- nutrients
- waste products
- gases
8
Q
what does the heart serve as?
A
a pump to establish a pressure gradient
9
Q
what does the atrium do in the heart?
A
receives blood into the heart
10
Q
what does the ventricle do in the heart?
A
pumps blood out of the heart
11
Q
what does the septum do in the heart?
A
divides the heart into left and right
12
Q
what are the 4 “great vessels”
A
- Aorta
- pulmonary artery (deoxy)
- pulmonary vein (oxy)
- vena cava
13
Q
what is the function of the pericardium?
A
- maintain heart position
- prevent heart from over filling
14
Q
what is the anatomy of the pericaridum?
A
- outer fiberous pericardium
- inner serous pericardium
2a. serous has 2 layers, parietal (outer) and visceral (inner)
15
Q
what does the superior vena cava do?
A
returns deoxygenated blood from the upper half of the body to the right atrium
16
Q
what does the inferior vena cava do?
A
returns deoxygenated blood from the lower half of the body to the right atrium
17
Q
what does the pulmonary artery/trunk do?
A
transports deoxygenated blood to the lungs
18
Q
what does the aorta do?
A
distributes oxygenated blood into systemic circulation
19
Q
describe the function of coronary arteries
A
cover the entire heart to provide arterial (oxygenated) blood for coronary circulation as the heart is an organ and needs energy and oxygen to survive
20
Q
which side of the heart has a thicker wall?
A
left
21
Q
why is the left side of the heart thicker?
A
it needs a higher pressure to pump blood around the systemic circuit (all of body, minus the lungs)
22
Q
why is the right side of the heart thinner?
A
it is only pumping blood to the pulmonary circuit (lungs)
23
Q
which side of the heart has a tricuspid valve?
A
right - low pressure
24
Q
what is another name for a tricuspic valve?
A
right atrioventricular valve
25
which side of the heart has a biscuspid valve?
left - high pressure
26
what is another name for the bicuspid valve?
1. mitral valve
2. Left atrioventricular valve
27
what are papillary muscles?
muscles in the ventricles of the heart, attached to the chordae tendineae to prevent the heart from prolapsing (inversion) during contraction
28
what is the job of the chordae tendineae?
to prevent prolapse of the the valves by being attached to the cusps
29
where is the aortic semilunar valve?
between the aorta and the left ventricle
30
where is the pulmonary semilumar valve?
between the pulmonary artery and the the right ventricle
31
what is the purpose of the semilunar valve?
to prevent backflow from arteries to ventricles
32
do the semilunar valves have a chordae tendineae?
No
33
are semilunar valves bi or tricuspid?
tricuspid
34
which circulation is the left heart functioning with?
Systemic Circulation
35
which circulation is the right side of the heart functioning with?
pulmonary circulation
36
is the vena cava a vein or artery?
vein, it carries deoxygenated blood to the heart
37
is the aorta a vein or artery?
artery, it carries oxygenated blood to the systemic circuit
38
does the brain change blood supply percentage?
No, it stays at 13%
39
where is most of our blood at any point in time?
84% is in the systemic circuit
40
where is the least amount of blood at any point in time?
16% in the pulmonary circuit
41
what are the 7 components of the CVS and their function?
1. heart, atria: recevies blood returning to heart from veins
2. heart, ventricles: contracts to generate pressure for blood flow
3. arteries: moves blood to organs and tissues, without loss of pressure
4. arterioles: smaller than arteries, controls resistance to blood flow, so distribuition of blood to body
5. capillaries: substance exchange between blood and cells
6. venules: collect blood from capillaries
7. veins: returns blood to heart
42
what does the pulmonary vein do?
transports oxygenated blood from the lungs to the heart
43
recite the 10 step circuit of blood flow in the body
1. D Superior and inferior vena cava pump blood into the right atrium
2. D right atrium pushes blood into the right ventricle via the tricuspid valve
3. D The right ventricle pushes blood into the pulmonary trunk via the pulmonary semilunar valve
4. D blood travels to the lungs via the pulmonary arteries
5. D/O Gas exchange occurs in the lungs, CO2 out, O2 in
6. O blood flows into 4 pulmonary veins to left atrium
7. O left atrium pumps blood into left ventricle via the bicuspid valve
8. O blood is pumped into the aorta through the aortic semilunar valve into the systemic circuit
9. O/D Gas exchange occurs between the body via capillaries in the systemic circuit and travels back to the heart
44
what is a diastole re the heart?
a Diastole is the heart at rest, filling with blood
45
what is a systole re the heart?
a systole is the heart contracting, so pumping blood out
46
what pressure gradient does blood flow in?
High pressure to low pressure
47
what are the 4 sounds of the heart beat?
1. closure of the AV valves (mitral and tricuspid)
2. closure of semilunar valves (aortic and pulmonary)
3. rapid filling, recoil of blood on ventricular wall
4. atrial contraction (shouldn't hear in healthy person)
48
what is End Diastolic volume? (EDV)
volume of blood in the ventricle before contraction
49
what is End Systolic Volume (ESV)?
volume of blood left in the ventricle after contraction
50
what is stroke volume?
amount of blood pumped out of the heart for 1 heart beat (single contraction)
51
how is stroke volume measured?
EDV-ESV
52
what is cardiac output?
volume of blood pumped out of the heart by each ventricle per minute
53
how do you calculate Cardiac output?
Heart rate x stroke volume
54
what is preload?
the volume of blood received by the heart (stretch)
55
what is afterload?
the pressure or resistance the heart has to overcome to eject blood
56
what is the primary determinant of preload?
left ventricular EDV
57
what is the primary determinant of afterload?
the resistance in the blood vessels
58
What does sympathetic stimulation do to stroke volume?
increases it due to an increase in contractile strength of the heart
59
what effect does the parasympathetic nervous system have on the stroke volume?
Minimal effect
60
does stimulation of the sympathetic nervous system increase or decrease the contractile strength of the heart?
increases
61
what are the 2 factors that contribute to stroke volume?
1. sympathetic activity
2. Frank Starlings Law
62
what blood vessels have valves?
veins and the venous system
63
what is the purpose of valves in blood vessels?
to enable unidirectional blood flow
64
how does skeletal muscle contribute in the CVS?
skeletal muscle contracts the vessels to increase pressure, enabling blood flow
65
what is the parasympathetic division known as in the CVS?
"brake" to the heart, it reduces the heart rate
66
which ANS division is a 'brake' to the heart?
the parasympathetic
67
what are the 2 types of cell in the heart?
1. contractile cells (99%)
2. non-contractile (pacemaker) cells (1%)
68
how do pacemaker cells depolarise?
spontaneously, aka autorhythmic
69
what is a demosome?
an adhesive junction that mechanically integrates adjacent cells
70
what is a gap junction?
1. a passage within the cell that allows direct communication between cells.
2. mediates electrical coupling of cardiomyocytes (speed and direction of cardiac conduction)
3. allows passage of ions and transmission of AP
71
what is a cardiac cell also known as?
myocyte
72
How are myocytes joined together?
intercalalted disks
73
what is excitation contraction coupling?
when an electrical stimulus is converted to a mechanical response
74
describe the flow of contraction coupling in the heart
1. (electrical) AP triggers from pacemaker cell and travels to sarcoplasmic reticulum (SR)
2. SR releases Ca2+
3. Ca2+ binds to troponin, triggering the cross bridge cycle
4. cardiomyocye contacts (mechanical)
75
where are pacemaker cells mostly located?
Sinoatrial Node (SA node)
76
how does spontaneous AP occur?
through cellular drifting, the resting MP is not stable and slowly drifts to threshold due to K+ channels closing and Na+/Ca2+ leaking out
77
What are the 3 pacemakers of the heart?
1. Sinoatrial Node (primary)
2. atrioventricular Node (secondary)
3. Pirkinji Fibers (tertiary)
78
what are the inherent rhythms of each pacemaker nodes?
1. Sinoatrial Node - 70-80 AP/m
2. atrioventricular Node 40-60 AP/m
3. Pirkinji Fibers 20-40 AP/m
79
describe the spread of excitement through the heart
1. Sinotrial Node
2. atrioventricular node
3. bundle of His
4. apex of ventricle
4. Pirkinje fibers
5. rest of ventricle
80
how do the nodes support each other?
when 1 node fails, the other kicks in to become primary, in a cascade effect
81
why is there a delay in propogation in the AV node?
to allow the atrium to contract first
82
what causes ventricles to contract?
Pirkinje fibers
83
which electrical signals connect with the atria?
1. Av node
2. Bundle of His
84
is propogation from Pirkinji fibers to apex fast or slow
Fast
85
where does ventricle contraction start?
at the apex
86
what is the purpose of a plateau in cardiac AP?
1. to allow for optimal chamber emptying
2. reduces likeihood of tetanus
87
why is there a plateau in cardiac AP?
due to a balance of influx and eflux of ions
88
how does the parasympathetic system reduce depolarision (reduce heart rate)
1. opening K+ channels and less leak of NA+ an Ca2+ channels
2. hyperpolarisation
3. slow depolarisation
4. release of chemicals such as acetylcholine
89
how does the sympathetic system increase depolarision (increase heart rate)
1. opening more Na+ and Ca2+ channels
2. close more K+ channels
3. no hyperpolarisation
4. faster depolarisation due to not reaching resting
5. use of chemicals such as noradrenaline
90
which blood vessel has the largest capacity?
veins
91
what is another term for veins?
capacitance vessels
92
what blood vessels are within the microcirculation?
1. arterioles
2. capillaries
3. venules
93
what are the similarities of veins and arteries?
1. tunica: intima, media, externa
2. subenodthelial layer
3. endothelium
4. vaso vasorum
94
what is the difference of a vein to an artery?
1. has valves
2. large lumen
3. rigid
4. thick tunics externa
5. smooth muscle walls
6. carry waste and deoxygenated blood
95
what is the difference of an artery to a vein?
1. small lumen
2. has internal and external lamina to allow for flexibilty
3. can withstand high pressures and adapts (flexible)
4. thin tunica externa
5. muscular walls
6. carry oxygenated blood
96
which Tunica do capillaries have?
intima
97
what do arterioles do?
regulate blood flow into tissues
98
what is the pressure measured in?
mm/Hg
99
what is the pressure quantity of thr CVS?
1. Heart-arteries 100mm/Hg
2. arteries-capillaries 35mm/Hg
3. capillaries-veins 18mm/Hg
4. Veins-Heart <18mm/Hg
100
why is there a drop in pressure in the CVS?
due ot being further away from the heart (pump)
101
where does gas exchange occur?
in the capillaries?
102
how many veins and arteries does the pulmonary circuit have?
2 arteries (deox)
4 veins (oxy)
103
what number is systolic blood pressure?
120mm/Hg
104
what number is diastolic blood pressure?
80 mm/Hg
105
what can veins do to manage thermal regulation?
shunt blood between superficial and deep veins
106
what is the blood composition %?
55% plasma (H2O and proteins)
1% Buffy Coat (Leukocytes and platelets)
44% RBC (erythrocytes)
107
what is the formula for blood flow?
Flow= pressure gradient/resistance
F=xP/R
108
describe blood flow (F)
volume of blood per unit of time through a vessel
109
describe blood pressure
hydrostatic pressure in arterial system that pushes blood through capillary beds
110
describe circulatory pressure
pressure difference between top of aorta and entrance to right atrium
111
describe hydrostatic pressure
pressure exerted by a liquid in response to an applied force
112
describe peripheral resistance (PR)
resistance of arterial system affected by vascular resistance/turbulence/viscotity
113
describe resistance (R)
force opposing movement
114
describe total peripheral resistance (TPR)
resistance of entire CVS
115
describe turbulence
resistance due to irregular, swirling blood at high flow rates or exposure to irregular surfaces
116
describe vascular resistance
resistance due to friction in a blood vessel, walls and blood
117
describe venous pressure
hydrostatic pressure in venous system
118
describe viscosity
resistance to flow from molecule interaction
119
what is the formula for: flow directly proportional to pressure gradient?
F(DP) xP
120
what is the formula for: flow inversely proportional to resistance
F (IP) 1/R
121
what is the formula for: flow directly proportional to pressure and inverse to resistance?
F (DP) xP/R
122
what is the formula for: flow directly proportional to BP, inverse to PR
F (DP) BP/PR
123
what is the formula for: resistance inverse to fourth power of vessel radius
R (DP) 1/R^4
124
how is pressure gradient measured?
difference between 2 ends of a vessel, not abolute pressures within a vessel
125
what are the 3 factors of resistance?
1. viscocity
2. length
3. radius
126
of the 3 factors of resistance, which is the most important in terms of the CVS?
radius
127
what is the opposite of turbulence?
Laminar
128
describe Poiseuilles Law
the precise relationship between flow, pressure and resistance
129
what is Poiseuilles law used for?
to determine the level of blockage in vessels
130
when are blockages in vessels most often found?
during sympathetic activity (stress test)
131
are arteries flexed or contracted during diastole?
contracted
132
are arteries flexed or contracted during systole?
flexed
133
do arterioles have high or low resistance?
high, due to small radius
134
why is there a fall in pressure in arterioles?
distance from heart, helps with downstream blood flow
135
how is blood supply determined to the organs?
1. arteriolar resistance
2. organ vascularisation
136
how is resistance modulated in arterioles?
1. vasodialiation
2. vasocontriction
137
what intrinsic controls affect arterioles?
1. paracrines or autoregulation
2. metabolic chemical transfer (CO2, O2, H+)
3. myogenic (stretch)
138
what extrinsic controls affect arterioles?
1. nerve
2. sympathetic stimulation
3. hormones: angiotensin 2, ADH, adrenaline, moradrenaline
139
how odes gas exchange occur in capillaries?
diffusion
140
why do capillaries have a large surface area?
they're tiny but a lot of them
141
do capillaries have a high or slow vilocity?
slow, to allow more gas transfer
142
what is the purpose of a precapillary sphincter?
to control blood flow to the capillaries, depending on metabolic activity
143
what happens to precapillary sphincters during high metabolic activity?
they relax, allowing blood flow
144
what happens to precapillary sphincters during low metabolic activity?
they contract, to restric blood flow
145
describe vascular compliance
the ability of a blood vessel wall to expand and contract passively with changes in pressure
146
what factors can effect vascular compliance?
1. age
2. disease
147
what is the formula for vascular compliance?
Compliance=change in arterial blood volume/change in arterial blood pressure
C= xV/xP
148
what 2 factors determine mean arterial pressure?
1. Cardiac Output
2. total peripheral resistance
149
what is the formula for Mean Arterial Pressure?
Mean Arterial Pressure = cardiac outputx total peripheral pressure
MAP=COxTPR
150
what is a pulse?
the throb of the arteries due to difference in pulse pressure
151
what is pulse pressure?
the difference between systolic pressure and diastolic pressure
152
what factors determine arterial blood pressure?
1. elasticity of arteries close to the heart
2. volume of blood forced into arteries at any one time
153
does the heart spend more time in systole or diastole?
diastole
154
how is MAP calculated?
MAP=DP+(SP-DP/3)
155
how is blood pressure measured?
using a sphygmomanometer and listening for korotkoff sounds with a stethoscope
156
what are the 5 Korotkoff sounds?
1. no sounds due to cuff pressure exceeding 120mm/Hg
2. Pressure when sound first occurs (SP~120mm/Hg)
3. pressure when sound dissapears (DP~80mm/Hg)
4. last sound heard at DP
5. no sound due to laminar flow
157
what are the 2 main neural mechanisms due to short term control?
1. blood vessel diameter changed, to alter resistance
2. blood ditribution to organs changed
158
which 2 controls are short term pressure regulators?
1. neural
2. hormonal
159
what control is the long term pressure regulator?
Renal
160
describe the baroreceptor reflex arc
1. arterial baroreceptors detect change in pressure
2. afferent nerves send signals to medulla oblongata
3. medullary cardiovascular centre sends efferent nerves to ANS
4. heart/arterioles and veins adjust to the change in pressure
161
what is the purpose of the baroreceptor reflex arc?
to provide rapid adjustment to MAP in the event of a sudden disturbance
162
how long doe it take for the baroreceptor reflex arc to react?
seconds to minutes
163
Where are the mechanorecptors for the baroreceptor reflex?
1. Cartoid sinus (neck- to monitor blood flow to brain)
2. Aortic arch (heart- to monitor systemic circulation)
164
Where is the baroreceptor reflex send to?
Medulla cardiovascular centre
165
Where is the medulla cardiovascular centre's?
Medulla (neck) and subdivides into
1. Cardiac centre (controls heart)
2. Vasometer centre (controls blood vessels)
166
What is the baroreceptor reflex arch?
1. Drop in blood pressure is detected by the cartoid sinus or aortic arch
2. Sends affrent signals to cardiac kr vasomotor centre
3. CVS responds by constricting vessels and increase breathing ( Inc. CO2
167
Explain chemical homeostasis for blood pressure arch (long term blood pressure reduction)
1. Drop in blood pressure detected
2. Endocrine system creates more ADH/angiotensin 2/aldosterone and releases to blood stream
3. Blood pressure rises
