A & P - Cardiovascular system Flashcards
(127 cards)
1
Q
name the three blood vascular systems
A
systemic
pulmonary
lymphatic
2
Q
what are the functions of the cardiovascular system?
A
deliver gases, nutrients and hormones to cells
removes waste products
3
Q
what does the cardiovascular system consist of?
A
blood - suspends substances
circulatory systems
the heart - pump
4
Q
which direction does the blood travel in blood vascular systems?
A
away from heart via arteries and returns via veins
5
Q
what connects arteries and veins and what function does it serve?
A
capillaries - site of gas and nutrient exchange
6
Q
what does the systemic circulation do?
A
delivers blood to most body tissues
7
Q
describe how blood travels around the systemic system and where it is oxygen rich and low
A
oxygen rich blood travels from left of heart and returns low in oxygen to the right side
8
Q
the systemic circulation is a high pressure system?
A
true
9
Q
what is the arterial pulse?
A
heart rate
10
Q
where would you take the arterial pulse?
A
where a superficial artery can be pressed against bone
- carotid
- radial
- ulna
- facial
- temporal
- dorsalis pedis
- posterior tibial
11
Q
describe how blood travels around the pulmonary circulation
A
delivers low oxygen blood from right side of heart to lungs, returns oxygen rich blood to left side of heart
12
Q
the pulmonary circulation is a low pressure system?
A
true
13
Q
name the three layers of the blood vessel, inner to outer
A
tunica intima - endothelium
tunica media - muscle layer
tunica externa - connective tissue
14
Q
what is the function of a blood vessel?
A
to endure changes in pressure
move with surrounding structures
remain open under all conditions
15
Q
name the three vessels of the blood vascular system
A
arteries
microcirculation
veins
16
Q
name three types of artery an it function
A
elastic
muscular
arterioles
17
Q
name two types of microcirculation vessels
A
venules
capillaries - continuous, fenestrated or sinusoid
18
Q
where can elastic arteries be found?
A
aorta
brachiocephalic
common carotid
19
Q
how does the structure of elastic arteries help its function?
A
thick tunica media with elastic fibres helps withstand continuous changes in pressure
20
Q
how does the structure of muscular arteries help their function and where are they found?
A
lots of smooth muscle in tunica media and thick tunica externa helps distribute blood to muscles and organs.
most named arteries are muscular arteries
21
Q
how does the structure of arterioles help their function?
A
1-2 layers of smooth muscle in tunica media make arterioles capable of vasoconstriction/dilation
22
Q
where would fenestrated capillaries be found?
A
kidneys
23
Q
where would sinusoid capillaries be found?
A
liver
24
Q
what is a capillary bed supplied by?
A
metarteriole
25
how many capillaries does a metarteriole contain?
1-10
26
what is the function of a metarteriole?
connect arterioles with venules
27
what controls the flow of blood to individual capillary beds?
precapillary sphincter
28
what forms a direct connection between arterioles and venules?
arteriovenous anastomoses
29
what is the function of the arteriovenous anastomoses?
to bypass the capillary bed and divert blood flow to venous circulation
30
what is the function of venules?
to collect blood from capillary beds and deliver to small veins
31
describe three properties of veins
thin walled
easily distensible
holds 54% of total blood volume
32
what does the lymphatic system consist of?
network of lymph vessels
lymph
lymphatic tissue and organs
33
what are the functions of the lymphatic system?
involved in body's defence mechanism
| provides drainage of interstitial fluid
34
fluid moves in and out of the capillary but how much fluid remains in the interstitial space?
app. 15%
35
what happens to the excess fluid left in the interstitial space?
enters the lymphatic system via the lymphatic capillary
36
what happens if the drainage of fluid by the lymphatic system isn't working properly?
oedema
37
what is the function of the lymph nodes?
to filter fluid - pick up foreign bodies to produce immune response
38
which areas of the body drain into the right lymphatic duct?
right side of head and right upper limb
39
which vein does the right lymphatic duct drain into?
right subclavian vein
40
which vein does the thoracic duct drain into?
left subclavian vein
41
where is the heart located?
between 2nd and 5th ribs, in the thorax
42
name the two types of pericardium which surround the heart
fibrous pericardium
| serous pericardium
43
what is the fibrous pericardium do and what is its structure?
inelastic sac of dense connective tissue around heart
| prevents overfill
44
what is the serous pericardium do and what is its structure?
2 layers - parietal and visceral - separated by pericardial cavity (contains fluid)
prevents friction
45
name the three layers of the heart from inner to outer
endocardium - endothelium
myocardium - cardiac muscle
epicardium - visceral pericardium
46
name the four heart valves
pulmonary semilunar valve
aortic semilunar valve
tricuspid (right AV) valve
bicuspid (mitral/left AV) valve
47
how are the atrioventricular valves opened?
by blood flowing from the atria to ventricles
48
how are the atrioventricular valves anchored to the papillary muscles and why?
cordae tendinae - to prevent eversion of valves during ventricular contraction
49
how are the semilunar valves opened?
by blood being pushed from ventricles
50
how are the semilunar valves closed?
blood in aorta and pulmonary trunk backflows during ventricular relaxation pushing cusps shut
51
do semi lunar valves have cordae tendinae?
no
52
which side of the heart pumps blood from the lungs to the systemic circulation? is the blood rich or low in oxygen?
left
| oxygen rich
53
which side of the heart pumps blood from the systemic circulation to the lungs? is the blood oxygen rich or poor?
right
| oxygen poor
54
what does the coronary circulation supply?
the outside of the heart - allows it to contract
55
how much blood does the coronary circulation receive per minute?
250ml/min
56
when is the blood supplied to the myocardium?
during ventricular relaxation
57
what is the position of the left coronary artery (LCA) ?
anterior interventricular and circumflex
58
what is the position of the right coronary artery (RCA) ?
marginal artery
| posterior interventricular
59
where do most cardiac veins drain into?
coronary sinus then right atrium
60
where does the anterior cardiac vein drain into?
directly into right atrium
61
how are cardiac cells interconnected?
by intercalated discs containing gap junctions
62
what are the function of gap junctions between cardiac muscle cells?
to promote coordinated contraction
63
cardiac cells act as a functional syncytium, what does this mean?
the cells function as one - contract together
64
is cardiac muscle auto-rhythmic?
yes - it contracts on its own
65
what is the function of the conducting system in the heart?
coordinates heart contraction
66
what does the conducting system in the heart consist of?
non- contractile cells that initiate electrical impulses
67
name 5 areas of the conducting system
- sinoartrial (SA) node
- artrioventricular (AV) node
- AV bundle (bundle of His)
- right and left bundle branches
- Purkinje fibres
68
what is the function of the SA node?
sets rhythm of heart
69
describe the contraction of the heart
SA node spontaneously reaches threshold
impulse spreads through atria
impulse passes through remainder of heart via conducting system
70
what modifies the rate of the heart?
ANS (would be 100b/p/m but modified to 60-80b/p/m
71
on an electrocardiogram what does the P wave represent?
depolarisation of atria (contracting phase)
72
on an electrocardiogram what does the QRS complex represent?
depolarisation of ventricles (contracting phase)
73
on an electrocardiogram what does the T wave represent?
repolarisation of ventricles (relaxed phase)
74
describe two differences between foetal circulation and post birth circulation
oxygen and nutrients via placenta and umbilical cord
| lungs need bypassing as not functional
75
name the 3 circulatory shortcuts in foetal circulation
ductus venosus
foramen ovale
ductus arteriosus
76
what is the function of the ductus venosus?
to connect the umbical vein to the inferior vena cava
77
what is the function of the foramen ovale?
connects the right and left atria
78
what is the function of the ductus arteriosus?
connects the pulmonary artery to the arch of aorta - by passing lungs
79
what causes the foramen ovale to close at birth?
pressure increases in systemic circulation on left side of heart
pressure falls in pulmonary circulation on right side of heart forcing formen ovale closed
80
why does the ductus arteriosus close?
fall in pressure in pulmonary trunk
81
what happens when the umbicial vessels close?
rise in pressure in aorta
82
explain the events of the cardiac cycle during one heart beat
1. ventricular filling (passive)
2. ventricular filling (atrial systole)
3. isovolumetric contraction
4. ventricular ejection
5. isovolumetric relaxation
83
what happens during the 1st stage in the cardiac cycle ventricular filling (passive)?
atria and ventricles relaxed
AV valves open
semilunar valves shut
blood flows into atria through AV valves into ventricles
84
what happens during the 2nd stage in the cardiac cycle ventricular filling (atrial systole)?
atria contract forcing blood into ventricles
85
what is the diastolic volume at the end of the 2nd stage in the cardiac cycle?
~ 130ml
86
what happens during the 3rd stage in the cardiac cycle isovolumetric contraction?
atria relax, ventricle contract
AV and semilunar valves closed
blood volume in ventricles unchanged
87
what does the closure of the AV valve produce?
1st heart sound - lubb
88
what happens during the 4th stage in the cardiac cycle ventricular ejection?
ventricular pressure exceeds aortic and pulmonary pressure - force semilunar valves open
blood forced into aorta and pulmonary trunk
89
what is the systolic volume at the end of the 4th stage in the cardiac cycle?
~ 60ml
90
what happens during the 5th stage in the cardiac cycle isovolumetric relaxation?
ventricles relax
semilunar valves close
AV valve remains closed
volume in ventricle unchanged
91
what does the closure of the semilunar valve in the 5th stage of the cardiac cycle produce?
2nd heart sound - dubb
92
what is the cardiac output and how is it measured?
volume of blood expelled by heart per minute
cardiac output = stroke volume * heart rate
CO= SV * HR
93
how do you calculate the stroke volume?
use the diastolic volume minus the systolic volume to get the stroke volume
eg. 130-60 = 70ml/b (SV)
94
name three things that affects the stroke volume
degree of stretch in myocytes (preload)
forcefulness of contraction (contractility)
pressure required to eject blood (afterload)
95
what determines the preload?
end diastolic volume (EDV)
96
what is end diastolic volume determined by?
venous return (VR)
97
what is venous return determined by?
volume of circulating blood
98
what aids venous return?
pressure gradient between veins and heart
respiratory pump
skeletal muscle pump
gravity
99
what increases forcefulness of contraction in the heart?
noradrenaline
adrenaline
hypercalcaemia
100
what reduces forcefulness of contraction in the heart?
hyperkalaemia
hypocalcaemia
myocardial hypoxia
myocardial hypercapnia
101
why must the pressure in the ventricles be higher than in the arteries?
to open semilunar valves
102
what are the average resting heart rates for a newborn, young adult and adult?
newborn - ~ 120bpm
YA - ~ 64 - 80 bpm
A - ~ 60 bpm
103
if an adults resting heart rate was above 100bpm what would they be suffering from?
tachycardia
104
if an adults resting heart rate was below 60bpm what would they be suffering from?
bardycardia
105
where is the heart rate modified? what would it be without modification?
cardiac centre - medulla oblongata
| SA node spontaneously fires at 100bpm
106
what does the cardioaccelerator centre do to the heart rate?
send sympathetic impulses to increase firing rate at SA node
| also increase force of contraction in cardiac muscle
107
what does the cardioinhibitory centre do to the heart rate?
sends parasympathetic impulses via vagus nerve to reduce firing rate at SA node
108
what is blood pressure?
the force that blood exerts on the walls of blood vessels
109
what is systolic blood pressure (SBP)?
max pressure when ventricles contract (~120mmHg)
110
what is diasystolic blood pressure (DBP)?
max pressure when ventricles relax (~80mmHg)
111
how do you work out the pulse pressure?
SBP - DBP (~40mmHg)
112
how do you work out mean arterial pressure?
DBP + 1/3 of pulse pressure
| eg. 80+ 40/3 = 93mmHg
113
what is used to measure blood pressure?
sphygmomanometer
114
when would you be suffering from hypertension?
chronic resting BP above 140/90mmHg
115
when would you be suffering from hypotension?
chronic low resting BP
116
how is blood pressure calculated?
BP = cardiac output * total peripheral resistance (TPR)
| (stroke rate HR)
117
what determines total peripheral resistance?
viscosity - stable
vessel length - unchanged
vessel radius - TPR adjusted by altering vessel radius
118
what system controls vessel radius?
sympathetic nervous system
119
in what state are the blood vessels usually maintained in by the SNS?
partial vasoconstriction (sympathetic tone)
120
which area of the SNS controls vessel radius?
vasomotor in medulla oblongata
121
name three controls of blood pressure
local control
short term control - neutral
long term control - hormonal
122
what happens during local control of blood pressure
autoregulation - ability of tissue to regulate own blood supply
123
which substances control local control of blood pressure and what role do they play?
metabolites - stimulate vasodilation
vasoactive chemicals - stimulate vasodilation
endothelins - stimulate vascoconstriction
124
name two baroreceptors involved in short term control of blood pressure
carotid sinus
| aortic sinus
125
name three cardiovascular centres which are involved in short term blood pressure control and what they do
vasomotor centre - vasoconstriction to increase TPR
cardiac accelerator centre - increase HR and force of contraction
cardiac inhibitory centre - reduce HR
126
explain the response of the baroreceptors to increased BP
-increased firing to cardiac and vasomotor
increased PNS activity, reduced HR
-inhibits cardioaccelerator, reduces SNS activity, reduce HR and vasodilation
127
explain the response of the baroreceptors to decreased BP
reduced firing rate to cardiac and vasomotor centres
