CVS.2 Flashcards
1
Q
what is the key role of the circulatory system
A
provide nutrients and remove waste
2
Q
what does the circulatory system require
A
driving force (heart)
conduit system (vascular bed) e.g. arteries, capillaries, veins
3
Q
what are the two juxtaposed systems
A
systemic (rest of body) and pulmonary (lungs)
4
Q
what is the route that blood takes from the left atrium to right ventricles for the systemic circulation
A
ventricle to aorta to arteries to arterioles to capillaries to vena cava to right atrium
5
Q
what is the route that blood takes for the pulmonary circulation
A
right atrium and ventricle to pulmonary artery to arterioles to capillaries to venules to pulmonary vein to LA to LV
6
Q
what is the equation for blood flow
A
Q= change in pressure gradient/ resistance
7
Q
if there is a bigger diameter e.g. the garden hose is wider what does this mean for resistance and blood flow
A
R= lower (flow can easier get through)
Q = Higher
8
Q
what is blood flow proportional to
A
pressure gradient
radius
9
Q
what is blood flow inversely proportional to
A
resistance
length
viscosity
10
Q
the walls of all types of blood vessels contain
A
endothelium
11
Q
what will decrease blood flow
A
decrease pressure gradient and decrease radius
12
Q
what % of blood volume is in veins
A
40$ - largest proportion
13
Q
if decrease area what does this mean for velocity
A
increase
14
Q
when is there the larges pressure changes
and this is also when pulsatile flow decreases
A
arterioles
15
Q
if the capillary thin wall what does this mean for diffusion distance
A
small
16
Q
if there is low velocity what does this mean for diffusion
A
longer time
17
Q
as branching is reduce as blood flows back to heart what does this mean for cross sec area
A
decrease
18
Q
when is the pressure lowest
A
right atrium
19
Q
what system does blood pressure lowest and pulsatile flow decreases
A
pulmonary circuit
20
Q
do arteries have high elastic tissue or high smooth muscle
A
high elastic
21
Q
high smooth muscle is seen more in arterioles or arteries
A
arterioles
22
Q
are arterioles involved in contraction/relaxation or elastic roil
A
contraction/ relaxation
23
Q
what are the two functions of elastic arteries
A
- distribute blood
- pressure reservoir
24
Q
when does recoil happen - during diastole or systole
A
diastole
25
when does stretching and store of potential energy occur
systole
26
how is the cardiac cycle important for blood flow
maintain arterial flow
27
arteries have a high compliance
- in ageing and CVD if decrease compliance and increase stiffness then what does this mean for blood flow
dysregular
28
what are the two main function of arterioles
1. determinant of resistance
2, controlling regional blood flow
29
do arterioles vasocontrict or vasodilate
vasoconstriction
30
what is the diastolic pressure
minimum pressure just before ventricles contract
31
when is the systolic pressure
maximum arterial pressure during peak ventricular ejection
32
what is the calculation for MAP
diastolic pressure + 1/3 x (SP-DP)
33
if blood pressure is lower 90/60mmHg
hypotension
34
what is a critical homeostatic variable
MAP
35
what does arterial pressure depend on
blood flow (Q)
Total peripheral resistance (TPR)
36
explain regional blood flow
blood flow is distributed across the body to different vascular beds to match demand - MAP remains stable
37
in blood distribution what are there changes in
resistance and flow
38
compared to the aorta, arterioles have a _____ diameter and _____ elastic tissue
smaller and less
39
what will decrease mean arterial blood pressure
reducing total peripheral resistance
- think of the equation of MAP=Q = TPR
40
in sympathetic NS what does noradrenaline bind to
- and what does it lead to
binds to a-adrenergic receptors
leads to vasoconstriction
41
low numbers of a-adrenergic receptors in brain means what for vasoconstriction
limited
- need constant flow
42
what areas of the body have high numbers of a-adrenergic receptors
skin and GI
43
what oxide relaxes smooth muscle
nitric oxide
44
what areas of the body have specialised innervation system of vasodilation
GI system
Reproductive (penis)
45
in hormonal control constriction and dilation have what hormone
adrenaline
46
what hormone does skin predominantly have and what vaso is this
more alpha that beta
vasoconstriction
47
what hormone does skeletal muscle predominantly have and what vaso is
more beta
vasodilation
48
what is it called when hormones play a role in long-term regulation
vasoactive
49
what two hormones are control long term of CO with increaseing BV
- antidiuretic - increase H2O reabsorption
- Angiotensin 11 - stimulate Na+ reabsorption
50
what is the hormone for long term control of cardiac output of decrease Blood volume and what does it do to water
Artial natriuretic peptide - decrease H2O reabsorption
51
local factors such as active hyperaemia and flow auto-regulation can alter what
vascular diameter
52
local factors are autoregulation what does this mean
self-regulating
no nerves or hormones involved
53
active hyperemia leads to whar vaso
meaning what for blood flow
vasodilation
- blood flow is increased
54
active hyperemia change blood to match what
changes in local metabolism
55
flow autoregulation is the control of blood flow to maintain what
flow with changes in perfusion pressure
56
autoregulation helps to maintain what
steady blood flow
57
in flow autoregulation
if decrease pressure then what does this mean for vaso
vasodilation
58
in flow regulation
increase pressure (smooth muscle)
vasoconstriction
59
direct sympathetic stimulation of systemic arterioles can cause
vasoconstriction mediated by a-adrenergic receptors
60
the aorta and large arteries maintain the flow of blood during diastole BECAUSE the strong elastic recoil of the arterial walls force blood away from the heart as aortic valve shut
- both true and causally related
61
what is smaller capillaries or veins
capillaries
62
what are the capillaries made up of
endothelium only
63
what is smallere venule, vein or vena cava
venule -> vein -> vena cava
63
capillaries have large total cross-sectional area what does this mean for blood velocity
very low
64
what is the main function of capillaries
exchange of nutrients and metabolic end products
64
what are venules made up of
fibrous tissue and endothelum
64
capillary hydostatic pressure is responsible for H2O out or in the capillary
ouut
64
what does capillary circulation controlled by
local metabolic factors, precapillary and metarterioles
65
osmotic force is responsible for H2O out or in the capillary
in o capillary
66
intersitial fluid hydostatic pressure responsible for putting H2O in or out of capillary
in
67
osmotic force due to interstitial fluid protein concentration resposible for H2O in or out
out
68
capillary osmotic pressure also known as
albumin
69
what does the balance of fluid depend on
location
69
what are the most important determined of capillaries fluid exchange
capillary hydrostatic and osmotic (capillary)
69
for capillary hydrostatic pressure what is the major determinant in the small arterioles
resistance - upstream
70
of the blood vessels, capillaries have the _____ cross-sectional area and the ______ blood flow velocity
highest, lowest
70
what increases net filtration = OUT
decrease hydro and increase osmotic
70
what increase net (re) absorbtion - IN
decrease hydro and increase osmotic
71
what tissue are involved in net filtration
kidney
72
what is the function of the veins
high capacitance vessels which mean blood volume reservoir
73
veins initally increase in pressure which mean there is a large increase in ___
volume
74
when noreadrenalin binds to a= adrenergic recptors what veno and does this increase or decrease flow
venoconstriction
increase flow
75
when does pressure differ - when standing up or lying down
standing - blood pools to lower limb
- increase with distance below heart
76
what prevent venous pooling
vein valves
77
what is it called when blood flows in both direction adn valves in the leg are damaged
varicose vein
78
does inhalation or exhalation facilitate venous return
inhalation
79
increase _____ and decrease ______ in inhalation
increase intra-abdominal
decrease intrathoracic
80
exhalation with diaphragm relaxing - prevent backflow or facillitae venous return
valves prevent back flow
81
fluid movement across a capillary wall is determined by the balance between capillary hydrostatic pressure and capillary osmotic pressure BECAUSE resistance in upstream arterioled is a major determinant of capillary pressure
bot true - not causally related
82
what amount of mmHg is arterial pressure homoestatically controlled at
precisely regulated at 90mmHg
83
in the negative feedback - homeostatic control loop what happens first afferent or efferent pathway
afferent (remember SAME)
84
what MABP receptor is in the aortic and carotid sinus
barorecpetors
85
what are baroreceptors
pressure
86
what cells in the arterial walls can respond to both increase and decrease of blood pressure
stretch sensitive cells
87
if increase in MAP what does this mean for stretch
increase stretch
88
what does the carotid baroreceptor feed into aortic or carotid sinus nerve
carotid sinus
89
when is there tonic activity
at rest
90
change in baroreceptor stretch means what
change in action potential frequency in afferent nerves
91
increase MAP means what for stretch
increase stretch and increase action potentials
92
why does there need to be rapid pulsatile discharge in cardiac cycle
short -term regulator of MAP
93
the integrator has the nucleus tractus solitatius where is this located
in the medulla
94
what is the integrator role
collect info
95
for both symp and parasymp - efferent output what is the order
pre-ganglionic to post-ganglionic
96
where does the efferent out put go for sympathetic
ganglia - down spinal
97
where does the efferent out put go for parasympathetic
to heart
98
in the automic nerve output low pressure goes to symp or parasymp
symp
- wanting to lower pressure
99
what occurs in response to an increase in MABP
decrease contractility
increase vasodilation
decrease HR
100
what is haemorrhage
lose of blood
101
what are the 3 stages of restoration for haemorrage
1. baroreflex
2. cardiovascular volume restoration
3. TBV restoration
102
what is an immediate response for haemorrhage
baroflex
103
what are three important things that effect MABP
- decrease venous return
- decrease CO
- decrease arterial blood pressue
104
in long term restoring of blood volume from haemorrahage what hormone is involved
increase renin-angiotensin- aldostron system
105
in long term restoring of blood volume from haemorrahage what what do you increase and decrease of renal
decrease renal perfusion pressure
increase renal sympathetic stimulation
106
what does an increase in renin lead to
increase in Ang 2 = increase in vasoconstriction
107
activation of baroreflec due to a drop in mean arterial blood press will result in
increase sympathetic nerve activity and vasoconstriction
108
is the barorecpetor are tonically inactive at rest
false
109
at rest arterial bp is mainatined at 120/80 ro inactivate the barorecptor
false
110
regulation of blood flow is not _____ for all organs. some vasular beds are _____
uniform
specialised
111
coronary arteries delievery blood where
to the heart
112
what surface are large vessl on
epicardial surface
113
where do smaller vessels penetrate into
myocardium
114
what amount of cardiac output does the 1st tissue perfused in the systetmic circualtion
5%
115
___ of aorta during diastole due to elastic tissue helps perfuse coronary arteries
recoil
116
low or high resistinac conduit vessles at epicardial surface
Low
117
cardiac muscle is what metabolidm and does every cell have capillary close
onley aerobic
- yes every
117
skeltal muscle is what metabolidm and does every cell have capillary close
aerobic and anaerobic
- no
118
where does coronary veins drain deoxgenative blood into
right atrium
119
coronary circulation is _____ and _____ circualtion in body
first and shortest
120
what is the function of the coronary sinus
collect blood from cardaic vein
- empties int RA
121
how musch or myocardial perfusion occurs during diastole
75%
122
what is the myocardium perfusion dependent on
aortic pressure
123
with increase O2 demand heart metabolism can't be compromised what does this mean
limited abilty to extract more
124
how many times higher is vasodilator reserver capacity
5 x
125
what effect of SNS i overcome by metabolic autoregulation
transient
126
what is the primary regulator of coronary flow
active hyperemia
127
if increase O2 consumption what vaso is this needed
vasodilation
128
what 2 metabolic messengers lead to vasodilation
nitric oxide, adenosine, hypoxia
129
what is hypoxia
low oxygen demand
130
the circumflex coronary supplies what area of heart
left atrium and posterior left vnticale
131
high flow, low pressure, low resistance, high compliance are part of what circulation system
pulmonary
132
what does low pulmonary perfusion pressure prevent
pulmonary capillary H2O loss
133
pooling of blood with gravity means what about pulmonary blood flow
high compliance
134
in the lungs the top of the lungs is postivie or negative
positive
135
what decreases and increases with the upper resiongs of the lungs
- hydrostatic pressure
- resistance
- blood flow
decrease hydrostatic pressure
increase resistance
decrease blood flow
136
what is hypoxic pulmonary vasoconstriction (HPV)
blood diverted away from poorly ventilated alveoli
137
in the endothelial regulation there is a balance between
constriction and dilation
138
n the endothelial regulation if there is a imbalance what would this lead to
pulmonary hypertension
139
alph receptors for ____ vessels and vaso____
large
vasoconstritriction
140
beta receptors for ___ vessels and vaso____
small
vasodilation
141
what is the circulation of adult and fetal
adult - series
fetal - parallel
142
what is the function of the chronic villi
1. absorb nutrients
2. remove waste
3. uptake of oxygen
143
what are the two fetal pulmonary vascular shunts that have 90% of CO flow through shunts
1. foramen oval
2. ductus arteriosus
144
how much blood uses the ductus venosus as a bypass
50-60%
145
how much O2 does the umbilical benous blood have
70-80%
146
what part of the body has higher metabolic demand
upper body of fetus
147
what areas of body in fetus receive most O2
Brain and heart
148
ductus arteriosus shunts blood from where
the pulmonary artery to aorta
149
the umbilical arteries carry what
low oxygenated blood from the fetus to the placenta
150
how does the circulation changes once given birth
lungs uptake of O2
151
what happens to the lungs when the baby first cries
inhaltion - inflate of lungs - lungs are filled with air
152
there is no more ________ vasoconstriction when lungs are filled with airs (at babies first cry)
hypoxic
153
the space around the chorionic villus contains what
- but not what
contains
- O2
- CO2
- maternal blood
Not
- fetal blood
154
pulmonary vascular resistance berfore birth is high BECAUSE oxygenated blood is shunted from right atrium to left atrium through foramen ovale
both true
- statements are NOT causally related
155
