Cvs 2 Flashcards
Amount of blood received by each organ is a function of its ____
activity
___% of cardiac output goes to the kidney every minutes
The kidney is about ___g
25
150
The brain weighs about ___kg and receives ___liters per minute
- 6
0. 75
Blood flow in turn is regulated by the individual organ’s _______
vascular resistance
Organ vascular resistance in turn is regulated by
- Extrinsic factors (_______)
- Intrinsic Factors (_____ mechanisms)
Neurohumoral
Local regulation
Local regulation of blood flow
Tissue factors – act on _____ to alter ____ by either _____ or ______
blood vessel
resistance
relaxation or contraction.
Vasodilators or vasoconstrictors
- Adenosine
- Inorganic phosphate
- Carbon dioxide
- endothelin
- Hydrogen ion
- Potassium ion
- increased Oxygen levels
- EDHF
- prostacyclin
- nitric oxide
Dilators
Dilators
Dilators
Constrictors
Dilators
Dilators
Constrictor
Dilators
Dilators
Dilators
Smooth Muscle ( ____ ) mechanisms
- Originate within the __________
- An increase in intraluminal pressure leads to _____ to counter the effect of pressure increase and vice versa
- vascular smooth muscle ____zes when stretched
myogenic
vascular smooth muscles (VSM)
contraction
depolari
Myogenic mechanisms
•Usually overridden by _____ mechanisms
metabolic
Extravascular Compression
•______ compressive forces alters _______ and consequently blood flow in organs.
•Extravascular pressure decreases the ______ pressure
•Could be both physiological or pathological
•Important in several vascular beds, e.g coronary, skeletal, pulmonary, cerebral and renal circulation.
Mechanical
vascular resistance
transmural
Autoregulation of Blood Flow
•The intrinsic ability of an organ to _____________ despite _______
•F = (____)/ __
maintain a constant blood flow
changes in perfusion pressure.
Pa - Pv; R
The flatter the plateau of autoregulatory curve the (higher or lower?) the autoregulation in such vascular bed.
Higher
_____,_____, and _____?circulations show a higher degree of autoregulation
______ and ______only show a moderate level of autoregulation
Coronary, cerebral and renal
Skeletal and gastrointestinal
Hyperemia – increase in _____ above normal level.
blood flow
Reactive HYPEREMIA–
- (rapid or Transient?) ___ease in organ blood flow following a brief period of _____, usually due to temporary arterial occlusion
- Lasts for ______
- Due to ____ and build up of _____
- Hyperemia consequently restores ___ level and _____ the metabolites
Transient
Incre
ischemia
several minutes
hypoxia
vasoactive metabolites
oxygen; washes out
Peak hyperemia is a function of the _______ of the organ
basal metabolic activities
Increased metabolic activity ___eases vascular resistance due to vaso______
Decr
dilation
Occurs during muscular exercise – _____ hyperemia
•___eased cardiac activity
•___eased mental activity
•___eased GIT activity
exercise or functional
Incr
Incr
Incr
Vascular tone reserve is very important in active hyperemia.
T/F
T
Coronary Circulation
The left coronary main artery is relatively (short or long?) in length.
•Divides into the ______ artery and ____ artery immediately after coursing behind the ____
Short
left anterior descending
circumflex
pulmonary trunk.
Branches of the left coronary artery supply blood primarily to the _____ and ____
left ventricle and atrium
Coronary circulation
Blood flow decreases during systole and increases during diastole
T/F
T
Coronary circulation exhibits (high or low ?) autoregulatory mechanisms.
High
in diseased states coronary circulation’s autoregulation is lost.
T/F
T
Mean coronary blood flow ranges from ___ml/min/100g of tissue at rest to over ___ml/min/100g tissue during exercise.
80
400
Coronary vasculature has a relatively high or low ?) vasodilatory reserve capacity
High
Coronary blood flow is primarily regulated by changes in _____.
metabolism
In coronary circulation, which wins?
Autonomic regulation or metabolic regulation
Metabolic regulation supersedes autonomic regulation.
Cerebral Circulation
•The brain is an highly oxidative organ, it consumes about ___% of resting total body oxygen consumption
•Although it represents about __% of the total body weight it receives about __% of the CO.
20
2
15
14
Measurement of CBF(cerebral blood flow)
•____ methods
- ______ is usually the substance of choice
- CBF = ___ml/min/100g. However, brain weighs about ____g
- Therefore CBF = ___ml/min
Ketty’s
Nitrous oxide
54
1600
750
Most important regulation in the cerebral circulation is ______?
Auto-regulation
Mechanism involved in Cardiovascular Response to Exercise
•Mechanical
Anticipatory __________ control
________ and _______ pumps
•Metabolic
___________ in active exercising muscles
•Autonomic
Central command and local muscle _____ and ______
•Humoral
______ response enhanced by _____ activities
•Alteration in arterial baroreceptor
_____ to prevent reflex ______
Central command
Abdominothoracic and muscloskeletal
Local vasodilation
mechano - and chemorecetors
Delayed; sympathetic
Reset ; bradycardia
CVS DURING EXERCISE
INCREASE IN CARDIAC OUTPUT
- ____ease heart rate by ___eased sympa and (reduced or increased?) para
- ___ease stroke volume by ___eased CVP and inotropy and lusitropy
Incr
Incr
Reduced
Incr; incr
Inotropy
______ of _____
Lusitropy
Is the rate of ________
Force of muscular contraction
Myocardial relaxation
CVS DURING EXERCISE
____ease in mean arterial pressure
____ease in pulse pressure
Incr
Incr
CVS DURING EXERCISE
INCREASE IN MAP AND PP
- ___ Increases more than ____ decreases
- stroke volume ____eases ___ pressure
CO; SVR
Incr; pulse
CVS DURING EXERCISE
___ease in CVP
____ease in SVR
Incr
Decr
CVS DURING EXERCISE
INCREASE IN CVP
-(sympathetic or parasympathetic?) ; muscular pump
DECREASE IN SVR
- metabolic vaso____ in active muscles and heart
- cutaneous vaso____ (sympa)
- vaso_____ in splanchnic(non active muscle) and renal (sympa)
sympathetic
dilation; dilation
constriction
During exercise despite increased HR, SV is maintained or even increased by:
____eased venous return
By _________ and ____ pumps
Venous (constriction or dilation?)
___eased atrial inotropy
___eased ventricular inotropy
(Enhanced or depressed ?) ventricular lusitropy
Incr
abdominothoracic and muscle
Constriction
Incr
Incr
Enhanced
During exercise despite increased HR, SV is maintained or even increased by:
Concomitant (increase or reduction?) in sympathetic adrenergic
___eased sympathetic cholinergic stimulation of the cutaneous vessels influenced by ________ centers in hypothalamus
Reduction
Incr
thermoregulatory
However, the point at which increased HR begins to decrease SV varies considerably in individual according to:
Age
Health status
Physical conditioningRE
T/F
T
The limiting point in exercise is when increase in _______ ————— _______
HR decreases SV.
CVS DURING PREGNANCY
Pregnancy causes significant changes in cardiovascular system as increased uterine mass and the developing fetus required ____eased blood flow.
To supply this flow:
CO increases by ____% - __% in the _______ trimester and ____ at _____ trimester
Incr
30; 50
1st and 2nd
plateau; 3rd
Increased CO in the first half of pregnancy is due to an increase in ___ consequent of increased ________ about ___% increase by end of 3rd trimester
Mainly due to effect of ______ on RAS
SV
blood volume
50
estrogen
By 3rd trimester , increased CO is due to increased ___; ____ beats/min
Despite increased CO, ABP generally (rises or falls?) due to disproportionate fall in ___
Caused partly by ______ changes (constricting or dilating?) blood vessels
Mainly by development of (high or low?)-resistance uterine circulation
HR
10-20
falls; SVR
hormonal
Dilating
Low
In pregnancy, which falls more , SP or DP
With reason
DP falls more than SP because of fall in SVR.
In pregnancy
There is ___eased Pulse Pressure
Incr
Pregnancy alters CV response to exercise due to:
(Elevated or depressed?) CO at rest
_________ of IVC
_________ syndrome
Elevated
Compression
Supine hypotensive
HYPOTENSION AND HAEMORRHAGE
- when systolic blood pressure is less than ___mmHg and diastolic blood pressure is less than ___mmHg
- caused by ______,______, or ______
90; 60
circulatory shock, haemorrhage, dehydration
Hypovolemic hypotension due to hemorrhage or dehydration can be treated by
____easing blood volume via blood of fluid transfusion
Occasionally accompanied by administration of (pressor or depressor?) agents e.g ___-adrenoceptor agonists
Incr
Pressor
alpha
Hypotension caused by cardiogenic shock Can be treated by
use of drugs that _____ the heart –___- adrenoceptor agonist e.g _____ or
____-dependent __ inhibitor e.g_____
stimulate
beta
dobutamine
cAMP; phosphodiesterase; milrinone
Hypotension caused by septic shock can be treated with
_____ agents in combination with ____ and ____
pressor
fluid and antibiotics
KIDNEYS
- ____% of body weight
- ___% of CO at rest
- blood flow at rest is ___ml/min/100g
- max flow is ___ml/min/100g
- weak __; moderate __; strong __
BRAIN
- __% of body weight
- __% of CO at rest
- min is __
- max is ____
- weak __; strong __; strong __
0.5; 20; 400; 600
M; S; A
2; 14: 55; 150
S;A;M
HEART
- __% of body weight
- __% of CO
- min is ___
- max is ___
- weak __ that is overridden by __ ; strong __; strong __
0.5
5
80
400
SM; A; M
SKELETAL MUSCLE
- __% of body weight
- __% of CO
- min is __
- max is __
- moderate __; moderate __; strong __;
40
18
3
60
S ; A; M
SKIN
- __% of body weight
- __% of CO
- min is __
- max is ___
- weak __; weak __; strong __
3
4
10
150
A; M; S
SPLANCHNIC
- __% body weight
- __% of CO
- min is ___
- max is ___
- moderate __; moderate __; strong __
6
23
23
250
A; M ; S
Lithium oxide is used to????
Measure cardiac output
