VASCULAR SYSTEM Flashcards
Components of the vasculature:
Arteries
Arterioles
Capillaries
Venules
Veins
______
• Thick walled, extensive elastic tissue & smooth muscle
Arteries
______
• High pressure
Arteries
Arteries
• The blood volume contained in them are called the ______
stressed volume
______
• Smallest branches of the arteries
Arterioles
______
• Site of highest resistance in the cardiovascular system
Arterioles
______
• Have smooth muscle walls which have extensive autonomic innervation
Arterioles
Arterioles
• ______ - in the skin and splanchnic arterioles
a1 adrenergic
Arterioles
• ______ - in the skeletal muscle arterioles
B2 adrenergic
______
• Have the largest cross sectional surface area
Capillaries
______
• Consist of a single layer of cells - thin walled
Capillaries
______
• Are the site of exchange of nutrients, water & gases
Capillaries
______
• Are formed from merged capillaries
Venules
______
• Progressively form larger and larger veins
Veins
______
• thin walled and are under low pressure
Veins
______
• Contains the highest proportion of blood in the cardiovascular system
Veins
Veins
• Blood volume in the veins is called the ______
unstressed volume
Veins
• Are innervated by ______
autonomic fibres
______ - greatest cross-sectional area
Capillaries
______ - Pressure varies bet. systole and diastole
Arteries
Velocity of blood flow
• Can be expressed by:
V = ______
Q/A
Velocity of blood flow
v = ______ (______)
Q = ______ (______)
A = ______ (______)
velocity, cm/sec
blood flow, ml/min
cross sectional area, cm^2
Velocity of blood flow
Therefore, velocity is higher in the ______ (smaller cross sectional area)
is lower in all the ______ - Why?
To maximize the ______
aorta, capillaries, exchange of substances
Blood flow
• Can be expressed by:
Q = ______
🔺P / R
Blood flow
Q = ______ (______)
🔺P = ______ (______)
R = ______
blood flow, ml/min
pressure gradient, mmHg
resistance
______ flow is in a straight line and ______ flow is not.
Laminar, turbulent
______ predicts whether blood flow is turbulent or laminar.
Reynold’s number
When Reynold’s number is increased, there will be ______ and ______ (bruits)
turbulence, audible vibrations
Reynold’s number is increased by:
______ (low haematocrit, anaemia)
______ (narrowing of a vessel)
reduced viscosity
increased velocity
______ (______)
• Describes the distensibility of blood vessels
Capacitance, compliance
______ (______)
• Is inversely related to elastance
Capacitance, compliance
Capacitance (compliance)
Capacitance is given by:
C = ______
V / P
Capacitance
C = ______ (______)
V = ______ (______)
P = ______ (______)
capacitance, ml/mmHg
volume, ml
pressure, mmHg
______ (______)
• Describes how volume changes in response to changes in pressure
Capacitance, compliance
Capacitance is much greater for ______ than for ______
veins, arteries
Changes in venous capacitance changes the ______
venous blood volume
decrease in venous capacitance decreases the ______ (______) and increases the ______ (______)
unstressed volume, venous volume, stressed volume, arterial volume
Capacitance of arteries ______ with age.
Arteries become stiffer and less distensible)
decreases
______
• pulsatile
• Varies during the cardiac cycle
• Systolic pressure
• Diastolic pressure
Arterial pressure
Pulse Pressure
______
• most important determinant of pulse pressure
Stroke volume
Pulse Pressure
• decrease in ______ due to aging can cause an increase of pulse pressure
capacitance
Pulse Pressure
• Generally ______ mmHg
~ 40
______
• average arterial pressure with respect to time
Mean Arterial Pressure