Physiology 1 Flashcards
(35 cards)
What is the purpose of the cardiovascular system?
To provide tissues with oxygen and nutrients, remove metabolic waste, and transport substances by bulk flow.
This includes carbon dioxide (CO2), H+ ions, hormones, and heat.
What are the main components of the cardiovascular system?
The heart and blood vessels (arteries, arterioles, capillaries, venules, veins).
The system contains approximately 4-6 L of blood.
What is pulmonary circulation?
Carries blood from the heart to the lungs and back.
Right ventricle to pulmonary arteries (deoxygenated), pulmonary capillaries (O2 picked up, CO2 off-loaded).
What is systemic circulation?
Carries blood from the heart to body organs and tissues and back to the heart.
Left ventricle pumps oxygenated blood to the aorta and branches.
What are the characteristics of the pulmonary circulation?
Low resistance to flow, lungs do not compete with systemic organs for blood flow.
The pulmonary circuit is a low energy circuit.
What is the significance of vascular beds arranged in parallel?
Allows for independent control of blood flow to individual organs and lower total resistance.
This is contrasted with series arrangements which would increase resistance.
Fill in the blank: The ________ circulation includes the liver, GI tract, spleen, and renal system.
splanchnic
What are capacitance vessels?
Veins and venules where the highest volume of blood is found.
These vessels store blood and can adjust their volume.
What happens to blood flow velocity as blood moves from the aorta to the capillaries?
Blood flow velocity slows down significantly in the capillaries.
Aorta: ~150 cm/sec, arteries: ~20 cm/sec, capillaries: ~0.05 cm/sec.
True or False: The total cross-sectional area of the capillaries is lower than that of the arteries.
False
The total cross-sectional area of capillaries is higher, approximately 1000 cm².
What is the average diameter of a capillary?
8 µm
What factors influence blood flow in relation to oxygen consumption?
Blood flow correlates well with oxygen consumption in organs like skeletal muscle, liver/gut, and brain.
Less correlation is seen in skin, kidneys, and heart muscle.
What happens during vasoconstriction?
The diameter of blood vessels decreases, reducing blood flow to specific areas.
What is flow autoregulation?
The ability of blood vessels to maintain consistent blood flow despite changes in perfusion pressure.
What is the role of the heart in the cardiovascular system?
Pumps blood throughout the body, maintaining circulation.
Describe the pressure characteristics in the cardiovascular system.
Ventricles: 0 to max; arteries: pulsatile; arterioles: major drop; capillaries, venules, veins: non-pulsatile.
How many capillaries are approximately present in the human body?
~5 x 10^9
What is the diameter of the aorta?
~2.5 cm
What are the two main veins returning blood to the heart?
Vena cavae
Their diameter is approximately ~3.2 cm.
What is the total cross-sectional area at the level of the capillaries?
1000 cm2
Which has a higher total cross-sectional area: venules and veins or arterioles and arteries?
Venules and veins
Is blood flow the same in all parts of the cardiovascular system?
Yes
What is the maximum blood flow velocity in the aorta?
~150 cm/sec
What is the mean blood flow velocity in arteries?
~20 cm/sec
