Ch1 Overview of the circulation Flashcards
What is the duration of systole during the cardiac cycle? A.) 2/3 of the cardiac cycle B.) 1/3 of the cardiac cycle C.) 1/2 of the cardiac cycle D.) 3/4 of the cardiac cycle
B.) 1/3 of the cardiac cycle
What is the duration of Diastole during the cardiac cycle? A.) 2/3 of the cardiac cycle B.) 1/3 of the cardiac cycle C.) 1/2 of the cardiac cycle D.) 3/4 of the cardiac cycle
A.) 2/3 of the cardiac cycle
What is the partial pressure of oxygen (Po2) in the pulmonary capillary bed? A.) 100 mmHg B.) 40 mmHg C.) 46 mmHg D.) 75 mmHg
A.) 100 mmHg
What is the partial pressure of carbon dioxide (Co2) in the pulmonary capillary bed? A.) 100 mmHg B.) 40 mmHg C.) 46 mmHg D.) 75 mmHg
B.) 40 mmHg
Partial pressures of the gases dissolved in the pulmonary capillary bed at the end of expiration must be equal to atmospheric pressures (760 mmHg). What are they?
Po2 = 100mmHg
Pco2 = 40 mmHg
Water vapor PH2O = 47 mmHg
Nitrogen PN2 = 573 mmHg
Oxygenated blood carries roughly how much oxygen at a Po2 of 100 mmHg? A.) 100 mL/O2/L B.) 400 mL/O2/L C.) 300 mL/O2/L D.) 200 mL O2/L
D.) 200 mL O2/L
Once blood makes its way into the tissue beds, how much oxygen does it unload ? A.) 10% B.) 25% C.) 35% D.) 45%
B.) 25%
and then takes up an additional burden of carbon dioxide.
What is the average Po2 of blood in the venules leaving the tissues? A.) 20 mmHg B.) 30 mmHg C.) 40 mmHg D.) 50 mmHg
C.) 40 mmHg
What is the average PCo2 of blood in the venules leaving the tissues? A.) 20 mmHg B.) 30 mmHg C.) 40 mmHg D.) 46 mmHg
D.) 46 mmHg
The aorta and large arteries are;
low volume and high pressure
The venules and veins are;
high volume and low pressure
Efferent (motor) nerves in the SNS controls what ?
arteriolar resistances outside of the brain, heart, and lungs.
Arterial pressure is continually monitored by what?
Arterial Baroreceptors located in;
Carotid sinuses at the bifurcations of the common carotids and in the arch of the aorta
What happens when the arterial baroreceptors detect an increase in arterial pressure?
Produces an increase in in impulses in the Afferent (sensory) nerves serving these structures.
High pressure detection in the carotid sinus sends signal through where?
Glossopharyngeal nerves to the brain (9th cranial nerve)
High pressure detection in the aortic arch generates what ?
Increase in Afferent traffic in sensory fibers contained within the vagus nerve. (10th Cranial Nerve).
Increase in B/P =
Medullary center send less Efferent impulses via the sympathetics to the arterioles and the structures relax a bit, bringing the pressure down.
Decrease in B/P =
Baroreceptors send fewer impulses to the medullary CV centers, resulting in more sympathetic efferent impulses which leads to more arteriolar constriction.
Q =
Quantity per time
Kidneys receive what % of cardiac output? A.) 100% B.) 75% C.) 50% D.) 25%
D.) 20 - 25% of flow at rest
1 L/m during exercise
Lungs receive what % of cardiac output? A.) 100% B.) 75% C.) 50% D.) 25%
A.) 100% ( The entire 5L/minute) of C.O.
What is the average cross-sectional area of the average human aorta? A.) 4.5 cm2 B.) 5.5 cm2 C.) 6.5 cm2 D.) 7.5 cm2
A.) 4.5 cm2
The fastest linear blood velocities are found in the Aorta because 5,000 cm3/min must pass through a narrow orifice of 4.5 cm2 area. What does this calculate into?
5,000/4.5 = 1,111 cm/min or 185 mm/sec
What is the linear blood velocity at the arteriolar level? A.) 185 mm/sec B.) 0.19 mm/sec C.) 2.1 mm/sec D.) 46 mm/sec
C.) 2.1 mm/sec
What is the linear blood velocity at the tissue capillary level? A.) 185 mm/sec B.) 0.19 mm/sec C.) 2.1 mm/sec D.) 46 mm/sec
B.) 0.19 mm/sec
This is similar to the capillary beds of the lungs.
What is the linear blood velocity at the Vena Caval level? A.) 185 mm/sec B.) 0.19 mm/sec C.) 2.1 mm/sec D.) 46 mm/sec
D.) 46 mm/sec
Where does the largest pressure gradient occur within the circulation ?
Across systemic arterioles
where a drop of 60 mmHg is common.
What is the mean pressure of the distal end of the arterioles which perfuses the capillary bed?
35 mmHg
The mean pressure of the distal end of the arterioles which perfuses the capillary bed is 35 mmHg.
What is the final pressure as blood enters the venules?
7 mmHg
What are the typical pressures in the RV?
22/0 mmHg
What are the typical pressures in the PA?
22/8 mmHg
15
What is the pressure gradient perfusing the lung? A.) 4 mmHg B.) 15 mmHg C.) 11 mmHg D.) 25 mmHg
C.) 11 mmHg
What is the pressure gradient perfusing the systemic circulation? A.) 4 mmHg B.) 15 mmHg C.) 11 mmHg D.) 95 mmHg
D.) 95 mmHg
