exam 2
Areas where large proteins and cells need to enter or leave the bloodstream (e.g. liver and spleen) LOCATION
Sinusoids
Why does exercise increase venous return?
The heart beats faster and harder increasing cardiac output and pressure.
Why do fluids leave the capillaries at the arterial end?
The net filtration pressure of the blood is higher at the arterial end than it is at the venous end.
What is(are) the physiological purposes of vasoreflexes?
To cause a generalized raising or lowering of blood pressure throughout the body and to selectively modify the perfusion of a particular organ by rerouting blood from one region of the body to another
The action potential from the brain to the heart travels along which nerve(s)?
Vagus nerve
Which of the following does not aid in venous return? -The thoracic (respiratory) pump -The skeletal muscle pump -Gravity -Venule suction -The pressure gradient
Venule suction
Vasoconstriction primarily results from contraction of smooth muscle in the tunica___________
media
The net osmotic pressure is equal at both the arterial and the venous ends of the capillary.
true
Which of the following is not a mechanism that assists venous return?
Central venous pressure being greater than pressure in the venules
Most tissues (e.g. skeletal muscle) location
Continuous capillaries
How do materials get from the blood to the surrounding tissues?
Diffusion, filtration and absorption, and transcytosis
Heart rate and stroke volume decrease with a decrease in parasympathetic stimulation.
False
Increased sympathetic stimulation causes vasodilation, bringing elevated blood pressure back to normal.
False
The lymphatic capillaries reabsorb as much as 20% of the fluid lost by the blood capillaries.
False
Organs that engage in rapid absorption or filtration of small molecules (e.g. small intestine, kidneys) LOCATION
Fenestrated capillaries
Action potentials are conducted from the baroreceptors to the brain via which nerve?
Glossopharyngeal nerve
Where are arterial anastomoses, in which two arteries merge, found?
In the coronary circulation
- Typically, fluid filters ____________ the arterial end of a capillary. -Fluid will then osmotically reenter at the ____________ end -This fluid delivers materials to the cells and removes its ____________ . -This shift in fluid balance at the arterial end is referred to as ____________ pressure. -This is the physical force exerted by a ____________ against a surface like a capillary wall.
- out -venous -waste -hydrostatic -liquid
place the following vessels in the order through which blood would pass, beginning with blood entering the systemic circuit after exiting the heart.
1. Conducting arteries 2. distributing arteries 3. resistance arteries 4. arterioles 5. capillaries 6. post-capillary venules 7. muscular venules 8. medium veins 9. venus sinuses 10. large veins
The ____________ is the first vessel blood enters upon exiting the heart. The ____________ expand and recoil with every heart beat due to a histologically dominant network of elastic tissue in the tunica media. Just prior to entering capillary beds, ____________ have become extremely thin and present only a few layers of smooth muscle. The site of gaseous exchange, or ____________ , are characterized by extremely thin walls with only endothelium and basal lamina, which better suits diffusional requirements. After exiting the capillary, ____________ contain no muscle and are the first vessel that blood enters on its way back to the heart. The ____________ contain abundant but irregularly spaced smooth muscle with frequent valves present in the tunica interna. The superior vena cava is an example of a ____________ that includes smooth muscle circularly and longitudinally arranged in the tunica media and externa, respectively.
1. aorta 2. large (elastic) arteries 3. arterioles 4. capillaries 5. venules 6. medium veins 7. large vein
Approximately what percent of fluid that exits the capillaries at the arterial end reenters the capillaries at the venous end?
90%
Where are baroreceptors found?
carotid sinuses