Chapter 19: Circulation Chapter Questions

Peripheral resistance is:

- Directly proportional to blood vessel length. - Directly proportional to blood viscosity.

Which vessel types may be porous enough to allow diapedesis?

- capillaries - venules

Sort these vessel types in the order of blood flow, starting with those that first carry blood away from the heart and finishing with those that eventually return blood to the heart.

1. arteries 2. arterioles 3. capillaries 4. venules 5. veins

Arrange the capillary types in order of most to least permeable.

1. sinusoid capillaries 2. fenestrated capillaries 3. continuous capillaries

Arrange the layers of a blood vessel wall, from superficial to deep.

1. tunica externa 2. tunica media 3. tunica intima

What is the mean arterial pressure (in mm Hg) in that same person discussed previously? Systolic blood pressure is 180 mm Hg and diastolic blood pressure is 90 mm Hg.

120

You are measuring a person's blood pressure following a brief bout of exercise. Their systolic blood pressure is 180 mm Hg and the diastolic blood pressure is 90 mm Hg. What is their pulse pressure in mm Hg?

90

decreased HR

= decreases BP due to decreased CO

increased SV

= increased BP due to increased CO

Explain the function of venous valves.

In veins, valves ensure that blood flow is unidirectional despite being under low pressure.

How does the presence of large fenestrations within sinusoids affect the movement of cancerous cells or bacteria?

It makes the movement of bacteria or cancer cells easier throughout the body. This is one of the drawbacks of this type of arrangement.

Which would you expect to change more following exercise, systolic or diastolic blood pressure? What impact would this have on pulse pressure? And why?

Systolic blood pressure will increase more than diastolic blood pressure. This will result in increased pulse pressure. Increased venous return and increased contractility of cardiac muscle causes increased stroke volume. Increasing stroke volume will increase systolic blood pressure and pulse pressure.

What would be the effect of capillaries with diameters less than 5μm?

The capillaries would quickly plug with red blood cells, making them ineffective in delivering nutrients to tissues.

Briefly describe the relationship between blood flow, blood pressure, and resistance using the formula discussed. What is the relationship between flow and pressure? What is the relationship between flow and resistance?

The general formula describing this relationship is F=ΔP/R. As shown, flow (F) varies directly with the difference in pressure (ΔP) and inversely with resistance (R). That is, as ΔP increases, F increases; as R increases, F decreases

why muse the aorta and branches be able to stretch so readily

These arteries must be able to stretch when pressure rises during ventricular systole and then recoil when pressure falls during ventricular diastole.

What would be the impact on venous physiology if the tunica media had many smooth muscle cell layers?

You would lose venous compliance and the ability of the veins to store extra blood. This would increase the amount of blood within the arterial side of the circulatory system, and hence blood pressure.

Which arteries are most directly responsible for controlling the amount of blood entering individual capillary beds?

arterioles

sinusoidal capillary

bone marrow

elastic arteries

closest to the heart and have relatively larger lumens than other arteries

tunica externa

collagenous connective tissue

increased blood vessel diameter

decreased BP due to decreased resistance

Which of the following effects would cause decreased venous return?

decreased breathing rate

Suppose that production of blood plasma proteins by the liver is significantly decreased. Will this directly cause an increase or a decrease in the net filtration pressure (NFP) in capillaries?

increase

Will the release of nitric oxide from the endothelial cells of an arteriole increase or decrease in response to a decreased pH of the tissue it serves?

increase

Which feature of the capillary wall results from incomplete tight junctions?

intercellular clefts

An artery with a relatively thick tunica media and a total diameter between 0.1 cm and 1 cm is most likely to be which type?

muscular artery

Name the vessel that drains blood from a capillary bed.

postcapillary venule

Look closely at Poiseuille's equation. If the viscosity (thickness) of a fluid moving through a tube were to decrease, what would happen to the value of ΔP?

pressure would decrease

tunica intima

simple squamous epithelium

continuous capillary

skin

fenestrated capillary

small intestine

tunica media

smooth muscle and elastic connective tissue

Which blood vessels carry oxygenated blood?

systemic arteries

muscular arteries

these arteries have the thickest tunica media of any vessel type

arterioles

these articles can be so small that their wall is only an endothelium and a thin layer of smooth muscle fibers

Which layer of the blood vessel wall is responsible for changing lumen diameter?

tunica media

Which component of the cardiovascular center can influence blood pressure by varying the total peripheral resistance?

vasomotor center