[Exam 3] Blood & Circulation

The heart pumps blood by increasing what?

Local pressure

As blood travels through the circulator system, what will it encounter?

Friction

The organ that generates pressure is the

heart

What are arteries?

Blood vessels that carry blood away from the heart

What are arterioles?

The smallest branches of arteries

What are capillaries?

The smallest blood vessels

What are venules?

Blood vessels that collect blood from capillaries

What are veins?

Blood vessels that return blood to the heart

The exchange between blood and interstitial fluid takes place in the

capillaries

3 multiple choice options

What is vasa vasorum?

Vessels of vessels

Where is vasa vasorum located?

In the walls of large arteries and veins

What is the function of vasa vasorum?

To supply oxygen, blood and nutrients to the cells of the tunica media and tunica externa

What are the three layers of the vessel walls, from most outer to most deep?

1. Tunica externa

2. Tunica media

3. Tunica intima

What is the tunica externa?

The most external layer of a blood vessel that contains connective tissue sheath

What is the tunica media?

The middle layer of the blood vessel that contains concentric sheets of smooth muscle in loose connective tissue

What is external elastic lamina?

The boundary that is in between the tunica externa and tunica media that is only found in arteries

What is the tunica intima?

The innermost layer of a blood vessel that is made from simple squamous epithelium and elastic fibers

The tunica intima is also called

endothelium

What does the tunica intima release?

Nitric oxide

What is nitric oxide?

A potent vasodilator

What are the characteristics of an artery?

1. Thicker walls

2. Exert higher blood pressures in order to accommodate oncoming high pressures

Differentiate between a collapsed artery and a vein.

A collapsed artery has a small, round lumen; a vein has a large, flat lumen.

Which blood vessel is more elastic, veins or arteries?

Arteries

2 multiple choice options

Which blood vessel has valves, veins or arteries?

Veins

2 multiple choice options

T/F: All veins have valves.

False; only some have valves

1 multiple choice option

Why don't all veins need valves?

Dependent on direction and distance of blood flow relative to gravity. Head/neck veins do not have valves

Which layer of the blood vessel is considered the endothelium, and also contains the subendothelial layer?

Tunica intima

Which layer of the blood vessel is comprised of smooth muscle and elastic fibers?

Tunica media

Which layer of the blood vessel is comprised of collagen fibers?

Tunica externa

What are elastic arteries?

Large blood vessels that keep blood flowing during diastole when ventricles fill with blood again

Elastic arteries are also called

conducting arteries

What two vessels are considered to be elastic arteries?

1. Aorta

2. Pulmonary arteries (and trunk)

T/F: Tunica media has few elastic fibers, but many muscular arteries.

False; the tunica media has many elastic fibers, but few muscular arteries.

What are muscular arteries?

Medium-sized blood vessels that are active in vasconstriction and vasodilation

Most arteries are what class of arteries?

Muscular arteries

2 multiple choice options

Muscular arteries are also called

distribution arteries to tissues

Which layer of the blood vessel contains many muscle cells?

Tunica media

The smallest arteries are called

arterioles

What are the characteristics of arterioles?

1. Small

2. Have little or completely lack tunica externa

3. Have thin or incomplete tunica media

Arterioles are primarily responsible for

Controlling flow into capillary beds via vasodilation and vasoconstriction

What structures will stretch during systole and recoil during diastole?

1. Elastic aorta

2. Pulmonary arteries

Capillaries have thin/thick walls.

Thin

1 multiple choice option

What are pericytes?

Cells that are present in capillaries to stabilize their walls and control permeability

Materials diffuse between

blood and interstitial fluid to exchange nutrients, bring oxygen and remove carbon dioxide

Continuous capillaries are abundant in

tight junctions

1 multiple choice option

What kind of capillaries will have complete endothelial lining?

Continuous capillaries

Where are continuous capillaries found?

1. Skin

2. Muscles

3. Thymus

4. All tissues except epithelia and cartilage

What are the functions of continuous capillaries?

1. Permit diffusion of water, small solutes and lipid-soluble materials

2. Prevent blood and cells and plasma proteins from crossing

*little exchange

Where are specialized continuous capillaries located?

1. CNS

2. Thymus

T/F: The thymus is part of the immune system.

True.

2 multiple choice options

What is the permeability of specialized continuous capillaries?

Very restricted

The blood-brain barrier is an example of a(n)

specialized continuous capillary

1 multiple choice option

Which capillaries will have pores in their endothelial lining?

Fenestrated capillaries

Which capillary will have gaps between adjacent endothelial cells?

Sinusoids (sinosoidal capillaries)

What is the function of fenestrated capillaries?

To permit rapid exchange of water and large solutes between plasma and interstitial fluid

3 multiple choice options

Where are fenestrated capillaries located?

1. Choroid plexus

2. Kidneys

3. Small intestine

3 multiple choice options

Where are sinusoids found?

1. Liver

2. Spleen

3. Bone marrow

3 multiple choice options

What is the function of sinusoids?

To permit free exchange of water and large plasma proteins between blood and interstitial fluid

3 multiple choice options

What is responsible for monitoring blood at sinusoids?

Phagocytic cells

3 multiple choice options

Phagocytic cells in the liver are called

Kupffer cells

3 multiple choice options

What happens to blood when precapillary sphincters open?

Blood will flow through true capillaries

What happens to blood when precapillary sphincters close?

Blood flows through metarteriole thoroughfare channel and bypasses true capillaries

Venous return is assisted by

1. Valves in veins

2. Respiratory pump

3. Skeletal muscle pump

How does the respiratory pump aid in venous return?

When you inhale and exhale, there are pressure changes and during inhalation, blood will flow towards the heart

How does the skeletal muscle pump aid in venous return?

It will squeeze veins to cause blood to move towards the heart

Pressure will pulsate in arteries between what two phases?

1. Ventricular systole

2. Ventricular diastole

What is mean arterial pressure?

Average pressure in the arterial circuit (the pressure that the tissues "see")

Pressure will decline sharply in what blood vessel?

Arterioles

When pressure has declined in arterioles, it will also continue to decline in what other blood vessel(s)?

1. Capillaries

2. Veins

Why is low pressure at tissues desirable?

This shows that there is an efficient exchange of nutrients, gases and other materials due to the presence of a smooth flow

What happens to your tissues if your BP is too high?

Tissues are susceptible to rupturing

What happens to your tissues if your BP is too low?

Tissues are not receiving enough blood, impairing the delivery of essential nutrients and oxygen

What factors determine peripheral resistance?

1. Blood vessel length

2. Vessel diameter

3. Blood viscosity

4. Obstructions in vessels

What determines cardiac output?

1. Stroke volume

2. Heart rate

What determines blood volume?

1. Water loss

2. Water gain

What determines blood pressure?

1. Peripheral resistance

2. Cardiac output

3. Blood volume

An increase in blood viscosity will

increase blood pressure

A decrease in vessel radius will

increase blood pressure

1 multiple choice option

An increase in blood volume will

increase blood pressure

A decrease in blood volume will

decrease blood pressure

1 multiple choice option

How does progesterone affect Na+ retention?

Progesterone leads to increase in Aldosterone which in turn increases Na+ retention of kidneys

An increase in aldosterone will lead to an increase in Na+ retention. This will ultimately lead to

bloating

How does the sympathetic nervous system increase blood pressure?

Sympathetic neurons will cause vasoconstriction of arterioles by releasing NE, and will increase peripheral resistance.

How does the parasympathetic nervous system decrease blood pressure?

Sympathetic neurons in the medulla are inhibited by parasympathetic neurons, causing vasodilation and lower peripheral resistance due to the release of ACh

What part of the brain is the cardiovascular center?

Medulla oblongata

3 multiple choice options

What does the medulla oblongata regulate?

1. Heart rate

2. Contractility

3. Blood vessel diameter

What are the centers of the medulla oblongata?

1. Cardioacceleratory center

2. Cardioinhibitory center

3. Vasomotor center

What is the function of the cardioacceleratory center?

To increase cardiac output

What is the function of the cardioinhibitory center?

To reduce cardiac output

What is the function of the vasomotor center?

To induce vasoconstriction to increase blood pressure

What nerves are responsible for controlling vasoconstriction?

Adrenergic nerves

When you exercise, what happens to blood flow?

sympathetic nervous system activated, blood flow to muscles will increase, thus inducing vasodilation

It is usual for vasoconstriction to occur when there is an increased sympathetic input, but in skeletal muscle, in the respiratory system and in the coronary circulation, blood vessels will dilate. Why is that the case?

Our skeletal muscles, respiratory system and coronary circulation contain different receptors.

Tributaries from portions of stomach, pancreas and portions of the large intestine will drain into the

splenic vein

Tributaries from the small intestine and portions of the large intestine, stomach and pancreas will drain into the

Superior mesenteric vein

What blood vessel will drain into the splenic vein?

Inferior mesenteric vein

What two veins will converge to form the hepatic portal vein?

1. Splenic vein

2. Superior mesenteric vein

What happens after the splenic vein and superior mesenteric vein form to make the hepatic portal vein?

Blood will flow into the liver

What happens after blood flows through the liver?

Blood will exit through hepatic veins

What happens after blood exits the liver via hepatic veins?

Blood will drain into the inferior vena cava