BIO-169-chapter 20: Vessels and circulation

Arteries

____ transport blood away from the heart to the capillaries

Capillaries

____ are microscopic, relatgiely porous blood vessels for the exchange of substances between blood and tissues

Capillaries’ narrow vessel diameter and thin wall are optimal for

exchange of substances between blood and body tissues

Veins

_____ drain blood from the capillaries, transporting it back to the heart

veins are structurally similar to the _______ valves of the heart

semilunar

Tunics

Vessel walls are composed of layers called _____.

Lumen

The tunics surround the _____, or inside space, of the vessel through which blood flows.

tunica intima, tunica media, tunica externa

The three tunics are:

media, externa

An artery has a thicker tunica ____ and a relatively smaller lumen, whereas a veins thickest layer is the tunica ____, and it has a larger lumen

Tunica intima

the innermost layer of a blood vessel

Endothelium

The _____ both provides a smooth surface as the blood moves through the lumen of the blood vessel and releases substances to regulate contraction and relaxation of smooth muscle within the tunica media

Tunica media

The tunica _____ is the middle layer of the vessel wall.

Vasoconstriction

Narrowing of the blood vessel lumen

Vasodilation

Widening of the blood vessel lumen

Tunica externa

The tunica ____ is the outermost layer of the blood vessel wall

Companion vessels

arteries and veins that supply the same body region and tend to lie next to one another are called:

Arteries

_____ progressively branch into smaller vessels as they extend from the heart to the capillaries

capillaries, arteries, veins

Which are major classes of blood vessels?

Arteries

Which class of blood vessel carries blood away from the heart to the body?

Tunics

The walls of arteries and veins have three layers called:

Companion

In the body, _____ blood vessels travel together and supply the same region.

Veins

Which blood vessels become larger and merge as they move toward the heart?

Arterioles

The smallest type of arteries are the:

Capillaries

The smallest blood vessels in the cardiovascular system are the:

Venules

The companion vessels to the arterioles are the:

Muscular arteries

Smaller and medium sized veins typically travel with:

False

True/false: Arteries contain valves to prevent the back flow of blood.

Elastic

____ arteries are the largest arteries, ranging from 2.5 to 1 centimeters. They are also called conducting arteries because they conduct blood from the heart to the smaller muscular arteries

Muscular

_____ arteries typically have diameters ranging from 1 centimeter to 0.3 millimeter. These medium sized arteries are also called distributing arteries because they distribute blood to specific body regions and organs

Atherosclerosis

A progressive disease of the elastic and muscular arteries which leads to thickening of the tunica intima and narrowing of the arterial lumen

Hypercholesterolemia

An increased amount of cholesterol in the blood which tends to run in families

angioplasty

surgical repair of a blood vessel where a physician inserts a balloon tip catheter into an artery and positions it at the site where the lumen is narrowed

Internal elastic, external elastic

The ____ _____ lamina seperates the tunica media from the tunica intima, and the ____ ____ lamina seperates the tunica media from the tunica externa

Aneurysm

ballooning of a weakened portion of an arterial wall which can rupture and cause massive blessing or death

Continuous capillaries, fenestrated capillaries, and sinusoids

Capillaries include three types:

Continuous capillaries

The most common type of capillary least permeable, allowing plasma and small solutes to pass

Fenestrated

____ capillaries are composed of a complete continuous lining of endothelial cells and a basement membrane and are found in the small intestine to absorb nutrients, aqueous humor, choroid plexus, endocrine glands, and the kidneys

Sinusoids

_____ have an incomplete lining of the endothelial cells with large openings, or gaps, and the basement membrane is either discontinuous or absent

Capillary bed

A group of capillaries formed together that works together

Metarteriole

A branch of an arteriole

True capillaries

Vessels called ____ _____ branch from the metatariole and make up the bulk of the capillary bed

precapillary sphincter

At the origin of each true capillary, a smooth muscle ring called the _____ _____ controls blood flow into the true capillaries

Venules

____ are the smallest veins, measuring from 8-100 micrometers in diameter and are companion vessels with arterioles and they marge to form veins

Valves

Most veins contain numerous _____, so as to prevent blood from pooling in the limbs

Sinus

A modified vein that has very thin walls and no smooth muscle is referred to as a:

End arteries

Arteries that provide only one pathway through which blood can reach an organ are referred to as:

anastomosis

An _____ is the joining together of blood vessels

Portal vein

A ____ _____ delivers blood to another organ first, before the blood is sent back to the heart

55%

When a person is at rest, approximately how much blood is being held within the veins, the body's blood reservoirs?

-25%

-75%

-55%

Vein

The simple pathway of blood flow to an organ or body region includes an artery, capillary bed, and a:

Elastic arteries

Which arteries are also called conducting arteries because they conduct blood away from the heart to the smaller muscular arteries?

Elastic artery

Which type of artery has a large proportion of elastic fibers throughout all three tunics, especially the tunica media?

Elastic arteries

The aorta, pulmonary arteries, brachiocephalic arteries, and common iliac arteries are examples of:

Muscular arteries

Which arteries are also known as distributing arteries because they distribute blood to the body organs and tissues?

Decreases

Arteriole vasoconstriction _____ blood flow into the an area

Cross sectional area

The ____ ____ __ of a vessel is the diameter of the vessels lumen

Blood flow velocity

rate of blood transported per unit time and typically measured in centimeters per second

Capillaries

The function of _____ is to allow for the exchange of substances between the blood and the surrounding tissues

Diffusion

Within systemic capillaries, substances such as oxygen, hormones, and nutrients move by _____ from their relatively high concentration in the blood into the interstitial fluid and then into the tissue cells

Vesicular transport

___ ____ occurs when endothelial cells use pinocytosis to form fluid filled vesicles, which are then transported to the other side of the cell and released by exocytosis

Bulk flow

___ _____ refers to the movement of large amounts of fluids and their dissolved substances in one direction down a pressure gradient

Filtration

_____, a process that occurs on the arterial end of a capillary, is the movement of fluid by bulk flow out of the blood through the openings in the capillaries

reabsorption

The movement of fluid by bulk flow in the opposite direction, back into the blood

hydrostatic pressure

The physical force exerted by fluid on a structure

blood hydrostatic pressure

Force exerted per unit area by blood as it presses against the internal surface of the vessel wall

External

The ____ elastic lamina in the walls of muscular arteries seperates the tunica media from the tunica externa

Coronary artery, brachial artery, inferior mesenteric artery

Which are muscular arteries?

-coronary artery

-brachial artery

-pulmonary artery

-inferior mesenteric artery

True

True/false: arterioles have a significant role in regulating systemic blood pressure and blood flow to different areas of the body.

tunica intima

The walls of capillaries contain only the ____ ____ allowing for rapid gas and nutrient exchange between the blood and tissues

Endothelium

Most capillaries consist solely of ________, which is composed of simple squamous epithelium resting on a basement membrane.

Continuous capillaries

Which type of capillaries use simple diffusion or pinocytosis to pass materials through the vessel walls?

-sinusoids

-fenestrated capillaries

-continuous capillaries

Muscle, skin

Where are continuous capillaries found within the body?

fenestrated capillaries

Which type of capillaries have pores within each endothelial cell and a continuous basement membrane?

Fenestrated capillaries

Which type of capillaries are found where a great deal of fluid transport between the blood and interstitial fluid occurs, such as the small intestine, ciliary process of the eye, most endocrine glands, and the kidney?

Sinusoids

Which type of capillaries are found in the bone marrow, spleen, and liver, where larger materials need to enter and exit the blood?

thoroughfare channel

In a capillary bed, the distal part of the metarteriole, called the ___ ____, connects to a post capillary Venule

precapillary sphincter

Relaxation of the ____ ____ allows blood flow into the the capillaries of a capillary bed

Perfusion

The specific amount of blood entering capillaries per unit time per gram of tissue is called:

Tumor angiogenesis

A critical event in development of a cancerous tumor is the formation of blood vessels within the tumor, and process called:

myogenic response

The contraction and relaxation of smooth muscle within blood vessels in response to changes in stretch of the blood vessel wall is the:

Vasodilators

Substances that cause smooth muscle relaxation, which results in both vasodilation of arterioles and opening of precapillary sphincters

vasoconstrictors

Substances that cause smooth muscle contraction

Autoregulation

The process by which a tissue itself regulates or controls its local blood flow in response to its changing metabolic needs

histamine and bradykinin

____ and _____ are inflammatory mediators, which are released in response to a trauma, an allergic reaction, an infection, or even exercise

Prostaglandins and thromboxanes

____ and ___ are local hormones released with tissue injury that can cause vasoconstriction

Blood pressure

___ __ is the force per unit area that blood experts against the inside wall of a vessel

Blood pressure gradient

The change in blood pressure from one end of a blood vessel to its other end

Systolic pressure

The highest blood pressure generated in arteries is during ventricular systole when the artery is maximally stretched; this value is recorded as the:

Diastolic pressure

The lowest pressure is during ventricular diastole when the artery recoils no further; this value is recorded as the:

Pulse pressure

The additional pressure placed on the arteries from when the heart is resting

Pulse

The rhythmic throbbing of an arterial wall as blood is being pumped through the vessel

Thrombus

Another word for blood clot

Varicose

_____ veins are dilated and have many curves and twists and may be a result of aging or some form of stress like standing for long periods of time and can occur anally like hemorrhoids

Resistance

The amount of friction the blood experienced as it is transported through the blood vessels

True capillaries

The bulk of a capillary bed is formed by the:

-metarteriole

-thoroughfare channel

-true capillaries

End arteries

arteries that provide only one pathway through which blood can reach an organ are referred to as:

Anastomosis

An _____ is the site where two or more arteries/veins converge to supply the same body region

Venous

A _____ anastomosis includes two or more veins draining the same body region

Arteriovenous anastomosis

Which would be present in the fingers, toes, palms, and ears to allow these areas to be bypassed if the body is becoming hypothermic?

Baroreceptors

Specialized sensory nerve endings that respond to stretch and sudden short term changes in blood pressure