A&P 2: Chapter 21

Created by Chrizzy12 

Upgrade to
remove ads

39 terms · Anatomy & Physiology 2 Lamar University Lecture-Armacost

Circulatory System (components)

fluid (blood), pump (heart), and tubes (blood vessels)

Arteries/Arterioles

these carry blood away from the heart, towards the body, and they differ in size and function

Elastic Arteries

arteries/arterioles: have a large diameter

Muscular Arteries

arteries/arterioles: have a medium diameter

Arterioles

arteries/arterioles: have a small diameter

Tunica Interna

arterial wall: inner lining of epithelium and elastic fibers

Tunica Media

arterial wall: elastic fibers and smooth muscle fibers, and thicker layer of smooth muscle fibers than in veins

Tunica Externa

arterial wall: outer lining of elastic and collagen fibers

Elastic Arteries

large diameter, located near the heart, has many elastic fibers in tunica media, and functions as pressure reservoir

Pressure Reservoir

when ventricle of heart contracts, wall of elastic artery expands to accommodate influx of blood, when ventricle relaxes, vessel wall rebounds, thus providing a more continuous flow of blood

Muscular Arteries

medium diameter, located further from the heart, and has many smooth muscle fibers in tunica media

Arterioles

small diameter, resistance vessels, and regulates blood flow by regulating resistance

Resistance

is an opposition to blood fow, mainly due to friction between blood and vessel wall; contraction of relaxation of smooth muscles in arterioles effects diameter of vessel, thus friction, thus this

Veins/Venules

these return blood to heart from body tissures (deoxygenated blood), and they differ in size and function

Venules

returns blood to heart from body tissues, has a small diameter

Veins

returns blood to heart from body tissues, has a large diameter; tunica intera and tunica media thinner than in arteries

Venous Valves

many veins have valves in prevent the back-flow of blood

Capillaries

small diameter, capillary wall consists of single layer of endothelial cells and a basement membrane, and function as exchange vessels; gases and small molecles move btwn blood and interstitial fluid of body tissues

Continuous Capillary

plasma membranes of endothelial cells are continuous, only gases and small molecules can pass across capillary wall, and is found in skeletal muscle, smooth muscle, connective tissue, and lungs

Fenestrated Capillary

plasma membranes of endothelial cells have small pores, large molecules can pass across capillary wall, and is found in kidneys, villi of sm. intestine, choroid plexuses of ventricles in brain, and some endocrine glands

Sinusoidal Capillary

plasma membranes of endothelial cells have large pores, large molecules and some cells can pass across capillary wall, and is found in bone marrow, liver, lymph, and some endocrine tissue

Capillary Exchange

exchange of gases and other substances btwn blood and interstitial fluid, across capillary walls

Diffusion

passive movement of individual molecules from an area of high concentration to an area of low concentration, until equilibrium is reached; driven by a concentration gradient

Transcytosis

active movement of molecules across endothelial cells of capillary wall via pinocytosis and exocytosis; active, driven by cellular energy

Bulk Flow

passive movement of large numbers of molecules from an area of high pressure to an area of low pressure; passive, driven by pressure gradient

Filteration

movement of fluid and associated molecules from blood to interstitial fluid; occurs at arterial end of capillary where blood pressure is higher than osmotic pressure of interstitial fluid; blood hydrostatic pressure (BHP) pushes molecules from blood

Reabsorption

movement of fluid and associated molecules from interstitial fluid to blood; occurs at venous end of capillary where osmotic pressure of interstitial fluid if higher than blood pressure; blood colloid osmotic pressure (BCOP) pulls fluids into capillaries

Hemodynamics

are the forces involved in blood flow

Blood Flow

volume of blood passing through a tissue per unit time (mL/min)

Blood Flow (factors)

this through a particular tissue depends on 2 factors: differences in blood pressure throughout the body, and differences in vascular resistance throughout the body

Blood Pressure

hydrostatic pressure exerted by blood on walls of vessels, generated by contraction of ventricles, and drops with increasing distance from heart

Vascular Resistance

is an opposition to blood flow due to friction between blood and vessel wall

Viscosity of Blood

vascular resistance factor: resistance increases as friction increases, is relatively constant, and has a minor effect

Length of Blood Vessel

vascular resistance factor: resistance increases as length increases, is relatively constant, and has a minor effect

Diameter of Blood Vessel

vascular resistance factor: resistance increases as diameter decreases, is not constant (contraction and relaxation of smooth muscles in vessel walls), and has a major effect

Venous Return

includes 3 mechanisms that return blood to the heart

Pressure Generated

a venous return: by contraction of left ventricle; but venous pressure is so low that it can barely overcome gravity

Skeletal Muscle Pump

a venous return: contraction of skeletal muscles in limbs generates pressure on veins, and valves in veins play an important role in preventing back-flow of blood

Respiratory Pump

a venous return: inhalation decreases pressure in thoracic cavity but increases pressure in abdominal cavity and on abdominal veins

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

NEW! Voice Recording

Click the mic to start.

Create Set