arteries, arterioles, capillaries, venules, and veins
Blood flow through the vessels
blood vessels that carry blood away from the heart
blood vessels that carry waste containing blood from the tissues back to the heart
innermost layer; squamous epithelium surrounded by connective tissue with elastic fibers
middle layer; smooth muscle, thickest layer, supports blood vessels
Tunica adventitia (externa)
outermost layer, attaches vessels to surrounding tissues.
Arteries have thicker walls, and veins have thinner walls. Arteries have rippled endothelium, and veins have smoother endothelium. Arteries have smaller and rounder lumen, and veins have larger and collapsed circular shaped lumens. Arteries do not have valves and veins do have valves.
What are the differences in arteries and veins
sympathetic nervous system and the endocrine system
What are the systems that monitor the diameter of vessels?
afterload on the heart, peripheral blood pressure, capillary bed flow, and vasculas spasm
Effects of vasoconstriction/vasodilation
* carry blood away from heart
* has 3 THICK layers in the wall
* may have the vasa vasorum
* vessel with fastest blood flow
Elastic (conducting) arteries
thick walled arteries near the heart, the aorta and its major branches. ex. aorta, pulmonary arteries, common carotid artery, subclavian arteries, and common iliac arteries.
Muscular (distribution) arteries
Distribute blood to body systems and thicker muscle walls.
small arteries that connect to capillaries
blood pressure in the arteries during relaxation of the ventricles
the sounds heard in the stethoscope while taking blood pressure
opposition to blood flow caused by friction of the blood vessel walls
expansion and recoil of arteries caused by contraction and relaxation of the heart
blood pressure in the arteries during contraction of the ventricles
narrowing of blood vessels; decrease in lumen size
enlarging of blood vessels; increase in lumen size
transports blood from the (r)ventricle to the lungs and back to the left atrium
carries blood from the (L)ventricle to the tissues in all parts of the body then returns the blood to the (r) atrium.
a bulge or bubble that develops at a weakened region in the wall of an artery
microscopic vessels that form a connection between arteries and veins; most numerous of blood vessels
veins that are twisted and dilated with accumulated blood
hydrostatic pressure to force (push) water and certain dissolved products through the capillary wall
attracts or pulls water into the capillary
exchange gases, nutrients, and metabolic waste between blood and tissue cells
an abnormal accumulation of interstitual fluid or swelling
the movement of blood through the vessels from the arteries to the capillaries and then into the veins
a force that opposes the flow of fluid
the rhythmic expansion of an artery that is caused by ejection of blood from the left ventricle
cause contraction of the smooth muscle in the walls of the veins
Autonomic Nervous System
plays a role in regulating blood flow by changing the vascular resistance through vasodilation and vasoconstriction
the difference between systolic and diastolic pressure
the amount of blood pumped by the heart in 1 minute
a condition in which blood cannot circulate normally because the vessels are not adequately filled
occurs when there is a loss in blood volume from severe hemorrhage
a powerful vasoconstrictor that increases b/p back to normal; also promotes the secretion of aldosterone
hardening of the arteries
* functions in the exchange of substances between blood and tissue cells
* wall consists of simple squamous epithelium
* vessel with greatest area
* vessel with slowest blood flow
* carries blood toward the heart
* has valves
* has 3 THIN layers in the wall
* vessel with lowest pressure
center that regulates heart rate
center that regulates blood vessel diameter
*receptors that respond when vessel walls stretch
*important for short term pressure regulation
Actions that moves blood through the veins
* skeletal muscle contraction
* respiratory movements
* smooth muscle vasoconstriction
vessels are partly constricted. "vessel muscle middle ground"
bulging in the vessel could rupture and cause death.
one of the three types of capillaries which occurs in most tissues. Their endothelial cells are held together by tight junctions, which forms an uninterrupted tube. Responsible for the blood brain barrier. Exchange mostly everything except, cells and plasma proteins.
on of the three types of capillaries which is riddled with holes. They are important in organs that engage in rapid absorbtion and filtration-- the kidneys, endocrine glands, small inestine, and the choroid plexuses of the brain
Are like fenestrated capillaries but they have gaps between adjacent endothelial cells and thin or absent basal lamina. They have irregular cross-sectional diameters. wider than capillaries. found w/i bone marrow, spleen, liver, penis, & some endocrine organs.
sites of chemical exchange between the blood and interstitial fluid
capillaries connects arterioles and venules
smooth muscles that encircle capillary entrances and regulate blood distribution in capillary pathways. Also allows or reduces the amount of blood flow in various areas of your capillary bed.
side by side arteries
When two arteries merge and provide alternative routes of blood supply to a tissue:
allow arteries to have direct connections w/ veins and bypass the capillary bed when needed
10 billion or 25,000 miles, or 1 time around the globe
The number of capillaries in the body?
small vessels that gather blood from the capillaries into the veins. lack a tunica media, but they do have a tunica externa.
medium sized veins
meida is then, contains few smooth muscle fibers, thickest layer is the adventitia, which contains longitudinal bundles of elastic and collagen fibers. It can do vasoconstriction.
ex. superior and inferior vena cavas, and great cardiac vein. , large vessels that transport large volumes of blood into the heart
flaps of tissue that open and close to allow the flow of blood in one direction only. The heart's valves are located at the entrances and exits of its chambers. formed from the inside of the tunica intima. folded in onitself.
70% of the blood is in the venous system, 30% in the arteries, capillaries and heart.
the oxygen remaining in the blood after it passes through the capillary bed, which can sustain life for 4-5 minutes even in the event of respiratory arrest
Pressure and resistance
Capillary flow is determined by what?
Blood pressure, capillary hydrostatic pressure, and venous pressure
3 types of pressure
arterial pressure start with 100mmHg @ the aorta and then drops to 35mmHg at the entrance of the capillary. Expressed by systolic/diastolic. Normal BP is 110/70 or 120/80
capillary hydrostatic pressure
Tends to force fluid out of capillary. pressure in the capillary bed, it plays a role in determining flow in/out of capillaries. 35mmHg to 18mmHg @ the veins.
pressure in the veins 18mmHg
total peripheral resistance
Degree of resistance to blood flow from systemic blood vessels
vascular resistance (friction)
Length: the longer the length more the friction. More blood is exposed to wall if diameter is changed.
small change in diamter will dramatically change resistance to flow.
blood thickness. hematocrit has to do with the thickness of the blood.
any upset in smoot flow. Mostly in larger vessels and heart chambers.
The amount of blood returning to the atria of the heart. 1. muscular compression (skeletal muscle), 2. respiratory pump, 3. vein diameter - larger increases alot venous return
amount of fluid in the blood; when low, blood pressure low; when blood volume high, causes pressure against the blood vessel walls, high blood pressure
diffusion, filtration, and reabsorption
Movement occurs across capillaries via what?
process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
shorter distance, concentration gradient (larger) differences btw concentration
diffusion is faster when?
plasma membrane, channel proteins, and between cells or through pores.
Diffusion can occur?
the process whereby fluids pass through a filter or a filtering medium
blood colloid osmotic pressure (BCOP)
Pressure exerted by proteins that have already passed through the first layer of the filtration membrane; also pushes in the opposite direction, toward the glomerulus; 30mmHg