Chapter 16: Vascular Flashcards
1
Q
arteries
A
carry blood away from the heart
2
Q
veins
A
return blood to the heart
3
Q
capillaries
A
connect the smallest arteries to the smallest veins
4
Q
tunica intima
A
- innermost layer of a vessel
- composed of endothelium
- smooth surface
- produces chemicals that cause dilation or constriction
5
Q
tunica media
A
- middle layer of a vessel
- thickest layer in arteries
- smooth muscle and elastic tissue
- allows vessels to change diameter
- innervated by ANS
6
Q
tunica externa
A
- outer layer of a vessel
- fibrous connective tissue
- supports and protects
- thickest layer in veins
7
Q
aneurysm
A
if a portion of the arterial wall weakens, the blood inside will push against the area and cause it to bulge
8
Q
conducting arteries
A
- largest arteries
- can expand and recoil
- elastic fibers in tunica media
- also called “elastic arteries”
- ex. aorta, common carotid artery
9
Q
distributing arteries
A
- carry blood farther away from the heart to specific organs/areas
- also called “muscular arteries”
- smaller than elastic arteries
- ex. brachial & femoral arteries
10
Q
arterioles
A
- smallest arteries
- also called “resistance vessels”
- can resist flow of blood
- help control blood pressure
- control how much blood enters an organ
- too numerous to be names
11
Q
metarterioles
A
short vessels that connect arterioles to capillaries
12
Q
characteristics of veins
A
- thinner walls than arteries
- great ability to stretch
- can carry varying amounts of blood with almost no change in pressure
- sometimes called “capacitance vessels”
- can constrict extensively
- lie closer to the skin’s surface than arteries
13
Q
large veins
A
- formed as medium-sized veins converge
- thick tunica externa
- ex. vena cavae, pulmonary veins, internal jugular veins
14
Q
medium-sized veins
A
- formed by the convergence of venules on their way toward the heart
- thicker, more elastic walls
- contain one-way valves that keep blood moving toward the heart and prevent backflow
- ex. radial, ulnar, saphenous veins
- veins in the legs have the most valves because they have to fight gravity when transporting blood back up to the heart
15
Q
venules
A
- smallest veins
- collect blood from capillaries
- thin walls
- porous; exchange fluid with surrounding tissues
16
Q
capillaries
A
- microscopic, very thin walls
- barely wide enough for blood cells to pass
- link arterioles to venules
- “exchange vessels” of the circulatory system
- transfers nutrients, wastes, and hormones between blood and tissues
17
Q
distribution of capillaries
A
- unevenly distributed
- tissues with high metabolic rates contain more (ie. liver, kidneys)
- fibrous connective tissues (lower metabolic rate) contain fewer (ie. tendons)
18
Q
distribution of capillaries
A
- unevenly distributed
- tissues with high metabolic rates contain more (ie. liver, kidneys)
- fibrous connective tissues (lower metabolic rate) contain fewer (ie. tendons)c
19
Q
distribution of capillaries
A
- unevenly distributed
- tissues with high metabolic rates contain more (ie. liver, kidneys)
- fibrous connective tissues (lower metabolic rate) contain fewer (ie. tendons)
20
Q
capillary organization
A
- capillaries organized into networks (capillary beds)
- form the microcirculation
21
Q
precapillary sphincters
A
- at beginning of each capillary bed
- regulates flow of blood into network
- open during exercise
- close during periods of rest
22
Q
sinusoid
A
- unique capillary
- irregular, blood filled spaces
- more permeable
- allow for passage of large substances (ie. blood cells, proteins)
- ex. allows blood cells formed in bone marrow and proteins formed in the liver to enter the bloodstream
23
Q
capillary exchange
A
- two-way exchange
- release chemicals to be used by surrounding tissues
- take up waste and substances that need to be transported to other parts of the body
- water moves in and out
24
Q
diffusion
A
- substances move from area of greater to lesser concentration
- oxygenated blood flows into the capillaries
- oxygen moves out of capillaries and into surrounding fluid
- CO2 diffuses into the capillary simultaneously
25
filtration
- occurs close to the arterial side of the capillary bed
- blood enters capillary through metarteriole
- higher pressure in the capillary pushes plasma and dissolved nutrients through the capillary wall and into surrounding tissue
26
colloid osmotic pressure
- happens when blood pressure inside the capillary drops
- albumin in the blood pulls tissue fluid and waste products into the capillaries
27
edema
water filters out of the capillaries faster than it is absorbed and it accumulates in the surrounding tissues
main causes:
- increased capillary filtration
- reduced capillary reabsorption
- obstructed lymphatic drainage
