Term
|
Definition
inner lining of the blood vessels
in direct contact with bool, which flows through lumen
innermost layer is endothelium
basement membrane
internal elastic lamina |
|
|
Term
|
Definition
middle layer
comprised of smooth muscle and elastic fibers
primary role is to regulate lumen diameter- vasoconstriction , vasodilation, regulates blood flow
primary muscle contraction also lessens blood loss when damaged
influences blood pressure |
|
|
Term
|
Definition
outermost covering
consists of elastic and collagen
external eleastic lamina is part of tunica media, between layers
contains nerves and tiny vessels - vasa vasorum
anchor vessels to surrounding tissues |
|
|
Term
|
Definition
carries blood away from heart
has thick media
does not have valves
have numerous elastic fibers, therefore high compliance - stretch without tearing
lack of norepinephrine |
|
|
Term
|
Definition
largest diameter arteries
THICK tunica media elastic fibers
includes aorta, pulmonary trunk, brachiocephalic, subclavian, common carotid, and common iliac |
|
|
Term
| muscular ( distributing arteries) |
|
Definition
contains more smooth muscle and fewer elastic fibers than elastic arteries
influences blood flow by vasoconstriction or vasodilation
size range
have distributing arteries - eventually branch to organs
tunica externa is THICKER than tunica media
due to reduced elastic tissue, cannot recoil or propel blood like elastic arteries
but tunica media maintains vascular tone- partial contraction |
|
|
Term
|
Definition
when two or more arteries join to supply the same region
provide alternate routes for blood to reach an area - collateral circulation
- circle of willis
have other arteries that supply the same area |
|
|
Term
|
Definition
regulate blood flow into capillaries
tunica interna is thin , the elastic lamina disappears at the metarteriole ( terminal end)
tunica media , forms precapillary sphincter
tunica externa , loose connective tissue , sympathetic nerves alters diameter and blood flow
arterioles resist blood flow prior to entering capillaries
- losing down the blood to have time for diffusion in capillaries |
|
|
Term
|
Definition
connect arteriole with venule
diameter is 5-10 um,permits one RBC
20 billion capillary networks - numerous surface area
microcirculation - blood flows from metarteriole to capillary to postcapillary venule
capillaries found near almost every cell
structure lack tunica media and externa
capillary bed , network of 10-100 capillaries that arise from single metarteriole
capillary types , continuous capillaries ( endothelial cell plasma membrane in bran , lungs, skeletal and smooth muscle) has intercellular clefts
fenestrated capillaries , has many pores, in kidneys, small intestines villi, choroid plexus
sinusoid , endothelial cells have large fenestrations , basement membrane absent, large intercellular clefts that permits blood vessels and proteind to pass
portal system |
|
|
Term
|
Definition
blood towards the heart
have a thinner tunica media, but have valves
postcapillary venules, receives bllod from capillaries, very porous , therefore significant exchange of nutrients and waste and wbc
postcapillary venules enlarge with more smooth forming muscular venules , no exchange here |
|
|
Term
|
Definition
tunica interna is thinner than arteries
tunica media is much thinner than arteries
tunica extrena is thickets layer
veins lack elastic laminae that arteries have
lumen is larger than artery
blood pressure low in veins |
|
|
Term
|
Definition
1. mostly in systemic veins and venules—64%
a. function as blood reservoirs
b. blood can quickly be sent to where it is needed
c. occurs by vasoconstriction
d. digestion and exercise
2. systemic arteries and arterioles—13%
3. systemic capillaries—7% |
|
|
Term
|
Definition
1. diffusion down the concentration gradient
a. usually into interstitial fluid
b. oxygen, glucose, amino acids, hormones
c. wastes leave interstitial fluid into capillary—carbon dioxide
2. how enter/leave capillary
a. lipid soluble through lipid bilayer of endothelium
i. oxygen
ii. carbon dioxide
iii. steroids
b. water soluble through intercellular clefts or fenestrations
i. glucose
ii. amino acids
c. most plasma proteins and rbcs are too large and cannot pass through capillary walls |
|
|
Term
|
Definition
a. recall these are in liver and spleen
b. have large intercellular clefts
c. permit proteins and blood cells to pass
d. example, liver cells make plasma proteins that are released into bloodstream |
|
|
Term
|
Definition
a. brain capillaries have tight junctions
b. this inhibits movement of materials
c. hypothalamus, pineal gland, and pituitary gland don’t have tight junctions |
|
|
Term
|
Definition
C. transcytosis
1. substance enclosed within tiny pinocytic vesicle
2. enters endothelial cell by endocytosis
3. leaves capillary into lumen by exocytosis
4. for large lipid insoluble molecules, insulin and antibodies |
|
|
Term
|
Definition
a. blood hydrostatic pressure BHP
i. generated by pumping heart
ii. water pressure in blood plasma against blood vessel walls
iii. 35mmHg at arterial end of capillary
iv. 16 mmHg at venous end of capillary
v. pushes fluid out of capillary into interstitial fluid
b. interstitial fluid osmotic pressure
i. pushes fluid from interstitial fluid into capillaries
ii. difficult to measure, 0 mmHg
c. blood colloid osmotic pressure
i. large proteins in plasma
ii. 26 mmHg
iii. pulls fluid from interstitial fluid into capillaries
d. interstitial fluid osmotic pressure
i. small number of proteins in interstitial fluid
ii. pull fluid from capillaries into interstitial fluid
iii. 5 mmHg
iv. proteins does not accumulate, goes into lymph
e. net filtration pressure is balance of (BHP + IFOP)- (BCOP+IFHP)
f. figure 21.7
i. arterial end
ii. venous end
g. about 85% of fluid filters out of capillaries is reabsorbed—remainder enters lymph capillaries |
|
|
Term
| bulk flow - filtration and reabsorption |
|
Definition
1. diffusion is solute exchanges between blood and interstitial fluid
2. bulk flow occurs when large numbers of ions, molecules in a fluid move together in same direction---much faster than diffusiosn
3. filtration is pressure driven movement of fluid and solutes from blood capillaries into interstitial fluid
4. reabsorption is pressure driven movement from interstitial fluid into blood capillaries |
|
|
Term
|
Definition
blood flow factors
blood flow is the volume of blood that flows through any tissue in a given time period
cardiac output example
blood flow depends on pressure difference (from high to low) and resistance (reduces blood flow) |
|
|
Term
|
Definition
1. blood pressure generated by ventricular contraction
a. hydrostatic pressure on wall of blood vessel
2. determined by
a. cardiac output
b. blood volume
c. vascular resistance
3. figure 21.8
a. systolic blood pressure is highest in arteries during systole 110mmHg
b. diastolic blood pressure lowest arterial pressure during diastole 70 mmHG
c. blood pressure progressively falls
d. venous end of capillary 16 mmHg
e. enters RV 0 mmHg
4. blood volume
a. 5 L 5.3 quarts
b. small decrease can be compensated for p.75
c. large decrease results in blood pressure drop
d. increase in blood volume increases blood pressure |
|
|
Term
|
Definition
a. 5 L 5.3 quarts
b. small decrease can be compensated for p.75
c. large decrease results in blood pressure drop
d. increase in blood volume increases blood pressure |
|
|
Term
|
Definition
resist blood flow
1. lumen size
a. smaller the lumen, greater blood flow resistance
b. vasodilation decreases resistance
c. vasoconstriction increases resistance |
|
|
Term
|
Definition
a. ratio of rbc to plasma volume
b. greater viscosity, higher resistance
c. dehydration increases blood pressure
d. hemorrhage decreases blood pressure |
|
|
Term
| total blood vessel length |
|
Definition
a. the longer the blood vessel, the greater the resistance
b. obese people have more living tissue, more blood vessels, higher
blood pressure
c. for each extra kg (2.2lb) of fat, 650 km (400 miles) of blood vessels |
|
|
Term
| systemic vascular resistance |
|
Definition
- total perpheral resistance
a. most blood vessels are large
b. arterioles are primary blood vessels to exert resistance by
vasoconstriction/vasodilation
c. vasomotor center in brain stem |
|
|
Term
|
Definition
1. blood returns to heart
2. pressure that causes this is pressure difference between left and right ventricles |
|
|
Term
| 3 ways to generate this pressure |
|
Definition
a. ventricular systole
b. skeletal muscle pump
c. respiratory pump |
|
|
Term
|
Definition
a. figure 21.9
b. at rest, both proximal valve and distal valve are open
c. muscle contraction pushes blood through proximal valve—milking;
distal valve closes
e. muscle relaxes, proximal valve closes, distal valve open
f. blood is caught in proximal valve |
|
|
Term
|
Definition
a. during inhalation, thoracic cavity pressure decreases and abdominal cavity pressure increases
b. abdominal veins are compressed, blood moves to decompressed thoracic veins and then RA
c. in exhalation, valves prevent blood backflow |
|
|
Term
|
Definition
1. velocity is inversely related to cross-sectional area
2. slowest in capillaries, 0.1 cm per sec
3. in aorta, 40 cm/sec
4. slow in capillaries, faster in arteries and veins |
|
|
