Exam 2- Chapter 18 Flashcards
tunica intima
-composed of endothelium, which provides a smooth surface
-endothelium is contious with the inner lining of the heart, endocardium
-contains internal lamina (a thin layer of subendotheial connective tissue + elastic fibers)
tunica media
-composed of smooth muscle cell + external elastic lamina (elastic fibers)
-smooth muscle cells control diameter of blood vessel –> amount of blood flow to organs
-sympathetic NS controls smooth muscle cells via vasomotor nerves
vasomotor nerves control _______ & _______
vasoconstriction: narrowing of diameter of blood vessel
vasodilation: increasing diameter of blood vessel
tunica externa
-composed of dense irregular connective tissue
-support blood vessel and prevents it from overstretching
vaso vasora
tiny vessels that supply oxygen to tunica media + extrena
elastic arteries/conducting arteries
-largest diameter
-includes aorta & immediate branches
-under the highest pressure bc its closes to the heart
muscular arteries/distributing arteries
-medium sized diameter
-well-developed tunica media
-regulate blood pressure
arterioles
-smallest arteries
-thin wall layer
metarterioles
-smallest arterioles
-controls blood flow to tissues
-feeds blood to capillary
baroreceptor
receptor that detects changes in pressure
chemorecptor
detects blood oxygen, carbon dioxide, + hydrogen ions concentration
anastomoses
when blood vessels branch into colateral circulation that leads to same location
arterial anastomoses
exist in heart, brain & around joints
venous anastomoses
megiboring veins are connected by small colaterals
capillary beds
location where gas exchange takes place
precapillary sphincter
controls amount of blood flowing into capillary
continous capillary
structure: endothelial cells + tight junction
location:
- skin
-nervous tissue
-connective tissue
-muscle tissue
function:
-least “leaky”
-few substances cross wall
fenestration cappilary
structure: fenestration
location:
-kidney
-endocrine glands
-small intestine
function:
-moderate “leaky”
-allow large volume of fluids + larger substances to cross wall
sinosudial capillary
structure: large pores
location:
-liver
-lymphoid organs
-bone marrow
-spleen
function:
-“leakiest”
-allow large substances (like cells) to cross wall
venules
small venules –> ONLY tunica intima
large venules –> have all 3 layers of blood vessel
-drains capillary beds
veins
-thin walled vessels
-large lumen
-return blood to heart
diffusion through membrane of endothelial cells
carbon dixiode, oxygen, certain lipids can enter/exit capillary wall through diffusing across membrane
diffusion + osmosis through gaps + fenestrations
-water + small substances (monosaccharides, amino acids) that are dissolved in water are able to move freely through pores
transcytosis
-how larger molecules cross endothelial cells
endocytosis: molecules are taken in
exocytosis: molecules are moved out
filtration
movement of fluid by force such as pressure or gravity
hydrostatic pressure (HP)
force that fluids exert on wall
blood pressure = hydrostatic pressure
osmosis
movement of water from low solute concentration to high solute concentration
osmotic pressure
force we must apply to solution to prevent water from moving into osmosis
edema
excessive amount of water in interstitial fluid
common cause: increase in HP or decrease in OP which causes SWELLING of capillary
hemodynamics
physiology of blood flow in cardiovascular system
blood pressure
outward force that blood exerts in walls of blood vessel
vascular resistance
any impedance to blood flow
venous return
blood must return ti the heart at SAME rate that is pumped into arterties
-essential for noraml CO –> blood pressure
sympathetic nervous system increases what hormones to increase blood pressure
SHORT term maintenance of HR
-norepinephrine
-epinephrine
-which increase HR & vasoconstriction
sympathetic nervous system increases what hormones to decrease blood pressure
SHORT term maintenance of HR
-acetylcholine
-decreases blood pressure by slowing HR
sympathetic nervous system increases what hormones to increase blood pressure
LONG term maintenance of HR
-antidiuretic hormone
triggers thirst + increases amount of water in kidney
-renin–>angiotensin ll
increases thirst causing sodium ion retention
-aldosterone
causes sodium ion retention
sympathetic nervous system increases what hormones to decrease blood pressure
LONG term maintenance of HR
-ANP
causes blood to excrete more water + sodium ions
velocity
blood flow over cross-sectional area
causes: velocity is slowest in arteries w high areas of cross-sectional areas
