E4 Ch. 20 Flashcards
list the 3 major types of blood vessels
arteries, capillaries, and veins
arteries
carry blood away from heart
arterioles
smallest arteries
capillaries
smallest blood vessels
venules
receive blood from capillaries
veins
receive blood from venules
name the 3 tunics that comprise blood vessels
tunic intima, tunica, media, and tunica externa
what is the tunic intima made up of
contains endothelium and subendothelial layer
purpose of the tunica media
sheets of smooth muscle, responsible for contraction (vasoconstriction) and relaxation (vasodilation)
lumen
central blood-filled space of a vessel
what are the different types of arteries
elastic, muscular (distributing), and arterioles,
describe elastic arteries
largest, diameter 2.5-1 cm, sometimes called conducting arteries
what structures are elastic arteries
aorta and its major branches
function of elastic arteries
high elastin content dampens surge of blood pressure
describe some features of muscular arteries
lies distal to elastic arteries, diameter 1cm- 0.3mm, thick tunica media, has internal and external elastic laminae
what are some features of arterioles
smallest arteries, dameter 0.3mm -10um, possess all 3 tunics,
what controls the diameter of arterioles
local factors in tissues, sympathetic NS
what is the site specific function of capillaries in the lungs
oxygen enters blood, carbon dioxide leaves
what is the site specific function of capillaries in the small intestines
receive digested nutrients
what is the site specific function of capillaries in the endocrine glands
pick up hormones
what is the site specific function of capillaries in the kidneys
remove of nitrogenous wastes
intercellular clefts
gaps of unjoined membranes, allow small molecules in and out of capillaries
what is the most common type of capillary
continuous capillaries, occur in most organs, least permeable
describe fenestrated capillaries
joined by tight junctions and desmosomes, have pores in endothelium
where do fenestrated capillaries mostly occur
areas where high rates of exchange occur; intestines, glomeruli of kidneys, and endocrine glands
list the different types of capillaries
continuous, fenestrated, and sinusoids
describe sinusoid capillaries
wide, leaky found in some organs, usually fenestrated, intercellular clefts wide open
where do sinusoid capillaries typically occur
bone marrow, and spleen
what are the 4 different routes in and out of capillaries (permeability)
direct diffusion, though intercellular clefts, cytoplasmic vesicles, and fenestrations
what is an example of low-permeability capillaries
blood brain barrier; have complete tight junctions, only vial molecules pas through
what molecules can pass though the blood brain barrier
oxygen, carbon dioxide, and some anesthetics
function of pre-capillary sphincters
regulate the flow of blood to tissue
what are capillary beds
network of capillaries running though tissues regulated by pre-capillary sphincters
describe venules
smallest veins, 8-10um, join to form veins
what are postcapillary venules
smallest venules
what are some differences found in veins when compared to arteries
larger lumen, thicker tunica externa, thinner walls w/ less elastin
what is the skeletal muscle pump
muscles press against thin-walled veins
vascular anastomoses
vessels interconnect to form this, organs receive blood from more than one arterial source
arterial astomoses
neighboring arteries from this, provide collateral channels
describe the systemic circulation
systemic arteries carry oxygenated blood away from heart to rest of body
what region of the vertebrae does the thoracic aorta lie
region of T5-T12
what region of the vertebrae does the abdominal aorta lie
ends ends at L4 right below the thoracic aorta
name the paired arteries that supply the head and neck
carotid arteries
what does the subclavian arteries branch into
vertebral arteries, thyrocervical trunk, and costocervical trunk
the superior and inferior vena cava returns blood from which regions of the body
superior vc- from body regions superior to diaphragm
inferior vc- returns blood from body region inferior to diaphragm
name the types of dural sinuses
straight, transverse, and sigmoid sinuses
describe the hepatic portal system
part of vascular circuit, picks up digested nutrients, delivers to liver for processing
where are the capillary beds of the hepatic portal system located
1st= stomach and intestines 2nd= liver sinusoids
name the veins associated w/ the hepatic portal system
superior/inferior mesenteric vein and splenic vein
what is portal systemic anastomoses
scarring and degeneration of liver
what is the cause and effects portal systemic anastomoses
leads to blockage of liver sinusoids which raises BP (portal hypertension), which leads to emergency anastomoses for portal blood
in the umbilical umbilical cord of a fetus which umbilical vessels are paired and unpaired
paired umbilical arteries, unpaired umbilical vein
