Anatomy - Chapter 21 Circulatory System: Blood Vessels

arteries

efferent vessels carrying blood away from heart, resistance vessels - withstand high BP

veins

afferent vessels carrying blood toward heart

capillaries

microscopic vessels connecting small arteries to small veins; nutrients, wastes, and hormones move between blood and tissue fluid

tunica interna, tunica media, tunica externa/adventitia

layers of arteries and veins

tunica interna

inner layer of vessels facing lumen, has simple squamous endothelium, slick lining, selectively permeable barrier

tunica media

middle layer of vessels, thick layer with smooth muscle, collage, maybe elastin, and responsible for vasoconstriction and vasodilation

tunica externa/adventitia

outer layer of vessels, loose connective tissue, anchors vessel to its surroundings

vaso vasorum

network of small vessels in large vessels

conducting/elastic arteries, distributing/muscular arteries, resistance arteries

categories of arteries

conducting/elastic arteries

biggest arteries, absorb some pressure but also maintain it (ex. aorta)

distributing/muscular arteries

midsized arteries, distribute blood to specific organs (ex. femoral artery)

resistance arteries

smallest arteries, less than 0.1 mm in diameter, arterioles are smallest examples, not named, metarterioles

metarterioles

short vessels linking arterioles and capillaries

carotid sinuses, carotid bodies, aortic bodies

elastic arteries that have neurons that sense BP and blood chemistry

carotid sinuses

baroreceptors in internal carotid artery wall, glossopharyngeal nerve transmits signals to vasomotor and cardiac centers of brainstem

carotid bodies

chemoreceptors near branch point of common carotid artery, glossopharyngeal nerves transmit signals to respiratory centers of brain

aortic bodies

chemoreceptors in aortic arch, they signal respiratory centers of the brain, innervated by vagus nerves

endothelium and basal lamina

structures of capillary wall

intercellular clefts, filtration pores, through endothelial cytoplasm by transcytosis (for hydrophilic solutes) or diffusion (for nonpolar solutes)

routes through capillary wall

capillary bed is active

precapillary sphincters relax (open) and capillaries fill with blood

capillary bed is inactive

precapillary sphincters close and blood flows from metarteriole to thoroughfare channel, bypasses capillary bed

capacitance vessels

contain most of the blood

postcapillary venules, muscular venules, medium veins, venous sinuses, large veins

types of veins, smallest to largest

postcapillary venules

15 to 20 micrometer diameter, very porous, allow for exchange

muscular venules

greater than 1 mm diameter, have smooth muscle in wall (tunica media)

medium veins

up to 10 mm diameter, individually named veins, contain valves

venous sinuses

large lumens, very thin walls, no smooth muscle (no vasomotion)

large veins

diameter greater than 10 mm, have smooth muscle in all tunics

skeletal muscle pump

muscle activity squeezes veins and forces blood through one-way valves toward heart

simple path, portal system, anastomosis

circulatory routes

simple path

artery to capillary to vein

portal system

sequence of two capillary beds

anastomosis

vessel merger without intervening capillary bed

pulmonary trunk, pulmonary arteries, lobar arteries, alveolar capillaries, pulmonary veins

all vessels in pulmonary circuit

pulmonary trunk

unpaired vessel, from right ventricle

pulmonary arteries

carry oxygen-poor blood, one on each side

pulmonary veins

carry oxygen-rich blood, two from each side enter left atrium

ascending aorta, aortic arch, descending aorta

major branches of aorta

aortic arch

contains brachiocephalic trunk, left common carotid artery, left subclavian artery

descending aorta

contains thoracic aorta and abdominal aorta

common carotid artery, external carotid artery, internal carotid artery, vertebral artery, cerebral arterial circle

arteries of head and neck

anterior cerebral artery, anterior communicating artery, posterior cerebral artery, posterior communicating artery

cerebral arterial circle (of Willis) contains:

dural venous sinuses, internal jugular vein, external jugular vein, vertebral vein

veins of head and neck

superior sagittal sinus, inferior sagittal sinus, transverse sinus

dural venous sinuses

brachiocephalic trunk, left common carotid artery, left subclavian artery

arteries of the thorax

subclavian vein, brachiocephalic vein, superior vena cava, azygous vein, hemiazygous vein

veins of the thorax

celiac trunk, superior mesenteric artery, renal artery, inferior mesenteric artery, common iliac artery

arteries of abdomen and pelvic region

common hepatic artery, left gastric artery, splenic artery

celiac trunk contains:

internal iliac artery/vein and external iliac artery/vein

common iliac artery/vein, contains:

inferior vena cava, hepatic vein, renal vein, common iliac vein

veins of abdomen and pelvic region

hepatic portal system

blood from GI tract sent to liver before heart

inferior mesenteric vein, superior mesenteric vein, splenic vein, pancreatic vein, cystic vein, left and right gastric veins

hepatic portal system contains:

subclavian artery, axillary artery, brachial artery, radial artery, ulnar artery, palmar arches

arteries of the upper limb

subclavian vein, axillary vein, cephalic vein, basilic vein, brachial vein, radial vein, ulnar vein, venous palmar arches

veins of the upper limbs

external iliac artery, femoral artery, popliteal artery, anterior tibial artery, posterior tibial artery, fibular artery

arteries of the lower limb

external iliac vein, femoral vein, great saphenous vein, popliteal vein, anterior tibial vein, posterior tibial vein, fibular vein

veins of lower limb