ch 21: blood vessels

arteries

efferent vessels carrying blood away from the heart

veins

afferent vessels carrying blood toward the heart

capillaries

microscopic vessels connecting small arteries to small veins

layers (tunics) of arteries and veins

• tunica interna

• tunica media

• tunica externa / adventitia

tunica interna

• has simple squamous epithelium

• slick lining

• selectively permeable lining

tunica media

• thick layer with smooth muscle, collagen, maybe elastin

• responsible for vasoconstriction and vasodilation

tunica externa / adventita

• loose connective tissue

• anchors vessel to its surroundings

vaso vasorum

large vessels have their own network of small vessels

arteries

resistance vessels that withstand high BP

categories of arteries

• conducting (elastic) arteries

• distributing (muscular) arteries

• resistance arteries

conducting (elastic) arteries

• biggest arteries

• absorb some pressure but also maintain it

• ex. aorta

distributing (muscular) arteries

• midsized

• distribute blood to specific organs

• ex. femoral artery

resistance arteries

• smallest arteries

• less than 0.1 mm in diameter

• ex. arterioles

• do not have specific names

metarterioles

short vessels linking arterioles and capillaries

carotid sinuses

baroreceptors in internal carotid artery wall

• ex. glossopharyngeal nerve transmits signals to vasomotor and cardiac centers of brainstem

carotid bodies

chemoreceptors near branch point of common carotid artery

• ex. glossopharyngeal nerves transmit signals to respiratory centers of brain

aortic bodies

chemoreceptors in aortic arch

• signal respiratory centers of the brain

• innervated by vagus nerves

capillaries

• exchange vessels

• nutrients, waste and hormones move between blood and tissue fluid

microvasculature

includes arterioles, venules and capillaries

types of capillaries

• continuous

• fenestrated

• sinusoid

continuous capillary

endothelial cells joined by tight junctions, but some intercellular clefts present

fenestrated capillary

endothelial cells have filtration pores facilitating exchange

sinusoid (discontinuous capillary)

irregular, tortuous passages with wide gaps between endothelial cells

routes through capillary wall

• intercellular clefts

• filtration pores

• through endothelial cytoplasm by transcytosis (for hydrophilic solutes) or diffusion (for nonpolar solutes)

occurs when a tissue is active

precapillary sphincters relax (open) and capillaries fill with blood

occurs when tissue is inactive

precapillary sphincters close and blood flows from metarteriole to thoroughfare channel

capacitance vessels

contain most of the blood

types of veins

• postcapillary venules

• muscular venules

• medium veins

• venous sinuses

• large veins

postcapillary venules

• 15 to 20 mm diameter

• very porous, allow for exchange

muscular venules

• greater than 1mm diameter

• have smooth muscle in walls (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

• diameters greater than 10 mm

• have smooth muscle in all tunics

venous valves

infolding of the tunica interna in some medium and large veins

types of circulatory routes

• simple path

• portal system

• anastomosis

simple path

artery to capillary to vein

portal system

sequence of two capillary beds

anastomosis

vessel merger without intervening capillary bed

types of anastomosis

• arteriovenous

• arterial

• venous

pulmonary trunk

• unpaired vessel

• from R. ventricle

pulmonary arteries

• carry oxygen-poor blood

• one on each side

lobar arteries

• R. lung

  • superior lobar artery, middle lobar artery, inferior lobar artery

• L. lung

  • several superior lobar arteries, variable number of inferior lobar arteries

systemic circuit

supplies oxygen and nutrients to all organs and tissues and removes metabolic wastes

ascending aorta

coronary arteries

aortic arch

• brachiocephalic a.

• L. common carotid a.

• L. subclavian a.

descending aorta

• thoracic aorta

• abdominal aorta

external carotid a.

• superior thyroid

• lingual

• facial

• occipital

• maxillary

• posterior auricular

• superficial temporal

internal carotid a.

• ophthalamic

• anterior cerebral

• middle cerebral

vertebral a.

basilar a.

• cerebrellar a.a.

arteries of the head and neck

• common carotid a. (R and L)

• internal carotid a.

• vertebral a.

• thyrocervical trunk

• costocervical trunk

cerebral arterial circle

• anterior cerebral a.

• anterior communicating a.

• middle cerebral a.

• posterior cerebral a.

• posterior communicating a.

veins of the head and neck

• dural venous sinuses

• internal jugular v.

• external jugular v.

• vertebral v.

dural venous sinuses

• superior sagittal sinus

• inferior sagittal sinus

• transverse sinus

• cavernous sinuses

arteries of the thorax

• branches of aortic arch

• visceral branches of the thoracic aorta

• parietal branches of the thoracic aorta

• branches of the subclavian and axillary

branches of aortic arch

• brachiocephalic (R. only)

• L. common carotid

• L. subclavian

visceral branches of the thoracic aorta

• bronchial a.a.

• esophageal a.a.

• mediastinal a.a.

parietal branches of the thoracic aorta

• posterior intercostal aa

• subcostal aa

• superior phrenic aa

branches of the subclavian and axillary

• internal thoracic a.

  • pericardiophrenic a.

  • anterior intercostal aa.

• thoracoacromial a.

• lateral thoracic a.

• subscapular a.

veins of the thorax

• tributaries of the SVC

• the azygos system

tributaries of the SVC

• subclavian v.

• brachiocephalic v.

• SVC

the azygos system

• Azygous v. (only on R.)

  • ascending lumbar v.

  • posterior intercostal vv.

  • esophageal v.

  • mediastinal v.

  • pericardial v.

  • bronchial v.

• hemiazygous v. (only on L.)

• accessory hemiazygous v.

major branches of the abdominal aorta

• inferior phrenic aa

  • superior suprarenal a.

• celiac trunk

• superior mesenteric a. (unpaired)

• middle suprarenal a.

• renal a.

  • inferior suprarenal a.

• gonadal aa. (ovarian / testicular aa)

• inferior mesenteric a. (unpaired)

• lumbar aa.

• median sacral a.

• common iliac aa.

  • external iliac a.

  • internal iliac a.

celiac trunk

unpaired stump to three branches

branches of the celiac trunk

• common hepatic a.

  • gastroduodenal a.

  • hepatic artery proper

• L. gastric a.

• splenic a.

  • pancreatic a.

  • L. gastro-omental a.

  • short gastric aa.

types of mesenteric arteries

• superior mesenteric a.

• inferior mesenteric a.

superior mesenteric a.

• inferior pancreaticoduodenal a.

• jejunal / ileal aa.

• ileocolic a.

• right colic a.

• middle colic a.

inferior mesenteric a.

• L. colic a.

• sigmoid aa.

• superior rectal a.

branches of the internal iliac artery

• anterior trunk

• posterior trunk

anterior trunk

• superior vesicle a.

• inferior vesicle a. (male); vaginal a. (female)

• middle rectal a.

• obturator a.

• internal pudendal a.

• uterine a.

• inferior gluteal a.

posterior trunk

• iliolumbar a.

• lateral sacral a.

• superior gluteal a.

tributaries of the IVC

• common iliac vv.

  • external iliac v.

  • internal iliac v.

• lumbar vv.

• R. gonadal v. (ovarian/ testicular)

• renal vv.

  • L. gonadal v.

  • L suprarenal v.

• R. suprarenal v.

• inferior phrenic vv.

• hepatic vv.

L. ascending lumbar v. becomes

hemiazygos v. above the diaphragm

R. ascending lumbar v. becomes

azygos v. above the diaphragm

hepatic portal v.

blood from GI tract sent to liver before heart

parts of hepatic portal system

• inferior mesenteric v.

• superior mesenteric v.

• splenic v.

• pancreatic vv.

• cystic v.

• L., R. gastric vv.

arteries of the shoulder and arm

• subclavian a.

• axillary a.

  • circumflex humeral aa.

• brachial a.

  • deep brachial a.

• radial collateral a.

• super ulnar collateral a.

arteries of the forearm, wrist and hand

• radial a.

• ulnar.

• interosseous aa.

  • common

  • anterior

  • posterior

• palmar arches

  • superficial

  • deep

superficial veins of the upper limb

• dorsal venous network

• cephalic v.

• basilic v.

• median cubital v.

• median antebrachial v.

deep veins of the upper limb

• deep and superficial palmar arches

• radial v.

• ulnar v.

• brachial v.

• axillary v.

• subclavian v.

arteries from the pelvic region to the knee

• external iliac a.

• femoral a.

  • deep femoral a.

  • circumflex femoral a.

• popliteal a.

  • genicular aa.

arteries of the leg and foot

• anterior tibial a.

  • dorsal a.

  • arcuate a.

• posterior tibial a.

  • medial and lateral plantar aa.

  • deep plantar arch

• fibular (peroneal) a.

deep veins of the lower limbs

• deep plantar venous arch

  • lateral and medial plantar vv.

• posterior tibial vv.

• fibular (peroneal) vv.

• popliteal v.

• anterior tibial v.

• femoral v.

• deep femoral v.

  • circumflex femoral v.

• external iliac v.

• internal iliac v.

• common iliac v.

superficial veins of the lower limb

• dorsal venous arch

• small (short) saphenous v.

• great (long) saphenous v.

angiogenesis begins

begins at 13 to 15 days of gestation

mesenchymal cells differentiate into

differentiate into blood islands

hemocytoblasts become

become blood cells

angioblasts become

become endothelial cells

neonatal circulation - step 1

foramen ovale closes and become fossa ovalis

neonatal circulation - step 2

ductus arteriosus constricts and becomes ligamentum arteriosum

neonatal circulation - step 3

umbilical arteries degenerate and become median umbilical ligaments

neonatal circulation - step 4

umbilical vein constricts and becomes round ligament of liver

neonatal circulation - step 5

ductus venosus degenerates and becomes ligamentum venosum of liver

neonatal circulation - step 6

blood returning to the heart is now oxygem-poor, systemic blood only

fetal circulation - step 1

blood bypasses the lungs by flowing directly from the right atrium thorigh the foramen ovale into the left atrium

fetal circulation - step 2

blood also bypasses the lungs by flowing from the pulmonary trunk thorugh the ductus arteriosus into the aorta

fetal circulation - step 3

oxygen-poor, waste-laden blood flows through two umbilical arteries to the placenta

fetal circulation - step 4

the placenta disposes of CO2 and other wastes and reoxygenates the blood

fetal circulation - step 5

oxygenated blood returns to the fetus thorugh the umbilical vein

fetal circulation - step 6

placental blood bypasses the liver by flowing through the ductus venosus into the IVCfetal circulation - step

fetal circulation - step 7

placental blood from the umbilical vein mixes with fetal blood from the IVC and returns to the heart