cardiovascular system - blood vessels anatomy chap. 22
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Cardiovascular system - Blood Vessels Anatomy Chap. 22. Arteries. Veins. Arterioles. Venules. Capillaries. Basic Anatomy of Circulatory routes. Carry blood towards the heart. Carry blood away from the heart. Connect capillaries to veins. - PowerPoint PPT PresentationTRANSCRIPT
Cardiovascular system -Cardiovascular system -Blood VesselsBlood Vessels
Anatomy Chap. 22Anatomy Chap. 22
Basic Anatomy of Circulatory routes
Arteries
Arterioles
Capillaries
Venules
VeinsCarry blood away from the heart
Control blood flow into capillaries & help regulate BP
Allow for “exchange” (filtration/reabsorption) of O2/CO2, nutrients/wastes
Connect capillaries to veins
Carry blood towards the heart
Structure of Blood Vessels
Arteries & Veins
Both are comprised of 3 layers of tissue - tunica interna, tunica media & tunica externa - surrounding “lumen” through which blood will flow:
All structural difference between arteries & veins primarily due to differences in pressure of blood flowing within
Lumen – larger diameter in veins compared to corresponding artery
Arteries & Veins
Tunica Interna – innermost endothelium of simple squamous epithelium + basement membrane
Arteries – have an “internal elastic lamina” of elastic CT to allow for expansion under pressure
Veins – may have “valves” (folds of endothelium + CT) to prevent backflow of blood due to low pressure
Arteries & VeinsTunica Media – middle layer containing smooth muscle (for contractility/vasoconstriction) & elastic CT (for elasticity)
Arteries – have relatively thick tunica media allowing for significant vasoconstriction & elasticity
Elastic/conducting arteries – relatively more elastic tissue than smooth muscle; ie. aorta, pulmonary trunk, etc. Muscular/distributing arteries - relatively more muscle tissue than elastic tissue; ie. brachial, femoral, etc.
Veins – relatively thin tunica media therefore no significant constriction/elasticity
Arteries & Veins
Tunica Externa (a.k.a. adventitia) – made of collagenous CT
Arteries – thin layer
Veins – thickest layer of vein, trying to support against gravity & low pressure
Arteries & Veins
Arterioles & Venules
Very small, almost microscopic vessels with only 2 layers of tissue surrounding lumen
Arterioles – endothelium (tunica interna) + very thin layer of smooth muscle cells (tunica media); regulate blood flow to tissues & affect arterial blood pressure
Venules – endothelium (tunica interna) + thin layer of CT (tunica externa)
Capillaries Microscopic, very thin-walled vessels comprised of endothelium with basement membrane; allows for filtration and reabsorption Found in all tissues of the body except for those that are “avascular” Usually form branching networks (“capillary beds”) within tissues for increased surface area blood flow into capillaries may be regulated by “pre- capillary sphincters”
Capillaries can be classified as continuous, fenestrated, or sinusoids
Circulatory Routes - overview
Circulatory Routes – Pulmonary Circuit
Circulatory Routes – Systemic circuit
Ascending aorta (gives off coronary arteries)
Aortic arch
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
Thoracic (descending) aorta
Abdominal aorta
Common iliac arteries
Arterial blood from left ventricle into ascending aorta
Venous return to right atrium through superior vena cava (SVC), inferior vena cava (IVC) & coronary sinus
Cerebral circulationBasilar artery (from union of vertebral arteries) + Internal carotid arteries
Cerebral arterial circle (“circle of Willis)
Cerebral circulation
Venous drainage from dural venous sinuses and cerebral veins into internal jugular vein and vertebral veins
LIVER
Hepatic Portal Vein
Cystic vein
Lt. gastric vein
Splenic vein
Inferior mesenteric
veinSuperio
r
mesenteric
vein
AORTA
(blood mixes in sinusioids)
Hepatic Veins
IVC
Hepatic arte
ry
Hepatic portal circulationVenous blood flow from GIT & spleen to liver – ensures delivery of nutrients to liver first
Hepatic portal circulation Cystic vein, left gastric vein, splenic vein, inferior & superior mesenteric veins Hepatic portal vein
Hepatic portal vein (deoxygenated/nutrient rich blood) + Hepatic artery (oxygenated blood) sinusoids of liver
Sinusoids of liver Hepatic veins IVC
Lt. Gastric v
Fetal CirculationPlacenta – O2/CO2 & nutrient/waste between mom & baby
Umbilical cord – (2) umbilical arteries (baby mom) & (1) umbilical vein (mom baby)
Umbilical vein (O2/nutrient rich blood) hepatic portal vein & ductus venosus IVC Rt. atrium
Rt. Atrium some blood to rt. Ventricle, most shunts across foramen ovale in interatrial septum lt. atrium lt. ventricle
Blood from Rt. Ventricle pulmonary trunk across ductus arteriosus to aorta
Aorta systemic arteries internal iliac arteries umbilical arteries placenta
Fetal Circulation
Fetal Circulation- Changes at Birth
Umbilical vein ligamentum teres (round ligament)
Umbilical arteries lateral umbilical ligaments
Ductus venosus ligamentum venosum
Foramen ovale fossa ovalis
Ductus arteriosus ligamentum arteriosum
Placenta delivered (“afterbirth”)
Systemic circuit - Arteries
Systemic circuit - Veins
Upper extremity arteries
Ulna veinRadial vein
Upper extremity arteries & veins
Arteries & Veins of lower extremity
Arteries & Veins of lower extremity
Arteries & Veins of lower extremity
Vessels of abdominal region
Lt. Gastric a