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HA Ch. 20 (22)
Blood Vessels and Circulation
Question | Answer |
---|---|
oxygenated blood flows...from the heart through... | away...arteries |
arteries diverge into...and then into | arterioles...capillaries of the organs |
deoxygenated blood leaving capillaries is collected into...which merge/converge into | venule...larger veins that carry blood towards the heart |
pattern of oxygenated/deoxygenated blood applies to both the | pulmonary and systemic circulation |
pulmonary circulation; in lungs.. | oxygen and carbon dioxide are exchanged |
systemic circulation; in rest of the body... | oxygen and nutrients are supplied to the body tissues |
three tunics or layers of blood vessel walls | tunica externa, tunica media, tunica intima |
tunica externa | ct layer consisting of collagen and elastic fibers (cells and fibers run longitudinally) |
tunica media | sheets of smooth muscle cells arranged circularly with circular sheets of elastin and collagen in between |
tunica intima (lumen); endothelium =...in vessels that are...and also has a | simple squamous epithelium...>1mm in diameter...subendothelial layer that lies just external to the endothelium |
tunica externa (function) | protects the vessel, further strengthens vessel walls and anchors the vessel to surrounding sturctures |
tunica media; vasoconstriction | decreases diameter of blood vessel when smooth muscle cells contract |
tunica media; vasodilation | increase diamter of blood vessel when relaxed |
tunica media's...convey..for.. | elastin and collagen...elasticity and strength...resisting the blood pressure placed on the vessel wall by each heartbeat |
tunica intima has | flat endothelial cells that form smooth surface, which minimizes the friction of blood moving across them |
arteries conduct...and veins conduct.... | blood flow away from the heart....blood towards the heart |
arterial... | BP vs venous BP |
veins have...compared to similar-sized arteries | wider lumens |
arteries have ...compared to veins | thicker tunica media |
veins have | thicker tunica externa |
veins have..arteries do not have... | valves |
walls of arteries are generally...compared to those of veins | ticker (retain their round shape) whereas veins tend to collapse |
elastic laminae exist in | arteries only, not in veins |
three types of blood vessels | arteries, capillaries, veins |
3 subtypes of arteries | elastic arteries, muscular arteries, arterioles |
arteries conduct blood | away from the heart |
in the systemic circuit, arteries carry | oxygen-rich blood to capillaries of organs/tissues |
in the pulmonary circuit, arteries carry | oxygen-poor blood to the lungs |
the tunica media is | thicker than the tunica externa in arteries |
elastic arteries are in the | aorta and major branches |
elastic arteries are the | largest arteries near the heart |
the elastic arteries are low... | resistance conduits meaning that they are conducting arteries |
elastic arteries have increased | elastin in walls, thick elastin sheets in tunica media |
there is a high...content in elastic arteries that dampens the... | elastin...surges of BP |
muscular arteries = | distributing arteries |
muscular arteries lie distal to the | elastic arteries |
muscular arteries supply | organs |
muscular arteries are muscular because | tunica media is thicker |
unique feature of muscular arteries: especially | thick sheets of elastin lie on each side of the tunica media |
(muscular arteries) internal elastic lamina between the | tunica intima and tunica media |
(muscular arteries) external elastic lamina between the | tunica media and tunica externa |
arterioles are the | smallest of the arteries |
arterioles are low... | resistant conduits meaning they are conducting arteries |
the tunica media of the arterioles consists of only | 1-2 layers of smooth muscle cells |
larger aterioles include | 3 tunics and internal elastic lamina |
smaller arterioles are comprised of | just a layer of smooth muscle cells and underlying endothelium |
arterioles regulate the amount of blood flow to | capillary bed and regulate systemic BP via changing arteriole diameter |
3 types of capillaries | continuous, fenestrated, sinusoidal cappillaries |
capillaries are the...of blood vessels, but are just...enough for | smallest...large...erythrocytes |
structure of capillaries | a single layer of endothelium is surrounded by basal lamina |
capillaries are the most | important blood vessel type because they renew and refresh interstitial fluid |
capillaries deliver | oxygen and nutrients |
capillaries remove | co2 and nitrogenous wastes |
capillaries in the lungs | oxygen enters the blood and co2 leaves it |
in the small intestine, capillaries | receive digested nutrients |
in endocrine glands, capillaries | pick up hormones |
capillaries in kidneys, | nitrogenous wastes are removed from the blood |
capillary beds are structures by which | capillaries supply cells in tissues and are networks of body's smallest blood vessels |
metarteriole | structural intermediate between arteriole and capillary |
thoroughfare channel | structural intermediate between capillary and venule |
thoroughfare channel proceed to join | venules, receive true capillaries along the way |
precapillary sphincters are | smooth muscle cells that wrap around the root of each true capillary where it leaves the metarteriole |
precapillary sphincter functions to regulate | blood flow to tissue, by opening and closing, according to the tissue's needs |
most tissues and organs contain a | rich capillary supply |
tendons and ligaments have | poor capillary supply |
epithelia and cartilage have | no capillary supply, blood supply from CTs |
cornea and the lens also have | no capillary supply, nourished by aqueous homor and other sources |
capillary permeability is the anatomical basis of how | substances are delivered and picked up |
capillary structure is | well suited for their function in the exchange of nutrients and wastes between the blood and the tissues through the tissue fluid |
tight junctions | block passage of small molecules |
intercellular clefts | small molecules exit and enter the capillary |
pericytes are...shaped cells whose... | spider...thin processes form awidely spaced network that does not interfere with capillary permeability |
pericytes | strengthen and stabilize the capillaries |
continuous capillaries are the more | common type |
cont. capillaries have...cells that are connected by...and occur in most.. | endothelial...tight junctions...organs such as skeletal muscles, skin and the central nervous system |
fenestrated capillaries have...that span the...and occur only where there are... | fenestrations(pores)...endothelium...exceptionally high rates of exchange |
sinusoids | sinusoidal capillaries |
sinusoids are...capillaries containing both | wide, leaky, twisted...expanded and narrowed regions |
sinusoids are usually | fenestrated |
sinusoids have...cells with fewer... | endothelial...cell junctions |
in some sinusoids... | intercellular clefts are wide open |
sinusoids occur wherever | extensive exchange of large materials, proteins or cells occur |
sinusoids function in decreasing | blood flow rate to allow time for the many exchange that occur across organ walls |
there are...routes of capillary permeability | four |
direct diffusion of...across the... | oxygen and co2...endothelium |
intercellular clefts allow | most of small molecules to enter and exit capillaries |
caveolae allow | large molecules to enter and exit |
fenestrations in...allow some... | fenestrated capillaries...small molecules to enter and exit |
low permeability capillaries exist in | blood brain barrier |
low permeability capillaries prevents all but the most | vital molecules from leaving the blood and entering the brain tissue |
low perm. caps have a lack of | structural features that account for capillary permeability |
low perm caps have complete | tight junctions in brain caps |
there are no...in low perm caps | intercellular clefts |
low perm caps have...but not... | cont. caps...fenestrated |
low perm caps lack | caveolae |
...and...may cross the BBB | uncharged...lipid soluble molecules (o2, co2, and anesthetics) |
3 types of veins | venules, veins, vena cavae |
veins conduct blood from | capillaries toward the heart |
in systemic circuit | o2 poor blood from capillaries |
in pulmonary circuit | o2 rich blood from the lungs |
venous BP | < arterial BP |
venules are the | smallest of the beins |
venules have | 1-2 layers of smooth muscle in tunica media and tunica externa |
postcapillaryvenules are the..venules which are comprised of... | smallest...endothelium on which lie pericytes |
venules function like | capillaries |
venules join or merge to form | veins |
veins hold fully | 65% of body's blood |
tunica externa of veins is...than... | ticker...tunica media |
vena cavae is the | largest of the veins |
vena cavae has a tunica externa that is...by... | further thickened...longitudinal bands of smooth muscle |
vena cavae have decreased | elastin content compared to arteries |
several mechanisms counteract the | low venous BP and help blood flow along its course towards the heart |
valves prevent | backflow of blood away from the heart |
valves are | cusps formed from tunica intima |
valves are most abundant in | veins of the limbs because superior direction of venous blood flow is opposed by gravity |
valves found in...counteract the low venous BP | veins of the head and neck |
there are no valves in the | thoracic and abdominal cavities |
...of our body and limbs counteract the low venous BP | normal movement |
skeletal muscular pump | contracting muscles press against veins, forcing valves proximal to area of contraction open and propelling blood towards the heart |
venous BP is lower due to | thinner walls, wider lumen, thinner tunica media, thicker tunica externa |
vascular anastomoses have...channels where... | collateral...vessels unite or interconnect |
vascular anastomoses provide | alternative pathways for blood to reach a given body region |
arterial anastomoses; most organs receive blood from | > 1 arterial branch and neighboring arteries often communicate with one another to form anastomoses |
arterial anastomoses occur around..where...may... | joints...active body movements...hinder blood flow through one channel |
occlusion in arterial anastomoses causes | severe tissue damage in some organs |
venous anastomoses occur more | frequently than arterial anastomoses |
venous anastomoses are visibly located through the | skin on dorsum of hand |
occlusion in venous anastomoses rarely | blocks blood flow or leads to tissue death |
vasa vasorum are | little veins in the tunica externa of larger arteries and veins |
vasa vasorum function as the | blood supply of blood vessel walls |
vasa vasorum nourish the | outer half of the wall of the larger vessel |
no vasa vasorum is found in | small blood vessels |
vasa vasorum may arise as | tiny branches from the same large vessel or as a small branch from other, nearby, arteries and veins |
pulmonary circulation begins as...which exits... | o2 poor blood leaves the right ventricle of the heart via the pulmonary trunk...anterior to the aorta and splits into right and left pulmonary arteries inferior to the aortic arch |
each pulmonary artery enters | each lung, at the medial aspect, and branches in the lungs as follows |
lobar arteries | repeated branching of arteries decrease in size and branch along with respiratory bronchi |
pulmonary capillaries that surround the..where...occurs across the... | alveoli...gas exchange...respiratory membrane |
pulmonary tributaries empty...into... | newly oxygenated blood...superior and inferior pulmonary veins |
superior and inferior pulmonary veins exit the | medial aspect of each lung |
each pair of pulmonary veins extend from the | lungs to the left atrium of the heart |
the systemic circulation beings with | o2 rich blood leaving the left ventricle of the heart through the aorta which progressively decrease in size |
size of arteries (largest to smallest) | elastic arteries, muscular arteries, arterioles |
arterioles become...in capillary beds, which... | metarterioles..nourish body tissues with oxygen and nutrients and thus blood becomes o2 poor |
blood flows through...procees to join...and ends with the. | thoroughfare channels...veins...two large vena cavae and the coronary sinus which empty into the right atrium of the heart |
the systemic arteries leave the...and begin as the...which is divided into... | heart...aorta...three parts (ascending aorta, aortic arch, descending aorta) |
ascending aorta branches into | 2 coronary arteries that supply the heart wall |
aortic arch branches into | 3 arteries that run superiorly and supply the head, neck, upper limbs and superior part of the thoracic wall |
3 arteries of the aortic arch | braciocephalic trunk, left common carotid artery, left subclavian artery |
brachiocephalic trunk ascends to the | right toward the base of the neck and further divides |
the brachiocephalic trunk divides into the | right common carotid artery and the right subclavian artery |
the r and l subclavian arteries give off branches...to the...and run.. | vertebral artery, thryocervical trunk, costocervical trunk...neck..laterally onto the first ribs, underlying the clavicle and continue laterally to supply the upper limbs |
the sections of the subclavian arteries exit...passing over the...and continue through the... | the thoracic cavity...outer border of the first rib...upper limb |
subclavian arteries are named according to the | specific region of the upper limb it supplies |
subclavian branches into the | axillary, brachial, radial, ulnar, plamar, digital |
most parts of the head and neck are supplied by the | common carotid arteries which divide into an external and internal carotid artery each |
both the r and l external carotid arteries supply | most tissues of the head external to the brain and orbit and send branches |
external carotid arteries send branches to the | superior thyroid artery, lingual artery, facial artery, occipital artery |
superior thyroid artery supplies the | thyroid gland and larynx |
lingual artery supplies the | tongue |
facial artery supplies the | skin and muscles of the anterior face |
occipital artery supplies the | posterior part of the scalp |
each external carotid ends near the | temporomandibular joint |
external carotid splits into the | superficial temporal artery and maxillary artery |
superficial temporal artery supplies | most of the scalp |
maxillary artery branches also to the | teeth, cheeks, nasal cavity and muscles of mastication |
the internal carotid arteries supply the | orbits and most of the cerebrum |
internal carotid enters the | sella turcica of sphenoid bone just posterior to the foramen and branches off |
internal carotid branches off as the | opthalamic artery(eyes and orbits), anterior and middle cerebral arteries(supplies 80% of the cerebrum) |
each anterior cerebral artery anastomoses with | each oter through a short anterior communicating artyer |
the posterior brain is supplied by the...which ascend the..sending branches to the... | r and l vertebral arteries...vertebral column...vertebrae and cervical spinal cord |
the right and left vertebral arteries join to form the | unpaired basilar artery within the cranium |
at the border of the pons and medulla, the basilar artery divides into a pair of...and is connected to the...by the.. | posterior cerebral arteries...middle cerebral arteries anteriorly...posterior communicating arteries |
together, the posterior cerebral arteries and the middle cerebral arteries and the anterior communicating artery, complete the formation of an | arterial anastomosis called the cerebral arterial circle |
the cerebral arterial circle forms a | loop around the pituitary gland and optic chiasma |
the cerebral arterial circle unites the | brain's anterior and posterior blood supplies provided by the internal carotid and vertebral arteries |
the cerebral arterial circle provides | alternate routes for blood to reach the brain areas that are affected if either a carotid or vertebral artery becomes occluded |
descending aorta runs | posterior to the heart and inferiorly on the bodies of the thoracic and lumbar vertebrae |
the descending aorta has two sections | thoracic aorta and abdominal aorta |
the thoracic aorta goes from...and supplies the... | T3-T12...thoracic organs and body wall |
abdominal aorta goes from...and supplies the...and divides into the...which supply the... | T12-L4...abdominal organs...r and l common iliac arteries...pelvis and lower limbs |
the common iliac arteries descend...and each section is named according to the | each limb...specific region of the lower limb it supplies |
the common iliac artery supplies the | femoral, politeal, anterior and posterior tibial arteries |
branches to the...and other...are.. | bodywall, kidneys...structures outside the peritoneal cavity...paired |
branches to the body wall, kidneys and other non peritoneal cavity structures originate along the | lateral surfaces of the abdominal aorta |
the major branches to visceral organs are...and arise on the... | unpaired...anterior surface of the abdominal aorta and they extend into the mesenteries to reach the visceral organs |
three unpaired arteries are the | celiac trunk, superior and inferior mesentary arteries |
the celiac trunk is superiorly located branch that delivers... | blood to the liver, stomach, esophagus, gallbladder, duodenum, pancreas, and spleen |
celiac trunk divides into | left gastric artery, splenic artery and common hepatic artery |
left gastric artery supplies | stomach and inferior portion of esophagus |
splenic artery supplies the | spleen and arteries to the stomach and pancreas |
common hepatic trunk supplies arteries to the | liver, stomach, gallbladder, and duodenal area |
the superior mesenteric artery arises about...inferior to the...to supply arteries to the | 2.5 cm...celiac trunk...pancreas and duodenum, small intestine and most of the large intestine |
the inferior mesenteric artery delivers | blood to the terminal portions of the colon and rectum |
the sytemic veins mostly run...but there are important differences in the... | ...with corresponding arteries...distribution of arteries and veins |
the superior vena cava arises from the | merging of the r and l brachiocephalic veins |
the r and l brachiocephalic veins are each formed by the | union of an internal jugular vein and a subclavian vein |
the inferior vena cava begins inferiorly as the | union of the two common iliac veins at the level of vertebra L5 |
the inferior vena cava; blood returning from the | abdominopelvic viscera and the abdominal wall reaches the heart via the IVC |
most venous tributaries of the IVC share the names of the | corresponding arteries |
veins of the head and neck; most blood draining from the | head and neck enters 3 pairs of veins |
3 pairs of veins in the head and neck | internal jugular veins from the dural sinuses, external jugular veins, vertebral veins |
veins of the upper limbs are either | deep or superficial |
deep veins include | palmar venous arches to the radial and ulnar veins which unite and form the brachial veins of the arm and enter the axilla as the axillary veins which become the subclavian vein at the first rib |
the palmar venous arches supply the | hand |
superficial veins include | cephalic veins, basilic veins, median cubital veins, median veins of the forearm |
veins of the thorax empty blood from the...into the...whereas blood from the...and from some of the...drains into the... | first few intercostal spaces...brachiocephalic veins...other intercostals spaces...thoracic viscera...azygos system |
the azygos system of veins is a group of...which flank the..and ultimately empty into the... | veins...vertebral column...SVC |
the azygos system consists of the | azygos vein, hemiazygos vein, and the accessory hemiazygos vein |
veins of the abdomen include the | lumbar, gonadal, renal, suprarenal, hepatic veins |
portal system is a set of...in which...lie between the | vessels...two capillary beds, interconnected by a vein...initial artery and the final vein |
hepatic portal system is a special | subcirculation that drains the digestive system |
veins of the pelivs and lower limbsare either | deep or superficial and ascend and merge to ultimately become the IVC |
deep veins of the pelvis annd lower limbs share the names of the | arteries they accompany |
the deep veins of the pelvis and lower limbs include the | plantar, tibial, fibular, popliteal, femoral, internal/external iliac, common iliac veins |
superficial veins of the pelvis and lower limbs includes the | dorsal venous arch of foot, great saphenous veins that empty into the femoral vein and the small saphenous veins that empty into the popliteal vein |