Lecture Outline #22: CV: Circulation Flashcards
BV 3 layers
1) tunica interna - thin endothelium
2) tunica media - smooth muscle
3) tunica externa - CT sheath around outside of vessel
lumen
opening in BV, where blood flows
arteries (function, lumen, appearance, 3 layers)
function: carry blood from heart to tissues
lumen: always open
appearance: round, thick walls
TI: internal elastic membrane
TM: thick middle layer
TE: collagen & elastic fibers - for contraction/expansion, few restriction because it is slippery
veins (function, lumen, appearance, 3 layers)
function: return blood to the heart from tissues
lumen: closed when no blood is within
appearance: not always round, has thin walls
TI: smooth walls, no elastic membrane
TM: thin muscle layer
TE: collagen fibers, few elastic fibers
lymphatics
function: return lymph (interstitial fluid) to heart
appearance: very thin-walled vessels with small valves
capillary beds (appearance)
very small so only 1 RBC is allowed to go through at a time, plasma is lost here.
lymphatics - edema
a chronic disease that occurs when the body’s lymphatic system is unable to properly remove excess fluid from tissues
Blood composition
Total: 1.2 - 1.8 gallons depending on body size
30mL are present in the brain
1/3 of blood is arterial while 2/3 of blood is venous (deep and superficial veins)
15% heart & lungs
20% brain, capillaries, arteries
65% skin, gut, liver, veins
how does the tunica media control blood flow
the tunica media is smooth m. that adjusts BV diameter (ANS controls lumen size)
- vasoconstriction (decrease in diameter)
- vasodilation (increase in diameter)
blood flow control - fight/flight response
dilation of capillary beds in m.s which increases O2 delivery aka shunting blood away from cap beds
restriction of blood supply to gut redistributing blood
blood flow control - rest/digest response
dilation of capillary beds in gut, shunting/bypassing blood, redistributing blood to gut (increase food absorption)
passing out (BVs)
parasym - GI vasodilation of vessels
sym - peripheral vessels & m.s vasodilate
arteries - types
1.elastic a. - lots of elastin, absorbs pressure fluctuations
2. Muscular a. - lots of smooth m., expand/control to control blood flow
3. Arterioles - distribute blood from larger a.s to caps
4. continuous capillary - continuous endothelial cell lining, least permeable (only small solutes can pass)
5. endothelial cells - inner single cell lining in BVs, regulates exchange btw blood & tissues
veins - types
- Large v. -
- medium v. -
- venule - smallest v.s, blood from caps to larger v.s
- fenestrated capillary - contain pores, more permeable (allow exchange of bigger molecules)
- endothelial cells - inner single cell lining in BVs, regulates exchange btw blood & tissues
general structure of a.s & v.s
a.s - branch into smaller and smaller arteries
v.s - combine into larger and larger veins
aorta structures
unpaired
ascending aorta
aortic arch
descending aorta
aortic arch
branches -
1. brachiocephalic a.
a. right common carotid a.
b. right subclavian a.
2. Left common carotid a.
3. left subclavian a.
descending aorta branches
1) thoracic aorta
- intercostal a.s (paired) vertebrae, spinal cord
2) abdominal aorta
- renal a.s (paired) kidneys
- gonadal a.s (paired) testes or ovaries
- lumbar a.s (paired) vertebrae, spinal cord, ab wall
3) common iliac a.s (paired)
- external iliac a.s (paired)
- internal iliac a.s (paired) inside pelvic cavity
anastomoses
where two a.s run into each other without a capillary bed
Ex: epigastric a.s, palmar loop, planter loop
collateral circulation
mainly at large joints
extra arteries that run along side of joint & main artery.
Ex: when flexing arm, main anterior a.s are ‘compressed’ posterior arteries keep arm bloodified.
palmar loop
in hand
ulner a.s are superficial and radial a.s are deep
2 palmar a.s
1 dorsal a.
when does femoral a. become the femoral a.
when the external iliac a. crosses the inguinal ligament, branches into deep femoral (goes to posterior side) and femoral a. (along femur)
when does popliteal become own artery
when the femoral artery passes through the adductor hiatus
what a.s does the popliteal a. split into?
splits in anterior tibial and posterior tibial arteries. The posterior tibial a. has the fibular a. branching off of it (lateral side)
venous drainage of inferior vena cava
phrenic v.s
hepatic v.s
renal v.s
lumbar v.s
gonadal v.s
common iliac v.s
venous drainage around spinal cord/throax area
Azygos v. - runs right side of vertebral column & drains intercostal v.s 1-12. Dumps into posterior aspect of superior vena cava
Accessory hemiazygos - runs left side adn drains intercostal v.s 1-7
Hemiazygos v.s - runs left side and drains intercostal v.s 8-12
Accessory + hemiazygos v.s drain into azygos v.
superficial v.s in superficial fascia of arm
- Cephalic v. - lateral side, dumps into axillary v. which immediately becomes subclavian v.
- basilic v. - medial side
- Median cubital - where cephalic & basilic v.s come together, place for drawing blood
superficial v.s in leg
- Great Saphanus v - anterior side of medial malleolus but runs on medial side of leg, dumps into femoral v. (if heart bypass needed, this vein is taken out)
- Small Sephanus v. - lateral side, dumps into popliteal v.
venous drainage of limbs & skin
2 brachiocephalic v.s that dump into superior vena cava, same v.s as a.s
medium & large v.s: valves
there is no pressure in veins to push blood so veins have valves. If there is movement, valve open superior to contracting muscles and valves closes inferior to contracting muscle.