Vasculature - 04

Question 1

what are the 4 divisions of the aorta?

Answer 1

arch of the aorta, ascending aorta, thoracic aorta, abdominal aorta

Question 2

celiac trunk

Answer 2

gives rise to blood to things such as proximal segment of GI tract e.g. liver, stomach, part of duodenum

Question 3

what are the unpaired arteries supplying the GI tract?

Answer 3

celiac trunk, superior and inferior mesenteric arteries

Question 4

superior mesenteric artery

Answer 4

supplies remainder of small intestine not covered by celiac artery and all of the colon until the descending portion

Question 5

inferior mesenteric artery

Answer 5

supplies the colon; sigmoid colon and rectum

Question 6

GI tract blood supply

Answer 6

has many anastomoses to ensure blood flow is always going to as many segments as possible of the intestine

Question 7

what are the paired arteries of the abdominal aorta?

Answer 7

lumbar arteries, renal arteries, gonadal arteries and suprarenal arteries

Question 8

what does the SVC drain?

Answer 8

head, neck, chest, upper limbs

Question 9

what veins are part of the coronary circulation?

Answer 9

Great cardiac vein, middle cardiac vein, small cardiac vein, anterior cardiac vein, coronary sinus

Question 10

what does the IVC drain?

Answer 10

abdomen, pelvis, lower limbs

Question 11

what are the major abdominal and pelvic veins?

Answer 11

L and R suprarenal veins, renal veins, lumbar veins, gonadal vein

Question 12

hepatic portal system

Answer 12

a capillary bed turns into a vein and then becomes another capillary bed elsewhere 9Liver); capillary bed accepts nutrients from GI wall and is delivered to 2nd capillary bed in liver to process nutrients and eliminate waste

Question 13

arteries

Answer 13

carry blood away from heart

Question 14

capillaries

Answer 14

site of gas and nutrient exchange

Question 15

veins

Answer 15

return blood to the heart (blood reservoirs)

Question 16

what are the 3 layers of an artery?

Answer 16

tunica intima, tunica media, tunica externa

Question 17

tunica intima

Answer 17

innermost later lining BV containing endothelium, basement membrane and internal elastic lamina

Question 18

tunica media

Answer 18

middle layer of BV wall where smooth muscle is found within arteries; allows us to change diameter of arteries to regulate BP, regulate blood flow to an organ/divert blood flow, contains more elastic fibers (external elastic lamina)

Question 19

tunica externa

Answer 19

aka tunica adventitia, consists of elastic and collagen fibers

Question 20

vasa vasorum

Answer 20

small vessels that supply blood to outer part of the larger vessels

Question 21

what are the 3 layers of a vein?

Answer 21

tunica intima, tunica media, tunica externa; however there are no elastic fibres and the wall thickness is much smaller due to low pressure of blood in the veins; veins also have valves

Question 22

elastic arteries (conducting arteries)

Answer 22

initial arteries coming off the heart, lots of elastic tissues and conduct blood away to heart and branch off into distributing arteries

• must handle pressure from contractions and provide pressure b/w heartbeats
• full of elastic fibers
• stretch and recoil

Question 23

muscular arteries (distributing arteries)

Answer 23

medium sized and have thick, muscular tunica media and have ability to cause tone in BV; capable of greater vasoconstriction/dilation to adjust rate of flow

Question 24

arterioles

Answer 24

resistance vessels with smaller and thinner walls, have the greatest effect on BV

Question 25

capillary structure

Answer 25

exchange vessels that only have 1 layer (endothelium + basement membrane) to allow for exchange of nutrients within body

Question 26

throughfare channel

Answer 26

major pathway of blood through a capillary; when cold, this is often the only one open in the skin

Question 27

how is blood flow controlled in capillary beds?

Answer 27

little aggregations of smooth muscle within vessel that act like a sphincter - pre-capillary sphincter

Question 28

what are the 3 types of capillaries?

Answer 28

continuous, fenestrated, sinusoidal

Question 29

continuous capillaries

Answer 29

continuous layer of endothelial cells tightly glued to one another + to basement membrane; minimal fluid getting out into tiss. - important in brain, lungs, muscles

Question 30

fenestrated capillaries

Answer 30

have little pores in the capillary beds, pores formed by endothelial cells, allow for nutrient exchange and some filtration, small enough that formed elements cannot pass through - useful in kidneys, choroid plexus

Question 31

sinusoid capillaries

Answer 31

huge gaps b/w endothelial cells (big enough for cells to move through), basement membrane incomplete. found in red bone marrow b/c it is where RBC and WBC are derived and need to enter blood; found in liver b/c of large nutrients from GI tract

Question 32

hydrostatic pressure

Answer 32

the pressure within a blood vessel that tends to push fluids and nutrients out of the vessel into tissues, formed elements and large proteins often don’t cross

Question 33

fluid movement at the arterial end of a capillary

Answer 33

net filtration

Question 34

oncotic pressure

Answer 34

the pressure of water to move back into the capillary, as the result of the presence of formed elements and proteins in the vessel

Question 35

fluid movement at the venous end

Answer 35

net reabsorption; some fluid has already been lost to tissues but will contain some waste that needs to be drawn back

Question 36

Starling’s Law of the Capillaries

Answer 36

fluid movement is governed by 4 forces: blood hydrostatic pressure, interstitial oncotic pressure, blood oncotic pressure, interstitial hydrostatic pressure

Question 37

what are the two methods of aiding venous return?

Answer 37

skeletal muscle pump and respiratory pump

Question 38

skeletal muscle pump

Answer 38

contraction of muscle compresses deep veins and “milks” blood back to the heart

Question 39

respiratory pump

Answer 39

inhalation moves the diaphragm down and increases pressure in the abdomen, compressing abdominal veins and forcing blood back to the heart

Question 40

blood distribution

Answer 40

60% blood volume is in systemic veins and venules, blood is diverted from it in times of need; less blood volume is in the systemic arteries and arterioles (~15%)