Vasculature

Question 1

Four divisions of the aorta

Answer 1

Arch

Ascending

Thoracic

Abdominal

Question 2

What makes up the descending aorta?

Answer 2

Thoracic + abdominal aortas

Question 3

Unpaired abdominal aortic arteries (x3)

Answer 3

Celiac trunk

Superior mesenteric a.

Inferior mesenteric a.

Question 4

Celiac trunk supply

Answer 4

Supplies the liver, stomach, spleen, pancreas + duodenum

Question 5

Superior mesenteric a. supply

Answer 5

Supplies the pancreas, SI and part of LI

Question 6

Inferior mesenteric a. supply

Answer 6

Supplies the rest of the LI

Question 7

Paired abdominal aortic arteries (x4)

Answer 7

Suprarenal

Renal

Gonadal

Lumbar arteries (x4): common iliac = last pair

Question 8

Paired abdominal/pelvic veins (x4)

Answer 8

Suprarenal

Renal

Gonadal

Lumbar

Question 9

Where do inferior + superior mesenteric veins drain?

Answer 9

Hepatic portal vein

Question 10

Where does blood go after the hepatic portal vein?

Answer 10

Sinusoids of the liver (detoxifies, then goes back into general circulation)

Question 11

Why does venous blood from GI organs go to the liver before IVC?

Answer 11

Allows for filtration of the blood before returning to the heart (detoxifies)

Question 12

Function of a conduit vessel + example

Answer 12

Transport blood –> regions of body

Aorta

Question 13

Function of a distribution vessel + example

Answer 13

Distribute blood specifically to different organs

Femoral a.

Question 14

Function of a resistance vessel + example

Answer 14

Allows for resistance in circulation

Arterioles

Question 15

Function of a exchange vessel + example

Answer 15

Movement of gases/fluids/nutrients in and out of blood

Capillaries

Question 16

Function of a capacitance vessel + example

Answer 16

Reservoir for blood

Veins

Question 17

Function of a lymph vessel + example

Answer 17

Maintains fluid balance

Lymphatics

Question 18

Layers of arteries

Answer 18

Superficial –> deep

Tunica intima: endothelium (smooth, secretes NO), basement membrane & internal elastic lamina (holes for diffusion)

Tunica media: SM cells (regulate diameter, stretch) & external elastic lamina (fenestrations + stretch)

Tunica externa: elastic + collagen fibers, vaso vasorum (nourishes outer walls when there is not enough diffusion)

Question 19

Layers of veins

Answer 19

Intima: endothelium, basement membrane

Media: much inner than a. (SM cells)

Externa: elastic + collagen + vaso vasorum

Question 20

Differences between veins and arteries

Answer 20

Walls of veins = thinner

Veins = no elastic layers but they have valves

Question 21

Characteristics of elastic arteries

Answer 21

Expand when BP increases & recoils when BP decreases

*Pressure reservoir –> storage of mechanical energy

During recoil = converts stored potential energy –> kinetic energy

Question 22

Atherosclerosis & elastic arteries

Answer 22

Walls of arteries become stiffer –> less stretching

Heart has to work harder during ventricular relaxation to maintain a good rate of BF

Question 23

Characteristics of muscular arteries

Answer 23

More elastic fibers in tunica media

More vasoconstriction/dilation to adjust rate of flow

Distributing arteries to direct BF

Question 24

Purpose of arterioles

Answer 24

Regulate BF into capillary networks to body tissues (regulates resistance)

Question 25

What is a metarteriole?

Answer 25

Terminal end of an arterial –> form branches + supply capillary beds

Proximal ends have SM cells that regulate BF

Question 26

What are precapillary sphincters?

Answer 26

At metarteriole-capillary junction –> monitor BF into the capillaries

Relaxed = blood into capillary bed

*This helps regulate where BF is needed

Question 27

Capillary composition

Answer 27

Mostly composed of endothelial cells

Has pericytes: contractile cells that wrap around the endothelial cell to regulate capillary BF

Question 28

Types of capillaries (x3)

Answer 28

Continuous: has a continual layer of endothelial cells (brain, lungs, CTs)

Fenestrated: lots of fenestrations = filtration (kidney)

Sinusoid: wide fenestrations + incomplete basement membrane, allows big molecules to pass through (bone marrow & liver)

Question 29

Capillary exchange: simple diffusion

Answer 29

Happens through intercellular clefts or fenestrations or right through endothelial cells

Lipid soluble molecules = through membrane

Water soluble molecules = through intracellular clefts

Question 30

Capillary exchange: transcytosis

Answer 30

Transport via vesicles

For large, lipid-insoluble molecules (insulin)

Question 31

Capillary exchange: bulk flow

Answer 31

Passive process –> large # of molecules will move together in same direction

Filtration from capillaries into interstitial fluid

Reabsorption from interstitial fluid into capillaries

Question 32

Starling’s Law

Answer 32

Promote filtration: blood hydrostatic pressure & interstitial oncotic pressure

Promote reabsorption: blood oncotic pressure & interstitial hydrostatic pressure

Question 33

What happens if filtration greatly > reabsorption?

Answer 33

Fluid accumulation (edema) in the interstitial space

Question 34

What gives rise to blood osmotic pressure?

Answer 34

Large molecules that cannot pass into the interstitial fluid

Question 35

Ways to aid venous return (x2)

Answer 35

Skeletal muscle pump: contraction of muscle milks blood towards heart

Respiratory pump: inhalation = diaphragm moves down = increased abdominal pressure = compression of abdominal vessels = blood moves towards heart

Question 36

What does a higher venous return mean?

Answer 36

Higher preload = higher stroke volume = higher CO to tissues

Question 37

What are the principle blood reservoirs?

Answer 37

Systemic veins and venules

Question 38

What allows for veins to act as blood reservoirs?

Answer 38

Thinner walls allow for distention