Systemic and Pulmonary Circulation

Question 1

What are arteries

Answer 1

• carry blood away from heart
• “conducting arteries”

Question 2

What are the medium-sized arteries

Answer 2

• “distributing arteries”
• high elastin component dampens the BP from heart contraction

Question 3

What are the divisions of medium-sized arteries?

Answer 3

Arterioles: divide into capillaries

Question 4

Describe capillaries

Answer 4

• substances are exchanged btwn blood and body tissues
• groups unite to form small veins: venules
• large enough for ONE erythrocyte at a time

Question 5

What are veins

Answer 5

Merging of venules forming larger blood vessels
- carry blood back to heart

Question 6

What is Vasa Vasorum

Answer 6

“Vasculature of vessels”
- network of smaller vessels located in the walls of larger blood vessels
- supply oxygen and nutrients to those larger blood vessels

Question 7

What are the layers of the artery wall

Answer 7

1. Tunica interna (closest to lumen)
   - smooth surface, prevents friction
2. Tunica media (thickest, highly elastic)
   - smooth muscle: vasoconstriction/dilation
3. Tunica externa (elastic+collagen fibers)
   - protects vessel, anchors it to surrounding structures

Question 8

What arterioles?

Answer 8

“resistance vessels”
- key role in regulating blood flow into capillaries
- change in diameter affects BP

Question 9

What are capillaries? where are they found?

Answer 9

“exchanging vessels”
- connect arterioles and venules
- extensive network in muscles, liver, kidneys, nervous system (use more O2 and nutrients)
- none are found in lining of epithelia, cornea, lens and cartilage (avascular)

Question 10

How many layers do capillaries have?

Answer 10

1: tunica interna

Question 11

What happens to capillaries when there is an increase in metabolic activity?

Answer 11

entire network fills w/ blood (normally low metabolic need: blood flows thru small portion of capillary network bc sphincters are contracted)

Question 12

What supplies the capillary bed?

Answer 12

Metarteriole

Question 13

What are the layers of venules?

Answer 13

• tunica interna
• tunica media

Question 14

How many layers to veins have?

Answer 14

3 (tunica interna/media/externa)

Question 15

Which can withstand higher pressure: arteries or veins?

Answer 15

arteries

Question 16

How is pumping of venous blood back to the heart done?

Answer 16

• pumping of heart
• contraction of skeletal muscles in lower limbs
• valves found in veins

Question 17

Explain venous valves

Answer 17

• each valve: 2 or more folds of tunica interna forming cusps projecting towards the heart
• leaky valves: varicose veins

Question 18

At rest where how is your blood distributed?

Answer 18

Most: veins/venules
Then: heart
Then: arteries/arterioles
Least: capillaries

Question 19

What is the systemic circulation composed of?

Answer 19

• Cerebral circulation
• Portal system (liver and digestive)
• all arteries branching from aorta (including coronary circulation)
• all veins draining into IVC, SVC, coronary sinus

Question 20

List the first main arteries of the head and neck (3)

Answer 20

• Brachiocephalic (right)
• subclavian (r. and l.)
• common carotid (r. and l.)

Question 21

What branches off the subclavian a.?

Answer 21

• vertebral a.
• internal mammary/thoracic and ant. intercostal aa. (9)

Question 22

What branches off of the common carotid a.?

Answer 22

• internal carotid
• external carotid

Question 23

What 7 branches does the external carotid split into?

Answer 23

• sup. thyroid a.
• lingual a.
• facial a.
• occipital a.
• post. auricular a.
• maxillary a.
• superficial temporal a.

Question 24

What does the maxillary a. split into

Answer 24

• infraorbital a.
• middle meningeal a.

Question 25

What does the superficial temporal a. split into?

Answer 25

- transverse facial a. - zygomatico-orbital a. - frontal a. - parietal a.

Question 26

What does the thoracic aorta split into?

Answer 26

- post. intercostal aa. (9) - abdominal aorta (past diaphragm)

Question 27

List the 8 branches of the abdominal a. What do they supply?

Answer 27

- celiac trunk (GI tract, spleen) - inf. phrenic a. (2) (diaphragm) - suprarenal (adrenal) a. (2) (adrenal/suprarenal glands) - renal a. (2) (kidneys) - sup. mesenteric a. (GI tract) - testicular/ovarian a. (2) (gonads) - inf. mesenteric a. (2) (GI tract) - common iliac a.

Question 28

What does the common iliac a. split into and what does each supply?

Answer 28

- external iliac (lower extremities) - internal iliac (pelvis/perineum)

Question 29

What does the celiac trunk split into?

Answer 29

- left. gastric a. - splenic a. - common hepatic a.

Question 30

What does the splenic a. become? what does it supply?

Answer 30

left gastroepiploic a. (supplies greater curvature of stomach and greater omentum)

Question 31

What does the common hepatic a. split into? what do they supply?

Answer 31

- right gastric a. (stomach and esophagus) - gastroduodenal a. (stomach, duodenum, pancreas, greater omentum) - right and left hepatic aa. (liver) - cystic a. (gall bladder)

Question 32

What does the gastroduodenal a. split into?

Answer 32

- sup. (ant.) pancreaticoduodenal a. - right gastroepiploic a.

Question 33

What does the superior mesenteric a. split into?

Answer 33

- inf (ant.) pancreaticoduodenal a. - middle colic a. - right colic a. - ileocolic a. - intestinal aa.

Question 34

What does the ileocolic a. split into?

Answer 34

- ileal a. - colic a.

Question 35

What do the intestinal aa. split into?

Answer 35

- jejunal aa. - ileal aa.

Question 36

What does the inf. mesenteric a. split into?

Answer 36

- left colic a. - sigmoid aa. - superior rectal a.

Question 37

What does the left colic a. split into?

Answer 37

- sup. left colic a. - inf. left colic a.

Question 38

Describe the superior vena cava

Answer 38

- drains head, neck, and upper limb - drains intercostal and lumbar regions by "azygos system"

Question 39

Describe the inferior vena cava

Answer 39

- no major veins draining the GI tract, gall bladder, and pancreas (use portal system) - liver drained by hepatic vv. - testicular/ovarian vv. on right side only (left go into renal v.)

Question 40

What is the azygos system?

Answer 40

hemiazygos v. (left, lumbar/lower thoracic) and accessory hemiazygos v. (left, upper thoracic) join azygos v. (right side of sternum) to drain into SVC

Question 41

What veins is the portal system composed of?

Answer 41

- sup. mesenteric v. - inf. mesenteric v. - splenic v. - hepatic portal v.

Question 42

Describe the portal system

Answer 42

- detours blood from GI organs and spleen through the liver before going to IVC - carries blood from one capillary network to another (2 separate capillary networks before going back to heart) - rich in substances after a meal

Question 43

What are some other veins

Answer 43

- internal iliac v. - external iliac v. - common iliac v. - renal vv. - hepatic vv. (branch off IVC)

Question 44

What is the role of pulmonary circulation?

Answer 44

carry deoxygenated blood from r. ventricle to air sacs within lungs (alveoli)

Question 45

What does the pulmonary trunk split into? what kind of blood does it carry?

Answer 45

- r/l pulmonary arteries (deoxygenated)

Question 46

What do the pulmonary aa. eventually become?

Answer 46

branches divide into capillaries around alveoli

Question 47

What happens at alveoli?

Answer 47

- CO2 passes into alveoli (exhaled) - inhaled O2 from air into blood - pulmonary vv. transport oxygenated blood to l. atrium - blood ejected into systemic circulation

Question 48

How do PULMONARY aa. compare to pulmonary vv.?

Answer 48

Arteries: less elastic, thinner walls, larger in diameter

Question 49

Is peak systolic pressure higher in right or left ventricle?

Answer 49

Left ventricle

Question 50

What does pulmonary edema (fluid in lungs) cause?

Answer 50

reduction rates of diffusion of O2/CO2 thus slows down exchange of respiratory gases in lungs

Question 51

Explain fetal circulation

Answer 51

- lungs, kidneys, and GI tract do not function until after birth (obtains O2 and nutrients by diffusion from maternal blood; eliminates CO2 and wastes the same way) - occurs through placenta - foramen ovale - ductus arteriosus

Question 52

What happens to circulation after birth?

Answer 52

- umbilical cord become a fibrous cord: medial umbilical lig. - umbilical vein becomes ligamentum teres - ductus venosus becomes ligamentum venosum - fossa ovalis forms - lig. arteriosum forms