Lecture 8

Question 1

Left and Right coronary arteries each have…

Answer 1

circumflex and interventricular branches

Question 2

Coronary arteries are the _____ branches of ____

Answer 2

first, aorta

Question 3

left coronary artery

• opens
• passes
• divides

Answer 3

opens from left aortic sinus
passes laterally beneath right auricle
divides into:
-right (subsinuosal) IV artery (right IV groove)
-right circumflex artery (in circular coronary groove)

Question 4

Which species does Right IV artery (subsinuosal) arise from left coronary?

Answer 4

dogs, ruminants

Question 5

in dogs, ruminants left coronary artery supplies-

right supplies-

Answer 5

80%- all IV spetum, all left and part of right ventricle
right supplies rest of right ventricle
left is larger in size than right

Question 6

which species does the Right IV artery (subsinuosal) come from R coronary artery?

Answer 6

horse, pig

Question 7

in horse, pig left coronary artery supplies-

right coronary artery supplies-

Answer 7

most of IV septum, most of LV, part of RV

part of IV septum, part of LV most of RV

both coronary arteries similar in size

Question 8

venous drainage of the heart via (2)

Answer 8

great cardiac vein-> coronary sinus on right side

coronary sinus- opens into r atrium (75% of total coronary flow)

Question 9

Metabolic active hyperemia

Answer 9

coupling of blood from to demand of O2
myocardium releases metabolic by products in proportion to work rate-> act as local vasodilators
Sympathetic NS stimulation causes coronary vasodilation indirectly by increasing cardiac work rate

Question 10

80% of coronary blood flow occurs when?

why?

Answer 10

during diastole

2/3 of coronary arteries are compressed during systole

Question 11

pulmonary circulation
basal tone-
sympathetic vasomotor nerves-
metabolic vasodilation-

Answer 11

is low- blood vessels are relaxed
plays NO major role
has no role, alveolar perfusion vastly exceeds metabolic demand

Question 12

alveolar hypoxia is a potent _____ of small pulmonary arteries

Answer 12

constrictor
dec blood to poorly ventilated alveoli
inc blood to well ventilated

Question 13

in systemic circulation local hypoxia causes ___

Answer 13

vasodilation, for more blood flow. pulmonary is opposite

Question 14

Cutaneous blood flow (3)

Answer 14

thermoregulation of core temperature
dermis well vascularized, epidermis is avascular
superficial and deep vascular beds- counter current heat exchange mechanisms

Question 15

Arterivenous anastomosis (3)

Answer 15

direct connections between dermal arterioles and venules
controlled by sympathetic vasoconstrictor fibers
dilate in warm, constrict in cold

Question 16

Cerebral blood flow

brain accounts for-

Answer 16

20% of resting O2 consumption

Question 17

Arterial supply to head- 2 main vessels

Answer 17

common carotid (l and r)
vertebral arteries (l and r)

Question 18

Common carotid arteries (3)

Answer 18

branch at allanto-occipital joint into:

• internal carotid artery
• external carotid artery

Question 19

vertebral arteries(2)

Answer 19

1st branch of subclavian

fuses with occipital artery turning into cerebrospinal artery

Question 20

Circle of willis(3)

Answer 20

Basilar artery anastomosis with internal carotid
supplies brain with oxygenated blood-
collateral circulation

Question 21

brain microcirulation consists of

Answer 21

functional end arteries-> blockage causes local ischemia

Question 22

Cerebral capillaries form a

Answer 22

tight blood brain barrier

Question 23

functions of Blood brain barrier (3)

Answer 23

protect from circulating solute and pathogens
maintain pH
lipid soluble molecule diffuse freely across

Question 24

venous drainage from the head (4)

Answer 24

external jugular vein
internal jugular vein
vertebral vein
all drain into cranial vena cava-> right atrium