Circulatory System

Question 1

tunica intima is composed of what?

Answer 1

endothelium and underlying subendothelial CT; includes internal elastic lamina in larger vessels

Question 2

tunica media is composed of what?

Answer 2

primarily smooth muscle cells and external elastic lamina (where present)

Question 3

tunica adventitia is composed of what?

Answer 3

fibroelastic CT (dense irregular CT with small amounts of elastic fibers?

Question 4

which are conducting arteries?

Answer 4

aorta, pulmonary, brachiocephalic, common carotid, subclavian, and common iliac

Question 5

incomplete internal elastic lamina is characteristic of which vessels?

Answer 5

conducting arteries; they also have no distinct external elastic lamina

Question 6

which arteries are innervated by postganglionic sympathetic nerve fibers?

Answer 6

muscular (distributing)

Question 7

what types of elastic lamina characterize muscular arteries?

Answer 7

well developed internal elastic lamina, and thick external elastic lamina

Question 8

characterize arterioles

Answer 8

sparse subendothelial CT, internal elastic lamina may not be present, ~1-3 layers of smooth muscle cells in t. media

Question 9

continuous (somatic) capillaries feature what?

Answer 9

continuous endothelium and basal lamina, no fenestrae

numerous pinocytotic vesicles (transcytosis)

Question 10

continuous capillaries are found where?

Answer 10

muscle, connective tissue, exocrine pancrease, gonads, and CNS (where occluding junction contributes to blood-brain barrier)

Question 11

fenestrated (visceral) capillaries feature what?

Answer 11

attenuated endothelium with large (60-80nm) fenestrae closed by thin (4-6nm) diaphragms, continuous basal lamina

Question 12

fenestrated capillaries are found where?

Answer 12

mucosa of GI tract, endocrine glands, renal, choroid plexus, ciliary body, and kidney (peritubular & glomerular capillaries); the last have no diaphragms

Question 13

discontinuous (sinusoidal) capillaries feature what?

Answer 13

wide gaps between cells, incomplete basal lamina, irregular, tortuous walls

Question 14

discontinuous capillaries are found where?

Answer 14

liver, and hemopoietic organs (bone marrow, spleen)

Question 15

important features of postcapillary venules?

Answer 15

incomplete layer of pericytes, important site of activity in inflammation (histamine & seratonin, fluid extravasation & migration of white blood cells)

Question 16

characterize muscular venules

Answer 16

1-2 layers smooth muscle, thin t. adventitia, no pericytes

Question 17

small-medium veins are characterized how?

Answer 17

possibly thin layer subendothelial CT, thin t. media with reticular & elastic fibers interspersed with smooth muscle, and well developed t. adventitia (multiple layers of collagenous fibers, few smooth muscle cells and elastic fibers)

Question 18

large veins are marked by what?

Answer 18

thick t. adventitia, with collagenous fibers and longitudinal arranged smooth muscle cells

Question 19

lymphatic capillaries are marked by what?

Answer 19

no basal lamina

Question 20

what is atherosclerosis?

Answer 20

foam cell (lipid laden macrophage) formation & fatty deposits in t. intima; may block vessel

Question 21

what is restenosis?

Answer 21

smooth muscle cell proliferation that follows angioplasty; may occlude vessel

Question 22

what is aneurysm?

Answer 22

ballooning out of artery, weakness in arterial wall

Question 23

causes of aneurysm?

Answer 23

atherosclerosis, syphilis, CT disorders (Ehlers-Danlos syndrom, Marfan’s syndrome)

Question 24

why is production of prostacylin by endothelial cells important?

Answer 24

inhibits platelet adhesion and clot formation