Histology

Question 1

Epicardium (what it is and 2 layers)

Answer 1

Visceral layer of serous pericardium (mesothelium)
Subepicardial layer - loose connective tissue w/ nerves/vessels/fat
Pericardial cavity - serous fluid

Question 2

Myocardium

Answer 2

Thickest layer, w/ muscles and electrical/hormone components

Question 3

Endocardium (4 layers)

Answer 3

Simple squamos epithelium
Fibroelastic layer
Dense connective tissue layer w/ elastic fibers
Subendocardial layer w/ Purkinje fibers and nerves

Question 4

3 Layers of Vessels (inside out and general components)

Answer 4

Tunica Intima - endothelium/subendothelium/internal elastic lamina
Tunica Media - smooth muscle layers, external elastic lamina
Tunica Adventitia - loose connective tissue, vessels, and nerves

Question 5

5 Functions of Endothelial Cells in Tunica Intima

Answer 5

Transcytosis (pinocytosis), diapedesis, clotting secretions, vessel tone, blood cell movements (marginalization)

Question 6

Tunica Media (2)

Answer 6

Has variable thickness of helically-arranged muscle cells

External elastic lamina only in large arteries

Question 7

Vaso vasorum

Answer 7

Vessels that supply large vessels, in tunica adventitia

Question 8

Elastic Arteries

Answer 8

Largest arteries, w/ >40 layers of smooth muscle and shittons of elastic fibers

Question 9

Muscular Arteries

Answer 9

Virtually all “named” arteries, vessels w/ 3-40 layers of smooth muscle and few elastic fibers that serve as distributing a.s. Also thick external elastic lamina

Question 10

Arterioles

Answer 10

Greatest resistance due to 1-2 layers of smooth muscle and very small lumen - largest muscle/lumen ratio

Question 11

Metarterioles

Answer 11

Discontinuous smooth muscle - capillary sphincter to regulate flow across capillary beds

Question 12

3 Specialized ChemoR and BaroR structures

Answer 12

Carotid Sinus - BaroR via IX
Carotid Body (b/w int and ext carotid a.s) - ChemoR via IX and X
Aortic Bodies - ChemoR via X

Question 13

Capillary General Structure

Answer 13

Single layer of simple squamos w/ lots of pinocytotic vesicles and TJs that sits right on basal lamina w/ no muscle layer or anything. About 7-7.5 microns wide to squeeze one RBC through at a time

Question 14

Pericytes

Answer 14

Stem cells for capillaries that sit on basal lamina just below

Question 15

3 Kinds of Capillaries (& locations)

Answer 15

Type I - Continuous Capillaries, in muscle/lung/nervous & connective tissue
Type II - Fenestrated, pores w/ diaphragms (2 layers of PM w/ no cytoplasm) in intestines/pancreas/kidneys/endocrine glands
Type III - Sinusoidal - large pores w/out diaphragms in liver, bone marrow, spleen, lymphoid organs, and some others

Question 16

Big Difference(s) b/w Type II and III Capillaries

Answer 16

II has complete basal lamina and diaphragms (except renal glumeruli), III does not

Question 17

Arteriovenous Anastomoses

Answer 17

Shunt around capillary beds for thermoreg and erectile tissue and some glomerula and metarteriole shit

Question 18

High Endothelial Venules

Answer 18

Specialized in lymph nodes w/ cuboidal cells for diapedesis of WBCs

Question 19

2 Valved Veins

Answer 19

Medium and large veins

Question 20

Muscle in Veins

Answer 20

Less, but might have some normal helically arranged in tunica media or longitudinally arranged in adventitia to peristals blood up from lower extremity