Circulatory System

Question 1

what are the 3 basic histological layers in the circulatory system?

Answer 1

1- tunica intimia
2- tunica media
3- tunica adventitia

Question 2

what composes the tunica intima?

Answer 2

endothelium with basement membrane and collagenous material

Question 3

what composes the tunica media?

Answer 3

muscle, connective tissue

exhibits most “variety” throughout system

Question 4

what composes tunica adventitia?

Answer 4

outer layer of connective tissue that surrounds vessel

Question 5

what is another name for the tunica adventitia of the heart?

Answer 5

epicardium and visceral pericardium

Question 6

what is the composition of the tunica adventitia of the heart?

Answer 6

thin layer of mesothelium that covers a serous membrane

secretes lubricating fluid, deep to mesothelium is a dense layer of fibrocollagenase tissue (with elastic fibers)

Question 7

what is another name for the tunica media of the heart?

Answer 7

myocardium

Question 8

where is myocardium most prominent?

Answer 8

left ventricle

Question 9

what is another term for the tunica intima of the heart?

Answer 9

endocardium

Question 10

what part of the heart has the thickest middle layer of endocardium?

Answer 10

atria

Question 11

what tissue type is responsible for expansion and recoil?

Answer 11

elastin tissue

Question 12

what are the “elastic arteries”? (6)

Answer 12

aorta
pulmonary aa
brachiocephalic a, common carotid a, subclavian a
common iliac a

Question 13

what are lamella?

Answer 13

fenestrated sheets between mm layers

Question 14

what are the consequences of age and blood pressure on lamella?

Answer 14

increased age and increased BP will increase lamella

Question 15

what histologically differentiates muscular arteries from elastic arteries?

Answer 15

muscular arteries will have more smooth mm and less elastin

Question 16

what are IEL/EEL?

Answer 16

IEL- internal elastic lamina (part of tunica intima)

EEL- external elastic lamina (part of tunica media)

Question 17

what is between lamellae?

Answer 17

smooth mm, elastin fibers, reticular fibers, proteoglycans

Question 18

what is the main function of arterioles?

Answer 18

control blood flow into capillary beds, accomplished through constriction of the pre-capillary sphincter (smooth mm)

Question 19

what is the vaso vasorum?

Answer 19

small network of blood vessels that supply the walls of larger vessels

Question 20

what is the nervi vascularis?

Answer 20

small nerves that supply the walls of blood vessels

Question 21

how do nutrients reach the inner arterial wall?

Answer 21

pinocytosis

Question 22

what is “microcirculation”?

Answer 22

vasculature responsible for blood distribution within organs to cells

Question 23

compare/contrast arterioles and capillaries

Answer 23

arterioles- well innervated, direct blood to capillary, smooth mm
capillaries- no innervation, no mm, direct blood into other vessels

Question 24

3 “players” in microcirculation

Answer 24

arterioles, capillaries, lymphatics

Question 25

typical capillary diameter

Answer 25

8-10 um

Question 26

basic capillary structure

Answer 26

single layer of epithelial cells with basal lamina

Question 27

what are pericytes?

Answer 27

contractile cells that wrap around endothelial cells of capillaries and venues throughout the body

Question 28

what dz process might pericytes be related to?

Answer 28

diabetic retinopathy

Question 29

what are the 3 types of capillaries?

Answer 29

continuous fenestrated discontinuous/sinusoid

Question 30

what are AV shunts?

Answer 30

structures that provide bypass of capillary beds

Question 31

where are AV shunts found?

Answer 31

skin, fingertips, lips, erectile tissue, clitoris

Question 32

discuss contraction vs relaxation of arteriole in AV shunt system

Answer 32

contraction- blood to cap bed | relaxation- blood to venule (bypass)

Question 33

what are the functions of AV shunts?

Answer 33

increase or blood flow to area - thermoregulation, erection (will enhance heat loss or cause erection)

Question 34

why are venous valves derived from?

Answer 34

tunica intima

Question 35

where is the main site of action of vasoactive substances like histamine and serotonin?

Answer 35

post-capillary venules

Question 36

which type of veins contain valves?

Answer 36

medium veins (lower extremity)

Question 37

what are the "large veins"?

Answer 37

SVC, IVC

Question 38

what are the main lymph ducts?

Answer 38

thoracic duct (left) and right lymphatic duct

Question 39

where does lymph empty back into circulation?

Answer 39

internal jugular and subclavian veins

Question 40

where are the purkinje cells located?

Answer 40

deep subendocardial layer

Question 41

what are the 3 layers of the endocardium?

Answer 41

1- luminal endothelial cells + sub endothelial CT 2- smooth mm and loose CT 3- deep subendocardial layer- loose CT, NAV, conducting system

Question 42

what is the composition of a semilunar valve?

Answer 42

lined externally by layer of endothelial cells | core of dense fibrous CT

Question 43

what happens to the aorta when heart is in diastole?

Answer 43

aorta contracts to maintain hydrostatic pressure

Question 44

where are the vaso vasorum and nervi vascular is located?

Answer 44

tunica adventitia

Question 45

what are elastic fibers arranged in in the aorta?

Answer 45

plates (also called lamella) with fenestrations

Question 46

in which vessel does the IEL appear as a prominent wavy line?

Answer 46

muscular artery | tunica intima

Question 47

what changes occur in the progression from larger to smaller arteriole?

Answer 47

progressive loss of IEL decrease in smooth mm thinning of adventitia and merging of adventitia with surrounding CT

Question 48

where are continuous capillaries found?

Answer 48

muscle, lung, CNS

Question 49

where are fenestrated capillaries found?

Answer 49

endocrine glands, kidneys, gallbladder, GI tract

Question 50

where are discontinuous/sinusoid capillaries found?

Answer 50

liver, spleen, bone marrow

Question 51

what are the characteristics of discontinuous/sinusoid capillaries?

Answer 51

wide diameter to slow blood flow for max exchange incomplete/missing basement membrane irregular pathways and junctions that facilitate diffusion

Question 52

why are lymph vessels more permeable than circulatory vessels?

Answer 52

they lack basement membrane and pericytes

Question 53

what is the thickest layer in medium veins?

Answer 53

t. adventitia

Question 54

what is the thickest layer ion large veins?

Answer 54

t. adventitia with longitudinal smooth mm layer

Question 55

in which layer of the esophagus are arterioles present?

Answer 55

submucosa