Heart Histology

Question 1

dyad of cardiac muscle cell

Answer 1

includes the SR and t tubule close to the z disc

Question 2

what are the parts of the intercalated discs in the heart?

Answer 2

gap junctions, and desmosomes are found in lateral and transvers portions of the intercalated disc

Question 3

what is the role of the purkinje fibers?

Answer 3

they are a conduction site that shares info through gap junctions to the cardiac myocytes… uses desmosomes and adherens…BUT do not have intercalated discs housing these

Question 4

do purkinje fibers have intercalated discs?

Answer 4

NO

Question 5

what are the three layers of the inner heart tissue?

Answer 5

endocardium, myocardium and epicardium

Question 6

what is the endocardium made of and what does it line?

Answer 6

simple squamous epithelium in the lumen of the heart

Question 7

what is the epicardium made of?

Answer 7

simple squamous epithelium…some call it a mesothelium

Question 8

can heart muscle or smooth muscle regenerate?

Answer 8

only smooth muscle

Question 9

how many nuclei does cardiac muscle have?

Answer 9

1 or 2 usually located centrally

Question 10

how many nuclei does smooth muscle have?

Answer 10

1 located centrally

Question 11

is cardiac or smooth muscle striated?

Answer 11

only cardiac

Question 12

caveolae location and role?

Answer 12

these are in smooth muscle and play a role in the uptake of the calcium after contraction of the muscle

Question 13

what is the equivalent of the Z disc in smooth muscle cells?

Answer 13

cytoplasmic densities serve as the location of attachment for the filaments

Question 14

what usually triggers the contraction of vasculature smooth muscle? what about visceral?

Answer 14

vasculature is the nerve impules

visceral is stretching

Question 15

tunica intima of artery/vein

Answer 15

innermost layer containing the endothelium and some elastic fibers

Question 16

tunica media of the artery/vein

Answer 16

second inner most layer of the artery that contains the smoth muscle and elastic tissue

Question 17

tunica adventitia of the artery/vein

Answer 17

outermost layer of the artery that mainly contains the connective tissue

Question 18

elastic arteries unique build

Answer 18

large arteries with fenestrated membranes and vaso vasorum to help stretch and react to high BP in aorta area

Question 19

fenestrated membranes of the elastic arteries

Answer 19

thick sheets of elastic fibers to help stretch the vessel

Question 20

vaso vasorum of elastic arteries

Answer 20

vessels that serve the vasculature walls to help keep oxygenated and active

Question 21

muscular arteries build/structure

Answer 21

internal elastic layer….smooth muscle…external elastic layer…

they do have vaso vasorum

Question 22

what is the classifying rule for arterioles?

Answer 22

they must have only 1-2 layers of smooth muscle…if they have any more they are considered a small artery

Question 23

what do arterioles regulate?

Answer 23

blood pressure

Question 24

metarterioles definition

Answer 24

these are in between arterioles and capillaries and consist of smooth muscle cells that are organized randomly and they can contract a sphincter to prevent flow to a capillary

Question 25

how are the endothelial cells of capillaries joined?

Answer 25

usually by tight junctions

Question 26

define continuous capillaries

Answer 26

the enodthelial cells are linked by tight junctions and have a continuous basal lamina with numerous pinocytic vesicles

Question 27

where are continuous capillaries located

Answer 27

lungs, glands, connective tissue, nervous tissue and muscle

Question 28

define the fenestrated capillaries

Answer 28

these capillaries instead of the tight junctions have holes…they still have a continuous basal lamina though

Question 29

where to find fenestrated capillaries

Answer 29

endocrine glands, intestine, pancreas, kidneys

Question 30

define sinusoidal capillaries

Answer 30

have much bigger holes that may actually be in between in the endothelial cells…no pinocytic vesicles

Question 31

where are sinusoidal capillaries located?

Answer 31

liver, spleen, bone marrow, lymph nodes, adrenal cortex

Question 32

define pericytes

Answer 32

these are pluripotent cells in capillaries that can be endothelial cells or smooth muscle cells…so they can contract and limit flow to the capillaries

Question 33

order of veins from large to small

Answer 33

large…medium/small…to venules

Question 34

what do some large veins have?

Answer 34

cardiac muscle as they approach the heart

Question 35

what can occur in venuoles?

Answer 35

diapidesis of RBCs

Question 36

does an artery or vein have a larger lumen?

Answer 36

veins have the large lumens

Question 37

describe a lymphatic capillary

Answer 37

small vessels that lack fenestrae and tight junctions so they are leaky and can collect interstitial fluid
have a very sparse basal lamina

Question 38

in muscular arteries…where do we find the elastic fibers and what are they called?

Answer 38

in the tunica intima…they are called the internal elastic lamina