3-J Cardiovascular Histology

Question 1

Decribe the endocardium

Answer 1

layer of endothelium and loose connective tissue (purkinje fibers of the conduction system pass through)

Question 2

Describe the myocardium

Answer 2

thickest layer containing bundles of cardiac myocytes oriented in spiral fashion anchored on the cardiac skeleton

Question 3

Describe the epicardium

Answer 3

aka the visceral pericaridum composed of squamous mesothelium and subjacent layer of fat and loose (fibrous) connective tissue that connect the epi and myocardium, contains some unilocular fat

Question 4

Which layer to cornonary vessels travel though?

Answer 4

pericardial CT

Question 5

Discuss the cardiac myocyte nucleus

Answer 5

centrally placed, euchromatic and shaped like a rounded rectangle

Question 6

Name the 3 important parts of the intercalculated disks

Answer 6

spot desmosomes (intertion of intermediate fibers for transmitting force) fascia adherens (insertion of actin filaments on the I band into the memebran to transmit force) and gap junctions (to transmit AP at area of least mechanical force)

Question 7

Name a cardio myocte specfic intermediate fillament

Answer 7

desmin of the desmosomes attach to adjacent Z bands

Question 8

Discuss the organelles of a cardiac myocyte

Answer 8

sarcoplasm is filled with myofibrils with large mitochondria at the poles of the cell, other organelles at poles of nuclei

Question 9

Describe the arrangement of t-tubules

Answer 9

T-tubules run along Z lines in diad with SR

Question 10

Recall the function fo the secretory products of cardiac muscle

Answer 10

ANF, increases salt excretion and relaxes vascular SM

Question 11

Why purkinje cells the largest in diameter

Answer 11

conduct AP very fast as part of the conduction system (PC are often surrounded by CT)

Question 12

Summarize our current understanding of the regenrative capacity of cardiac muscle

Answer 12

there are a significant number of mitotic cardiomyocytes but not to the scale of cells damaged by an AMI

Question 13

What is the consequence of MI scar tissue?

Answer 13

compromises cardiac function causing other parts of the heart to hypertrophy, dialate and fail

Question 14

What is cardiomyopathy?

Answer 14

disease of the heart that leads to abnormally enlarged size, thickend or stiffened walls reduce the pumping abilitity leading to hypertrophy or dialation.

Question 15

What are the best cell types to regenerate myocardium

Answer 15

cell therapeutic populations like pluripotent stem cell or adult stem cells (from mesenchymal stem cells or resident cardiac stem cells)

Question 16

What are the causes of familial hypertrophic cardiomyopathy

Answer 16

disease of the sarcomere caused by point mutations in myosin, troponin, tropomyosin or C protein

Question 17

Spot desmosomes are also called ______ and are associated with intermediate filaments called desmin and are intermixed with fascia adherens.

Answer 17

maculae adherens

Question 18

What are fascia adherns

Answer 18

attach the actin filaments of the terminal sarcomeres to the myocyte membrane and permit the transfer of force from one myocyte to the next

Question 19

Cardiac muscle uses ________ calcium for contraction.

Answer 19

extracellular

Question 20

What is the role of connective tissue in the cardiac tissue? (2)

Answer 20

support the cardiac myocytes with nutrition (blood vessels) and as an attachment point for cardiac cells (cardiac skeleton)

Question 21

Bonus: The next major research hurdle to be overcome in cardiac regenerative medicine is

Answer 21

to find the means by which a patients own stem cells can be activated in a rapid and efficient manner