12_Ctb 1.7 Cardiac Muscle

Front 1

Skeletal muscle consists of three tissues: Skeletal myocytes, Endothelial, and Connective Tissue Fibroblasts. Cardiac Tissues has three tissue types as well...what are they?

Back 1

1. Cardiac myocytes
2. Endocardium (inner most layer of cells lining the chambers)
3. Cardiac fibroblasts

Front 2

Similar to Sk m, each cardiac myocyte is surrounded by:

Back 2

Basal lamina

Front 3

Skeletal muscle fibers are large and can have thousands of nuclei located peripherally. What about cardia myocytes?

Back 3

Smaller with nucleus located centrally.

Front 4

Cardiac muscle is primarily: (Energy production means). This is metabolic strategy is reflected in its cellular matrix, including:

Back 4

It is high aerobic, therefore:
1. Highly fascular
2. Lots of mitochondria
3. Lots of myoglobin
4. Lots of lipid droplets

Front 5

The creatine kinases can be used to diagnose skeletal or cardiac tissue damage. Which one is used to identify each respectively?

Back 5

1. MM-CK = skeletal
2. MB-CK = cardiac

Front 6

What structural feature of cardiac cells allow the cells to beat together?

Back 6

Intercalated discs.

Front 7

In a cross section of cardiac myocytes, what would you expect to see with respect to vascularization?

Back 7

Since it is highly vascularized, you'd expect to see venules and capillaries

Front 8

This is a longitudinal section of a cardiac cell. What are the arrows pointing to and what are the two major differences seen here compared to skeletal muscle?

Back 8

Arrows are pointing to the M line where MB-CK is located (MM-CK in skeletal). And glycogen granuals - Sk doesn't have this - nor does it have as many mitochondira.

Front 9

In this cardiac cross section, the blue boxes are covering IDs for what structures?

Back 9

1. Basal lamina
2. Sacroplasmic reticulum

Front 10

Cardiac muscles has Z-bands with an additional transverse component (arrorw) - what is this for?

Back 10

To transmit contractile force, thereby increasing the strength in contractility.

Front 11

The lateral part of the intercalated discs have Fascia Adherens and Desmosomes. Where are these structures primarily located? Why is this important? What is the major component of the Fascia Adherens?

Back 11

Located between cells. Important for cell-to-cell communication and sync'd beats. Fascia adherens mostly consists of N-cadherins.

Front 12

The Intercalated Discs of cardiomyocytes also have a lateral part for cell-to cell signaling. What are these structural components?

Back 12

Gap junctions (syn nexus) bade up of connexin molecules and some desmosomes.

Front 13

What is the critical difference between fascia adherens and zonula adherens?

Back 13

Zonula Adherens complete encirles the cells vs Fascia Adherens that does not.

Front 14

The atrial myocytes are larger or smaller than ventricular myocytes? Do they have have more or less sarcomeric structure?

Back 14

1. Smaller
2. Less

Front 15

Atrial myocytes contain membrane bound granules near their nuclei that contain:
What does it do?

Back 15

A hormone termied Natriuretic Factor that causes the kidney to eliminate water and sodium, vasodilation, etc.

Front 16

What type of myocytes does the Bundle of His contain?

Back 16

Purkinje myocytes

Front 17

When developing coronary arteries secrete endothelin, they cause nearby myocytes to differentiate - what is the order of differentiation?

Back 17

Endothelin --> cardiac myocyte --> Purkinje fiber. May form the basis for regenerating cardiac pacemaker tissue.

Front 18

The endocardium is composed of a single layer of:

Back 18

Endothelial cells

Front 19

What are the most abundant cell type in the heart (although most numerous, they do not take up the most volume bc they're small)

Back 19

Cardiac fibroblasts.

Front 20

If you saw a pt exhibiting symptoms of DMD, what would you measure? What about a pt with heart attack?

Back 20

DMD = MM-CK
Heart Attack = MB-CK

Front 21

What are cardiac myocytes innervated by?

Back 21

Branches of the vagus nerve (X) and autonomic nerves.

Front 22

Of the three troponins, what is released/measured when a heart attack happens?

Back 22

cTnI

Front 23

Heart attack wound healing begins at day:
Cardiac fibroblasts secrete this: and then this: Ultimately creating a scar by day::

Back 23

1. Day 2-3
2. Fibroblasts secrete collagen--III, then collagen-I to ultimately create scar by day 5

Front 24

Heart attack wound healing begins at day:
Cardiac fibroblasts secrete this: and then this: Ultimately creating a scar by day::

Back 24

1. Day 2-3
2. Fibroblasts secrete collagen--III, then collagen-I to ultimately create scar by day 5

Front 25

What are the five steps of heart attack:

Back 25

1. Myocyte death
2. Inflammation
3. Wound healing
4. Angiogenesis
5. Scar formation

Front 26

What are the five steps of heart attack:

Back 26

1. Myocyte death
2. Inflammation
3. Wound healing
4. Angiogenesis
5. Scar formation

Front 27

Can cardiac myocytes divide?

Back 27

No

Front 28

Can cardiac myocytes divide?

Back 28

No

Front 29

With respect to the cell cycle, what is an example of how researchers are trying to repair injured heart tissue?

Back 29

By disinhibition of the tumor suppressors that normally keep cardiomyocytes in replicative senescence (Go of the cell cycle). Class eg., Rb, p16

Front 30

What is the niche of adult cardiac resident stem cells? What two cell marks are used to identify them?

Back 30

They are found outside of the cardiac myocyte and just outside of the blood vessels. They are identified via cell markers: islet-1 and/or c-KIT

Front 31

A few promising studies show that adult cardiac stem cells can be transplanted and improve heart function. However, Lough doesn't believe that the cells were replaced but that this happened:

Back 31

The paracrine effect - where the transplanted cells secrete factors that enhance cells in the myocardium.

Front 32

Rather than stem cell harvest, fibroblasts can be converted to stem cells using:
What are these converted cells called?

Back 32

1. 4 TF are injected into fibroblasts
2. They become induced pluripotent cells
3. Cardiogenic growth factors are added
4. They become cardiomyocytes
5. Transplantation

Front 33

What are two problems with using iPSCs?

Back 33

1. They take a lot of time to make
2. They often turn into tumors or unwanted cell types.