Histology - Muscles

Front 1

Where do skeletal and cardiac muscle cells get their calcium from?

Back 1

Skeletal - the sarcoplasmic reticulum
Cardica - extracellular space

Front 2

Back 2

Front 3

What determines the strength of a muscle contraction?

Back 3

The number of motor-units rectuited.

Front 4

How is a muscle stimulated to contract? ( steps)
1. AP arrives in terminal knob
2.
3. ACth causes...
4. DHP
5. ..... = contraction

Back 4

1. AP arrives causing influx of Ca
2. Influx of Ca stimulated exocytosis of Acetylcholine which diffuses across the cleft
3. ACth causes a depolarization of the muscle cell that travels down the T-tubules
4. The DHP receptor (in T-tubule membrane) is voltage sensitive and will open the Ryanodine recepto (in SR membrane), a passive Ca channel
5. The Ryanodine receptor of the SR opens, releasing Ca into the cytoplasm and this Ca causes a contraction

Front 5

Define endomysium

Back 5

delicate connective tissue that surrounds individual muscle cells

Front 6

Define epimysium

Back 6

a dense investment of collagen fibers that surrounds a skeletal muscle, and is continuous with the tendon/aponeurosis of the muscle (also continuous with the perimysium

Front 7

Back 7

Front 8

Describe smooth muscle (shape of cell & nucleus)

Back 8

Spindle shaped cells with long oval nuclei. Cytoplasm is homogenous (ie no striations)

Front 9

Describe arrangement of filaments in smooth muscle:
thin
thick
intermediate

Back 9

criss-cross the cytoplasm. The actin (thin) filaments are anchored to "dense bodies" in cytoplasm or cell membrane.
Thick filaments lie between the thin filaments
Intermediate filaments anchor the dense bodies in place and align thick and thin.

Front 10

How can you distinguish smooth muscle from connective tissue?

Back 10

Look for the nucleus - in connective tissue the nuclei is beside the pink stuff (ie collagen). In smooth muscle the nuclei (sometimes wrinkled) is inside the pink stuff.

Front 11

What type of cell is this? How can you tell?

Back 11

Cardiac muscle - pale central nucleus

Front 12

What type of cardiac muscle cell is this? How can you tell?

Back 12

Pirkinje fiber - it is larger and more pale staining. Their myofibrils are concentrated at cell periphery, creating a dark eosinophilic border around the cell

Front 13

What type of tissue is this? What two cells are present (how can you tell)?

Back 13

Smooth muscle - long pale oval nucleus. The darker, smaller nuclei (with no obvious cytoplasm) is a fibroblast)

Front 14

What type of cell is this?

Back 14

Contracted smooth muscle - some cells always contracted and nuclei becomes compressed