Muscle

Question 1

What connects cardiac muscle cells?

Answer 1

intercalated discs

Question 2

What is the cell membrane of a muscle cell called?

Answer 2

Sarcolemma

Question 3

What does muscle arise from?

Answer 3

Mesoderm

Question 4

What are the stem cells of skeletal muscle called?

Answer 4

Satellite cells

Question 5

What is epimysium?

Answer 5

Dense connective tissue that surrounds the entire muscle

Question 6

What is perimysium?

Answer 6

Connective tissue that surrounds fasicles

Question 7

What is endomysium?

Answer 7

Connective tissue that surrounds myofibers

Question 8

What causes the appearance of striation in skeletal and cardiac muscle?

Answer 8

Alternating I-bands and A-bands of sarcomeres

Question 9

What are the regulatory proteins on actin?

Answer 9

• Tropomyosin

- Troponin

Question 10

What does Titin do?

Answer 10

Connects myosin to the Z-disc, looks like a spring

Question 11

What does myomesin do?

Answer 11

-connects myosin to the M-line

Question 12

What does nebulin do?

Answer 12

it is a spacer/linker protein between actin

Question 13

What does creatine kinase do?

Answer 13

• it is the source of emergency high energy in muscle cells

- Transfers phosphate groups form phosphocreatine to ADP

Question 14

What holds cardiac muscle cells together at the intercalated discs?

Answer 14

-desmosomes

Question 15

What are the stem cells of smooth muscle called?

Answer 15

-Pericytes

Question 16

What are Dihydropyridine receptors?

Answer 16

• Voltage receptor

- Changes shape to activate Ryanodine

Question 17

What are ryanodine receptors?

Answer 17

• Ca2+ release channels in SR

- Stimulated by confirmation change in Dihydropyiridine

Question 18

What catalyzes the relaxation of skeletal muscle?

Answer 18

Smooth ER calcium ATPase (SERCA)

Question 19

how does EC coupling work in cardiac muscle?

Answer 19

• Extracellular Ca2+ enters cell via DHP receptor
• Increase in [Ca]i causes RYR receptors to open
• Calcium induced calcium release (CICR)

Question 20

How do cardiac muscle cells relax?

Answer 20

• Ca pumpted into SR by SERCA

- Ca/Na antiporter on sarcolemma

Question 21

What do smooth muscle cells use instead of troponin?

Answer 21

Calmodulin (CaM)

Question 22

What makes up the motor unit?

Answer 22

• Nerve
• Neuromuscular Junction
• Muscle

Question 23

Type 1 Skeletal muscle fibers

Answer 23

• Slow, sustained force generation
• Use aerobic oxidative metabolism
• RED

Question 24

Type 2 Skeletal muscle fibers

Answer 24

• Fast, but unsustained force generation

- anaerobic glycolytic

Question 25

What happens when the baseline cytoplasmic calcium concentration of cardiac muscle cells is increased?

Answer 25

-Increased force of contraction

Question 26

when is the Active tension of muscle cells at its maximal value?

Answer 26

When the overlap of actin and myosin is maximal, when the most potential interactions of myosin heads and actin occur

Question 27

What is preload?

Answer 27

• isometric tension generation at a given length

- Want to optimize in cardiac patients

Question 28

What do cardiac glycosides (Digitalis) do?

Answer 28

inhibit Na-k ATPase, causing a decreased Na gradient in cardiac muscle cells. Leads to an increased amount of intracellular Ca, because Na/Ca antiporter is impaired

Question 29

What generates afterload for cardiac muscle cells?

Answer 29

Increased blood pressure

Question 30

What takes the place of T-tubules in smooth muscle cells?

Answer 30

Caveolae

Question 31

What is a myocardial scar?

Answer 31

• Cardiac muscle does not have satellite cells, so it cannot regenerate
• Damaged areas are normally replaced by proliferating fibroblasts and growth of connective tissue, forming myocardial scars