M 2.1

Question 1

• Located in the heart and large vessels attached to the heart
• Branched cylindrical fiber with one centrally located nucleus; intercalated discs join neighboring fibers; striated
• Develop from mesodermal cells that migrate to and envelop the developing heart while it is still in the form of endocardial heart tubes

Answer 1

Cardiac Muscle Tissue

Question 2

Cardiac Muscle Fiber
Length: Long - _______um

Answer 2

50 - 100 um

Question 3

Cardiac Muscle Fiber
Diameter: Large - _______um

Answer 3

10 - 20 um

Question 4

Cardiac Muscle Fiber
Structure:
- Contains ______ and _______ filaments arranged in sarcomeres and same bands, zones and Z discs as in skeletal muscle

Answer 4

myosin; actin

Question 5

Cardiac Muscle Fiber
Structure:
- Contains ________ central nuclei

Answer 5

one or two

Question 6

Cardiac Muscle Fiber
Structure:
- Fibers are ___________

Answer 6

branched

Question 7

Cardiac Muscle Fiber
Structure:
- Characterized by dense junctional complexes called __________that contain gap junctions and desmosomes

Answer 7

intercalated disks

Question 8

Cardiac Muscle Fiber
Structure:
- T tubules located at Z lines; _______ than in skeletal muscle
- Sarcoplasmic reticulum _____ well developed
- Regulatory proteins: __________ and ________

Answer 8

larger; less; tropomyosin; troponin