5.5.14 Mammalian Muscle Structure (learning)

Question 1

Types of muscle in animals

Answer 1

• Skeletal
• Smooth
• Cardiac

Question 1

What is skeletal muscle

Answer 1

• Attached to skeleton
• Striated muscle fibres (contractile proteins with lots of nuclei)

Question 2

What are the parts of muscle fibres called?

Answer 2

Cell surface membrane = Sarcolemma
Cytoplasm = Sarcoplasm
Endoplasmic Reticulum = Sarcoplasmic Reticulum (SR)

Question 3

What does the sarcolemma do?

Answer 3

• T tubules fold in from outer surface
• Run close to the Sarcoplasmic Reticulum

Question 4

What does the sarcoplasm do?

Answer 4

• Mitochondria and myofibrils
• ATP for muscle contraction
• Myofibrils are bundles of actin and myosin filaments that slide past each other during muscle contraction

Question 5

What does the sarcoplasmic reticulum do?

Answer 5

• Membrane contains protein pumps
• Transporting calcium ions into lumen of SR

Question 6

What is the structure of myofibrils?

Answer 6

• In sarcoplasm
• 2 types of protein filament
• Thick filament of myosin
• Thin filament of actin

Question 7

Cardiac Muscle

Answer 7

• Only in heart
• Myogenic (initiates its own contraction)
• Does not tire of fatigue
• Fibres connected via intercalated disks
• lots of mitochondria in muscle fibres

Question 7

Smooth Muscle

Answer 7

• Unconscious control of body parts
• Contains myosin and actin but no banding or striation
• Gut walls
• Blood vessel walls
• 1 nucleus