15.7 Structure Of Skeletal Muscle
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (24 张)
What are the 3 types of muscle in the body?
• cardiac muscle • smooth muscle • skeletal muscle
What are the tiny muscle fibres called?
Myofibrils
What is the cytoplasm found in the muscle fibres called?
Sarcoplasm
What do muscle fibres share?
Nuclei and sarcoplasm
Which organelles are in high concentration in the sarcoplasm?
• Mitochondria - Endoplasmic reticulum
What 2 types of protein filament is myofibrils made up of?
• actin - myosin
What is actin?
Thinner protein filament and consists of 2 strands twisted around one another
What is myosin?
Thicker protein filament and consists of long rod- shaped tails with bulbous heads that project to the side
What are I bands short for?
Isotropic bands
What are A bands short for?
Anisotropic bands
What is the A band made up of?
Actin and myosin
What is the I band made up of?
Actin
What is the H zone?
Where only myosin is present
What is the z line?
Line in the centre of each I band
Sarcomere definition
Distance between adjacent z-lines
What is tropomyosin?
Fibrous protein strand around the actin filament
Slow- twitch fibre adaptations
• large store of myoglobin • lots of blood vessels • numerous mitochondria
Fast- twitch adaptations
• lots of thicker myosin filaments • lots of glycogen • lots of enzymes for anaerobic respiration • store of phosphocreatine
What are the 2 types of muscle fibres?
• slow twitch - fast twitch
Speed of contraction in slow- twitch fibres
Slowly
Strength of contraction in slow- twitch fibres
Not powerful
How long does the contraction last in slow- twitch fibres?
Longer period
What are slow- twitch fibres adapted for?
Endurance work e.g marathon
Where are slow- twitch fibres found?
Calf muscle