Muscles- Striated and Smooth Flashcards
(39 cards)
Where are striated muscles present
In skeletal muscle and in the heart (cardiac) muscle
What type of muscle is this
Striated muscle
What are the three main parts of skeletal muscle
- Epimysium 2. Perimysium 3. Endomysium
What holds the muscle together
Connective tissue
What are the 3 connective tissue elements of skeletal muscle main from
Collagen and fibroblasts
What does connective tissue provide
A route for blood vessels and nerves to get to teh muscle fibre
What is a sarcomere
The basic structural unit for muscle contraction
What are the two types of filaments in a muscle
Thick myosin and thin actin
What leads to overall shortening (contraction) of a muscle
Shortening of individual fibres. Actin filaments are pulled closer together meaning sarcomeres shorten myofibrils and whole muscle shortens.
What are the subcellular organelles involved in muscle contraction
- Sarcolemma 2. Mitochondria 3. Myofibrils 4. Tubules of sarcoplasmic reticulum. 5. T tubule
What is the basis for shortening or muscle fibres
Sliding between muscle filaments is the basis for shortening muscle fibres
Outline the events that lead to contraction in striated muscle
- Muscle cell is excited (depolarised) by nerve action potential.
- Depolarisation carried into the depths of the cell by T-tubules.
- Ca2+ is released from the sarcoplasmic reticulum.
- Ca2+ binds to troponin, releasing its hold on actin filaments.
- Tropomyosin molecules can now change position
- Myosin can now bind to actin by cross bridges.
- Actin filaments move closer together = contraction.
What are the 3 different types of skeltal muscle fibres
Type 1 Type 2A Type 2B
Describe type 1 fibres
(slow-oxidative)- ‘slow twitch’, fatigue-resistant
Describe type 2A muscle fibres
(fast-oxidative)- ‘fast twitch’, less fatigue resistant than type 1
Describe type 2B muscle finres
(fast-glycolytic)- ‘fast twitch’, fatigue easily
Which type of muscle fibres are the postural muscles of the neck, back and legs rich in
Type 1 fibres
Which type of muscle fibres are the muscles of the shoulders and arms rich in
Type 2B (short periods of time, large amount of tension)
Which type of muscles fibres are the legs rich in
Type 1 and Type 2B (walking and running)
How do cardiac muscle fibres differ from striated muscle fibres (5 things) Neil Buys Irregular Apples Greviously
- Nucleus is quite central in cardiac
- Cardiac muscle fibres branch
- Cardiac muscle fibres have transverse structures called intercalated discs which join neighbouring muscles
- Cardiac muscle fibres are instigated by the ANS
- Individual cardiac muscle cells are connected by gap junctions
What is the purpose of intercalated discs in cardiac muscle fibres
To join muscle fibres together for strength
What is the function of gap junctions
They allow depolarisation of one cell to pass to another
What organelle is abundant in both types of striated muscle fibres and why
Mitochondria to provide energy as contraction requires a lot of energy
Where does smooth (non-striated) muscle occur (5 things Hairy Baboons Itch Nasty Scrotum)
- Walls of hollow organs. 2. Walls of blood vessels. 3. Iris of the eye 4. Nipples 5. Skin- attached to hair follicules.
