8. Muscles - Marco Narici Flashcards
1
Q
What 2 types of cells are in the nervous system? Describe each one
A
- Neurones = transmits electrical impulses
- Supporting cells =
In CNS - glial cells, oligodendroctyes and microglia
In peripheral nerve - Schwann cells
2
Q
Nerve cell structure
- Also known as?
- What 3 things does it consists of?
A
- Neurone
2. Cell body, dendrites and axon
3
Q
Neurone structure
- What does the cell body contain?
- What do the dendrites do?
- What does the axon do?
- Which 2 ways can an axon end?
A
- Cell organelles
- Conducts nerve impulses towards the cell body
- Conducts nerve impulses away from the cell body
- Terminates as a swelling which synapses with the next neurone
Ends as a motor end plate on a skeletal muscle cell
4
Q
Neurone
- Why do neurones have large nucleus and nucleolus?
- Size of nerve cell body?
- What 2 things are there a lot of for protein synthesis?
- What 3 features do all neurones have?
A
- High metabolic requirements
- Large
- RER and ribosomes
- Dendrites, soma and axons
5
Q
Structure of a spinal nerve
- What will be the function of the neurones?
- What type of nerves are all spinal nerves?
- What are the 3 coverings?
A
- Some will have sensory function and some will have motor function
- Mixed nerves
- Epineurium
Perineurium
Endoneurium
6
Q
Spinal nerve
- Describe the epineurium
- Describe the perineurium
- Cells that form the inner surface of the perineurium are joined by what?
- What is a bundle of nerve fibres also known as?
- Describe the endoneurium
A
- Dense layer of fibrous tissue
- Layers of flattened cells separated by layers of collagen; surrounds a bundle of nerve fibres
- Tight junctions
- Fascicle
- Thin layer of tissue surrounding individual axons and myelin sheath
7
Q
Myelin
- What is it made out of?
- It can be formed from the cell membrane of what in the CNS?
- It can also be formed from the cell membrane of what in peripheral nerves?
- What is the node of Ranvier?
- What is found here?
- It is also the anatomical basis of what?
- In the CNS, all axons are what?
- Is this the case in peripheral nerves?
A
- Lipid
- Oligodendroctyes
- Schwann cells
- The gap between the myelin covering formed by adjacent Schwann cells
- Majority of the sodium ion channels
- Saltatory conduction
- Myelinated
- No, some axons are non-myelinated (but are embraced by supporting cells)
8
Q
Muscle types
- Describe skeletal muscles in 3 ways
- Describe cardiac muscle in 3 ways
- Describe non-striated/smooth muscle in 3 ways
A
- Striated / rapid & strong contractions / usually voluntary nervous control
- Striated / contracts rhythmically / involuntary
- Contractions slow and sustained / involuntary / can be single unit or multi-unit
9
Q
Skeletal muscle
- A single skeletal muscle is made up of what?
- Within this, what is there?
- Each muscle fibre contains what?
- What does this contain?
A
- Multiple fascicles
- Multiple skeletal muscle fibres
- Multiple myofibrils
- Myofilaments made of action, myosin and other proteins
10
Q
Striated muscle contraction
- How is striated muscle shortened?
- What 2 things become shorter?
- What stays the same?
- What is shortening dependent on?
- Equation for force generated?
- Equation for velocity if contraction?
A
- Thick filaments pulling thin filaments towards the centre of the sarcomeres
- H zone and I band
- A band
- Calcium-dependent
- F = number of sarcomere in parallel
- V= number of sarcomere in series
11
Q
Muscle fibre arrangement
What are the 2 ways skeletal muscle fibres can be arranged?
A
Parallel-fibres muscles
Pennate-fibred muscles
12
Q
- Parallel-fibred muscles: fibre length? Relevance to function?
- Pennate fibred muscles: fibre length? Fibre number? Relevance to function?
A
- Longer fibres
Capable of greater shortening velocity - Shorter fibres but more fibres
Stronger but slower contracting
13
Q
Motor units
- Each alpha motor neurone in the spinal cord can innervate what?
- A single muscle fibre receives innervation from what?
- Define motor unit
- Define Henneman’s size principle
A
- Several muscle fibres
- One motor neurone only
- An alpha motor neurone in the spinal cord and all the muscle fibres it innervates
- The degree of contraction of a whole muscle relies on recruiting motor units from smallest to largest
14
Q
What are the 3 muscle fibre types? What is each one also known as?
A
- Slow oxidative fiber = SO = type 1
- Fast oxidative glycolytic fiber = FOG = type 2a
- Fast glycolytic fiber = FG = type 2x
15
Q
Slow oxidative fiber = SO = type 1
- Twitch type?
- Metabolic type?
- Myosin ATPase activity?
- Source of ATP?
- Glycogen content?
- Fibre diameter?
- Resistance to fatigue?
- Functional role?
A
- Twitch type? Slow
- Metabolic type? Slow oxidative
- Myosin ATPase activity? Low
- Source of ATP? Oxidative phosphorylation
- Glycogen content? Low
- Fibre diameter? Low
- Resistance to fatigue? High
- Functional role? Posture/ endurance
16
Q
Fast oxidative glycolytic fiber = FOG = type 2a
- Twitch type?
- Metabolic type?
- Myosin ATPase activity?
- Source of ATP?
- Glycogen content?
- Fibre diameter?
- Resistance to fatigue?
- Functional role?
A
- Twitch type? Fast
- Metabolic type? Fast oxidative-glycolytic
- Myosin ATPase activity? High
- Source of ATP?oxidative phosphorylation and glycolysis
- Glycogen content? Moderate
- Fibre diameter? Moderate
- Resistance to fatigue? Moderate
- Functional role? Medium endurance