Functional Anatomy Flashcards
Epimysium
Connective tissue that surrounds the muscle
Fascicle
A bundle of muscle fibres
Perimysium
Connective tissue that encloses a bundle of muscle fibres (fascicle)
Muscle Fibre
Muscle Cell
Myofibril
Smaller fibres that are found in a muscle fibre: consist of thick and thin myofilaments
Sarcomere
Unit of muscle contraction
Myofilaments
Thick and thin threads found in myofibril
Actin
Thin myofilaments attached to the Z line
Myosin
Think myofilaments attached to cross bridges
Z-lines
Found at either end of a sarcomere
Cross bridges
Tiny projections on myosin filaments that attach to the actin filaments pulling the actin filaments upon contraction
H Zone
Space between the actin filaments
I Band
The gap between the end of the myosin and the Z line
The function of nerves
Send electrical impulses from the brain down the spinal cord to the muscles. Impulses cause the muscle to contract.
Function of the Spinal Cord
Part of the CNS, relays information from the brain to the body and from the body to the brain. Uses reflex arc to prevent injury.
The function of the motor unit
Refers to muscle fibres which are influenced by each nerve
Function of Dendrites
Receive signals/information from the CNS
Function of the Axon
Long part of the nerve tending from nerve body where information is transmitted to target cells. Carries impulses away from the cell body.
The Function of Neurons
A nerve cell. Consists of a cell body, dendrites, an axon, passing an electrical impulse from one cell to another
The Function of Myoglobin
Transfers oxygen to the muscles
The 6 Steps of the Sliding Filament Theory
- The influx of calcium, triggering the exposure of the binding sites on the actin.
- The binding of myosin to actin. Myosin is in a ‘high-energy’ state when grabbing the actin.
- The power stroke of the cross bridge that causes the sliding of the thin filaments.
- The binding of ATP to the cross bridge, which results in the cross bridge disconnecting from the actin. The myosin head is in a ‘low-energy’ state.
- The hydrolysis of ATP, which leads to the RE-energising and repositioning of the cross bridge. Myosin is back in its ‘high-energy’ state.
- The transport of calcium ions back into the sarcoplasmic reticulum.
Force-Velocity Relationship Concentric Contraction
Force decreased/velocity increased
Force-Velocity Relationship Eccentric Contraction
Force increased/velocity decreased
Force-Velocity Relationship Isometric Contraction
Force = 0
Force-Velocity Relationship
An increase in force causes a decrease in velocity and vice versa. Trade-off occurs due to a decrease in time available for cross bridges to be formed. The more time = more cross bridges formed = a greater contractile force. Slower velocity allows more force to generate. Higher velocity exercises produce lower force.
Force-Length Relationship
Muscles contract most effectively when the muscle pair is in balance and it is in the midrange of the joint it flexes.
Force-Length Relationship Shortened Muscle
If muscle tries to contract when shortened it will pull against elongated opposing muscle. It applies an elastic counterforce the contracting muscle must overcome.
Force-Length Relationship Bicep Muscle
When fully extended, there are few cross bridge attachments and little force is produced. When bicep is fully flexed, sarcomeres are fully contracted and cannot pull any closer lacking force. 120 degrees is where the bicep has the most cross bridge attachment points and can create the most force.
Contraction Time of Type 1, Type 2A and Type 2B Fibres
1: Slow
2A: Fast
2B: Very Fast
Size of Motor Neuron of Type 1, Type 2A and Type 2B Fibres
- Small
2A. Large
2B. Very Large
Resistance to Fatigue of Type 1, Type 2A and Type 2B Fibres
- High
2A. Intermediate
2B. Low
Activity Used For of Type 1, Type 2A and Type 2B Fibres
- Aerobic
2A. Long Term Anaerobic
2B. Short Term Anaerobic
Force Production of Type 1, Type 2A and Type 2B Fibres
- Low
2A. High
2B. Very High
Mitochondrial Density of Type 1, Type 2A and Type 2B Fibres
- High
2A. High
2B. Low
Capillary Density of Type 1, Type 2A and Type 2B Fibres
- High
2A. Intermediate
2B. Low
Oxidative Capacity of Type 1, Type 2A and Type 2B Fibres
- High
2A. High
2B. Low
Glycolytic Capacity of Type 1, Type 2A and Type 2B Fibres
- Low
2A. High
2B. High
Major Storage Fuel of Type 1, Type 2A and Type 2B Fibres
- Triglycerides
2A. CP, Glycogen
2B. CP, Glycogen
Mitochondrial Density Definition
Ability to convert energy into ATP
Oxidative Capacity Definition
The capacity of a muscle to use oxygen
Glycolytic Capacity Definition
Ability to produce ATP with little oxygen. A measure of how glycogen is converted to ATP