Topic 6 - Muscular System Flashcards
Some functions of ______ tissue include body movement, substance movement, control of substance movement and thermogenesis.
Muscle
Some characteristics of all types of ______ tissue include:
- Electrical excitability
- Contractility
- Extensibility
- Elasticity
Muscle
The ability to respond to certain stimuli by producing electrical signals called action potentials.
Electrical Excitability
The ability of muscle tissue to generate tension/force when stimulated by an AP.
Contractility
The ability of muscle to stretch/lengthen without being damaged. The muscle can still contract when stretched.
Extensibility
The ability of muscle tissue to return to its original shape after contraction or stretch.
Elasticity
Alternating light and dark bands that are characteristic of skeletal muscle.
Striations
T/F - Skeletal muscle is under voluntary/conscious control, but is also subject to involuntary control.
True
Order the following components of skeletal muscle in the correct hierarchy:
- Fascicle
- Myofibril
- Muscle
- Muscle Fibre (aka. Muscle Cell)
1) Muscle
2) Fascicle
3) Muscle Fibre (aka. Muscle Cell)
4) Myofibril
A component of skeletal muscle that is named, measured in cm and can be subdivided into bundles of fasciles.
Muscle
A component of skeletal muscle that is measured in mm and made up of many muscle fibres.
Fascicle
A cylindrical-shaped component of skeletal muscle containing a lot of mitochondria, is multi-nucleated, measured in µm and filled with myofibrils.
Muscle Fibre (aka. Muscle Cell)
The cell (plasma) membrane of the muscle cell.
Sarcolemma
Tiny invaginations that tunnel in from the sarcolemma towards the centre of the muscle fibre.
Transverse Tubules (T-Tubules)
The cytoplasm of the muscle fibres that contains a lot of glycogen.
Sarcoplasm
A protein that binds oxygen that has diffused into the muscle fibre and delivers it to the mitochondria.
Myoglobin
Specialized contractile organelles measured in µm that extend the length of the muscle fibre/cell. They are held in place by cytoskeletal proteins.
Myofibrils
Fluid filled tubes and sacs running along and surrounding each myofibril. They store and release calcium into the cell when it’s needed.
Sarcoplasmic Reticulum
Myofibrils are composed of a number of __________ arranged in series (end to end).
Sarcomeres
The functional unit of a myofibril containing myofilaments that overlap and this interaction is what generates force/contraction. It also creates light and dark strips, which give skeletal muscle its striated appearance.
Sarcomere
What are the 2 contractile proteins (aka. myofilaments) contained in the sarcomere?
1) Actin
2) Myosin
A contractile protein that makes up the thin filaments of the sarcomere.
Actin
A contractile protein that makes up the the thick filaments of the sarcomere.
Myosin
To generate tension, skeletal muscle cells must be stimulated by a nerve signal from a _____ neuron.
Motor
A neuron/nerve cell that conducts APs to muscle cells.
Motor Neuron
The axon of the _____ neuron connects with the muscle. When it reaches the muscle, it branches out into a number of axon _________.
Motor
Terminals
Each axon terminal of the motor neuron forms a junction called the _____________ junction with the sarcolemma of a number of different muscle cells.
Neuromuscular
T/F - The axon terminal of a motor neuron and the sarcolemma touch to form the synaptic cleft.
False - The axon terminal of a motor neuron and the sarcolemma NEVER ACTUALLY touch. THERE IS A GAP BETWEEN THEM called the synaptic cleft.
The the signal arrives at the neuromuscular junction, it releases a ________________ (e.g. acetylcholine) which cross the synaptic cleft.
Neurotransmitter
When a nerve signal crosses the synaptic cleft, it stimulates the __________ as it is then continued by the muscle fibres and spreads out across this cell membrane.
Sarcolemma
After spreading out across the sarcolemma, the signal then travels down the __________ _______ and stimulates the sarcoplasmic reticulum to release _______. This in turn allows the myosin to connect with the actin.
Transverse Tubules
Calcium
T/F - Actin pulls the myosin together, then it disengages and starts the cycle again.
False - MYOSIN pulls the ACTIN together, then it disengages and starts the cycle again.
T/F - The “ratcheting” of actin and myosin uses ATP and will shorten the muscle with repetition.
True
When APs stop, the ____________ _________ pumps calcium back inside (this uses ATP). Without sufficient calcium, the _____ filaments cannot continue their ratcheting of the ____ filaments. Tension generation stops.
Sarcoplasmic Reticulum
Thick
Thin
The motor neuron and all the skeletal muscle fibres it innervates.
Motor Unit
T/F - Axon terminals of one motor unit will overlap with the axon terminals of another motor unit.
False - Axon terminals of one motor unit WILL NOT overlap with the axon terminals of another motor unit.
