Muscluar System Flashcards
Describe Skeletal Muscle?
The skeletal muscle is a voluntary striate muscle that is usually attached at either end to bones.
What is the name are the points where muscle joins the bones called?
The point where muscle joins the bone at the stationary end is called its origin. Where the muscle joins the bone at the other end is called the insertion.
What usually connects muscle with bone?
Tendons.
What is skeletal muscle composed of?
It is composed of muscular tissue, connective tissue, nervous tissue and blood vessels.
What is muscular tissue used for?
- movement.
- stability of the body.
- control of body passages and openings.
- heat production.
What activities are muscle cells able to carry out?
- excitability.
- conductivity.
- contractility.
- extensibility.
- elasticity.
What are the main similarities and differences between skeletal muscle and cardiac muscle.
Whilst both are striated muscle, skeletal muscle is under voluntary control whilst the cardiac muscle is involuntary.
Describe a muscle fibre?
A muscle fibre is a long slender cell with multiple nuclei.
What is the sarcolemma?
The sarcolemma is a thin membrane covering a striated muscle fibre.
What is the sarcophagi?
It is the cytoplasm of a muscle cell.
What does the cytoplasm of a muscle cell contain?
It contains large amounts of glycosomes as well as myoglobin. It is mainly occupied by myofibrils.
What important protein does myofibrils contain?
The myofibrils contain actin which is component that makes up most of thin protein.
Define Contractility?
Skeletal muscle contracts only when stimulated by somatic motor neuron.
Where do muscle fibres and nerves meet?
They meet at a complex of synapses called neuromuscular junction.
What is located at the end of each nerve tip?
At the end of a nerve fibre is a synaptic knob.
What separates the synaptic knob and the sarcolemma?
The gap between the synaptic knob and the sarcolemma is called the synaptic cleft.
What does the synaptic knob contain?
It contains synaptic vesicles, which contain presynaptic neurons which in turn contain thousands of neurotransmitter molecules filled with a chemical called ACh.
What enzyme causes muscle relaxation?
Acetylcholinesterase also known as AChE.
How does AChE work?
It is found in the synaptic cleft and as part of the sarcolemma breaks down ACh to terminate stimulation of the muscle fibre.
Describe how smooth muscles are different to skeletal muscles?
Smooth muscles are involuntary and have slow sustained contractions. It is not striated and has a different type of myosin.
What are the two types of smooth muscle?
- Multi unit
- Visceral.
Where are the multi unit found?
They are found in the eye and blood vessels.
Where are visceral smooth muscles found?
Visceral smooth muscles are found in hollow organs.
What is the wave like motion of smooth muscles in tubular organs called?
Peristalsis.
What affects peristalsis?
Neurotransmitters called norepinephrine.
What else are norepinephrine involved in?
This is also involved in the fight or flight process.
