Muscles Flashcards
Week 4 (21 cards)
What are the functions of the muscular system?
- Maintain posture
- Stabilise joints
- Produce movement
How does the muscular system maintain posture?
Through the continuous contraction of muscles, making one tiny adjustment after another.
How does the muscular system stabilise joints?
Muscle tendons play an important role in reinforcing and stabilising joints that have inadequately fitting articulating surfaces.
Provide an example of muscle tendons reinforcing and stabilising joints
E.g. the tendons of muscles play an important role in providing support to the shoulder joint.
How do we produce movement?
Skeletal muscles which are voluntary are attached to bones.
When we want to produce movement e.g. walking, swimming, the CNS sends a message from the brain to the relevant muscle to contract, resulting in “pulling the bone” causing movement to occur.
What does “pulling the bone” allow the body to do?
This enables the human body to respond quickly to changes in the external environment e.g. changing direction in a game of sport
What are the 3 types of muscles in the body?
- Smooth muscles
- Cardiac muscles
- Skeletal muscles
Where are smooth muscles located?
Located in the walls of internal organs such as blood vessels, the stomach, intestines, and the urinary bladder.
What are smooth muscles?
Smooth muscle fibres are involuntary, meaning they contact rhythmically and without conscious effort. They are less powerful than skeletal muscles, however can contract indefinitely whilst withstanding fatigue.
What is a cardiac muscle?
The muscle of the heart
Describe the cardiac muscle
It is striated and can contract rapidly. Its contraction is involuntary and fatigue-resistant.
What are skeletal muscles?
Skeletal muscles attach to and move bones by contracting and relaxing in response to voluntary messages from the nervous system.
What is the role of skeletal muscles?
It is responsible for moving the skeleton via the contraction or shortening of muscles.
What are the two types of skeletal muscles?
- Fast twitch fibres (white)
- Slow twitch fibres (red)
Describe the characteristics of a slow-twitch fibre
- Slow contraction speed – used for endurance activities
- High capacity for aerobic ATP production
- Fatigue resistant
- Contract repeatedly for continuous activity
E.g. Endurance cyclist (up to 80% slow twitch)
Describe the characteristics of a fast-twitch fibre
- Rapid contraction speed – used for speed, -strength and power-based activities
- High capacity for anaerobic ATP production
- Fatigue more quickly – no oxygen
- Generate greater force and more powerful contraction as they are larger than red fibres
E.g. Sprinter (up to 90% fast twitch)
What are the characteristics of a skeletal muscle?
- Contractability
- Extensibility
- Excitability
- Elasticity
What is excitability?
The ability to contract in response to chemical and/or electrical signals
What is extensibility?
The capacity of a muscle to stretch beyond its normal resting length.
What is contractability?
The ability of a muscle to contract or shorten
What is elasticity?
The ability of a muscle to return to the original resting length after it has been stretched
