Muscles Flashcards
What are the 3 types of muscle
involuntary, voluntary, cardiac
Involuntary
contracts under unconscious control
contracts in response to stimulation by nerves or chemicals such as hormones which circulate around the body
Voluntary
under our conscious control
stimulated by the nervous system
cardiac
a type of involuntary muscle found in the walls of the heart
striated
stimulated by electrical patterns that crate a co ordinated contraction of the heart muscle to propel blood out of the heart
functions of muscles
movement
stabilising the body
storing and moving substances within the body (helps move blood around the body)
generating heat (help maintains body temp)
4 key points relating to muscle action
a muscle can only pull, can’t push
muscle crosses at least one joint
can only work in its line of fibre
works in pairs
Muscles and ageing
loses size and strength
muscle fibres reduce in number and shrink in size
muscle tissue replaced more slowly and lose muscle tissue is replaced with a tough fibrous tissue making it less flexible
changes in the nervous system cause muscles mohave reduced tone and ability
Fascia
the entire muscle is surrounded by a broad protective fibrous sheath called the epimysium
Fasicles
bundle of muscle fibres
muscle fibre
each individual muscle fibre is surrounded by a thin later of fascia called the endomysium
myofibril
consist of a series of thick and thin protein filaments called actin and myosin
sarcomere
the smallest functional unit of myofibril
concentric contractions
when a muscle contracts, develops tension and shortens, a concentric contraction takes place
Eccentric
when a muscle contracts, develops tension and lengths an eccentric contraction takes place
Isotonic
movement that is occurring as a result of contraction with one bone getting closer or further away from another bone depending upon the contraction
