8.Muscles Of The Head Comnpleted Flashcards
What is the essential function of the muscle
Is to contract/or shorten- a unique charter is tic that sets it apart from other body tissues
]as a result- muscles are responsible for all body tissue movements Anne can be viewed as the machines of body
What are the three types of muscle ?
1- skeletal- striated, voluntary
2- cardiac, striated, involuntary
3- smooth involuntary
What are skeletal muscle fibres>
Fibres are Packaged into organs called skeletal muscles that attach to skeleton
Fibres are large, cigar shaped,multinucleate cells
Largest of muscle fibres
Also known as striated muscle and voluntary
Describe an overview of skim structure
Striated
Structure: joined muscle cells from muscle fibres surrounded by endomysium
Bundles of f form fascicles surrounded by perimysium
Multiple fascicles form muscle surrounded by epimysium
Muscle and epimysium are covered by fascia
Muscle attaches to bones via tendons
Explain the mysiums of skim
Endomysium- ct sheath enclosing each muscle fibre
Peri- fibrous membrane wrapping several sheathed muscle fibres, which forms bundle called fascicle
Epi- tougher overcoat of ct which bounds many fascicles
Tendon/aproneurosis - the ends of epi that extend beyond muscle blend into either cork like tendon, sheath like aponeurosis
Describe the cardiac muscle
Is found in the heart only where it forms the bulk of heart wall
Heart serves as a pump- propelling blood through blood vessels to all body tissues
Sriated
Uni nucleate
Involuntary control
Describe the smooth muscle
No striations
Involuntary
Found mainly in walls of hollow organs
Uni nucleate
Arranges un layers- normally one running circularly and one longitudinally
These layers can change size/shape of orga as they contract/relax
What is the function of the skeletal muscle ?
Produce movement
Maintain posture/body position
Stabilise joints
Generate heat
Describe the interactions of sk m in body
Muscles can’t push- only pull as they contract- most body movement results from two+ muscles working together or against each other
They are arranges so that whatever one can do, the other muscles can reverse
In general - groups of m that produce opposite movements lie on opposite sides of joint
Prime mover- muscle that has major responsibility for causing a particular movement
What are antagonists?
Antagonists- muscles that reverse/oppose movement- when prime move is active- antagonist = stretched and relaxed- they can be prime movers in their own right but for different actions
Ie biceps brachii and brachial muscles of arm (prime moral of elbow flexation|) are antagonised by triceps brachii |(a prime mover of elbow extension?
What are synergists?
Help primers move by producing same movement or by reducing under sir able movements.
When muscle crosses two/more joints its contraction will cause movement in all the joints crossed unless synergists are used to stabilise them
What are fixators?
Specialised synergists, they hold a bone still or stabilise the origin of a prime mover
Naming skeletal muscle fibres
Direction of m fibres- rectus - straight
Relative size of m- maximus(largest), minimus (smallest)
Location of muscle
Number of origins- biceps,triceps,quadriceps
Location of muscles origin and insertion- sternocleidomastoid ( sterno= sternum cleido= clavicle)
Shape of muscle- deltoid - triangular
Action of muscle- flexor, extensor, adductor
What are the arrangement of fascicles ?
Circular
Convergent
Parallel
Fusiform
Pennate- up pen ate -bi-multi
Describe muscle of the scalp
Occio-pito-frontalis
Orgin- occipital belly : lateral thirds of superior nuchal line on occipital bone and mastoid part of temporal n bone
Frontal belly- fibres continuos with those of procerus medially and orbicularis oculi laterally
Insertion- into galea aponeurotia
Innervation- posterior auricular branch of facial nerve v11
Action- draws back scalp, raises eyebrows, wrinkles forehead in expression of surprise
