week 6 Flashcards
define neuromuscular system
the combination of the nervous system and the muscles working together to permit movement.
where at what is myelin sheath produced
PNS by the Schwann Cells
what are muscle tissue
is specialised for contraction to allow movement
whats skeletal muscle
voluntary movement eg. limbs, body, face
whats cardiac muscle
involuntary eg. heart
whats smooth muscle
involuntary eg. blood vessels, bladder
how do muscle tissue produce movement
shorten and thicken (contraction)
skeletal muscle function
Produces skeletal muscle movement Maintains posture and body position Supports soft tissues Guards entrances and exits of tracts Helps maintain body temperature by shivering
where is a skeletal muscle located
run form on bone to another, crossing at least one joint
what are skeletal muscle composed of
muscle belly- contains contractile ability
tendons - attach to the bone
what is muscle tissue properties
excitable- sustain action potentials within themselves
conductive
elastic-will come back to original position
properties of skeletal muscle fibre
Long cylindrical, striated fibres. Multinucleate – numerous peripheral nuclei Sarcolemma = plasma membrane Sarcoplasm = cytoplasm Contain many mitochondria
two types skeletal muscle fibres
- Type I (slow-twitch) :contract much longer (less rapid) and don’t fatigue as easily (maintenance of muscle tone)
- Type II (fast-twitch):contract rapidly however fatigue quickly, less as you get older = slow reaction time.
whats myofibrils
- Densely packed, rod-like elements
- Contain sarcomeres - contractile units
- sarcomeres contain myofilaments
whats sarcomas
Smallest contractile units (functional units) of muscle fibres
Align along myofibril like freight cars of a train
Composed of thick and thin myofilaments made of
19
contractile proteins
process of muscle contraction
- Myosin attaches to the actin
- Pulls the actin towards the centre of the sarcomere
- Sarcomeres shorten, muscle fibres shorten, entire muscle contracts, movement occurs
whats neuromuscular junction
situated midway along length of muscle fibre
Axon terminal and muscle fibre separated by gel-
filled space called synaptic cleft
motor units in muscle usually contract
contract asynchronously - helps prevent fatigue
whats muscle tone
A muscle at rest is always partially contracted (taut)
tone of the muscle at rest is maintained as different motor units contract at different times, a small number being active at any one time.
when is muscle tone absent
Muscle tone is absent during deep sleep and unconsciousness.
whats flaccid
A muscle with a degree of tone less than normal is
whats spastic
A muscle with a degree of tone greater than normal is
whats muscle regeneration
Skeletal muscle fibres can’t divide
If damaged, limited regeneration
Most of a damaged area will be “patched” by fibrous scar tissue which is non-contractile
whats hypertrophy
response to regular, forceful use of a muscle
Increase in number of contractile proteins
Increase in diameter of individual fibres not an increase in number of muscle fibres
whats atrophy
-response to disuse
-Initially fibres shrink as contractile proteins are broken down and recycled
Muscle fibres may later degenerate and be replaced by fibrous tissu
causes of neuromuscular disease
Neuropathy: • failure of electrical impulse to be conveyed to nerve Junctionopathy: • failure of chemical message to bridge the synaptic gap Myopathy: • failure of muscle to contract Genetic mutation Viral infection Autoimmune disorder Hormonal disorder Metabolic disorder Dietary deficiency Certain drugs and poisons
symptoms of neuromuscular diseases
muscle weakness or parlysis muscle wastage continuous muscle spasm muscle twitcing muscle pain breathing or swallowing difficulties
whats Duchenne muscular dystrophy
is a genetic disorder characterized by progressive muscle degeneration and weakness due to the alterations of a protein called dystrophin that helps keep muscle cells intact
whats myasthenia gravis
is a chronic autoimmune neuromuscular disease that causes weakness in the skeletal muscles, which are responsible for breathing and moving parts of the body, including the arms and legs.
whats motor neurone disease
is the name given to the group of diseases in which the motor neurones undergo degeneration and die
whats Parkinson’s disease
s a disorder of the nervous system. It results from damage to the nerve cells in a region of the brain that produces dopamine, a chemical that is vital for the smooth control of muscles and movement.
whats Multiple Sclerosis(MS)
is a long-lasting disease that can affect your brain, spinal cord, and the optic nerves in your eyes. It can cause problems with vision, balance, muscle control, and other basic body functions
whats Cerebral Palsy(CP)
is a problem that affects muscle tone, movement, and motor skills. It hinders the body’s ability to move in a coordinated and purposeful way. … CP often is caused by brain damage that happens before or during a baby’s birth, or during the first 3-to-5 years of a child’s life.
