WEEK 7 Flashcards
what are the five functions of the muscles
1- producing body movements
2- stabilising body positions
3- support soft tissues
4- storing and moving substances within the body
5- generating heat
what are the four similar characteristics between the three types of muscle tissue
- excitability= can transmit electrical signals
- contractility= can contract, shorten with force to create movement
- elasticity= can return to original length when relaxes
- extensinbility= extend their lengths
describe smooth muscles and where they are located
located- walls of hollow structures eg blood vessels when changing diameters
- involuntary control= spontaneous rhythmic cycles, influenced by hormones
- no tendons
describe smooth muscles in histology ( x5)
- uni nucleated= one nucleus
- spindle shaped
- non striated
- can divide
- can regenerate
describe the cardiac muscle and where is it located
- located only in the heart
- involuntary control
- pacemaker cells
- influenced by ANS and hormones
describe cardiac muscle histology ( x5)
- uni nucleated
- striated
- branched
- intercalated discs
- stores oxygen
- cannot divide
describe the skeletal muscles ( x6)
- most abundant muscle in the body
- voluntary control
- controlled by the nerves of the CNS
- can be influenced by hormones
- contraction= shorten muscle
- relaxation= lengthen muscle
describe skeletal muscle histology ( x6)
- very long
- multinucleate
- striated
- stores oxygen
- cannot divide
- can repair
what is hypertrophy
increase usage which increases tissue size due to an increase in cell size
what is hyperplasia
increase in tissue size due to increase in cell number
define atrophy
decrease usage therefore decreases in tissue size due to decrease in size of cells
what is a fascicle, fibre, myofibril and myofilaments
fasicle= functional unit in which muscle fibres work together
fibre= individual cells
myofibril= contractile fibres
myofilaments= thin filaments, thick filaments, elastic filaments
what does the myofibril structure consist of ( x5)
- actin
- myosin
- titin
- myofilaments are responsible for muscle contraction
- sarcomere= contractile unit
how does muscle contraction occur ( x4)
- occurs at the levee of microfibrils
- during contraction and relaxation, actin and myosin slide past eachother
- contraction is stimulated by the presence of calcium
- requires atp as an energy source
describe sliding filament theory x3
1- increased overlap of actin and myosin
2- sarcomeres shorten
3 - muscles contraction
describe the 6 stages of the contraction cycle
1) myosin head is already energised
2) calcium binds to troponin
3) myosin head then forms cross bridge with the actin
4) the ADP and p is released myosin head moves the actin chain towards the centre of the sarcomere
5) atp attaches to the myosin head and releases it from the actin chain
6) myosin re energised forms another cross bridge down the actin chain
what are the 8 steps in summary of muscle contraction and relaxation
1- ach rleeases in the nmj which binds to receptors
2- action potential reaches T tubules
3- sarcoplasmic reticulum releases calcium
4- active site exposure: cross bridge formation
5- contraction cycle begins
6- ach broken down by the ache
7- sarcoplasmi reticulum recaptures calcium
8- contraction ends
9- relaxation occurs; passive return to resting length
what are the four changes in the muscle system when ageing
1- changes in muscle sizes
2- loss of strength and elasticity
3- decreases in exercise tolerance
4- slower recovery form injury
what are the skeletal changes in puberty
- increase in sex hormones therefore increase release of HGH
- stimulate osteoblast to build prone mass
skeletal system disorders- what is osteopenia
- early loss of bone mineral density
- low than normal peak density but not low enough
skeletal system disorders- what is osteomalacia
softening of bones due to a lack of vitamin D, phosphate and low hormones that regulate blood claim levels
sekeltal system disorders- what is osteoporosis
- decreased total bone mass
- higher risk of fractures
skeletal system disorders- what is rheumatism
pain and stiffness in the muscular system or skeletal
skeletal system disorders- what is kyphosis
- drop in muscle tone and loss of posture
- drop in ADH production, loss of intervertebral disc
joint disorders- osteoarthritis
- degenerative, age related wear and tear disease
- bone ends up rub together
joint disorders - rheumatoid arthritis
- systemic, chronic, disease of synovial membrane
- affects both sides of the body
