Muscles Flashcards
3 types of muscles
smooth muscles, cardiac muscles, skeletal muscles
Smooth muscles
-lines the intestines and other organs-bladder, iris, BV
-unconscious/passive
-long and tapered at each end arranged in parallel lines
-contains one nucleus
-slower than skeletal muscles to contract
-does not tire easily
Cardiac Muscles
-In the heart
-In the atri and ventricles
-responsible for pumping the heart
-striatd - for electrical impulse
-unconsious/passive
-one nucleus
-branched like spider web
Skeletal muscles
-conscious and active
-find all over body
-usually atached to the skeleton
-over 600 in body
-many nuclei and more nutrition
-fiberous
-
Components ranked by skrinking size that make up a muscle
Muscle - muscle fiber bundle - musclee fiber - myofibrils - myofilament -
muscle cell/fiber, describe diagram
a box repersents sarcolemma - cell membrane
Sarcoplasm - cytoplasm
- mitochondria in either corner
-t tubules in the middle
Process of sliding filament model
- a nerve cell/neuron causes the release of calcium ions in sarcoplasmic reticulum
- Calcium binds to troponin wich causes the tropomyosin to move, revieling binding sites for myosin heads
- myosin heads bind to landing sites and form a CROSS BRIDGE FORMATION
- Myosin Heads flex, pulling actin POWER STROKE
- Using ATP, myosin heads release from binding sites CROSS BRIDGE DETACHEMENT
- Cycle restarts further down the line MYOSIN REACTIVATION
Actin
- thin filamet 5 nm
two stranded
myosin
- thick filament 11 nm
two stranded
rod shaped end =heads
globular hinged end = Tails
motors because they convert ATP to Ek
Sarcomere
- Functional unit for muscle contraction
- Sarcomere contracts but actin and myosin don’t
Skeletal muscles functions
- Move and support body. Contraction = bone movement
- regulates body temperature - Ek = heat
- atachement - tendon = muscles to bone, ligament = bone to bone
- protection - absorb shock impact
Smooth muscle function
Viscera - These muscles line digestive tract = peristalsis (moves food & waste)
- Plays a role in the urination in the bladder
- The stomach, arterioles, iris in eye, nipple, sphincters
(digestive tract) all contain smooth muscle
Sarcomere during relaxation
I bands - bands on either side - grow
H zone - middle zone - increase in size
A band is the same
Sarcomere during contraction
I bands shrink
H zon dissapears
A band is the same
