L4 - Muscle Flashcards
Built-in heart rhythm
Autorhythmicity - regulated through a system of pacemakers
Muscle tissue composition
Elongated cells: muscle cells/muscle fibres/myocytes
Muscle tissue mechanism
Use energy from hydrolysis of ATP to generate force
ATP
Adenosine triphosphate
Muscle tissue function
- produce body movements
- maintain posture (stabilising body positions)
- generate heat
- protection
- storing/moving substances within body (peristalsis - smooth muscles, pump blood - cardiac muscles)
Types of muscle tissue
Skeletal, cardiac, smooth
Skleteal muscle features
~650 named skeletal muscles in body
Skeletal muscle control
voluntary (contraction is under conscious control but doesn’t always require conscious control - e.g posture)
Skeletal muscle location
Attached to bones by tendons
Skeletal muscle function
motion, posture, heat, protection
Skeletal muscle examples
Stapedius, sartorius
Stapedius features
- smallest at 1.25 mm
- stabilises smallest human bone (stapes) in the ear
- changes tension (muscle tightens) to control sensitivity of hearing by altering the amount of sound vibration transmitted through eardrum
- supplied by a small branch of facial nerve
Bell’s Palsy
paralysis of nerve causes changes in facial appearance and hyperacusis (extra loud sound perception)
Sartorius features
- longest at up to 60 cm
- in the thigh and in charge of twisting to be able to see the bottom of feet
- hip: flexor, abductor, lateral rotator
- knee: flexor
Skeletal muscle structure
- Striated (alternating light and dark bands within fibres under microscope)
- relatively big, long, cylindrical, ordered cells/fibres
- Multinucleate with many peripheral nuclei pushed to the side
Connective tissue in muscle
Epimysium, perimysium, endomysium, tendons
Epimysium location
surrounds anatomical muscle (very outer layer - fibrous fascia)
Epimysium composition
dense irregular connective tissue
Epimysium function
stops muscles from sticking to other muscle
Perimysium location
around fascicles
Fasicles
a bundle of cells grouped together which can move as individual units
Perimysium composition
dense irregular connective tissue
Endomysium location
- around muscle fibres/cell
- sits outside the sarcolemma
Endomysium composition
Areolar connective tissue - mostly reticular fibres