Musculoskeletal system Flashcards
What are the three functions of muscles
Change posture
Movement of internal organs
And locomotion
What are the three types of muscle cells
Skeletal, cardiac and smooth
What is syncytium
One multi nuclear cell made from the fusion of many uni nuclear cells.
What is an example of structural syncytium
Skeletal muscles
What is an example of functional syncytium
Cardiac and smooth muscles
What are properties of skeletal muscles
They’re connected to bones via tendons, they’re striated and tire quickly
What is the cardiomyocyte
Cells that make up cardiac tissue
What are properties of cardiomyocytes
Their nucleus is centrally located, they have an abundance of mitochondria and myoglobin (for oxygen storage). They have a branching structure.
what happens during a muscle contraction
Depolarisation reaches the muscle cell, causing the voltage gated L type ca2+ ion channel to open.
Ca2+ enters, this causes ca2+ to be released from the sarcoplasmic reticulum via the ryanodine receptor (RYR)
Ca2+ binds to troponin C on tropomyosin causing it to change shape moving from the actin binding site.
Myosin head binds to the actin binding site forming a cross bridge. Myosin head cocks forward (power stroke) causing a contraction.
Ca2+ is taken in by the SR via the ca2+ ATPase pump, releasing ATPase into the cytoplasm.
ADP on myosin head dissociates and atp binds. ATPase hydrolyses the atp to form ADP whihc releases energy returning the myofibril to its original length and myosin head to its starting position.
What us epithelial tissue
tissue that covers external surfaces and hollow internal surfaces except blood vessels and lymph system.
3 functions of epithelial tissue
protective barrier
Secretes substances
Absorption
And sensation
what is stratified epithelial tissue
layers of epithelial tissue but the bottom layer is connected the ba segment membrane
What is pseudo-stratified epithelial tissue
All the cells are connected to the basement membrane however they differ in length.
What is simple epithelial tissue
all the cells are connected to the basement membrane and are the same size.
What are simple, cuboidal and columnar cells
Simple: square shaped and flat
Cuboidal: cuboid shape
Columnar: tall with a square face
