Exam 3 Flashcards
Actin or myosin?
Thin filament protein
Involved tropomyosin & troponin
Actin
Actin or myosin?
Thick filament protein
2 heads and a tail
Binds/ splits ATP to ADP+P
Myosin
What is a muscle twitch?
Single action potential to skeletal muscle that causes brief contraction
Phase 1 or 2 or muscle twitch?
Contraction begins, Ca2+ bound to troponin, cross bridge cycle happens
Phase 1
Phase 1 or 2 of muscle twitch?
Peak of twitch, enough Ca2+ back out of cytoplasm= fewer cross bridges so force production falls, cell turns to resting
Phase 2: relaxation
What is a motor unit?
Single motor neuron and all muscle cells it Innervates
What is tetanus?
No relaxation between muscle summination causes maximal contraction
What are causes of muscle fatigue?
1) ATP production can’t keep pace with ATP use
2) decreased rate of AcH release
4 sources of ATP used in muscle metabolism
1) stored ATP
2) creating phosphate
3) anaerobic glycolysis
4) oxidative metabolism
Four major functions of GI
1) peristalis/ mixing movements
2) secretion into GI tract or bloodstream
3) digestion= chemical, mechanical breakdown
4) absorption from GI tract to blood or lymph
3 phases of digestion in order
Cephilac phase
Gastric phase
Intestinal phase
Six types of cells in gastric pits
1) Surface mucous cells
2) mucous neck cells
3) parietal cells
4) chief cells
5) G cells
6) D cells
What do mucous cells do
Secrete mucin to protect stomachs wall
What do mucous neck cells do?
Secretes acidic mucin
What do parietal cells do?
Secretes hydrochloric acid/ is instrinsic factor
What do chief cells do?
Secretes pepsinogen
