Muscle Biology Flashcards
What are the 3 muscle types?
- Smooth.
- Cardiac.
- Striated.
What are 3 the characteristics of smooth muscle?
- Involuntary.
- 1 nucleus.
- Spindle shape.
Where are smooth muscles found?
- Blood vessel walls.
- Reproductive tract.
- GI tract.
What are the 3 characteristics of cardiac muscle?
- Involuntary.
- Mononuclear.
- Striated.
Where is cardiac muscle found?
The heart.
What are the 4 characteristics of striated muscle?
- Voluntary.
- Multinuclear.
- Spindle-shaped.
- Striated.
What is the other name for striated muscle?
Skeletal muscle.
What is each muscle fiber in reality?
A large, multinucleated cell.
What is a fascicle?
Many muscle fibers bundled together.
What is the epimysium?
What is the perimysium?
What is the endomysium?
Where is intermuscular fat found?
Between the individual fibers.
Where is intramuscular fat found?
Between the fascicles.
What two other types of tissue, besides muscular, connective, and adipose, is found in skeletal muscle?
- Vascular tissue.
- Nervous tissue.
What is the sarcolemma?
The plasma membrane of the muscle cell.
What is the sarcoplasm?
The cytoplasm of the muscle cell.
What is the function of the sarcoplasmic reticulum?
To control the storage, release, and retrieval of calcium in the muscle cell.
What is the sarcomere?
The contractile unit of the muscle cell.
What is the appearance of the sarcomere: smooth or striated?
Striated.
What is the other name for actin filaments?
Thin filaments.
What is the other name for myosin filaments?
Thick filaments.
What are the functions of Z-discs/Z-lines?
To anchor the actin chains.
What are the 2 regulatory proteins in the sarcomere?
- Troponin.
- Tropomyosin.
What is troponin?
What is tropomyosin?
What is step 1 of muscle contraction?
The neuron releases ACH into the neural-muscular junction.
What is step 2 of muscle contraction?
ACH signals Na+ channels to open, causing the muscle fibers to depolarize.
What is step 3 of muscle contraction?
The depolarization results in the releases of Ca2+ from the sarcoplasmic reticulum.
What is step 4 of muscle contraction?
Ca2+ binds troponin, causing the tropomyosin to move out of the myosin binding site.
What is step 5 of muscle contraction?
The myosin head binds to the myosin binding site on the actin and pulls it using energy from ATP.
What are transverse tubules or T-tubules?
Channels that ensure the sarcolemma and sarcoplasmic reticulum maintain contact through carrying the action potential to the interior of the cell.
What does the sarcoplasm contain?
- Soluble proteins.
- Glycogen granules.
- Lipid droplets.
What 2 soluble proteins of importance are found in the sarcoplasm?
- Glycolytic enzymes.
- Myoglobin.
What are the 2 functions of myoglobin?
- Carries oxygen to the mitochondria.
- Gives meat and meat fluids a red color.
What products are produced during aerobic respiration?
- ATP.
- CO2.
What products are produced during anaerobic respiration?
- Creatine.
- Lactate.
- ATP.
Where does the ATP go?
To the myofibrils to support muscle contraction.
What % of skeletal muscle is water?
75%.
What % of skeletal muscle is protein?
20%.
What % of skeletal muscle is fat?
1-10%.
What % of skeletal muscle is glycogen?
1%.
How is muscle fiber characterized?
- Contractile properties.
- Metabolic properties.
- Different myosin heavy chain isoforms.
What are the characteristics of slow twitch/Type 1 muscle?
- Low intensity contractions.
- Fatigue resistant.
What types of muscles are slow twitch?
- Postural.
- Respiratory.
What occurs during the oxidative pathway of ATP regeneration?
- Pyruvate is oxidized by the mitochondria.
- Red, due to being myoglobin rich.
What occurs during the glycolytic pathway of ATP regeneration?
- Pyruvate is converted into lactic acid.
- White, nearly devoid of myoglobin.
Can muscle fibers switch types?
Yes.
What influences the muscle types that are found in the muscle?
- Breed.
- Gender.
- Age.
- Physical age.
- Environmental temperature.
- Feeding practices.
What is collagen/tropocollagen?
Fibrils stabilized by intra-or intermolecular bonds called cross-links.
How are intramolecular bonds cross-linked?
Disulphide or hydrogen bridges.
How are intermolecular bonds cross-linked?
- Pyridinoline.
- Deoxypyridinoline.
What does the degree of cross-linking depend upon?
- Muscle type.
- Species.
- Genotype.
- Age.
- Sex.
- Level of physical exercise.
What are proteoglycans?
What do proteoglycans form?
Large complexes with other proteoglycans and fibrous proteins.
What do proteoglycans bind?
- Cations.
- Water.
What happens to intermuscular fat during cutting?
It is trimmed.
What % of storage lipids are found in muscle adipocytes? Lipid droplets within myofibrils?
- 80%.
- 5-20%.
What 7 factors cause variation in fat?
- Species.
- Muscle.
- Age.
- Breed.
- Genotype.
- Diet.
- Rearing conditions.
