Muscle Physiology Flashcards
Tissue covering of EACH muscle tissue
Epimysium
Cover many fascicle of muscle tissue
Perimysium
Surround each muscle fiber
Endomysium
Smallest anatomic unit capable of contraction
Muscle fiber
Thin threadlike substances with light and dark bands of striation
Myofibrils
2 types of myofibrils
Actin and myosin
Structural functional subunit between 2 adjacent Z lines
Sarcomere
Boudaries of sarcomere where actin is inserted
Z disk
Proteins bounde to actin and myosin
Troponin/tropomyosin
Interconnect sarcolemmal membrane and sarcoplasmic reticulum
Transverse tubules
What give the skeletal muscle its striated appearance
Overlapping of actin and myosin
Center of sarcomere which contain MYOSIN
A band
Contains ACTIN only. Transected by Z disk
I band
I- thin “acthin”
Center of sarcomere which contain myosin and DOES NOT OVERLAP
H zone
Center of H zone
M line
Muscle fiber with Deep red, higher myoglobin content
Slow muscle fibers
Muscle fiber with whitish hue
Fast muscle fibers
Consist of small specialized muscle fibers encapsulated by connective tissue
Muscle spindles
2 types of muscle spindle
Nuclear bag
Nuclear chain
2 types of innervation of muscle spindle
Primary sensory- annulospiral
Secondary sensory- flower spray
Absence of ATP in muscles will result in
Rigor mortis
What is important in the detachment phase of skeletal muscle RELAXATION
ATP
What accumulates during rigor mortis?
Phosphoric acid
Lactic acid
MC form of progressive motor neuron disease
ALS
aka Lou Gehrig disease
Rapidly progressive fatal neurologic disease that attack the nerve cells responsible for controlling voluntary muscle
ALS
Gene mutation in ALS
Superoxide dismutase gene
Result to ROS damage
What neurotransmitter in increased in ALS?
Glutamate— lead to increased excitation— death of neuron
Gene that regulates glutamate release
SOD-1
Part of spinal cord affected in ALS
Anterior horn cells– both UMN and LMN symptoms
Telltale sign of ALS
Atrophy of tongue
Small intracytoplasmic eosinophilic inclusions seen in LMN of pt with ALS
Bunina bodies
Drug that increase survival of pt with ALS
Riluzole
Median survival of ALS
3-5 years
Type of contraction where there is change in muscle length
Isotonic muscle contraction
Ex: biceps curls
Type of contraction where there is NO change in muscle length,and only EXERT TENSION
Isometric muscle contraction
Electrical stimulation of myocytes above the threshold potential results in a limited efflux of calcium from SER stimulating a SINGLE CONTRACTION
Twitch
Occurs if muscle is stimulated high enough, and individual muscles twitches combine to produce SUSTAINED contraction
Summation and tetany