Muscular system lecture 5 Flashcards
Muscle function
Movement, maintain posture, protection and support, regulate elimination of waste, heat production
Muscle characteristics
Excitability, Conductivity, Contractility, Extensibility, Elasticity
Excitability
only muscle and nervous tissue responds to stimuli
Conductivity
able to send electrical signal along tissue
Contractility
muscle slide past each other and shortens
Extensibility
muscle can be stretched
Elasticity
contracted muscle return to original resting length
Fascicles
Internal structure organized into bundle of fibers
Perimysium
surrounds individual fasicle
Epimysium
surrounds entire muscle
Endomysium
surrounds individual fibers
Tendons
dense regular connective tissue, attach muscle to bone or skin
Aponeuroses
Dense irregular connective tissue, attach muscle to bone or skin
Sacroplasm
Cytoplasm of a muscle cell
Sarcolemma
t-tubles tunnels that carry signal deep into the cell
Multiple peripheral
nuclei
Sacroplasmic recticulum
regulates release of calcium
Myofibrils
bundle of proteins capable of contracting
Myosin
Actin
Myosin
thick filaments composed of protein(dark)
Actin
thin filaments composed of protein(light)
as well as troponin and tropomyosin
Myoglobin
Stores oxygen for aerobic respiration
Glycogen
storage of glucose
Thick filaments
composed mostly of myosin protein, has 2 head and 2 tails wrapped around each other, heads have binding cites for actin
Thin filaments
contain protein actin, binding sites are blocked by tropomyosin, blocking action removed when Ca+2 binds with tropomin molecule
Sacromere
reginon between the 2, Z disc
Z Line
attachment sites of thin filaments of Z disc
A band
region with dark filaments
I band
region without thick filaments (lighter)
H-zone
region between ends of thin filaments within A band
Nerve impulse(action impulse)
Ca+2 release triggers muscle contraction
M-line
attachment site for thick filaments
Neuromuscular Junction
location where neurons meets muscle
Neurotransmitter acetylcoline
released from somatic motor neuron, moves through space between muscle and nerve, triggers new action potential in skeletal muscle
Motor unit
one motor neuron and all of the fibers innervates
Sliding filament theory
muscle contracts and shortens, filaments overlap, I band reduces in size, H zone disappear
Phosphate transfer
a phosphate is chemically transferred onto ADP to form ATP
2 source of Phosphate transfer
Creatine phosphate
ADP
Glycolsis
anaerobic respiration in cytoplasm- 2 pyruvates and ATP, produces ATP from 10 seconds to 1min mark
Aerobic Respiration
happens in mitochondria, produces ATP from 1min mark until completion
Speed of contraction
fast, slow, depends on how quickly enzymes break down ATP
Oxidative fibers
rely on aerobic process of ATP
Glycolytic fibers
rely on anaerobic process of ATP
Slow oxidative fibers(red)
Aerobic ATP production, not powerful but hold contractions for a long time (planks)
Intermediate fibers (pink)
aerobic ATP, lower oxygen supply, fast, powerful contractions
Fast glycolytic fibers
anaerobic ATP production, Fast/powerful contractions (sprinting)
Red Fiber
more oxygen, lots of myoglobin, blood vessels, mitochondria, lipid stores, weaker, fatigue-resistant (endurance)
White Fibers
powerful but tired fast, little myoglobin, fewer blood vessels/mitochondria, glycogen stores
Aerobic exercise
increase in muscle capillaries, number of mitochondria, and myoglobin sythesis
Resistance exercise
muscle hypertrophy(bulky), increased strength, endurance, and done density
Overload principle
forcing muscle to work promotes increased muscle strength and endurance, muscle adapts to increased demand, muscles must be overloaded to produce further gains and strength
