Ch 9: Continued Flashcards
Sarcoplasm
Skeletal muscle cells cytoplasm
Sarcolemma
Muscle cell membrane
Transverse tubule
Invagination of sarcolemma
Sarcoplasmic reticulum
Modified ER system of skeletal muscle cell that stores and releases calcium
Terminal cisternae
Enlarge terminal segments of the Sarcoplasmic reticulum
What is the depolarization phase caused by?
Sodium channels open (influx)
- k+ channels close
What is the re-polarization phase caused by? 
Potassium channels open (efflux)
- sodium channels closed 
What are the three channels of a muscle fiber
Sodium channel, potassium, channel, sodium, and potassium pump (ATP)
What is an influx?
Moving substance from outside to inside 
What is the dip called on the graph? 
Hyper polarization
What is hyper polarization caused by?
Slow, closing of potassium channel
Ligand gated channel 
Neuro transmitter used in muscle contraction also called acetylocholine
Voltage gated channel
Open/close in response to small voltage change across the plasma membrane
Can a NMJ be a synapse
Yes 
Presynaptic membrane
Membrane before synapse
(nerve)
Postsynaptic membrane
 Membrane after synapse
-muscle cell
Motor unit
Single motor neuron, and all muscle fibers innervated
Large motor unit numbers
Mini muscle fibers
Small motor unit numbers
Few muscle fibers 
Order of muscle contraction steps
- Action potential simulates
- AP cause voltage gated calcium channel to open.
- Acetylcholine Is released from presynaptic vesicles. 
- Acetylcholine stimulates sodium channels on postsynaptic to open.
- Sodium diffuses into fiber, initiating action potential to travel to T tubules and sarcolemma
- Action potential energy tubules, cause Sarcoplasmic reticulum to release calcium
- On Acton, calcium, binds to troponin, and moves triple myosin, and myosin to move.
- ATP molecules are broken by ADP & P to release energy to move myosin heads.
- Heads of myosin, mytolam bend causing act into slide past myosin, as long as calcium is present the circle repeats
What is the triad composed of?
Terminal cistetnae and t-tubule
Phases of muscle contraction
- Lag/ latent
- contraction
- relaxation
Lag/ latent phase
Action potential sweeps Across sarcolema and Sarco plasmic reticulum to release store, calcium, and cross bridge
Contraction phase
15 millisecond and power stroke
Relaxation phase
25 millisecond, calcium levels is falling and decreased number of cross bridge
“ all or none” term
Muscle contracts or doesn’t 
Threshold
Stimulus to produce a response
(weak stimulus)
Twitch term
Rapid contraction and relaxation 
Telanus
Muscle remains contracted 
Rigor mortus
No, ATP is available, so no release of cross bridges for relaxation 
Isotonic
Muscle contracts
(shortens)
Isometric
No contraction
-no change in life
*E.C
What is Creatine phosphate energy source?
Creatine phosphate
(10 sec)
What is Anaerobic respiration energy source?
Glucose
-Up to three minutes
- -O2
What is aerobic, respiration, energy source?
Glucose, fatty acids, amino acids
-up to hours
- +O2
What is Glycolysis?
Splitting glucose (6 carbons) into two molecules (3 carbons each)
How does effects of activity or lack of affect muscles?
Change in size of muscle fibers
-Getting more fit or getting fat
Hyptertrophy
Increase in muscle size
Atrophy
Decrease in muscle size
What type of twitch with a sprinter have?
Fast twitch
( they would get tired faster)
What type of twitch with a marathon have?
Slow twitch
(more endurance)
What type of muscle fatigue’s are there?
Psychological
Muscular
Synaptic
Psychological muscle fatigue
Mental state
Muscular fatigue
ATP depletion
Synaptic muscle fatigue
Lack of acetylcholine and occurs in the NMJ
Characteristics of smooth muscle
-Lack of striation (involuntary control)
-Avioli (similar to T tubules of striated muscle)
- Act to store calcium
Calcium binds to calmadulin
Myosin phosphatase
Enzyme causes smooth muscle cell relaxation
Dense body
Non-contractile intermediate filaments
* doesn’t have all or none property*
And has pacemaker cells
Transmitter regulation
Ligon, neurotransmitters are acetylcholine and NE
-use Epinephrine , norepinephrine, and oxytocin
Cardiac muscle
Striated and has one nucleus (involuntary)
- Calcium regulates contraction
- Longer duration, and re-factory period
How does Powerstroke occur?
From cross bridge