Summary from last class:
EPOC: Recovery from exercise (anaerobic or aerobic) is aerobic in nature. You must get anaerobic athletes into some amount of aerobic shape. How much aerobic exercise they need depends on what sport, what position they play, what type of this sport they play. Hard aerobic training destroys explosiveness and strength. Test this by a vertical jump. Make sure their vertical jump stays the same week from week. (High level athletes).
EPOC can stay elevated for very long periods of time after exercise. EPOC is greater after anaerobic exercise. For the average out of shape American: they are still burning calories after exercise during EPOC. Sometimes can stay up for a week. Takes a lot of extra calories to keep EPOC going. Greater EPOC after resistance training. 2-3 resistance training sessions per week could help the average out of shape American lose weight right off the bat.
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STARTING MATERIAL FOR TEST 2:
Neuromuscular System:
Refers to the Nervous system and the muscular system interacting.
Muscular System:
1. Skeletal/ striated muscle
2. Cardiac muscle (heart)
3. Smooth- muscle that surrounds hollow organs and blood vessels.
1. Skeletal/ striated muscle
2. Cardiac muscle (heart)
3. Smooth- muscle that surrounds hollow organs and blood vessels.
Nervous system:
Two basic components:
1. Central
A. brain (two parts most related to movement)
* Motor cortex: part of the brain where we store how to perform very simple movementpatterns. i.e. for us: walking. Don’t have to think about doing. Automatic. Can call these patterns up immediately.
*Cerebellum: part of the brain where we store complex type movement patterns. Must focus and concentrate to do them. E.g. Professional dives off of a diving board during the learning phase. Ie Walking for babies.
Constant repetition transfers the storage from the Cerebellum to the Motor Cortex. This is the goal. When you have to use these movement patterns in real situations you will be able to call up the movements quickly.
B. Spinal cord: very thick nerve from base of scull down to sacrum.
2. Peripheral Nervous System: all the nerves that run into and out of the spinal cord, to and from muscles (and organs).
A. Sensory/afferent: feelings; pain, cold, heat, pressure: carries info from muscle to CNS.
B. Motor/ efferent Nerve: carries info from CNS to muscle (telling it to generate force or tension, contract).
Action Potential is how a nerve sends a message (electrical energy).
Fig. 1.
Neuron: smallest structural and functional unit of a nerve. A nerve cell Pg. 12
1. Central
A. brain (two parts most related to movement)
* Motor cortex: part of the brain where we store how to perform very simple movementpatterns. i.e. for us: walking. Don’t have to think about doing. Automatic. Can call these patterns up immediately.
*Cerebellum: part of the brain where we store complex type movement patterns. Must focus and concentrate to do them. E.g. Professional dives off of a diving board during the learning phase. Ie Walking for babies.
Constant repetition transfers the storage from the Cerebellum to the Motor Cortex. This is the goal. When you have to use these movement patterns in real situations you will be able to call up the movements quickly.
B. Spinal cord: very thick nerve from base of scull down to sacrum.
2. Peripheral Nervous System: all the nerves that run into and out of the spinal cord, to and from muscles (and organs).
A. Sensory/afferent: feelings; pain, cold, heat, pressure: carries info from muscle to CNS.
B. Motor/ efferent Nerve: carries info from CNS to muscle (telling it to generate force or tension, contract).
Action Potential is how a nerve sends a message (electrical energy).
Fig. 1.
Neuron: smallest structural and functional unit of a nerve. A nerve cell Pg. 12
The NMJ is the Neuromuscular Junction (defined later).
The vast majority of motor neurons have myelin sheath insulation for the nerve to focus the electrical message. It is mostly made of fat and speeds the message. A message sent down a nerve with a mylonated sheath travels about 200 mph while a message sent down an unmylonated nerve only goes about 20 mph. Because the brain is made of mostly fat, it is impossible for humans to have 0% body fat.
Fig. 2
O= Na+ gate ion channels
X= Closed gate
X= Closed gate
At REST: the nerve is not sending a message. There is a difference in charge between the inside and outside of the nerve. + charged outside and - charged inside. High concentration of K+ (potassium) on the inside, high concentration of Na+ (sodium) on the outside. The charge difference comes from there being much more sodium on the outside than potassium on the inside.
Fig. 3
O= Na+ gate ion channels
X= Closed gate
Triangles= K+ gated ion channels
1st step of a nerve sending a message (action potential) is called depolarization. During depolarization Na+ rushes into the cell. This is a passive process: it does not take energy. These ions naturally move from high concentration to low concentration. At this point the charge is reversed to + on the inside and - on the outside.
Fig. 4 K+ rushes out of the cell from high concentration to low concentration.
If your muscle is picking up a light weight, your nerves don’t have to fire often. Maybe a couple of times to get it to contract. If you are picking up a heavy weight, your nerves will send many messages to:
1. Continue muscle activity
2. Strengthen the contraction of the muscle
To do this we must get the nerve back from re-polarization to Rest state. This takes energy in the form of ATP and requires use of the Na+/K+ pumps. For every 3 Na+ it pumps out, it pumps 2 K+ into the cell. It takes more energy to do this while we are learning a movement pattern than if we already know it very well.
1. Continue muscle activity
2. Strengthen the contraction of the muscle
To do this we must get the nerve back from re-polarization to Rest state. This takes energy in the form of ATP and requires use of the Na+/K+ pumps. For every 3 Na+ it pumps out, it pumps 2 K+ into the cell. It takes more energy to do this while we are learning a movement pattern than if we already know it very well.
This whole process happens as a chain reaction down the length of the nerve axon until the message (action potential) reaches the muscle.
(cliff’s notes of the other drawings)
Please see book or this link for a picture of the Neuromuscular Junction. http://en.wikipedia.org/wiki/Neuromuscular_junction
The Neuromuscular Junction:
The NMJ (neuromuscular junction) is the place where the motor neuron stimulates the muscle cell.
The muscle and the nerve do not touch. How do we get the message from the nerve to the muscle?
The NMJ (neuromuscular junction) is the place where the motor neuron stimulates the muscle cell.
The muscle and the nerve do not touch. How do we get the message from the nerve to the muscle?
The action potential moves down the axon to the NMJ. This forces Ca+ to be taken into the end of the axon which triggers the vesicles to combine with the cell walls and release their Acetyl choline (ACH) into the gap. ACH binds to ion channels on the muscle causing an action potential.
The action potential runs down the length of the muscle and down the t-tubules (nerves that are located in the muscle). Inside the cell, the sarcoplasmic reticulum (that stores Ca+ ions) receives the action potential which triggers the SR to release its Ca+ into the muscle.
This Calcium then binds to troponin, changing the configuration of itself and tropomyosin, rolling the tropomyosin of of the active sites on actin. The cross bridges of the myosin are immediately attracted to the active sites. With the release of energy from ATP the cross bridges act spontaneously binding with actin’s active sites, and bending backward (power stroke) to pull actin along. This is the Sliding Filament Theory. ACTIN SLIDES OVER MYOSIN TO CAUSE MUSCLE CONTRACTION.
Sliding Filament theory: A muscle shortens and lengthens when the thin/actin filaments slide past the thick/myosin filaments without the filaments changing length themselves. See pages 5-7 of the class packet.
Actin: thin filament
Myosin: thick filament
Tropomyosin: located on actin and cover the active sites.
Troponin: located on the tropomyosin
Actin active sites: where myosin cross bridges connect to slide actin over it.
Myosin: thick filament
Tropomyosin: located on actin and cover the active sites.
Troponin: located on the tropomyosin
Actin active sites: where myosin cross bridges connect to slide actin over it.
For more information outside your text, I have found these links to be helpful:
Sliding Filament Theory
How Stuff Works link for How a muscle contracts (nice pictures)
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