Lecture 10 P2 Flashcards
(30 cards)
Isometric vs isotonic contractions
Isometric contractions are where there is no change in the length of the muscle. (No motion occurs)
Isotonic contractions are where the muscle length does change producing limb motion
How are graded contractions created?
Increase in AP frequency producing summation and tetanus or recruiting more motor units (vary by size)
Examples of isotonic movements
1) force of contraction is > than load
2) same tension, movement
3) muscle stretches
Examples of isometric contractions
1)Load>greater than force of contraction
2) muscle does not change length
Ex of large motor units
1) 1 motor neuron with 1000 muscle fibers
2) the quadriceps muscle
Ex of small motor units
1) 1 motor neuron and 10 muscle cells
2) eye muscles
Ex of conscious motor control
1) Primary motor cortex
ex of subconscious motor Control
Basal nuclei
Cerebellum
Midbrain
Where is the upper motor neuron cell body
Located in the in primary motor cortex
Golgi tendon organ
- Senses muscle tension
- Uses inhibitory neuron
- The sensor that causes muscle relaxation
Muscle spindle organ
- sensor for knee jerk reflex
- sensor that causes muscle contractions
- senses muscle stretch
- ## located in belly of muscle
If you try hard to lift up a box but it is too heavy, your muscles are still contracting using “isometric or isotonic” contractions to generate force
Isometric contractions
You are working with a senior woman who is confined to a chair due to risk of falling. You suggest “isometric or isotonic” exercises? Why?
Isometric, by using isometric exercises, the senior can sit in a chair and exercise while not moving the painful joints
Ex of twitch
- single muscle contraction
- response to 1 AP
Ex of summation
- Partial fusion of a muscle contraction
- result of rapidly generated action potentials
Ex of tetanus
Result of radially generated action potentials
- a full contraction
During summation, the increase in frequency of ___?____ causes an increase in ____?_____ that increases the available myosin binding sites on actin and “increase or decrease” in the force of muscle contractions
A) Action potentials
B) Ca +2
C) increase
What fuels are stored in the body
Fats and carbs
In what form are fuels stored in the body
Fats = triglycerides
Carbs = glucose that’s stored as glycogen
Where are fuels stored in the body?
Triglycerides stored in fat cells and muscle
Glucose stored as glycogen in the liver and skeletal muscle
What fuel sources can muscle use to produce atp
Primarily fats and carbs, but if I’m starvation mode, protein will be used
Using what stored fuel source as atp will cause weight loss
Triglycerides
What intensity of exercise works best for weight loss?
Mild exercise
What does the term graded contraction refer too
The ability of the skeletal muscle to generate the right amount of force needed to move a specific load
