Exam 2 physiology lecture

eccentric contraction

muscle lengthens as it maintains tension

Where is the motor cortex located?

located in the precentral gyrus of the frontal lobe. In front of the central sulcus.

What is plyometrics?

Generate greatest amount of force in the shortest amount of time "Explosive jumping"

Isometric

No change in muscle length

Where is the primary somatasensory located?

Post central gurus Parietal lobe

What does the motor cortex do?

controls voluntary contractions of specific muscles or groups of muscles. Electrical stimulation of any point of the primary motor cortex causes contraction of specific skeletal muscle fibers on the opposite side of the body.

White matter tracks-the big picture

Motor and descending pathways red. Sensory and ascending pathways blue

Five key functions of interneurons

Connecting branches between neurons that can be both excitatory and inhibitory. 5 types: 1. 1a inhibits the alpha motor neuron of the antagonist muscle 2.1b inhibits alpha motor neuron the the agonist muscle 3. Renshaw cells causes self inhibition (inhibitory interneuron) 4. Propriospinal interneuron Connects afferents and efferent over different spinal levels (inhibitory and excitatory) 5. Contralateral interneurons. Cause motion on the other side. (Inhibitory and excitatory)

What causes muscles to be injured?

Fatigued or weak muscles, when performing unique tasks for the first time, already injured. Muscle belly is the weakest, tendon with fast loading rates, bone tendon weakest with static loads.

What does the primary somatosensory do?

Process tactile information. permits you to determine the size, shape, texture, and weight of an object by feeling it and to sense the relationship between one part of the body and another.

Know the White matter tracts of spinal cord

The white matter tracts in the spinal cord serve as the "highways" for action potential propagation. Sensory input travels along these tracts toward the brain, and motor output travels from the brain along these tracts toward skeletal muscles and other effector tissues.

Understand the whole pathways and identifying the key structures fo the patella knee reflex (muscle spindle)

This stretch reflex involves extension of the leg at the knee joint by contraction of the quadriceps femoris muscle in response to tapping the patellar ligament (see Figure 12.3). This reflex is blocked by damage to the sensory or motor nerves supplying the muscle or to the integrating centers in the second, third, or fourth lumbar segments of the spinal cord. It is often absent in people with chronic diabetes mellitus or neurosyphilis, both of which cause degeneration of nerves. It is exaggerated in disease or injury involving certain motor tracts descending from the higher centers of the brain to the spinal cord.

concentric contraction

muscle shortens as it maintains tension