WK5-Nervous System Flashcards
What is multiple sclerosis (MS) and how do patients who have this condition benefit from exercise training?
MS is a condition of immunological origin wherein the CNS nerves are de-myelinated which affects their ability to conduct electrical impulses. People who have MS suffer from mental depression, fatigue, muscle weakness, poor motor control, loss of balance, and overall loss of quality of life over time. Evidence indicates that exercise training in patients with MS can increase quality of life, strengthened muscles and increased endurance as well reduction of mental depression.
Describe the events that categorize an action potential.
An action potential is the depolarization of a cell due to an influx of Na+ that was initiated by a stimulus that meets or exceeds the threshold. Na+ enters the cell and depolarizes the cell, the axon then propagates the action potential, K+ then leaves the cell to repolarize the cell for the next action potential.
Define the all or none law.
The all of none law states refers to the development of a nerve impulse. There is no partial activation of a nerve cell, an impulse will travel the length of an axon retaining the voltage it had when the action potential was initiated.
What is an excitatory post synaptic potential ( EPSP) ?
when a neurotransmitter is released from a presynaptic nerve onto the terminal of a post synaptic nerve and produces a rise of graded depolarizations. If enough neurotransmitter is released then neuron is depolarized to threshold and an AP is generated.
compare and contrast temporal and spatial summation ?
both are ways of an EPSP reaching threshold. during temporal summation input signals arrive at the synapse at different times to produce an action potential. during spatial summation, inputs from many different axons converge on one postsynaptic membrane and produce an action potential.
What is an inhibitory post synaptic potential (IPSP) ?
IPSP is when a neurotransmitter increases the decreases the resting membrane potential of a cell causing it to be hyperpolarized, thus it resists depolarization.
What is kinesthesia ?
awareness of the position and movement of the parts of the body by means of sensory organs (proprioceptors) in the muscles and joints.
What are the three different types of JOINT proprioceptors and how do they work ?
Free nerve endings: sensitive to touch and pressure, stimulated at the beginning of movement, but they adapt to transmit steady signals as movement is terminated
Golgi Type: found in ligaments around joints, work similarly to free nerve endings
Pacinian corpuscles: found tissues around joints and adapt rapidly during movement, helps to detect the rate of joint rotation.
All 3 give feedback about the rates of limb movement.
What are the MUSCLE proprioceptors and how do they work ?
Muscle Spindle: muscle spindles are found within muscle fibers in intrafusal fibers, they are more abundant in muscles that do fine motor movements, they sense transmit length information to the CNS about the muscle to contract to resist stretching, and are innervated by gamma motor neurons.
Golgi Tendon Organ: live in the tendon and monitor muscle tension in the extrafusal fibers, they prevent excessive force during muscle contraction.
What is a motor neuron and how does it relate to a motor unit?
a motor neuron is a somatic neuron that innervates skeletal muscle, also called an alpha motor neuron. A motor unit consists of a motor neuron and all of the muscle fibers its branches innervate.
What is the relationship between the size principle and the term motor unit recruitment ?
Motor unit recruitment is the process by which motor neurons recruit muscle fibers during contraction. the size principle states that smaller fibers will be recruited first and larger fibers follow as more force is needed.
What is meant phsyiologically by mind over matter ?
Mind over matter refers to the idea that the CNS may play a “ central governor” role in the onset of exercise induced fatigue as stimulus provided by muscles reduced EPSP transmission and thus reduces force production, however this is just a theory.
What are some common signs of traumatic brain injuries or concussion among athletes ?
headache, nausea, difficult remembering, difficulty concentrating, mentally foggy, sadness, emotional, nervous, drowsy, difficulty with sleep
What occurs to the two branches of the autonomic nervous system during exercise ?
During Exercise;
sympathetic: activated
parasym: depressed
During Rest;
sym: depressed
parasym: activated
How does exercise improve and brain health ?
the research suggests that regular exercise contributes to the formation of new neurons, synapses, growth factors, neurotransmitters and angiogenesis, these factors may improve memory as well.
