Unit 1, Semmy 2

Question 1

List the steps of the reflex arc

Answer 1

1) receptor picks up stimulus
2) sensory neuron carries AP to CNS
3) Integration @ CNS
4) motor neuron carries AP to effector organ
5) effector organ gives response

Question 2

List the levels of motor control

Answer 2

1) Segmental level (lowest level of control)
2) Projection level (intermediate level of control)
3) Precommand level (highest level of control)

Question 3

describe the projection level of control

Answer 3

consists of precentral gyrus and brainstem. Works by neurons acting through direct (upper motor neurons in motor cortex, ex: vol. skel. m. movements) and indirect (brainstem nuclei, ex: reflexes and CPG activity) motor pathways through projection fibers

Question 4

describe the segmental level of control

Answer 4

consists of reflexes and spinal cord circuits controlling automatics movements. Works by activating ventral horn neurons which acts on specific muscles.

Question 5

describe the precommand level

Answer 5

consists of neurons in cerebellum and basal nuclei for coordinating activity and when it starts/stops. Works through cerebellum by acting on motor pathways via projection areas in brainstem and acts on motor cortex via thalamus. Basal nuclei inhibit motor centers at rest (problems w it lead to parkinsons disease)

Question 6

list the order of events in the muscle stretch reflex

Answer 6

stimulus: stretched muscle, AP to CNS via sensory neuron, sensory neuron synapses w alpha motor neuron of stretched muscle and inhibitory interneuorn to inhibit motor neuron of antagonistic muscle

Question 7

what does needs to be known to have a response to the muscle stretch reflex and how does the muscle get this information?

Answer 7

1) length of muscle, muscle spindles
2) amount of tension, tendon organs

Question 8

describe the different neurons (sensory and motor) involved in the muscle stretch reflex

Answer 8

Sensory type 1- responds to speed of stretch
sensory type 2- responds to degree of stretch
motor gamma- acts on intrafusal muscle fiber
motor alpha- acts on extrafusal muscle fibers

Question 9

name the 8 major endocrine organs

Answer 9

1) pineal gland
2) pituitary gland
3) thyroid gland
4) parathyroid gland
5) thymus
6) adrenal gland
7) pancreas
8) gonads

Question 10

where is the autonomic NS main integration center?

Answer 10

hypothalamus