S11 NEuro Neural Control Effectors

Question 1

Motor neuron’s cell body is in the

Answer 1

ventral horn of the spinal cord

Question 2

Neuromuscular junctions in skeletal muscle have what receptors and what neurotransmitters

Answer 2

nicotinic muscular receptors acetylcholine

Question 3

turn of events leading to muscle contraction

Answer 3

Act released from axon terminal of motor neuron binds to motor end plate receptors elicits an end-plate potential, triggering action potential action potential propagates along the sarcolemma and down T tubules action potential triggers release of Ca from Sarcoplasmic reticulum Ca binds to troponin exposing myosin-binding sites cross bridge cycle begins (muscle fiber contracts)

Question 4

intrafusal fibers of the spindle are of two types

Answer 4

nuclear bag and nuclear chain fibers Dynamic stretch reflexes mediated primarily by nuclear bag fibers (1a afferents; annulospiral endings) - nuclear region is broader, and the nuclei are arranged several abreast - Primary endings are selectively sensitive to the onset of muscle stretch but discharge at a slower rate while the stretch is maintained Static stretch reflexes mediated primarily by nuclear chain fibers (II afferents; flowerspray endings) - nuclei lined up in chains. - Secondary endings are less sensitive to the onset of stretch, but their discharge rate does not decline very much while the stretch is maintained.

Question 5

Golgi organs detect

Answer 5

muscle tension

Question 6

monosynaptic muscle reflex

Answer 6

one sensory neuron, one synapse and one motor neuron knee jerk: stimulate extensor muscle and inhibit the flexor (polysynaptic)

Question 7

Pupillary light reflex and consensual response

Answer 7

Light is shined on right eye for example info travels through optic nerve to the right and left pretectal nuclei. the pretectal nuclei stimulate both sides of the eddinger-westphal nucleus even though the light was perceived only in the right eye the right and left sides of eddinger-westphal nuclei generate action potentials through the right and left oculomotor nerves, causing both pupils to constrict. post synaptic cell bodies in ciliary ganglia

Question 8

excitation-contraction coupling. two types of smooth muscle in terms of organization

Answer 8

single-unit smooth muscle: operates like a single unit because of extensive gap junction connections. Varicosity: swellings that release NT. If u activate one part, all is activated. multi-unit: activate one and only one activated. More ability for fine control.

Question 9

The phosphatidylinositol pathway in VSM

Answer 9

The phosphatidylinositol pathway in VSM