a&p chpt 13.1-13.8

A person w/ polio has lost the use of his leg muscles. In which area of his spinal cord would you expect the virus-infected motor neurons to be?

in the anterior gray horns of the spinal cord, where the cell bodies of somatic motor neurons are located.

One of the first somatic reflex to develop is the suckling reflex, which type of reflex is this?

innate reflex

Where is cerebral spinal fluid that surrounds the spinal cord located?

its located in the subarachnoid space, which lie beneath the epithelium of the arachnoid mater and superficial to the pia mater.

Define Spinal Reflex?

rapid, automatic response triggered by specific stimuli.

Identify the basic characteristics of polysynaptic reflexes?

- involve pools pools of interneurons - inter-segmental in distribution. - involve reciprocal inhibition.

List the five circuit patterns found in neuronal pools?

1.) divergence 2.) convergence 3.) serial processing 4.) parallel processing 5.) reverberation

Identify 3 spinal meninges?

1.) dura mater 2.) arachnoid mater 3.) pia mater

Identify the major networks of nerves know as plexuses?

1.)cervical 2.) brachial 3.) lumbar 4.)sacral 5.) coccygeal

After injuring her back, Tina exhibits a positive Babinnski reflex. What does this imply about Tina's injury?

A positive Babinnski reflex is abnormal in adults, it indicates possible damage of descending tracts in the spinal cord.

Name the components of the CNS and the PNS?

CNS= brain and spinal cord PNS= cranial nerves and spinal nerves

Injury to which of the nerve plexuses would interfere with the ability to breathe?

Damage to the cervical plexus

Damage to which root of the spinal nerve would interfere with motor function?

Damage to the ventral root of a spinal nerve, which is composed of both visceral and somatic motor fibers.

During a withdrawal reflex of the foot, what happens to the limb on the side opposite the stimulus? what is the response called?

During a withdrawal reflex, the limbo the opposite side is extended. this response is called a crossed extensor reflex.

Compression to which nerve produces the sensation that your leg has "fallen asleep"?

Sciatic Nerve

Differentiate between sensory nuclei and motor nucei?

Sensory nuclei= receive and relay sensory info from peripheral receptors. Motor nuclei= issue motor commands to peripheral effectors.

What is the minimum number of neurons in a reflex arc?

TWO. -one must be a sensory neuron that brings impulses to the CNS and the other a motor neuron that transmits a response to the effector.

Define reflex?

a rapid automatic response to a specific stimulus. it is an important mechanism for maintaining homeostasis.

Define reinforcement as it pertains to spinal reflexes?

enhancement of spinal reflexes, it occurs when the postsynaptic neuron enters a state of generalized facilitation caused by chronically active excitatory synapse.

A weight lifter is straining to lift a 200kg barbel above his head. shortly after he lifts it to chest height, his muscles appear to relax and he drops the barbell. which reflex has occurred?

tendon reflex

A disease that damages myelin sheaths would affect which portion of the spinal cord?

the columns of the spinal cord, because the columns are composed of bundles of myelinated axons.

Define neural pool?

the functional group of interconnected neurons organized within the CNS.

An anesthetic blocks the function of the dorsal rami of the cervical spinal nerves. Which areas of the body will be affected?

the skin and muscles of the back of the neck and of the shoulders.

For the patellar reflex, how would the stimulation of the muscle spindle by gamma motor neurons affect the speed of the reflex?

when stretch receptors are stimulated by gamma motor neurons, the muscle spindles become more sensitive. as a result, little if any stretching stimulus would be needed to stimulate the contraction of the quadriceps muscles in the patellar reflex. the reflex response would appear more quickly