ch 13

cervical plexus

C1-C5

brachial plexus

C5-T1

reciprocal inhibition

The simultaneous contraction of one muscle and the relaxation of its antagonist to allow movement to take place. hamstring cant contract while quad is contracting

tendon reflex

collagen fibers get squeezed together tightly and send signals to brain to not contract as strongly.

functions of spinal cord

conduction, neural integration, locomotion, reflexes

crossed extension reflex

contraction of extensor muscles in the limb opposite from the one that is withdrawn to balance equilibrium

stretch reflex

coordination between synergist and antagonist muscles. quad gets stretched, quad flexes. muscle spindles get stimulated and sends signals to cerebellum and cerebellum sends signals back to muscle.

meninges of spinal cord

dura, arachnoid, pia

the anterior horns

in the spinal cord, the somas of the lower motor neruons are found in

posterior ramus

innervates muscles and skin of back

anterior ramus

innervates the anterior and lateral skin and muscles of the trunk and gives rise to nerves of the limbs

long roots

make up cauda equina L2-C1

gamma motor neurons

nerve fibers that adjust the tension in a muscle spindle are called

spinal tracts

sensory- asending. motor- desending

the obturator nerve

the brachial plexus gives rise to all of the following nerves except

none of them

the intercostal nerves between the ribs arise from which spinal nerve plexus

epineurium

the outermost connective tissue wrapping of a nerve is called the

white matter

axons. highways for axons. no synapses

reticulospinal

balance and posture of arms and legs. desending pathway of blocking pain signals D

vestibulospinal

balance and posture of head and body D

pelvic

which of these is not a region of the spinal cord

lumbar plexus

L1-L4

sacral plexus

L4-S4

spinothalamic tract

1st comes in thru posterior root and synapses with 2nd in gray matter, decussates across to go in white matter, and shoots all the way up to thalamus where it synapses with 3rd to go to cortex

gracile and cuneate tract

1st comes in thru posterior root in the G/C fasciculus and goes up to G/C nucleus in medulla to synapse with the 2nd. the it goes thru and out of the medial lemniscus and shoots up to thalamus where it synapses with 3rd to go to cortex

they are monosynaptic

All somatic reflexes share all of the following properties except

corticospinal tract

UMN- signals start with pyramidal cells in primary motor cortex. the axon travels down to anterior medulla where both decussate (that forms medullary pyramids) and go to white matter on spinal and travel down and cross to gray matter to synapse with LMN to leave thru anterior root to a skeletal muscle

polysynaptic reflex arc

a pathway that signals travel over many synapses on their way back to the muscle. involves an interneuron

spinothalamic MC

a patient has a gunshot wound that caused a bone fragment to nick the spinal cord. the patient now feels no pain or temperature sensations form that level of the body down. most likely, the _____ was damaged.

flexor withdrawl reflex

a quick contraction of flexor muscles to remove a limb from harm. followed by crossed extension reflex

reciprocal inhibition MC

a stretch reflex requires the action of ____ to prevent an antagonist muscle from interfering with the agonist

muscle spindle

a type of sense organ that has enlongated fibrous capsules with intrafusal fibers that detect stretch and extrafusal fibers that flex.

the cauda equina

below L2, the vertebral canal is occupied by a bundle of spinal nerve roots called

terminal filum

beyond medullary cone as pia. at S2 fuses with dura to form coccygeal ligament and anchors to spinal cord to coccyx 1.

cauda equina

bundle of nerve roots that innervates legs and pelvic organs

medullary cone

end of spinal cord

spaces of spinal cord

epidural, subarachnoid (CSF), subdural

denticulate ligaments

extensions of pia that anchor to spinal cord against side to side movement

reflex integrating center

found in spinal cord gray matter. type of neural integration of how strong the reflex will be.

gracile, cuneate

g- below T6, cuneate- above T6 body movement, proprioception, fine touch A

spinoreticular

pain from tissue injury A

spinothalamic

pain, temperature A

corticospinal

precise limb movement D

spinocerebellar

proprioception, goes to cerebellum. ipsilateral tract A

somatic reflexes

quick, involuntary, stereotyped reactions of glands or muscles to a stimuli

tectospinal

reflex turning head to sight/sounds D

gray matter

soma and dendrites. synaptic transmission. neural integration

decussate

to cross