anatomy exam 3

central nervous system (CNS)

brain and spinal cord

somatic nervous system

actions are voluntary and within our control

autonomic nervous system

actions are “automatic” and involuntary

the path of a nerve impulse

dendrites, cell body, axon, axon terminals, synaptic end bulb

gray matter

cell body of a neuron due to the ribosomes within the cell body

Schwann cells

wrap around an axon in the PNS and become myelin sheath

bipolar neuron

cell body is in the center; found in the ears, eyes and nose

pseudounipolar neuron

cell body hangs; sensory neurons housed in dorsal root ganglia

afferent neurons

sensory neurons that receive a signal and carry information towards the CNS

efferent neurons

motor neurons that carry out the response or action

oligodendrocytes

wrap around axons forming the myelin sheath

microglial cells

eat pathogens in the CNS

astrocytes

form the blood-brain barrier by wrapping around capillaries

blood brain barrier

connects capillaries with neurons. minimizes what can cross from blood to the brain

ependymal cells

move cerebrospinal fluid/line brain ventricles and the central canal

gray matter is called what in the PNS

ganglia

white matter

bundles of axons

white matter is called what in the CNS

the tract

white matter is called what in the PNS

the nerve

peripheral nervous system (PNS)

made up of cranial nerves and spinal nerves. contains the afferent and efferent neurons, as well as the autonomic and somatic nervous systems.

plexus

a network of nerves as it comes off the spine

cervical plexus

contains the phrenic nerve

brachial plexus

contains the radial, medial, and ulnar nerves

lumbar plexus

contains the femoral nerve

sacral plexus

contains the sciatic nerve

how many pairs of spinal nerves are there

31

action potential

wave of polarity changes

polar

two different electric charges

node of Ranvier

node of the axon

sulcus

2 halves that come together

cervical enlargement

enlargement of the spinal cord in the upper back, made of gray matter

lumbar enlargement

nerves to and from the pelvis and below

conus medullaris

tapered end of the spinal cord

filum terminale

fibrous tissue strand that extends from the conus medullaris to the coccyx to help stabilize the spinal cord. extension of the pia mater

how many pairs of cervical spinal nerves are there

8

how many pairs of thoracic spinal nerves are there

12

how many pairs of lumbar spinal nerves are there

5

how many pairs of sacral spinal nerves are there

5

how many pairs of coccygeal spinal nerves are there

1

cauda equina

spinal nerves distal to the conus medullaris. they hang down until they reach their respective foramina

gray matter in the cross-section

looks like the letter H

gray commissure

cross-bar of H

central canal

cavity in the center of the spine (contains CSF)

ventral medial fissure

space in front middle of cross section

dorsal median sulcus

line in back middle of cross section

dorsal gray horns

arms of the H

ventral gray horns

legs of the H

dorsal root ganglion

cell bodies of afferent neurons. contains the cell bodies of the PNS

epidural space

where the spinal cord sits

dura mater

made of fibrous CT, most superficial meninge

subdural space

space between the dura mater and arachnoid mater, contains serous fluid

arachnoid mater

middle meninge, spider-like in appearance

subarachnoid space

space between the arachnoid mater and pia mater. contains CSF

pia mater

innermost meninge, most delicate. adheres to the surface of the spinal cord

adipose tissue

cushions between hard bone and spinal cord structures

3 functions of the spinal cord

takes information to the brain, takes inforamation from the brain, reflexes

lumbosacral enlargement

widened area of the spinal cord located in the lower back, made of gray matter

cerebrospinal fluid

fluid in the spinal cord. circulate between the arachnoid and pia maters

nerves

tracts of the CNS

dorsal roots:

bundles of axons

reflex

sensing something and reacting without consulting the brain

reaction

sensing something and reacting by consulting the brain

parathyroid gland

essential gland, patch inside the thyroid, puts calcium in the bloodstream

pancreatic islets

release insulin and glucagon

pancreatic acini cells

aid digestion

alpha cells

along the edge of the pancreatic islet

beta cells

not along the edge of the pancreatic islet

pancreatic duct

carries digestive enzymes to the small intestine

spinal nerves

bundles of nerves off the spinal cord

epineurium

surrounds the spinal nerve

each fascicle of the spinal nerve contains what?

myelinated axons

what are fascicles surrounded by

the perineurium

what are myelinated axons surrounded by

the endoneurium

ONLY what has a cell body

a neuron

dorsal ramus

branching off of dorsal and ventral roots in the back of the spinal cross section. innervates the muscles and skin of the back

ventral ramus

branching off of dorsal and ventral roots in the front of the spinal cross section. innervates the ventral surface

cervical plexus

C1-C5. Innervates the head, contains the frontic nerve that innervates the diaphragm.

brachial plexus

C6-T1. innervates the arm

T2-T11

the intercostal nerves. They innervate the abdominal and intercostal muscles

lumbar plexus

L1-L5. contains the femoral nerve, innervates the interior part of your leg and the pelvic region

sacral plexus

S1-S5. contains the sciatic nerve, innervates the posterior or side of the leg and the gluteus maximus

phrenic nerve

found in the cervical plexus, provides motor control of the diaphragm

median nerve

found in the brachial plexus, controls forearm flexion and movements of the finger and thumb

radial nerve

found in the brachial plexus, supplies motor function to the triceps

ulnar nerve

found in the brachial plexus. responsible for motor control of specific hand and forearm muscles.

femoral nerve

found in the lumbar plexus. moves the hips, legs, ankles and feet

sciatic nerve

found in the sacral plexus. provides motor control to the posterior thigh and muscles of the legs and foot

how many neurons does the brain contain

86 million

medulla oblongata

regulates breathing, heart rate, and blood vessels/blood pressure

pons

superior to the medulla oblongata. bridge to the cerebellum

midbrain

superior part processes visual info, inferior part processes auditory info

thalamus

relays sensory/motor information to the cerebral cortex

epithalamus (pineal gland)

produces melatonin

hypothalamus

controls fight or flight/rest and digest responses (autonomic). produces ADH and oxytocin

diencephalon

contains the thalamus, epithalamus, and hypothalamus

mammillary body

responsible for mamillary reflexes like feeding habits, swallowing, licking reflexes of infants

pituitary gland

makes essential hormones and tells other endocrine glands to release hormones

cerebellum

controls motor functions of the body

arbor vitae

“tree branches” of the inner cerebellum