neurobiology & structures of the head

rostral

towards the nose

cranial

towards the head

caudal

towards the tail

dorsal

towards the top/spine

ventral

towards the bottom/belly

medial

towards the midline

lateral

away from the midline

proximal

towards the trunk of the body (for limbs)

distal

away from the trunk of the body (for limbs)

palmar

towards the palm of the hand

plantar

towards the sole of te foot

adaxial

toward the longitudinal central axis of the limb

abaxial

away from the longitudinal central axis of the limb

medial plane

divide down the midline

sagittal plane

dive into medial & lateral not at the midline

transverse plane

divide into cranial & caudal (body trunk) or proximal & distal (limbs)

dorsal plane

divide into dorsal & ventral

extension

increase the hinge angle

flexion

decrease the hinge angle

abduction

move limb away from the body

adduction

move limb towards the body

supination

rotate palm upwards

pronation

rotate palm downwards

what comprises the central nervous system?

brain and spinal cord

what does the central nervous system do?

process external stimuli

what are the divisions of the brain?

forebrain

midbrain

hind brain

what are the divisions of the forebrain?

diencephalon & telencephalon

what comprises the diencephalon?

thalamus & hypothalamus

what does the thalamus do?

relay station for vision, taste, & sound sensations

what does the hypothalamus do?

regulate temperature & blood pressure

what are the divisions of the midbrain?

tectum & tegmentum

what does the tectum do?

process visual & auditory information

what does the tegmentum do?

eye movement & reflexes

what are the divisions of the hindbrain?

metencephalon & myelencephalon (medulla)

what comprises the metencephalon?

cerebellum & pons

what does the cerebellum do?

coordinated muscle movement & motor learning

what does the pons do?

facial touching, chewing movement, unconscious functions

what does the medulla do?

sensory input & motor output

what comprises the peripheral nervous system?

autonomic and somatic nervous system

whhat does the peripheral nervous system do?

respond to stimuli

what does the somatic nervous system do?

voluntary sensory & motor control

what does the autonomic nervous system do?

involuntary motor function

divided into sympathetic & parasympathetic systems

what are the classifiations of neurons?

structure or function

what is the structural classifications of neurons?

unipolar

bipolar

multipolar

axonic

what is a unipolar neuron?

one projection from the cell body

what is a bipolar neuron?

two projections from the cell body

what is a multipolar neuron?

more than 2 projections from the cell body

what is an anaxonic neuron?

only a cell body & dendrites

no axon

what are the functional classifications of neurons?

motor (efferent)

sensory (afferent)

interneurons

what are motor neurons?

deliver a physical response to target tissues from CNS

what are sensory neurons

receive sensory information from a stimulus to send to CNS

what are interneurons?

neurons only in the CNS that connect functional neurons

what do dendrites do?

receive signals from other cells

what does the cell body do?

process received signals

what does the axon do?

respond to the processed signal

what do telodendria do?

send the signal to other neurons

what are glial cells?

cells that bind to axons

what are the types of glial cells

schwann cells & oligodendrocytes

where are schwann cells found?

in the ganglia of the peripheral nervous system

where are oligodendrocytes found?

in the nuclei of the central nervous system

what do glial cells do?

form myelin sheaths & provide structural support

regulate paracrine communication

what is a myelin sheath?

a lipid membrane that insulates & stabilizes the axon

how does myelination effect information relay?

thicker nodes = faster because of increased electrical reistance

longer nodes = faster because length to jump is shorter

what is neuronal convergence?

when many neurons feed signal into one neuron

what is neuronal divergence?

when one neuron sends signal to many neurons

cranial nerve 1

olfactory

sensory

smell

cranial nerve 2

optic

sensory

vision

cranial nerve 3

oculomotor

motor

eye movement & pupil reflex

cranial nerve 4

trochlear

motor

eye movement

cranial nerve 5

trigeminal

mixed

facial sensation & movement

what are the branches of the trigeminal nerve?

opthalamic branch

maxillary branch

mandibular branch

what does the opthalamic branch do?

sensory

vision & forehead sensation

what does the maxillary branch do?

sensory

teeth, gums, upper jaw, sinuses, lips

what does the mandibular branch do?

sensory & motor

close lower jaw & sensation

cranial nerve 6

abducens

motor

eye movement

cranial nerve 7

facial

mixed

taste, movement of face, ear, neck

what are the branches of the facial nerve?

auriculopalpebral branch

dorsal buccal branch

ventral buccal branch

what does the auricopalpebral branch do?

motor

external ear muscles, orbicularis oculi, upper eyelid

what do the dorsal & ventral buccal branches do?

motor

lip, nose, & cheek movement

cranial nerve 8

vestibulocochlear

sensory

hearing & balance

cranial nerve 9

glossopharyngel

mixed

taste & throat sensation

swallowing movement via pharyngeal muscles

cranial nerve 10

vagus

mixed

regulate PNS

glottis closure via pharyngeal muscles

innervate pharynx, larynx, soft palate muscles

cranial nerve 11

accessory

motor

neck movement

cranial nerve 12

hypoglossal

motor

tongue movement

what is neuronal resting membrane potential?

the charge difference between the inside and the outside of the cell

how is resting membrane potential determined?

dynamic equilibrium of unequal charge distribution

Na+/K+ pumping & permeability

how is resting membrane potential created?

movement of 2 K+ ions inside of the cell

movement of 3 Na+ ions outside of the cell

create electrochemical gradient

inside the cell is more negatively charged

outside the cell is more positively charged

what is an action potential?

an electrical impulse causes the depolarization and repolarization of a cell to transmit a signal

what is depolarization?

when the internal charge of a cell becomes more positive

step 1 of an action potential

cell is at resting membrane potential (-70 mV)

step 2 of an action potential

stimulus causes depolarization to start (-70 to -50 mV)

step 3 of an action potential

membrane depolarizes to threshold levels (-50 mV)

Na+ voltage-gated channels open & Na+ enters

step 4 of an action potential

rapid Na+ entry depolarizes inside cell after membrane is depolarized (-50 mV to 30 mV)

step 5 of an action potential

repolarization starts

Na+ channels close & K+ channels open slowly (30 to -50 mV)

step 6 of an action potential

repolarization

K+ moves out of the cell (-50 to -80 mV)

step 7 of an action potential

hyperpolarization

K+ voltage-gated channels close (-80 mV)

step 8 of an action potential

Na+ ions, K+ ions, and ATPase return cell to resting membrane potential (-80 to -70 mV)

what is axon conduction?

the process when an axon transmits an action potential from the cell body to synapses for nerve transmission

what is nerve transmission?

the process of sending an electrical impulse across the synaptic cleft from one axon to the dendrites of another

what is synaptic signalling?

the process of releasing neurotransmitters from the synaptic vesicles of the pre-synaptic cells to bind to the receptors of the post-synaptic cell