Nervous System Jackie Hernandez p.5

Parts + Functions of the spinal cord

Neurotransmitter

Cranial nerves

spinal Nerves

Reflex arc

classification of neurons

Compare and contrast autonomic NS

Tissues

Parts + function of Brain

Divisions + subdivisions

Action potential + Nerve impulses

Major Functions

Central nervous system

Effectors

receptors

sensory neurons

Motor neurons

two roots

Numbered in sequence

1st pair=mixed nerves

31 pairs

ventral

Dorsal

motor

sensory

Lumbar nerves

cervical nerves

Thoracic nerves

Sacral nerves

coccygeal nerves

12 pairs

5 pairs

8 pairs

5 pairs

Subdivisions

Peripheral Nervous system

Central nervous system

sensory fibers

automatic fibers

Somatic fibers

spinal cord

brain

Parts

Functions

spinal reflexes

transmits impulses to + from brain

ascending tracts

descending tracts

house spinal reflexes

cauda equina (horse's tail)

dorsal root ganglia

white matter

lumbar enlargement

gray matter

cervical enlargement

central canal

Posterior + anterior horns

carries motor info from brain to muscles/glands

carries sensory info to brain

unipolar neurons

Bipolar neurons

Motor neuron

Multipolar Neurons

sensory neurons

Interneurons neurons

forms links between other neurons

multipolar neurons laying with CNS

some cell bodies aggregate in nuclei

Many dendrites + 1 axon arising from body

Most neurons are multipolar (cell bodies)

found in special senses

2 processes extending from the cell body

dendrite + 1 axon

1 process extending from the cell body

splits into 2 parts function

1 axon

conduct impulses from CNS to peripheral neurons

multipolar neurons

impulses from peripheral receptors to CNS

some bipolar

usually unipolar

afferent

some neurons produce one transmitter while other produce 2 or more

actions depend on type of receptor

includes acetylcholine, amino acids, neuropeptides

more than 100 neurotransmitters

diffuse across cleft + bind to receptors on membrane

stores + released from synaptic cleft

communication accomplished by a chemical

released in response to a nerve impulses

impulse conduction

Action potential either happens or not

Saltatory conduction

continuous conduction

myelin sheath insulates axons

impulses jump from one node of ranvier to the next

occurs in myelinated axons

conduct impulses over the entire length of their membrane

occurs in unmyelinated axon

occurs when charge reaches -55mv

reached cells respond by going back to their rest place

neurons are all the same strength

neuroglia

cells that support neurons

fills space, structurally support, protect +insulate neurons

doesn't generate or conduct nerve impulses

CNS

oligodendrocytes

Microglia

function as phagocytes for bacterial cells, cellular debris + produce scar tissue for injury

small cells

forms myelin sheath around axon in brain+ spinal cord

Sensory functions

Thinking, movement, internal process of physiology

motor functions

Integrative Functions

processing info for decision making

coordination of sensory info in CNS

transport info to CNS

info travels from receptors to sensory neurons

detect internal/external changes

nerve impulses conducted along motor neurons to effectors

effectors: muscle/glands responds to decision made in CNS

Parasympathetic division

Sympathetic division

short preganglionic fibers arise from neurons in gray matter

axons exit spinal cord from ventral roots

axons leave spinal nerves proceeds into sympathetic ganglia

fight or flight senses

synapse with postganglionic neurons, long axons return to spinal nerves + proceed to visceral effector

Pf extends outward in cranial or sacral nerves

long preganglionic fibers arise from brain stem + sacral region

rest + digest

synapse in terminal ganglia in or close to visceral effectors organs

12 pairs of underside of brain

1st pair arises from cerebrum + 2nd pair from thalamus

designated by number + name (superior to inferior)

most are mixed (sensory + motor nerve fibers)

Largest + most complex portion of the NS

4 Lobes

4 main parts

brain stem

cerebellum

diencephalon

Cerebrum

parietal

occipital

tempral

Frontal

Connective tissue coverings

Epineurium

Endoneurium

Perineurium

bundles

covering around fascicles of nerve fibers

outer covering of nerves

axons

covering around individual nerve fibers