A&P Final

sensory input

gathering information; monitors changes occurring inside and outside body

changes

stimuli

integration

process and interpret sensory input and decide if action is needed

motor output

response to integrated stimuli; response activates muscles of glands

nervous system based on

structures and activities

structural classification

central and peripheral nervous system

functional classification

sensory and motor division

sensory

afferent

motor

efferent

CNS organs

brain and spinal cord

CNS function

integration and command center; interpret incoming info; issues outgoing instructions

PNS contains

nerves extending from brand to spinal cord

PNS function

communication lines

sensory division

nerve fibers carry information to CNS; somatic and visceral sensory fibers carry information to their respective parts

motor division

nerve fibers carry impulses away from CNS organs

motor division parts

somatic and autonomic

autonomic nervous system parts

parasympatyhetic and sympathetic

group of support cells

neuroglia

neuroglia functions

support, insulate, protect neurons

CNS glial cells

astrocytes, microglia, ependymal, oligodendrocytes

astrocytes

abundant start-shaped; form barrier between capillaries and neurons; control chemical environment of brain

microglia

spiderlike phagocytes; dispose of debris

ependymal

line cavities of brain and spinal cord; cilia assist with circulation of cerebrospinal fluid

oligodendrocytes

wrap around nerve fibers in CNS; produce myelin sheaths around axons of CNS

PNS glial cells

satellite, schwann

satellite cells

protect neuron cell bodies

schwann cells

form myelin sheath in peripheral nervous system in jelly roll like fashion around axons

myelin sheath

fatty material covering axons; speed nerve impulse transmission

nodes of Ranvier

gaps in myelin sheath along axon

neurons

nerve cells

neuron function

specialized to transmit messages

neuron regions

cell body and processes

cell body

nucleus and metabolic center of cell; nissl bodies and neurofibrils

processes

fibers that extend from cell body

nissl bodies

specialized rough endoplasmic reticulum

neurofibrils

intermediate cytoskeleton; maintains cell shape

processes outside of cell body

dendrite and axons

dendrites

conduct impulses toward cell body; neurons may have hundreds of these

axons

conduct impulses away from cell body; neurons only have 1

neuron cell body location

mostly in CNS

gray matter

outer layer in cerebral cortex; mostly cell bodies and unmyelinated fibers

white matter

made of axons with myelinated fibers; fiber tracts deep to gray matter; corpus callosum connects hemispheres

ganglia

collections of cell bodies outside CNS

tracts

bundles of nerve fibers in CNS

nerves

bundles of nerve fibers in PNS

sensory neurons

carry impulses from receptors to CNS; cutaneous sense organs; proprioceptors

proprioceptors

detect stretch or tension

free nerve endings

pain and temp receptors

Meissner’s corpuscle

touch receptors

Lamellar corpuscle

deep pressure receptors

interneurons (association neurons)

in neural pathways in CNS; connect sensory motor neurons

structural classification

based on number of processes extending from cell body

multipolar neurons

many extensions from body; all motor and interneurons; most common

bipolar neurons

one axon and one dendrite; located in sense organs; rare in adults

unipolar neurons

have short single process leaving cell body; sensory neurons found in PNS ganglia; conduct impulses toward and away from body

irritability

ability to respond to a stimulus and convert to nerve impulse

conductivity

ability to transmit impulse to other neurons, muscles or glands

somatic reflexes

response that stimulate skeletal muscles

autonomic reflexes

regulate activity of smooth muscles, heart and glands

reflexes characteristics

rapid, predictable, involuntary responses to stimulus; occur over reflex arcs

reflex arc elements

sensory receptor, sensory neuron, integration center, motor neuron, effector organ

sensory receptor

reacts to stimulus

motor neuron

carries message to an effector

effector organ

muscle or gland to be stimulated

cerebrum

left and right halves; billions of neurons; two hemispheres and four lobes; planning, reasoning, analyzing, string/accessing memories

cerebellum

left and right halves (two hemispheres with convoluted surfaces); coordinate skeletal muscle movements, maintain proper balance, posture; controls balance and equilibrium; precise timing for skeletal muscle activity

diencephalon

epithalamus, thalamus, hypothalamus; hormone, information filter, controls autonomic centers for BP, thirst, production of emotions

brainstem

medulla oblongata/pons/midbrain; respiration/ cardiovascular activities and digestion

cerebral hemispheres

paired superior parts of the brain; includes more than half of brain mass; the surface is made of ridges and grooves

brain ridges

gyri

brain grooves

sulci

regions of cerebral hemisphere

cortex (gray matter), white matter, basal nuclei (deep pockets of gray matter)

lobes of cerebrum

frontal, parietal, occipital, temporal

fissures

divide cerebrum into lobes

primary somatic sensory area in cerebrum

receives impulses from body’s sensory receptors; located in parietal lobe posterior to central sulcus; sensory homunculus is a spatial map; left side receives impulses from right side

lobe for visual area

occipital lobe

lobe for auditory area

temporal lobe

lobe for olfactory area

temporal lobe

primary motor area of cerebrum

sends impulses to skeletal muscles; located in frontal lobe; motor neurons from corticospinal tract; motor homunculus is a spatial map

Broca’s area

involved in speaking abilities; usually left hemisphere

other cerebrum specialized areas

anterior and posterior association areas; speech area

basal nuclei (ganglia)

islands of gray matter buried within the white matter

diencephalon

enclosed by cerebral hemispheres; made of thalamus, hypothalamus, epithalamus

thalamus

surrounds third ventricle, relay station for sensory impulses, transfers impulses to correct part of cortex for localization and interpretation

hypothalamus

autonomic nervous system center; regulates temp, controls water balance, regulates metabolism; houses limbic center for emotions; regulates pituitary gland; houses mammillary bodies for smell

epithalamus

forms roof of third ventricle; houses pineal body (endocrine gland); includes choroid plexus which forms cerebrospinal fluid

brain stem

attaches to spinal cord; midbrain, pons, medulla oblongata

midbrain

composed of tracts and nerve fibers; two building fiber tracts, cerebral peduncles, convey ascending and descending impulses; four rounded protrusions, corpora quadrigemina, visual and auditory reflex centers

medulla oblongata

lowest part of brain stem; merges into spinal cord; includes important fiber tracts; contains important control centers; heart rate, BP, breathing, swallowing, vomiting

reticular formation

diffuse mass of gray matter along brain stem; involved din motor control of visceral organs; reticular activating system

reticular activating system

plays role in awake/sleep cycles and consciousness; filter for incoming sensory information

protection of CNS

scalp and skin, skull and vertebral column, meninges, cerebrospinal fluid, blood-brain barrier