GVSU BMS 208 Nervous System

gathering information (detecting internal and external changes)

sensory input

analysis (interpreting sensory input)

integration

where does integration happen?

in the brain and spinal cord

response (release of hormones, shivering when cold, etc...)

motor output

any change in environment (internal or external)

stimuli

organs of the CNS

brain and spinal cord

PNS is composed of

all neural tissue outside the CNS

afferent means...

sensory

efferent means...

motor

the afferent division delivers _____ information from the receptors (PNS) to the CNS

sensory

detects stimuli we consciously perceive/control

somatic sensory

found in smooth or cardiac muscle

visceral sensory

the efferent division delivers _____ information away from the CNS to the muscles and glands

motor

examples of somatic motor

smooth muscle, cardiac muscle, glands

skeletal muscles are...

effectors

autonomic (visceral) motor

parasympathetic and sympathetic nervous systems

part of the involuntary nervous system that serves to slow the heart rate, increase intestinal and glandular activity, and relax the sphincter muscles

parasympathetic nervous system

contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, and increase heart rate

sympathetic nervous system

job of receptors

to detect change

neuron

cell

ganglia

gang of cell bodies outside the nervous system

neuroglia

supportive cells of nervous tissue; smaller and more numerous than neurons

do neuroglia transmit electrical signals?

no

functional unit of the nervous system

neurons; most form during fetal development and the same ones are still functioning in the elderly

initiate, transmit, and interpret electrical signals

neurons

soma

cell body

control center of the neuron; interprets or sends signals on; contains a the cell nucleus and organelles

soma

conducts electrical signals away from the soma

axon

receive signal and transfer it to the soma

dendrites (could have one or hundreds depending on the specific neuron)

a bundle of axons

a nerve

club-shaped endings by which axons make synaptic contact with other nerve cells or with effector cells

axon terminals

vesicles that contain neurotransmitters and take signals from the neuron to the next thing

synaptic knobs

chemical messengers

neurotransmitters

how are neurons classified?

by structure: how man processes come off of the soma and
function: what they do for us (the direction in which the electrical signal travels)

neurons that have one process coming off of the cell body; dendrites not directly connected to soma

unipolar neurons

what kind of neurons are unipolar neurons?

sensory neurons

neurons that have two processes coming off of the soma; very uncommon in humans

bipolar neurons

the two processes coming off of the soma in bipolar neurons

dendrite and axon

neurons that are very uncommon in humans

bipolar neurons (mostly located in the nose and eyes of humans)

99% of all neurons lie completely in what?

the CNS

the most common neuron; more than two processes come off of the soma

multipolar neurons

multipolar neurons are what type of neurons?

motor neurons (carry electrical signals away from the CNS)

"nerve glue"

neuroglia

star-shaped neuroglia due to many processes

astrocytes (largest in CNS)

glia cell that helps form the blood-brain barrier; provides structural support and replaces damaged neurons

astrocyte

simple cuboidal epithelial glia cells

ependymal cells

line brain and spinal cord cavities; help produce cerebral spinal fluid

ependymal cells

least common glia cells; smallest; immunologic

microglia cells

defends against pathogens

microglia cells

glia cells who's extensions wrap around CNS axons

oligodendrocytes

helps form myelin sheath on axon; do not regenerate if damaged (myelin sheath will go away)

oligodendrocytes

glia cells clustered around ganglia

satellite cells

protects and regulates nutrients for cell bodies in ganglia

satellite cells

glia cells wrapped around PNS axons; can regenerate if damaged

neurolemmocytes

forms myelin sheath on neurons of the PNS

neurolemmocytes

glia cells of the CNS

astrocytes, ependymal cells, microglia cells, oligodendrocytes

glia cells of the PNS

satellite cells, neurolemmocytes

unmyelinated areas

neurofibril nodes

insulates, protects, and allows for faster conduction of electrical signals

myelination

are all neurons myelinated?

no

point of junction between two neurons (or other cells) and consists of 3 elements

synapse

neuron before the synapse that contains neurotransmitters

pre-synaptic neuron

neuron after the synapse that contains binding sites

post-synaptic neuron

neurons are released into and travel through this to bind to the receptor sites on the post-synaptic neuron

synaptic cleft

surrounds the entire nerve

epineurium

surrounds the fassicle

perineurium

surrounds individual axons

endoneurium

more synapses means...

more intelligence

cranial nerves are part of the...

PNS

3 regions of the human brain

forebrain, midbrain, and hindbrain

the brain develops from which germ layer?

the ectoderm germ layer (outermost germ layer)

forms the neural tube

ectoderm germ layer

6 weeks into development

the neural tube expands into individual vesicles

11 weeks into development

nervous tissue is expanding and folding

does a child brain resemble and adult brain?

yes

cerebrum and cerebral nuclei

telencephalon

the cerebrum has how many lobes?

5

location of conscious thought processes and is the origin of all complex intellectual functions

the cerebrum (the part of the brain that is all folded up on itself)

fold of cortical tissue (any ridge)

gyrus

gap between gyri (any shallow depression)

sulcus

deep groove

fissure

deep groove that divides the brain into right and left hemispheres

longitudinal fissure

A deep fissure of the cerebral cortex separating the temporal lobe from the frontal and parietal lobes

lateral sulcus

disease caused by widened sulcus

alzheimer's

lobe deep to the frontal bone

frontal lobe

primary motor cortex

pre-central gyrus

responsible for voluntary motor function, concentration, verbal communication, decision making processes, personality mood, and planning

frontal lobe (pre-central gyrus (primary motor cortex))

lobe deep to the parietal bone

parietal lobe

primary somatosensory cortex

post-central gyrus

responsible for general sensory functions (feeling shape, structure, texture, etc...)

post-central gyrus (primary somatosensory cortex)

lobe deep to temporal bones

temporal lobe

responsible for auditory and smell

temporal lobe

lobe deep to occipital bone

occipital lobe

responsible for processing incoming visual information and visual memories

occipital lobe

small lobe deep to the lateral sulcus

insula

responsible for taste and emotional responses/empathy

insula

contains cell bodies, dendrites, and unmyelinated axons

gray matter

contains myelinated axons

white matter

tough, hard bundles of myelinated axons that serve as a link between to two hemispheres of the brain

corpus collosum

paired masses of gray matter

cerebral nuclei