Nervous System - The "Basics" Flashcards
Exam 3
what are the 4 main functions of the nervous system ?
communication/coordination/control
sensory
integration
motor
sensory funcition def
the gathering of information
what are receptors mostly
modified neurons
what does the sensory function for the NS
receptors
integration def
make decisions based on info gathered
involved with memory/intelligence/learning/ and emotion
what thing does the integration function for the NS
brain and spinal cord
motor def
sending instructions
what are the two main components of the nervous system
the central nervous system and the peripheral nervous system
what is in the CNS
brain and spinal cord
integration
What is in the PNS
spinal nerves and branches
cranial nerves and branches
sensory and motor
how many spinal nerves are there?
how many cranial ?
31 pairs of spinal
12 pairs of cranial
said before but
what are the 2 components of the PNS (functionally wise)
sensory and motor
what is sensory in the PNS
goes towards the CNS
Afferent
what is motor in the PNS
goes away from CNS
Efferent
what are the 3 main components of the Afferent division of the PNS (sensory aspect)
Special Sensory
Somatic sensory
Visceral sensory
what is special sensory
concentrated in the head
reception tends to be complicated
what is somatic sensory
gathers info from skin and skeletal muscle
what is visceral sensory
in smooth muscle, cardiac muscle, glands, guts
What are the 2 main components of the Efferent division of the PNS (motor)
somatic motor
autonomic nervous system
What is somatic motor in relation to
The efferent nervous system
Skeletal muscle
voluntary control
what is autonomic ns in relation to
viscera
involuntary control
what are the 3 types of nervous systems apart of the autonomic NS
Enteric NS, Sympathetic NS, and Parasymphatetic NS
what is enteric nervous system in relation to
it is within the guy/digestive tract
what does the sympathetic NS do
it is a stimulating effect. more alert
a stress response
fight for flight mode
primes body for intense skeletal activity
what is the sympathetic ns a neurotransmitter of
norephrine (acts like adrenalin)
what does the parasymphathetic nervous system do
is a relaxing effect
rest and digest and repair
maintenance
counterbalances SNS
what is the parasymphathetic ns a neurotransmitter of
acetylcholine
examples of effectors
skeletal muscle, smooth muscle, cardiac muscle, and glands
what are the 2 types of cells within the nervous system
neurons and neuroglia
what are neurons (info)
basic functional unit
cells that recieve and send signals
have electrical impulses
what are neuroglia (info)
supporting and or protecting cells of the neurons
surround the neurons also
they are non excitable
what does the number of neuroglia increase
the complexity of the nervous system (behaviors)
what can increase synapses when neuroglia are grown in a lab
astrocytes
what are some characteristics of neurons in depth
longevity (long life)
amitotic ( dont divide) (besides those involved in smell and taste)
High metabolic rate (needs lots of glucose and oxygen)
Excitable (able to generate an action potention)
Conductive (series of AP generates)
Secretory (neurotransmitters)
What is Action potential
a rapid reversal of electrical potential across cell membrane electrical behavior
characteristics of neruons simple
longevity
amitotic
High metablic rate
Excitable
Conductive
SEcretory
what are the structural parts of a neuron
dendrites
cell body (soma)
Axon
Telodendria
dendrites def simple
cytoplasmic processes that receive sensory input
have a large surface area
cell body def simple
in charge of integration
axon def simple
sends instructions to effectors
works with action potentials
telodendria def simple
the final branching of axon
are dendrites highly or lowly branced
highly
what are dendritic spines
parts of dendrites that are extensions from dendrites to further increase surface area
what are 3 parts of the cell body
perikaryon
nucleus
axon hillock
perikaryon def and whats in it
cytoplasm basically
includes
nissl bodies, mitochondria, and cytoskeleton
what is in the nucleus
nucleolus
what does the axon hillock do
it is able to generate the first action potential
what are some of the parts of an axon
initial segment
axon collaterals
telodendria
synaptic knobs
what is the initial segment of an axon
the axon hillock
what are axon collaterals
large branches of axon
what are telodendria
final branching of axon
what are synaptic knobs
also called terminal boutons
very tips of axon telodendria
what is chemical synapse needed for
for a neuron to communicate with different cell types
what are the 3 steps of chemical synapse
presynaptic cell
synaptic cleft
postsynaptic cell
what is the presynaptic cell
a neuron that sends message terminal bouton
is synaptic vesicles with a neurotransmitter present
what happens at the synaptic cleft
when the action potential arrives at terminal bouton, neurotransmitter are realsed in gap. then the neurotransmitter diffuses across the gap
what is the postsynaptic cell
the cell being communicated with . it is a neurotransmitter binding to neurotransmitter receptors.
what can binding enough receptors at the postsynaptic cell change
cell behavior
where is the term tract used
CNS or PNS
within CNS
where is the term Nerve used
CNS or PNS
within PNS
are bundles of neuron processes myelinated or unmyelinated
myelinated axons
what do myelinated axons do
conduct electrical impulses
ascending/descending tracks
what are the terms for neuron processes (2 types)
tract in CNS
and
Neve in PNS
what are the terms for cell bodies (2 types )
Nuclus in CNS
and
Ganglion in PNS
are groups of cells bodies myelinated or unmyelinated
unmyelinated
what is at the dorsal root ganglion
cell bodies of sensory neurons
what are the 4 structural classifications of neurons
anaxonic
unipolar
bipolar
multipolar
anaxonic def
structural classification of a neuron
they are small cells with lots of small processes . they look similar
unipolar def
structural classification of a neuron
the axon and dendrites are fused
very long axon with cell body off to one side
bipolar def
structural classification of a neuron
one axon and one dendrite attached to cell body
in eyes and ears
multipolar def
structural classification of a neuron
most common type
lots of dendrites, one axon
seen in all motor neurons
what are the 3 behavioral classifications of neurons
sensory (afferent)
motor (efferent)
interneurons (association)
afferent neurons do what
send info to CNS
most are unipolar
they monitor environment
Efferent neurons do what
send instructions to effectors
are multipolar
assiciation neurons do what
go between other neurons
involved wiht higher functions like coordination
found in CNS
how many types of neuroglia are there
6
do nuroglia conduct electrical impulses
no
are neuroglia mitotic
yes
what are the 4 types of neuroglia of the CNS
astrocytes
Oligodendrocytes
Microglia
Ependymal cells
astrocytes info overview
Neuroglia of the CNS
look like stars
have a large cell body with many processes
Oligodendrocytes info overview
Neuroglia of the CNS
long processes that wrap around axon
Microglia info overview
Neuroglia of the CNS
Small with many processes
Ependymal cells info overview
Neuroglia of the CNS
Line cavities within the brain and spinal cord
what is the most numerous Neuroglia of the CNS
astrocytes
do astrocytes have one specific funciton?
no, they have the most diverse function
what do astrocytes maintin in the brain
the blood-brain barrier because they are found between blood vessels and nervous tissue: they isolate nervous tissue
what do astrocytes control
intersitial environment. they control they ion concentration within the ECF
how do astrocytes create a 3D framework for the CNS
they provide structure that anchors other cells
like scaffolding
what do astrocytes guide
neuron development through the migration of neuron (provide paths)
what do astrocytes repair
damaged neural tissue
how do astrocytes repair damaged neural tissue
fill gaps/spaces folliwn injury
form scar tissue
prevent regrowth of connections (btw axons and dendrites)
how do astrocytes for the blood brain barrier
have 2 layers where astrocyte processes line capillaries and papillary epithelium
why are the capillaries in the brain relatively impermeable
they lack pores
have tight junctions between adjacent cells
and anything that crosses the barrier must go through cytoplasm of 2 cell layers
OVerall role of astrocytes
secrete chemicals that tell the endothelium to behave as it does (Be less permeable)
what are microglia derived from
mesoderm
what do microglia start out as
white blood cells
where do microglia migrate
through neural tissue
do microglia do phagocytosis, if yes, how
yes
they clean up infected areas
they are an immune response
what nueroglia is an immune response
microglia
what do oligodendrocytes wrap around and what does that form
wrap around axons to form myelin sheaths
where does AP occur in myelin
at the gaps… NODES
is myelin sheath grey or white matter
white matter
what is white matter
regions of CNS with many myelinated axons
what is gray matter
unmyelinated areas of CNS, has a higher number of ribosomes and cell bodies
what do ependymal cells form
ependyma
what does ependyma do
lines ventricals and central canal and cavities inside the brain and spinal cord
produces and circulates cerebral spinal fluid
what do tufts of capillaries covered by ependyma allow for
filtration of blood
What is the ventricular systme
dorsal tubular nerve code
movement of CSF
ventricular system order
lateral ventricles
interventricular foramen of monro
3rd ventricle
cerebral aqueduct of sylvius
4th ventricle
central canal
medial and lateral aperatures
subarachnoid space
what are the 3 main functions of Cerebrospinal fluid
protection - acts like a cusion from trama
Bouys CNS - lessens weight
CHemical stability - rinses wastes
What 3 things are in relation to the resorption of CSF
Arachnoid villi
Dural sinus
Jugular veins
order of how CSF is resorption
arachnoid villi project from the arachnoid membrane to the dural sinus. csf is delivered between the 2 to dural sinus. it is returned to blood through jugular veins
what are 2 cells of neuroglia in the PNS
schwann cells
and
satellite cells
what are schwann cells and what do they form
what are their gaps
they are layers of phospholipds that surround axon
form the myelin sheath as well as neurilemma
their gaps are nodes
what happens at nodes
action potentials are generated
what are neurilemma, what forms them
cytoplasm and nucleus get squeeze into outer layer. caused by schwann cells
what are the 4 things that happen if an axon is cut
- distal portion dies
- Phagocytosis will clean up area
- Schwann cells create a tunnel and secrete chemicals to attract the growing axon
- remyelinate
what do satellite cells surround
cell body within ganglia
what do satellite cells regulate
the environment around a neuron (chem stability and remove debris)
Epineurium def
surrounds entire nerve
dense, irregular ct
perineurium def
portions of epineurium that penetrate the nerve and divide it into fasciles
endoneurium def
portions of the perineurium that penetrate fasciles and separate individual axons
is outside schwann cells
order of sizes within the layers of a nerve
largest, epineurium
then perineurium
smallest, endoneurium
