Lecture 2: Intro to the nervous system Flashcards
what is the nervous system (2)
A biological system that can
1) receive and process info (stimuli) from the enviroment (internal/external)
2) coodinarte and carry out approciate action to respond to those stimuli
in vertebrates ,waht are the 2 major components of the nerovous system
central and peripheral
what makes up the CNS
brain and spinal cord
what makes up the PNS
all nerves outside of the CNS
what are the 2 functional divisions of the peripheral nervous system
somatic nervous ssystem (under our control)
visceeral (automonic)
what is thee stimuli for the somatic nervous system of PNS
largely external (ex: touch, vibration, external forcees due to gravity, responses from muscles )
true or false: in the somatic nervous system of the PNS the responses are voluntary
true (ex: motor contol of skeltal muscles)
what is the stimuli for the visceral (autonomic)
primarily internal (ex: body temp, jheart rate)
true or false: the responses for the autonomic nervous system are under our control
false, they are involuntary
what are the two divisions of the PNS
sensory/afferent
motor/efferent
afferent means
sensory
efferent means
motor
what comes from the imbound stimuli
visceral sensory info *heart rate, hunger etc(
somatic sensory (pressure, touch, bursea)
what system is responsible for processing and coordination
CNS
what is the outbiond action of the PNS
viscceral moptor (gland, secretion, vasodilation)
somatic motor (msucle contaction, joint movement)
what is the schematic for the nervous system in the somatic
somatic sensory inbound
CNS
somatic motor
what is the basic cellular unit of the nervous system (messengersr(
the neuron
how do nerous communication
chain like connections
info travelling along nervous is what direction
unidirectional
true or false: info travelling along neurons is bidirectional
unidiectiona l
what is the fucntion of the dendrite
receives info and generally short
what is the function of the cell body
process info
what is the function of the myelin of a neuron
insulation, increases speed of electrival impulses
what is the function of the axon
relays info in the form of electricity
can be very long
what is a synapse function
passes info onto other nervous of effect orfan chemically
what is the direction of impiulse along neuron
The dendrites receive incoming nerve impulses from other neurons.
This impulse travels from the dendrite to the cell body
and then at the end of the axon transmits the impulse to another neuron or receptor.
what are the 2 types of neuron types in the SOMATIC PNS
multipolar motor
pseudounipolar (sensory/afferetn)
what poriton of the stomatic PNS is the multipolar neuron part of
the motor efferent
what poriton of the stomatic PNS is the pseudo-unipolar neuron part of
sensory/afferent
what is the flow of info in multipolar neurons part of the motor soamtic PNS
dendrite
cell body
axon
target organ (effector (muscle) = PNS
what is the flow of info in pseudounipolar neurons in the sensory portio of the soamtic PNS
sensory receptors (eg in the skin, synovium)
through branches axon
to cell body (no dendrites)
CNS
true or false: pseudounipolar neurons have no dendrrites
true
what is a spinal nerve
bundle of sensory AND nmotor neurons that emerge fro mthe spnal cord (CNS) at regualr intervals to modulatee sensory and motor info from the PNS
why is the spianl nerve considered mixed
hs sensory and motor neurons
(as well as somatic and visceral)
true or false: in a spinal nerve the nerve is mixed but the flow of info is still unidirectional
true
where are internurons located
in the spinal cord
what are interneurons
Interneurons are the central nodes of neural circuits, enabling communication between sensory or motor neurons and the central nervous system (CNS)
what is a nerve
bundle of sensory and motor axons (all parts in the periphery are mixed)
what is the posterior root ganglion
group of cell bodies for the sensory neurons
what is the ventral horn
group of cell bodies for the motor neurons
the ventral horn contains what type of neuron cells
contains motor neuron ceell bodies for that spinal nerve
hat are the parts of a spinal cord (be able to identify)
.
true or false: ventral portion is for sensory
ventral=motor
posterior=sensory
what type of neurons does the psoterior root ganglion contrain
sensory neuron cell bodies for the spinal nerve
what are the parts of the spinal nerve
rootlets
roots
spinal nerve
rami
posterior ramus
antierior ramus
(dorsal root ganglion)
what are rootlets
axon bundlees from sensory neurons (posterior) and motor neurons (anterior), closest to the spinal cord
what are roots C
convergence of the rootlets, psoterior root cotnacts celel bodies of sensory nervons
the posterior root cotnacins cell bodiees of what types of neurons
sensory
what is spinal nerve
convergence of the roots, emerges from the vertebral column
what emeerges from the vertebral colium
spinal nerve
what is rami
first split fo the spinal nerve
what does the rami split into
posterior ramus and anteerior ramus
what does the posterior ramus innervate
intrinsic back muscels and associated skin
what does the anterior ramus innverate
everything but the intrinsic back muscles
expla nthe passage of info through the spinal cord
somatic sensory nerve to the post ramus
spinal nervous
posterior root ganglion (in the spinal nerve)
posterior root
posterior rootlets into the dorsnal horn
out the ventral horn
rootlets
roots
spinal nerve
anterior ramus
how does the innervation of myofibers occur (what type of neurons)
via motor neurosn
what is a motor unit
1 motor neuron innervating multiple muscle fibers)
true or false: motor units usually work in grousp
true
what is the fancy name for skeletal muscle fibers
myofibrils
true of false: the spianl nerves emerge at regular intervals from superior to inferior
true
how are spinal/segmental nerves pairs named
in relation of the vertebra
how many thoracic nerves are there
12
how many lumbar nerves aree there
5
how many sacral nerves are there
5
how many cervical nervs are there
8
he thoracic, lumbar, sacral and coccyx nerves are named in relation to which vert
the superior vert
the cervical nerves arew named in relation to the
inferior venterbal
where does c8 nerve lie
betweeen c7 and t1
what are the componentst fo the strcuture of the spinal cord
posterior horn
lateral honr
anterior horn
grey matter
white matter
central canal
posterior median sulcus
anterior median fissure
anteriolateral sulcular
posterolateral sulcus
be able to label the strcuture of the spinal cord
l
what is the cervical enlargment name
brachial plexus (c5-t1)
where is brachial plexus
c5-t1
what is the lumbar enlargements
lumbosacral plexus (l1-s4)
where is the lumbosacrial plexus
L1-S4
true or false: the spinal cord extends the length of vertebral column
false, the cord ends short
explain growth of the spinal cord
in the embryo: spinal cord fills the length of the vertebral columb
at birth: spinal cord ends at l3
adult: spinal cord ends at L1/L2
what is the end of the spinal cord called
conus medullaris
what is the ‘horses tail” of the spinal cord
cauda equina
what is cauda quina
axons of ingerior spinal nerves
true or false : near cervical the nerves emerge verticallt
false, more flat andd towards the sacral aspect is is more vertical
what are the protective laters of the spinal cord called
menings
what are the 3 meningers of the spina lcord
dura mater
arachnoid mater
pia mater
what is the outermost lyers of the menigns
dura
conus medularis is the…
end of the spinal cord
what are denticulate ligamnets
the anchor
help buffer movement of the spinal cord
what is filum terminale
derived from the pia mater
=suspends/supports the spinal cord
what meninge is the filum terminale derived from
pia mater
wht is the space above the dura caleld
extradural/epidural space
what is the space under the dura mater called
subdural space
what is the spalce under the arachnoid layer caleld
subarachnoid space
were does CSF circualte
subarach space
how many pairs of spinal nerves are there
31
spinal nerves stay called spinal nerves throughout the body
false, they cross over, branch etc to form named peripheral nerves that inenrvatie multiple structures
true or false: each spinal nerves will have a dscrete area of sensory innervation and will inenervate speccific set of muscles
true
areawhat is a dermatome
area/region of skin innervated by a single spinal nerves
what is a myotome
group of muscles innervated by a single spinal nerve
