nervous system Flashcards
3 main functions of the nervous system
sensory, integration, motor
Sensory: detecting changes in your environment (internal or external)
Integration: processing and decision making
Motor: telling the body what to do in response
two components of the nervous system
CNS - central nervous system
PNS - peripheral nervous system
aspects of the CNS (2)
brain and spinal cord
aspects of the PNS (4)
everything thats not in the CNS (all but brain and spinal cord)
-nerves (cranial and spinal)
-ganglia
-sensory receptors in skin
enteric plexuses in small intestine (aka the guts brain)
which component of the nervous system is for decision making
CNS
afferent vs efferent
afferent = bringing towards
efferent = carrying away
are sensory nerves afferent or efferent
afferent
are motor nerves afferent or efferent
efferent
what is the ganglia
where two nerves meet up and cast a signal
the central nervous system is further divided into two..
SNS - somatic NS
ANS - autonomic NS
SNS (receptors and motor) - conscious or unconscious?
conscious understanding and voluntary control/movement
ANS further divides into:
-sympathetic and parasympathetic divisons
-enteric NS
ANS - para and sympathetic devisions - (receptors and motor) - conscious or unconscious?
the brain picks up the signal on an unconscious and involuntary level
ENS
-can often function without sending signals back to the CNS
-involuntary
neurons
-core functions cells in the NS
-transmit signals
3 components of the neuron structure
cell body, dendrites, axon
cell body contains..
typical organelles
dendrites
extension of the cytoplasm that direct nervous signals into the cell body
axon
extension of the cytoplasm that carry signals ways from the cell body
myelin sheath
fatty tissue wrapped around the axon that makes signals flow faster
another name for non-nervous cells in the CNS
glial cells
4 types of non-nervous/glial cells in CNS
astrocytes, oligodendrocytes, microglial cells, ependymal cells
purpose of astrocytes
-regulate what comes in contact with the neuron
-help hold things together
purpose of oligodendrocyte
create myelin sheath
purpose of microglial cells
destroy viruses and bacteria
purpose of ependymal cells
line specific open cavities
2 types of non-nervous cells in the PNS
satellite cells, schwann cells
satellite cells
regulate nutrient and waste movement between neuron and external env
(like astocytes but for the PNS)
schwann cells
wrap around the axons in the PNS to form myelin sheaths
(like oligodendrocytes but for the PNS)
Multiple sclerosis (MS) is a break down of ___ that slows transmission and create stiffness
myelin sheaths
where does the brain develop in the fetus
in the neural tube
three primary brain vesicles
fore, mid, hind-brain
5 lobes of the brain
frontal, parietal, occipital, temporal, insula
frontal lobe location
front
parietal lobe location
upper sides
occipital lobe location
low sides
temporal lobe location
back
insula location
deep to all other lobes (not visible on the surface)
brain fissure
a division between two segments of the brain (ie the left and right hemispheres)
gyrus
bumps on the outermost layer of the cerebrum
sulcus
valleys on the outermost layer of the cerebrum
grey matter
in the outermost section of the brain (cortex)
white matter
lighter colour on the inside (comes from myelinated axons)
which vesicle/region hold the cerebellum
hindbrain
forebrain (deep grey matter)
thalamus, hypothalamus, basal nuclei/ganglia
thalamus
passes sensory signals towards the cerebrum
hypothalamus
controls the ANS and the endocrine system
what does the endocrine system produce?
hormones
basal nuclei
collection of cell bodies in the CNS that passes voluntary motor signals from the cerebrum
how does parkinsons affect basal nuclei
additional involuntary movements pass though
forebrain (white matter) - tracts of grouped together myelinated axons
commissural tracts, protection tracts, association tracts
commissural tracts
axons that connect the left and right sides of the brain
protection tracts
axons that cary sensory info out toward spinal cord and bring back motor signal
association tracts
stay within their respective hemi (left or right)
longitudinal fibers/tracts
travel though the hemi
arcuate fibers/tracts
stay within their lobe
midbrain
responsible for eye movement and visual/auditory reflex
peduncles
attach the cerebellum to the midbrain
hindbrain
pons and medulla oblongata
pons
regulate breathing
medula oblongate
regulates vital functions (heart rate, breathing, blood pressure)
vermis
connects the right and left hemi’s to the cerebellum
meninges
protective areas surrounding the brain and spinal cord that allows cerebral spinal fluid to access all areas of the brain
three layers of cranial meninges
dura mater
arachnoid mater
pia mater
dura mater
external layer
arachnoid mater
spider layer
pia mater
tender layer
venus sinus (veins)
spaces between two dura mater layers that collects poorly oxygenated blood
where is CSF (cerebral spinal fluid) made
in the ventricles
3 functions of CSF
protects brain fro impact, buoyancy, marker of NS health
four ventricles
lateral (x2), third, fourth-ventricle
total number of spinal nerve pairs in the spinal cord
31 (one pair at each vertebral layer)
where does the spinal cord end?
L2
conus medullaris
marks the bottom of the spinal cord
filum terminale function
acts as an anchor from the conus medullaris to the coccyx
what is filum terminale made of
pia mater
cauda equina
spinal nerves that continue below the spinal cord
where does a spinal tap take place
between L2 and L3
internal structure of the spinal cord (3 things)
myelinated axons, sensory neurons, motor neurons
sensory neurons
enter through the posterior to bring info from the body to the spinal cord
motor neurons
exit through the anterior to bring info out from the spinal cord into the body
cranial nerves vs spinal nerves
cranial - connect directly to the brain
spinal - pair at each vertebral layer
each spinal nerve divides to form the first branches
posterior rami, anterior rami
sensory and motor neurons in both
spinal nerve plexi
network of nerves that works together to innervate an area
innervate
supple the area
4 plexi
cervical, brachial, lumbar, sacral-plexus
what the the thoracic region have inplace of plexi?
intercostal nerves
Cervical plexus (C1 – C4)
innervates areas around the neck, upper shoulders and chest
phrenic nerve
through the thorax to the diaphragm helps with breathing
comes from the anterior rami of C3,C4,C5
(memory note: C3, 4, 5, keeps the diaphragm alive)
Brachial plexus (C5-8 – T1)
innervates upper limbs and thorax
Musculocutaneous nerve
innervates anterior arm muscles
median nerve
innervates anterior forearm (wrist and hand)
ulnar nerve
funny bone - innervates little hand muscles
radial nerve
forearm muscles and posterior arm
Lumbar plexus (L1 – L4)
mainly innervates lower limbs
femoral nerve
innervates anterior thigh
Secral plexus (L4-5 – S4) — NOT A QUESTIONS, just know the region (L4-5 – S4)
obturator nerve
innervates adductors
sciatic nerve
-biggest nerve in the body (size of 2 fingers)
-pressure on it when you sit
how many cranial nerves are ther
12 pairs
names of the 12 pairs and their functions
Memory note for names: Oh, oh, oh, to touch and feel Vanessa Grant’s vagina and hymen
Memory note for function: some say marry money but my brother says big brains mean more
Olfactory n S
Optic n S
Oculomotor n M
Trochlear n M
Trigeminal n B
Abducens n M
Facial n B
Vestibulocochlear n S
Glossopharyngeal n B
Vagus n B
(Spinal) Accessory n M
Hypoglossal n M
somatic (SNS) vs autonomic (ANS)
SNS, a single neuron can begin in the spinal cord and travel to its destination
ANS, there is always going to be at least 2 neurons involved in a motor signal
name of the two neurons used to transmit a motor signal in the ANS
pre and post ganglionic neuron
which one is not myelinated (travels slower) - pre or post ganglionic
post
Parasympathetic and sympathetic divisions of the ANS
usually work in opposition of each other
neurons in cranial nerve 10
ensure resting heart rate isnt too fast
sympathetic neurons between t1 and L2 of the spinal nerve are helpful for:
fight or flight/emergency situations
