Please enable JavaScript.
Coggle requires JavaScript to display documents.
Nervous System Celeste Perez P.6 (Parts of the brain and what their made…
Nervous System Celeste Perez P.6
Major functions of the
nervous system
Integrative Function
It analyzes sensory information, stores some aspects and makes desicions regarding appropriate behaviors
Motor Functions
It may respond to stimuli by initiating muscular contractions or glandular secretions
These muscles glands are called effectors
Sensory Function
detects changes within the body and outside the body
Names of all the lobes and their functions;
Temporal
olfactory area
smell
auditory area
hearing
Parietal
primary somatosensory cortex
behind central sulcus in post central gyrus
receives impulses for touch, pain, proprioception
Frontal
primary motor cortex
in front of cerebral sulcus in precentral gyrus
controls voluntary actions of specific muscles or groups of muscles on the groups on the opposite side of body
Association area
concerned with more complex integrative functions, such as memory, emotions, reasoning, will, judgement and intelligence
Broca's areas
coordinates muscles movements for speech
language comprehension
Occipital
visual area; vision
visual recognition
Peripheral Nervous System
Autonomic Nervous System
brings info from receptor in internal organs to CNS and motor neurons to smooth muscle, cardiac muscle and glands
responses are involuntary
ANS divided:
Somatic Nervous System (SNS)
brings information from skin special senses body wall and limbs to CNS, and motor neurons to skeletal muscles
voluntary portion of PNS
Symphetic Nervous System
"fight or flight"
emergency or now- normal situations
Parasympathetic Nervous System
"feed and breed"
normal everyday situations
most organs receive input from both divisions
PNS divided into:
Major divisions and subdivisions of the nervous system
Central Nervous System (CNS)
most nerve impulses that influence effector/ organs begin in CNS
memories are formed and stored
thoughts and emotions are generated
information is integrated
consists of brain and spinal cord
Peripheral Nervous System (PNS)
consists of cranial and spinal nerves
Two primary:
Sensory afferent neurons
carry info from body toward CNS
Motor/efferent neurons
carry instructions away from CNS to target or effector organs of body
Coverings;
perneurorium
surronds fascicles
epineurium
surronds entire nerve
endoneurium
surronds individual neuron
Reflex arc
reflex- rapid, predictable and involuntary responses to stimuli
reflex arc- direct route from a sensory neuron to an inter neuron motor neuron to an effector
Anatomy of the spinal cord;
extends from medulla and ends at 2nd lumbar vertebra in adults
31 pairs of spinal nerves
connective between the brain brainstem to the rest of the body
conus medulans- end of cord
two enlargements
cervical enlargement-c4, t1, nerves to and from upper limb
lumbar enlargement
t9, t12,nerves to and from lower limbs
cauda equina= "horse's tail"
after conus medulans. spinal cord divides into nerves that leave at lower levels
Neurotransmitters;
synaptic end bulbs may contain 2 or 3 different neurotransmitters
needs to be removed or will influence nerve indefinitely
at least 30-50 different neurotransmitters identified
Action potential;
strong enough stimulation or nerve impulse causes Na+ gates to open Na+ rush into cell causing depolarization (membrane potential goes towards not polarized and momentarily becomes positively charged)
If a strong enough depolarization occurs, threshold potential is reached (+30) and impulse is sent down axon
nerve impulse is transmitted during action potential
K+ rush out of neuron after Na+ rush in, which causes a depolarization of the membrane back to resting potential
the layers of the meninges;
Arachnoid mater
thin membrane that lacks blood vessels
subdural space- fluid filled area between dura and subarachnoid maters
spider web= like collagen and elastin fiber
Pia mater
innermost, nearly transparent layer; has many nerves and blood vessels
follows contours of brain and spinal cord
subarachnoid space- space between arachnoid and pia mater; filled with cerebrospinal fluid
Cerebrospinal fluid
protects and cushions and nourishes brain and spinal
formed by choroid plexuses of brain
ependymal cells from a blood-cerebrospinal fluid barrier
protecting brain from harmful substances
CSF flows in subarachnoid space and in four ventricles
Dura Mater
dense irregular C.T. with many blood vessels and nerves
attached to periosteum
outermost layer
meningitis inflammation of meninges
Cerebral Aqueduct
connects 3rd and 4th ventricles
Classification of neurons;
Bipolar
one main dendrites and one axon
usually found in special sense organs
Uni polar
just one process and are always sensory neurons. Axon terminals are in CNS and cell bodies in ganglia
Multi polar
several dendrites and one axon
neurons of CNS are mostly this type
Neuron
Nerve tissue are made of neuron (nerve cell) and neuroglia
parts of the neuron
dendrites
receiving portions, short, tapered and highly branched
axons start as a single fiber, but may give off branches called collateral axon
cell body
contains nucleus and other organelles
end bulbs contain synaptic vesicles that contain neurotransmitter (chemical messengers)
Neuron are made of:
Axon and collateral end in axon terminals
Myelin
Most axons are are surrounded by a myelin sheath
myelin acts as an insulator
increases the speed at which impulse travels
gaps between myelin sheath are called the nodes of Ranvier
Functional Classification
Sensory/ afferent neurons
transmit sensory impulses (towards CNS) have specialized receptor ends at tips of dendrites of the dendrite are in contact with specialized receptor cells in skin or sense organs.
Motor or efferent neurons
transmit motor nerve impulses from CNS to effectors
Inter neurons
multi polar neuron in CNS that form links between other neurons
Types of Neuroglia in CNS
Astrocyte
hold neurons close to blood vessels
help form the blood-brain barrier
star shaped cells with many processes
Oligondendrocyte
most common
form the myelin sheath for neurons of CNS
Neuroglia
Glia means "glue"
act in support, guiding development, and stimulation and maintenance
Microglia
small, have fewer processes, are phagocytes
protect the CNS by phagocytizing microbes and clearing away debris from inflammation and tissue damage
Ependymal cells
form the cerebrospinal fluid (CSF) and also assist in its circulation
Neuroglia of PNS
Schwann Cells
supply myelin sheaths to axons in the PNS
also aids in the regrowth of damaged peripheral axons
satellite cells
flattened cell found around cell bodies of neurons in ganglia
Ganglia
bunched up cell bodies in PNS
Membrane Potential
Plasma membrane has electric voltage difference across membrane measured in volts.
nerve impulses is an electrical message down the axon
cells generate small voltage across their cell membrane
Resting Membrane Potential
Nerve at rest or inactive
Membrane at rest is polarized fewer potassium (k+) ions inside; more sodium ions outside (less negative inside)= -70v
Types of Responses
summation
occurs when another stimulus of same type arrives before effect of first stimulus wears off, addictive effect of two stimuli
graded response
stronger stimulus stronger response
All or none response
nerve will or will not generate nerve impulse
refractory period
time during which no stimulus can cause another action
Types of conduction
continuous conduction
unmyelinated axon conducts an impulse over its entire surface
salatatory conduction
myelinated axon jump from one node to next much faster
Synapse
postsynaptic neuron
neuron after synapse
nerve impulse travels from presynaptic to postsynaptic neuron
an impulse traveling down an axon of a presynaptic neuron reaches synaptic end bulb, opens ca+ channels
presynaptic neuron
neuron before the synapse
Ca++ rushes into cell causes synaptic vesicles to fuse with cell membrane and release their neurotransmitter into the synaptic cleft
gap between neuron
Parts of the brain and what their made of:
Vermiss
a narrow, worm shaped structure in between both sides, of the cerebellum
white matter tracts are called "arbor vitae" tree of life
cerebral peduncles- connect cerebellum to other parts of brain
Midbrain
Gyri
convolutions (bumps)
Pons
connects spinal cord with brain and links parts of brain with one another by way of tracts (nerve fibers within CNS)
Aid in control of breathing
Sulci
grooves
Medulla Oblongata
regulates:
cardiac center- heart rate
vasomotor center- constricts blood vessels
respiratory center- rate and depth of breathing
Fissures
deeper grooves
Cerebrum
Longitudinal Fissure
separates brain into right and left cerebral hemispheres
Lateral Fissures
divides temporal lobe from frontal and parietal lobes
Cerebral Cortex
dark outer area consists of gray matter contains cell bodies of 75% of all neurons in the nervous system
Central Sulcus
divides frontal and parietal lobes
no distinct boundary between parietal and occipital lobes
Transverse Fissures
separates cerebrum and cerebellum
white matter of brain lies under cortex and makes up bulk of cerebrum
diencephalon
superior to brain stem surrounded by cerebrum
limbic system
emotional aspects of behavior and aids in memory the pleasure center
Pituitary Gland
hangs down anterior portion of the hypothalamus
cerebrum
largest portion
Thalamus
relay station for sensory impulses to cerebral cortex
plays a role in emotions, memory, awareness and cognition
surrounded by the third ventricle
Hypothalamus
under the thalamus
controls regulation eating and drinking (water balance)
regulation of consciousness, emotional and behavior, diurnal (circadian) rhythms synchronizes day night cycle
controls body temperature
Brainstem
Cerebellum
"little brain"
coordination, balance, and posture
damage would show loss of muscle tone and inaccurate movements
Brain Stem
connects spinal cord to diencephalon
Parts of Midbrain
cerebral peduncles
"little feet of cerebrum"
corpora quadrigemina
reflex center for movement in response to sound and visual stimuli
Reticular Formation
responsible for maintaining consciousness and awakening from sleep
cross section anatomy
gray matter forms an "H" in center
gray commissioner where fibers cross from side to side
two grooves divide spinal cord:
anterior median fissure (deeper)
posterior median sulcus
two spinal nerves extend out from the spinal cord
dorsal root
ventral root
two nerve root joint to become the 31 pairs of spinal nerves
gray matter
divides into horns
posterior horns- located in the back
lateral horns- located on the side cell bodies of motor neurons to cardiac and smooth muscle and glands
part of autonomic nerve system
anterior iventral horns- cell bodies of motor neurons to skeletal muscle
central canal- center of gray commisure; continuous with fourth ventricle
white matter
white matter is divided into into columns
anterior , posterior, lateral white columns
each carries one type of info
ascending tracts- impulses towards brain
descending tracts- impulses from brain
spinal cord has two functions:
white matter tracts serve as info highways to and from brain
gray matter receives and integrates info, especially for spinal reflexes
name of tracts indicates position in cord where it begins and ends and direction of impulse
Peripheral nerves
peripheral nervous system is made of 31 pairs of spinal nerves plus 12 pairs of cranial nerves
most are mixed nerves-carrying both sensory and motor info.
Cranial Nerves
Olfactory
sensory nerve that controls sense of smell
Optic
arises from retina functions with vision
Oculomotor
controls most of the eye muscles
trochmotor
superior oblique muscle of eye
trigeminal
3 branches- chewing, skin of face
abducens
inner rectus eye muscle abducts the eye
facial
motor to muscles on the face
vestibulococholear
hearing and equilibrium
glossopharyngeal
motor of secretion of saliva; taste and regulation of blood pressure
vagus
smooth muscle contractions and relaxation, secretion of digestion organs it supplies
accessory
motor; swallowing, movement of head sensory
hypoglossal
motor- movement of tongue during speech and swallowing
Autonomic Nervous System
sympathetic nervous system is associated with the fight of flight
parasympathetic nervous system is associated with the aily body functions
Branch of PNS
Sympathetic Division
originates in the thoracolumbar segments of the spinal cord
synapses in ganglia near spinal cord
short pre-ganglianic and long postganglionic neuron
NEUROTRANSMITTERS
epinephrine and norepinephrine
effector oragns
eyes, lungs, heart, etc.
remember; "E" for exercise, excitement, and emergency
Parasympathetic Division
originates in brain stem and sacral
synapses in ganglia near effector organs
long pre-ganglionic and short postganglionic neuron
neurotransmitter- Acetylcholine
effector organs- salivary glands, digestive and reproductive organs
remember "D"; digestion, defecation, and diuresis
Drugs and affects on the brain
Alcohol
hard liquor
it is taken by drinking
it is a depressant
and it slows brain and nerve activity and impairs reasoning and balance and speech and judgement
cocaine
crack
it is taken by snorting, injecting, or smoking
crack came from the cocoa plant as a powder
it is a stimulant
it speeds up brain and nerve activity and they are numbing causing increased energy
dissociative drugs
PCP, ketamine
taken by swallowing
its a pill
its type of drug is a depressant
it relaxes the brain and causes hallucinations and nausea and slow breathing
GHB and Rohypnol
it is taken by swallowing, it is a pill
it is a depressant
and relaxes brain and can causes hallucinations
Heroine
morphine
it is injected
it is a powder
it is a mild depressant
it can have a bad withdraw but when induced to be this way people feel relief from pain
Marijuana
canabis
you can smoke it,vape it, or swallow
it is a depressant
you feel relaxed and pleasant, however, you feel paranoia and impair thinking