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Central Nervous System (Major Parts of the Brain (Hypothalamus (under the…
Central Nervous System
Major Functions of the Nervous System
3 main functions
Integrative Function
it analyzes sensory information, stores some aspects, and makes decisions regarding appropriate behaviors
thinking portion of the brain
Motor Function
it may respond to stimuli by initiating muscular contractions or glandular secretions
these muscles or glands are called effectors
Sensory Function
detects changes (stimuli) within body and outside body
Sensory input :arrow_right: Integration :arrow_right: Motor output
(Seeing :arrow_right: processing :arrow_right: doing)
Major Parts of the Brain
Cerebrum
largest portion
control all movement divided into the four lobes
Brain Stem
consists of medulla oblongata, midbrain and pons
control over messages sent to brain
Diencephalon
consists of thalamus and hypothalamus
superior to the brain stem, surrounded by cerebrum
can only be seen when the brain is cut open
Cerebellum
"little brain"
function coordinate voluntary movement and regulates it for example posture, balance, and coordination
consists of cerebral cortex and arbor vitae
Meninges
three connective tissue layers
for protection and covering
consists of dura mater, arachnoid mater, and pia mater
Thalamus
surrounded by the third ventricle
relay station for sensory impulses to cerebral cortex
plays a role in emotions, memory, awareness and cognition
Hypothalamus
under the thalamus
controls regulation eating and drinking (water balance)
controls body temperature
regulation of consciousness, emotional and behavior, diurnal (circadian) rhythms- synchronizes day-night cycle
Lobes and their Functions
Frontal
forehead
coordinates muscle movements for speech(on left side), concerned with more complex integrative functions, such as memory, emotions, reasoning, will, judgment, intelligence, and language comprehension
Temporal
above ears
controls smell and hearing
Parietal
top sides
receives impulses for touch, pain, proprioception (ligaments being stretched) , vibrations, and temperature
Occipital
back
controls vision
Classifications of Neurons
multipolar
several (highly branched) dendrites and one axon-neurons of Central Nervous System are mostly this type
bipolar
one main dendrite and one axon-usually found in special sense organs
unipolar
just one process, and are always sensory neurons. Axon terminals are in Central Nervous System and cell bodies in ganglia
Functional Classification
sensory or afferent neurons
transmit sensory impulses (toward CNS)
have specialized receptor ends at tip of dendrites or the dendrites are in contact with specialized receptor cells in skin or sense organs
send down brain and spinal cord to give information of what's happening in the body
most are unipolar, some are bipolar
motor effect-neurons
transmit motor nerve impulses from CNS to effectors
carry out action necessary depending on information received
interneurons
multipolar neurons in CNS that form links between other neurons
multipolar neurons can receive information from multiple sensory neurons and then relay that information to multiple motor neurons
found between connection of sensory and motor neurons
Meninges
Dura mater
outermost layer
dense, irregular Connective tissue with many blood vessels and nerves
attached to periosteum
meningitis- inflammation of meninges (can be dangerous)
Arachnoid mater
spider-web like collagen and elastic fiber
thin membrane that lacks blood vessels
subdural space- fluid filled area between dura and subarachnoid maters
Pia mater
innermost, nearly transparent layer; has many nerves and blood vessels
follows contours of brain and spinal cord
subarachnoid space- area filled between arachnoid and pia mater; filled with cerebrospinal fluid (provide nutrients)
Drugs that affect the brain
Heroine
Dopamine and inhibitory neurotransmitters. Body's naturals opiates activate opiate receptors, the release of inhibitory neurotransmitters is shut down. Dopamine can be released without inhibition
Neurons with opiate receptors are in parts of brain responsible for transmission of pain signals, stress response, and emotional attachment
also known as: smack, H, skag, junk, black tar
taken by injecting, snorting, smoking
class of drug derived from poppy plant
Ecstasy
Serotonin neurotransmitter. The transporter becomes temporarily 'confused' and starts to do its job in reverse. transports serotonin out cell. Overstimulates cell
Affects a persons mood, sleep, perception, and appetite
also known as: MDMA, E, X
taken by mouth
produce both energizing effects and distortions in time and perception
Marijuana
also known as: pot, herb, grass, widow, ganja, hash
smoked as a cigarette (joint), in a pipe, a bong, hollowed-out cigar (blunt)
peaceful or euphoric sensation
Dopamine and inhibitory neurotransmitter. Cannabinoid receptors turn off the release of inhibition, dopamine can be released
A person using this drug has slowed down movement, making them feel relaxed and calm
Methamphetamine
Dopamine neurotransmitter. Transporters start working in reverse, actively pumping dopamine out cell and into synapse. Overstimulates cell
The user feels intense pleasure and exhilaration
also known as: speed, meth, chalk, ice, crystal
taken by mouth, snorting, injecting, smoking
A drug that has strong effects on brain and nervous system
Alcohol
also known as: beer, wine, liquor, whiskey, vodka, rum, and gin
taken by drinking
a drug that temporarily produces a calming or drowsy effect
Affects areas in the brain involved in memory formation, decision making and impulse control
GABA inhibitory neurotransmitter and glutamate neurotransmitter
interacts with GABA receptors and make them even more inhibitory. Then binds to glutamate receptors preventing glutamate from exiting cell
Cocaine
also known as: coke, C, snow, flake, blow, crack
taken by snorting, injecting, or smoking
a class of drug that speeds up activity in the brain and nervous system
The effects are nausea, respiratory failure, strokes, and seizures
A person's actions when on the drug is they are fidgety and unable to be still
Dopamine neurotransmitter. Transporters are blocked. Dopamine binds again and again to the receptors overstimulating the cell
LSD
Serotonin neurotransmitter
Sometimes LSD may inhibit them and sometimes it may excite them
Feelings of wakefulness and evoking a startle response to unexpected stimulus
Spaces and Ventricles
subarachnoid space
area between arachnoid and pia mater; filled with cerebrospinal fluid
subdural space
fluid filled area between dura and subarachnoid maters
Lateral Ventricles
largest cavities and contains cerebrospinal fluid
fourth ventricle
upper portion of medulla, diamond shaped
cerebral aqueduct
connects third and fourth ventricle and cerebral spinal fluid flows
third ventricle
located by two halves of the brain, sends and receives messages from the lateral vertices and contains cerebrospinal fluid
Tissues (structure and function of a neuron)
Nerve tissue is made up of neurons (nerve cells) and neuroglia
Structure
cell body: contains the nucleus and other organelles
dendrites: receive portion, short, tapered, and highly branched
axon- start as a single fiber, but may give off branches called collateral axon
Function
sensory or afferent neurons- transmit sensory impulses toward CNS and have specialized receptor ends at tips of dendrites or the dendrites are in contact with specialized receptor cells in skin or sense organs
motor effect-neurons- transmit motor nerve impulses from CNS to effectors
interneurons- multipolar neurons in CNS that form links between other neurons
Action Potential
nerve impulse is transmitted during action potential
If a strong enough depolarization occurs, threshold potential is reached (+30) and impulse is sent down axon
K+ rush out of neuron after Na+ rush in, which causes a repolarization of the membrane back to resting potential
Strong enough stimulation or nerve impulse causes Na+ goes to open :arrow_right: Na+ rush into cell causing depolarization
Major Parts and Functions of Spinal Cord
Function- two way conduction pathway to and from brain. Major reflex center also relays messages between the brain and the rest of the body
Major parts
Pia mater- follows control of brain spinal cord action, almost transparent layer
Posterior of dorsal horn of gray matter- two posterior projections of the gray matter of the spinal cord
Anterior or ventral horn of gray matter- two anterior projections of the gray matter of the spinal cord
Spinal Nerve- carries motor, automatic, and sensory signals between spinal cord and brain
Lateral horn of gray matter
White matter- paler tissue which consists of nerve fibers and its myelin sheaths
Ventral root of spinal nerve- axons of the motor neurons from ventral horns are sent out through ventral root
Arachnoid mater- thin membrane which lacks blood vessels and has spider-like collagen and elastic fibers
Dura mater- outermost layer, attached to periosteum, many blood vessels and nerve: dense irregular, connective tissue
Dorsal root ganglion- the fibers from the cell bodies's sensory neurons are found here which is an enlarged area
Central Canal- surrounded by gray matter and contains CSF
Dorsal root of spinal nerve- fibers of the cell bodies's sensory neurons enter through the dorsal root
Structure- glistening white continuation of the brain stem which is approximately 17 inches long. Attached to vertebral column