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nervous system Diego Lopez-patzan 7 (major parts of the brain and its…
nervous system Diego Lopez-patzan 7
major functions of the nervous system
Sensory Function – detects changes (stimuli)
within body and outside body
motor functions: it may respond to stimuli by initiating muscular contractions or glandular secretions
Integrative Function – It analyzes sensory,information, stores some aspects, and makes
decisions regarding appropriate behaviors
major divisions and sub divisions of the nervous system( also subdivision of pns)
central nervous system: brain, spinal cord, function: receive incoming sensory information, Issue instructions,thoughts, emotions, memory, information.
peripheral nervous system: extend from the brain and spinal cord. functions: spinal nerves carry impulse to and from the spinal cord. cranial nerves carry impulses to and from the cranial
subdivisions of the pns
sensory nerves( afferent): relay information
from skin,muscles and glands to CNS. Motor nerves( efferent) : carry's impulses from cns to organs ans muscle.
two divisions of the motor: somatic nervous system and autonomic nervous system. SNS:Conscious voluntary control part of PNS
ANS: Automatic, unconscious, involuntary
control
sympathetic ns: fight or flight response. parasympathetic ns: feed and breed
major parts of the brain and its functions. / lobes
frontal lobe: concentration, problem solving, decision making.
diencephalon :processes sensory input and controls many homeostatic processes
occipital: visuals, visual interpretation
thalamus: relaying sensory signals( motor signals)
temporal: hearing, auditory
hypothalamus: links the nervous system to the endocrine system
parietal: processing speech
cerebrum largest portion and associated with higher mental functions
pituitary gland: secretes hormones into bloodstream
brain stem :coordinates and regulates visceral activities
pons: relays signals from the fore brain to cerebellum. sleep, swallowing and bladder control
medulla obologata: respiration, heart regulations,digestions
mid-brain: motor movement, auditory and visual processing
cerebellum:coordinates muscular activity
structure and functions of a neuron
myelin: fatty substance that surrounds axon, insulates signal
Allows signal to be sent faster
node of ravier:spaces between myelin/Schwann cells
axon: start as a single fiber, but may give off branches called collateral axon; the portion that conducts signal away from the cell body
cell body: contains nucleus & other organelles, is the metabolic center
neurotransmitters: chemical messengers
dendrites: portion of neuron that receives
impulse and sends signal to the cell body (highly branched)
the layers of the meninges: meninges cover and protect the brain.
arachnoid mater: Very thin, lacks blood vessels
pia mater:covers every fold of
brain. attached to the surface of the brain, containing many blood vessels
outer(dura mater) tough white dense ct containing many blood vessels
Spaces &
ventricles
The lateral, third and fourth ventricles are structures within the brain that contain cerebrospinal fluid, a clear, watery fluid that provides cushioning for the brain while also helping to circulate nutrients and remove waste
The cerebral aqueduct acts like a canal that passes through the midbrain and connects the third ventricle with the fourth ventricle of the brain and the cerebrospinal fluid (CSF) finds its natural pathway through the cerebral ventricles and the canal connecting these ventricles.
The choroid plexus serves two roles for the body: it produces cerebrospinal fluid and provides a toxin barrier to the brain and other central nervous system tissue.
spinal cord structure and functions/ anatomy.
functions: to transmit impulses to and from the brain. to house spinal reflexes
structure: Connection between the brain and brainstem to
the rest of the body
White matter, made up of bundles of myelinated nerve fibers (nerve tracts), surrounds a butterfly-shaped core of gray matter housing interneurons and cell bodies.
Two deep longitudinal grooves (anterior
median fissure and posterior median
sulcus) divide the cord into right and left
halves.
Two spinal nerves extend out from the spinal cord (dorsal
and ventral roots)
Posterior/dorsal horns (sensory) – located in the
back
Anterior/ventral horns (motor) Cell bodies of motor neurons to skeletal muscle (or other effector organs) = info exiting spinal cord
Ascending Tracts carry sensory information to the
brain
Descending Tracts carry motor information from the
brain to the rest of the body
classifications of neurons
sensory transmit impulses TO CNS (the spinal cord and
brain) FROM all parts of the body
motor
transmit impulses away FROM CNS (the brain and spinal cord) to EFFECTORS (only 2 kindsof tissue: muscle and glandular epithelial tissue
inter neuron :
transmit impulses from sensory neurons to motor neurons; multipolar neurons in cns
unipolar fused axon and dendrite (sensory)
bipolar one dendrite, one axon (sensory)
multipolar many dendrites, one axon
action potential
:the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.
step 1 stimulus begins depolarization.: threshold potential is the critical level to which a membrane potential must be depolarized to initiate action.
step 2: depolarization: Neurotransmitters are released from the presynaptic cell to bind to The receptors on the postsynaptic cells. when binded they allow sodium to enter the cell
step 3:Repolarization is a stage of an action potential in which the cell experiences a decrease of voltage due to the efflux of potassium (K+) ions along its electrochemical gradient
step 4: hyper polarization: Step 3 hyperpolarization: Large amounts of k+ ions exit the cell going below the original charge
step 5: resting:Sodium pumps pump three sodium ions out and two potassium ions in ,in order to get back to the resting state
drugs and its affects:
Methamphetamine: increased alertness and decreased appetite ,overheating ,heart failure Harming behavior, mental illness
Opioids effects pleasure, drowsy, slow breathing, addictiveness, withdrawals feel like the flu
Opioids effects pleasure, drowsy, slow breathing, addictiveness, withdrawals feel like the flu
MDMA or ecstasy: increase in energy, muscle cramping, emotional, jaw clenching, sweating, overheating
Cocaine effects: increased energy ,decreased appetite, paranoia, irregular heartbeat ,heart attack ,death
Nicotine: calming, withdrawal, intense craving, ,sleep depriving ,cancer ,heart disease and lung disease
Alcohol effects: slow brain functions, impaired coordination, speech, reaction time and too much may result in death
brain diseases:
If cerebrospinal Fluid can not drain properly, causes enlargement of the ventricles =Hydrocephalus
Meningitis: Infection in the meninges that can spread to the CNS, Dangerous, often fatal
Contusion causes tissue destruction, permanent damage
•Intracranial hemorrhage- bleeding in the skull, edema
CVA (Cerebrovascular Accident) - aka stroke-blood flow to brain tissue is blocked causing cell death.
reflex arc
sensory receptor → afferent nerve ending detects stimulus
sensory/afferent neuron→ sends signal to CNS (reflex center)
synapse/interneuron integration center→ connection between sensory neuron and motor(efferent) neuron
Motor/efferent neuron→ delivers response to target organ
effector→ target organ responds to signal
menegines or coverings:
arachnoid mater: middle , thin, looks like cobwebs
Inner = Pia Mater (gentle
mother) covers every fold of brain.
duramater: tough white dense ct, outer layer
functions protecting the brain
neurotransmitters : a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure
Compare and contrast ans
the sns controls voluntary parts while the ans controls involuntary
they are both motor neurons
sns is external environment while ans is internal.