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Alexia Avalos Period: 1 …
Alexia Avalos Period: 1 Nervous System
Cranial Nerves
12 pairs of cranial nerves; arise from underside of brain
Mixed nerves, have sensory and motor nerve fibers, some sensory, other primarily motor
first pair arise from cerebrum, second pair from thalamus, most arise in brainstem
12 pairs designated by number and name; number in order, from superior to inferior
Reflex Arc
Reflexes: autonomic responses to changes in and out of body, help maintain homeostasis swallowing and etc
control heart rate, blood pressure, and carry out autonomic responses, vomiting, sneezing, swallowing, and etc
Paterallar (knee-jerk) reflex
: only neurons sensory, and motor and lacks an interneuron
Sensory neurons transmit nerve impulses to spinal cord; synapse with motor neurons and issue motor command
Reflex helps maintain upright posture
Withdrawal Reflex:
Occurs response tuching something painful; stepping on a tack
Involves sensory neurons, interneurons, and motor neurons
Sensory receptors send pain messages along sensory neurons to spinal cord
Sensory neurons send impulses to interneurons, info coordinated
Interneurons issue motor commands to motor neurons
Motor signals sent to flexor muscles to contract
Connective Tissue Coverings
Epineurium
:
outer coverings of nerve
Perineurium
:
covering around fascicles (bundles) of nerve fibers
Endoneurium:
covering around individual nerve fibers (axons)
Major Divisions and Subdivisions of the Nervous System
Central NS:
Brain and Spinal Cord
Integration of info and decision-making
Peripheral NS:
Cranial and Spinal nerves that connects CNS to body
Sensory (afferent) and motor (efferent) divisions
Somatic NS:
control voluntary skeleton muscles
Autonomic NS:
control voluntary effectors (smooth and cardiac muscles and glands)
control visceral motor functions of smooth muscle, cardiac, and glands
Sympathetic Division:
active in stress or emergency conditions (fight and flights)
Parasympathetic Division:
active under normal, restful conditions
Major parts and functions of the Spinal Cord
Lumbar Enlargement:
rise to nerves serve bottom limbs
thickened region near bottom on Spinal Cord
Cervical Enlargement:
thickened area near top of Spinal Cord
provide nerves to upper limbs
Cuada Equina (horses tail)
form where spinal cord tapers to point inferiorly
consists of spinal nerves in lumbar and sacral areas
Functions:
transmit impulses to and from brain and to house spinal reflexes
ascending tracts: carry sensory info to brain; descending tracts carry motoe info frm brain to muscles/glands
spinal reflexes: controlled reflex arcs pass through spinal cord
Disorders/ Diseases
Cerebrovascular Accident (Stoke)
Description
: Rottenness and Back
Causes
: Diabetes, increasing age, high cholesterol
Symptoms
: Serve headache, change in alertness, loss of coordination
Treatment
: Hospitalization, Surgery to repair vessels, stroke rehabilitation
Autism:
Description:
Disorder and abnormal brain development
Causes:
Family History, Hereditary, Environmental
Symtoms:
Anxiety, depression, repeated behaviors
Treatments:
Medication, coping skills, specialized therapy
Alzheimer's Disease
Description:
Lost memory and old
Causes
: Family History, Hereditary, Over 60
Symptoms:
Memory Loss, Confusion, disorientation, and unfounded suspicions
Treatment:
Medication, Uncurable, and Stem cells
Spinal Cord Injury:
Description
: Crack, Gap, Broken
Causes:
Direct injury and diseases, assault, fall, accident, weakened vertebral column
Symptoms
: Weakness, loss of feeling below damaged site, spastic muscles
Treatments:
Surgery, Spinal traction, and physical therapy
Meningitis:
Description:
Spots
Causes
: Bacterial, viral infection, Drug allergies, tumors
Symptoms
: Nausea, vomiting, stiff neck, irritation
Treatments:
Antibiotics, vaccines, bacterial
Multiple Sclerosis:
Description
: Nerve in multiple sclerosis and fatigue
Causes:
Hereditary, Family history, Environmental factors
Symptoms:
Incontinence, frequent urination, vision, hearing loss, and muscle weakness
Treatments
: Assistive devices, Healthy lifestyle choices, steroid treatments
Compare & Contrast the Autonomic NS
Sympathetic Division:
Active in stress or emergency conditions (fight and flight)
Preanglionic fibers in smypathetic arise from neurons in gray matter in thoracic and lumbar regions of Spinal cord
Axons exit spinal cord via ventral roots of spinal nerves
Axons leave spinal nerves and proceed into symatheitic (paravertebral) ganglia, chain of sympathetic ganglia close to vertebral column on each side
Synapse with postganglionic neurons where long axons return to spinal nerves and proceed to visceral effector
Preganglionic fibers pass through paravertrbral ganglia and synapse in collateral ganglia, closer to target organs
Parasympathetic Division:
Active under normal and restful conditions
Preganglionic fibers in parasymapthetic arise from brainstem and sacral region of spinal cord
Preganglionic fibers extend out in cranial or sacral nerves and synapse terminal ganglia close to or in visceral effector organs
Postgangionic fibers continue in effector organs
Major parts and functions of the brain
Cerebrum:
provide higher brain functions
interpretations of sensory input
initiating voluntary muscular movements
stores info for memory
integrates info for reasoning
intelligence
personality
Cerebral Cortex:
Frontal Lobe:
control number of higher intellectual processes ( planning, problem-solving)
Parietal Lobe:
function in understanding speech and choosing proper words
Occipital Lobe:
help analyze visual patterns and combine visual mages with other sensory info
Temporal Lobe:
controls the auditory system
Thalamus:
sorting and directing sensory info arriving from other parts of neurons system to cerebral cortex
channels sensory impulses, except for sense of smell
produce general awareness of sensation: pain, touch, and tempt
Hypothalamus:
maintain homeostasis by regulating a wide variety of visceral activities and by lining endocrine system with NS
regulate heart rate and arterial blood pressure
regulate body tempt, water, and electrolyte balance, hunger, and body weight
controls movement and secretions of digestive tract
help regulate sleep and wakefulness
stimulate posterior pituitary gland to secrete stored hormones
Limbic System:
controls emotional experiences and expression
modifies behavior by producing feelings of fear, anger, pleasure and sorrow.
generating pleasant/unpleasant feelings about experiences limbic system guides behavior that may enhance chance of survival
Brainstem:
Pons
centers help regulate rate and depth of breathing
Midbrain:
contains main motor pathways between cerebrum and lower portions of NS
Medulla Oblongata:
transit ascending and descending impulses between brain and spinal cord
Vasomotor center:
control vasoconstriction and vasodilation of blood vessels; help control blood pressure
Respiratory Center:
control rate and depth of breathing
has controls reflexes such as coughing, sneezing, swallowing, vomiting
Cerebellum:
integrates sensory info about position of body parts
coordinates skeletal muscles activity
maintain posture
ensures movement occur in desire manner
Tissues
Dura Mater:
outermost layer
consist of tough, dense connective tissue, and thick
sheath around SC seperated from vertebrae by Epidural Space
Arachnoid Mater:
middle layer
between arachnoid and pia mater: subarachnoid space, contain cerebrospinal fluid (CSF)
Pia Mater:
innermost layer
Drugs of Abuse (Mouse Party)
Heroine:
Neurotransmitters affected:
Inhibitory and Dopamine
Specifically Affects:
This drug mimics opiates and binds to opiate receptors; turning off dopamine inhibition. This makes dopamine to flood the synapse.
Mood Causes
: This drug makes the person feel pain signals, stress response, and emotional attachment
Ecstasy:
Neurotransmitters affected:
Serotonin
Specifically Affects:
Ecstasy mimics serotonin and is taken up by serotonin transporters. This makes serotonin come out of the cell. Therefore, the left over serotonin overstimulates the cell.
Mood Causes:
Affects person's mood, sleep perception, and appetite
Marijuana:
Neurotransmitters Affected:
Inhibitory and Dopamine
Specifically Affects:
This drug contains THC, which mimics anadamide, binds to cannabrnoid receptors. Therefore, this turns off the inhibition and dopamine allowed to go into the synapse.
Mood Causes
: Marijuana removes unnecessary short memory, slow down movement. This drug makes the person feel relax, calm, and high
Methamphetamine
Neurotransmitters Affected:
Dopamine
Specifically Affects:
Meth mimics dopamine, so it is taken into the cell. Therefore, Meth goes inside dopamine vesicles, which takes dopamine molecules out. Moreover, dopamine is kicked out of the cell, which overstimulates it.
Mood Affects:
This drug is very addictive because it makes the user to feel pleasure and exhilaration
Alcohol:
Neurotransmitters affected:
GABA Inhibitory and Glutamate
Specifically Affects:
Alcohol delivers double sedative punch which interacts with GABA receptors. In addition, Alcohol binds to gluamate receptors which prevents glutamate from the cell.
Mood Causes:
Alcohol affects memory formation, decision-making, and impulse control
Cocaine:
Neurotransmitters Affected:
Dopamine
Specifically Affects
: Cocaine blocks dopamine transports, which makes the dopamine trapped in the synaptic cleft. As a result, dopamine binds to the receptors making it overstimulating the cell
Mood Causes:
Cocaine makes the user fidgety and unable to stay still
LSD
:
Neurotransmitters Affected:
Serotonin
Specially Affects:
LSD interacts with receptors and inhibit them to excite them. Therefore, this leads to complex sensory effects.
Mood Causes:
This drug makes the user have feelings of wakefulness and evoking startle response to unexpected stimulus
Spinal Nerves
31 pairs arise from spinal cord except first pair; mixed nerves
8 pairs cervical nerves, 12 pairs thoracic nerves, 5 pairs lumbar nerves, 1 coccygeal nerves
2 roots: sensory dorsal root and motor ventral root
Dorsal root have dorsal root ganglion that house cell bodies of sensory neurons in spinal cord
Ventral and dorsal root unite forming spinal nerves; extend out vertebral canal through intervertebral foramen
Classification of Neurons
Sensory (afferent) neurons:
conduct impulses from peripheral receptors to CNS; uni polar: some polar
Interneurons (associated/internuncial) neurons:
multi polar neurons lying in CNS form links between other neurons, cell bodies of interneurons aggregate in specialized masses, nuclei
Motor (efferent) neurons:
multi polar neurons conduct impulses from CNS to peripheral effectors (muscles/glands)
Multipolar Neurons:
many dendrites and axon arising from cell bodies; most neurons with cells bodies in CNS
Bipolar Neurons:
have processes extending from cell body, dendrite and axon, found in special senses, eyes, nose, ears
Unipolar Neurons:
process extending from the cell body, splits into 2 PTS function as 1 axon; peripheral processes has dendrites near a peripheral body part, and central process runs in CNS, cell bodies found in ganglia outside CNS, sensory neurons
Major Functions of the Nervous System
Sensory Functions:
Provide by sensory receptors; detect internal/external changes
Info travels from receptors to sensory neurons; transport info to CNS
Integrative Function:
Coordination of sensory info in CNS
Processing info is basis for decision-making
Motor Functions:
Nerve impulses conduct along matter neurons to effectors
Effectors muscle or glands that respond to decisions made in CNS
Neurontransmitters
More than 100 transmitters
Action Potential pass along axon and over surface of synaptic knob
Synaptic Knob membrane become more permeable to calcium ions and diffuse inward
Synaptic vesicles fuse to snaptic knob membrane
Synaptic vesicles release their neurotransmitter in synaptic cleft
Action Potential & the Nerve Impulse
Action Potential
Voltage-gated Na+ channels open, changing charge to about +30mV
Change from - to + charge inside neuron; depolarization inside and outside are +
When AP reach, cell respond by returning to resisting potential by process of replorization (-70 mV)
Nerve Impulse
Neuron membrane maintain resting potential
Threshold stimulus received
Sodium Channels in trigger zone of axon open
Sodium Ions diffuse inward, depolarizing axon membrane
Potassium channels in axon membrane open
Potassium ions diffuse outward, repolarizing axon membrane
Resulting AP causes local electrical currents that stimulates adjacent portions of axon membrane
Series of AP occur along axon