Priscilla Anzaldo P2 Nervous

Major Functions of Nervous System

Major Divisions/Subdivisions of Nervous System

Tissues

Classification of neurons

Connective Tissue Coverings

Major Parts/Functions of Brain

Major Parts/Functions of Spinal Cord

Action Potential and Nerve Impulse

Cranial Nerves

Spinal Nerves

Neurotransmitters

Compare and Contrast Autonomic Nervous System

Reflex Arc

Disorders & Diseases & Injury

Drug of Abuse On Mice

Heroine

Neurotransmitters affected: Inhibitory and Dopamine neurotransmitters

How it affects neurotransmitter: Heroine shuts down inhibitory neurotransmitter allowing dopamine to release into synapse

Symptoms: Creates a sedation feeling, affects transmission of stress and emotional attachment

Ecstasy

Neurotransmitters affected: Seratonin neurotransmitter

How it affects neurotransmitter: Ecstasy is taken by seratonin transporters confusing the transporter and transports seratonin out of the cell into receptor

Symptoms: effects mood, sleep, perception, appetite and contains addictive properties

Marijuana

Neurotransmitters affected: Inhibitory and Dopamine neurotransmitters

How it affects neurotransmitter: THC binds to natural cannabinoid receptor turning off release of inhibitory neurotransmitters releasing dopamine

Symptoms: removes short term memory, slow movement, calm behavior

Methamphetamine

Neurotransmitter affected: Dopamine Neurotransmitter

How it affects neurotransmitter: meth enters dopamine vesicles forcing dopamine out, excess dopamine is released out the cell and into the synapse

Symptoms: affects brains reward pathway, intense pleasure and exhilaration

Alcohol

Neurotransmitters affected: GABA and Glutamine neurotransmitter

How it affects neurotransmitter: makes GABA receptors inhibitory, alcohol binds to glutamine preventing it from leaving the cell

Symptoms: affects memory formation, decision and impulse control

Cocaine

Neurotransmitters affected: dopamine neurotransmitter

How it affects neurotransmitter: blocks dopamine transporter inhibiting dopamine neurotransmitter

Symptoms: effects voluntary movement, causes fidgeting

LSD

neurotransmitter affected: serotonin neurotransmitter

how it affects neurotransmitter: LSD inhibits and excites receptors by resembling serotonin

Symptoms: wakefulness, startle response to unexpected stimuli, hallucinations

External Inferior

External Superior

Internal Sagittal

Frontal lobe: thinking, memory, behavior

Parietal lobe: language, touch

Occipital lobe: sight

Longitudinal fissure

Sulcus

Gyrus

Transverse fissure

Temporal lobe: hearing, learning, feelings

Dura Mater

Pia mater

Arachnoid mater

cerebrum

cerebellum: balance, coordination

cerebral hemisphere L&R

Central Sulcus

olfactory bulbs: determine smells

optic nerves: transfer visual info to eyes

optic chiasma: relay electrical signals

optic tract

infundibulum

mamillary body: memory

cerebral peduncle: developing new motor skills

pons: relays info from cerebrum to cerebellum

medulla oblongata: adjust heart rate, respiratory rhythm, regulated vomiting, hiccupping, swallowing, coughing, sneezing

spinal cord: breathing, heart rate, temp.

Corpus callosum

Septum Pellucidum

Lateral ventricle

Fornix: emotional reaction, consciousness

Third ventricle

Thalamus: sorts, edits, relays ascending input (learning and memory)

Hypothalamus: regulates body temp, food intake, water balance, rhythm and drive

Corpa quadrigemina: vision and hearing

Pineal body/gland: produces melanin

Cerebral aquedut

4th ventricle

Abor vitae

Internal Coronal

Cerebral cortex: receives input from multiple sensory areas and sends output

White mater: protects fibers

Injury

cerebellum: process input from cortex, thinking, language, emotion, balance and coordination

midbrain

Left: speech/ language

Right: art, creative thinking, intuition

concussion: temporary alteation in function

disorders

diseases

contusion: permanent damage

Subdural Hemorrhage: pressure from blood

ischemia: tissue deprived of blood supply

cerebral edema: swelling of brain

Hemiplegia: paralysis on one side

translent ischemic Attacks: temporary episodes of reversal cerebral ischemia

Alzheimers disease: progressive degenerative disease of brain, results in dementia

Parkinson's disease: degeneration of dopamine- releasing neurons

Huntington's disease: fatal hereditary disorder caused by accumulation of protein in brain cells causing "flapping movement"

midbrain: motor movement

pons: relays info from cerebrum to cerebellum, controls respiratory rate and depth

medulla oblongata: relays ascending sensory pathway impulses from skin

reticular formation: maintains cerebral cortex alertness, filter out repetitive alertness, regulates skeletal/ visceral muscle activity

  1. Olfactory
  1. Optic
  1. Oculomotor
  1. Facial
  1. Vestibulocochlear

4.Trochlear

  1. Abducens

10.Vagus

  1. Glossopharyngeal
  1. Hypoglossal
  1. Trigeminal
  1. Accessory

sensory function; smell

motor function: none

PS fibers: none

sensory function: vision

Motor function: none

PS fibers: none

sensory function: none

motor function: yes

PS fibers: yes

Sensory function: none

Motor function: yes

PS fibers: no

sensory function: general sensation

motor function: yes

PS fibers: no

sensory function: none

motor function: yes

PS fibers: no

sensory function: taste

Motor Function: yes

PS fibers: yes

Sensory function: hearing

motor function: some

PS fibers: no

sensory function: taste

motor function: yes

PS fibers: yes

Sensory Function: taste

motor function: yes

PS fibers: no

Sensory function: none

Motor function: yes

PS fibers: no

sensory functon: none

motor function: yes

PS fibers: none

central nervous system

peripheral nervous system

brain

spinal cord

somatic nervous system

motor efferent division

somatic nervous system

autonomic nervous system

sympathetic division

parasympathetic division

8 pairs of cervical nerves

12 pairs of thoracic nerves

5 pairs of lumbar nerves

5 pairs of sacral nerves

1 pair of coccygeal nerves

each pair is connected to spinal cord via 2 types of roots

  1. Ventral roots: contain motor efferent fibers from ventral horn neurons and innervate skeletal muscles
  1. Dorsal roots: contain sensory afferent fibers from, sensory neurons in dorsal root ganglia. conduct impulses from peripheral receptors

components

  1. receptor: site of stimulus action
  1. sensory neuron: transmits afferent impulses to CNS
  1. Integration center: monosynaptic or polysynaptic region in CNS
  1. Motor Neuron: conducts different impulses from integration center to effector organ
  1. Effector: muscle fiber or gland cell that responds to efferent impulses by contracting or secreting

efferent pathways and ganglia

target organ responses to neurotransmitters

effectors

overlap of somatic and autonomic function

somatic: innervated skeletal muscle

Autonomic: innervates cardiac/ smooth muscle & glands

somatic: cell body in CNS, single, thick, myelinated group od A axon extends in spinal/ cranial nerves directly too skeletal

Autonomic: pathway uses a 2-way neuron chain

2-way neuron chain

  1. preganglionic neuron: cell body in CNA with thin, lightly myelinated preganglionic axon extending to ganglion
  1. Postganglionic neuron: cell body synapses with preganglionic axon in autonomic ganglion with nonmyelinated postganglionic axon that extends to effector organ

somatic: all motor neurons release ACh effect is always stimulatory

autonomic: preganglionic fibers release ACh, postganglionic release norephrine or ACh at effectors, effect is stimulatory or inhibitory depending on receptors

most spinal/ cranial nerves contain both somatic and automimic fibers

generation of action potential

  1. resting state: all gated Na+ and K+ channels closed
  1. Depolarization: Na+ channels open
  1. Repolarization: Na+ channels are inactivating, K+ channels are open
  1. Hyperpolarization: some K+ channels remain open, not all channels reset

propagation of action potential

propagation allows action potential to be transmitted from organ to axon length toward terminal

AP only occurs in forward direction

Once initiated AP is self- propagating

function classified in 2 groups

  1. Effects: excitatory vs. inhibitory
  1. Actions: direct vs. indirect

excitatory: depolarizing

inhibitory: hyperpolarizing

direct: neurotransmitter binds directly to and opens ion channels

indirect: neurotransmitter acts through intracellular second messengers

classified by chemical structure and function

ACh

released at neurotransmitter junctions

synthesized from acetic acid and choline

degraded by enzyme AChE

Biogenic amines

catecholamines: dopamine, norepinephrine, epinephrine made from tyrosine

indolamines

seratonin: made from tryptophan

histamine: made from histidine

Amino acids

Peptides (neuropeptides): strings of amino acids

endorphins: natural opiates, reduce pain perception

gases and lipids

endocannabinoids: act like THC

  1. sensory input: info gathered by sensory receptors for internal/ external changes
  1. integration: processing and interpretation of sensory input
  1. Motor output: activation of effector organs (muscles and glands) produces a response

3 types based on direction in which nerve impulse travels relative to CNS

  1. Sensory: transmit impulses from sensory receptors toward CNS (unipolar)
  1. Motor: carry impulses from CNS to effectors (multipolar)
  1. Interneurons (association neurons): lie between motor/ sensory neurons, shuttle signals through CNS pathways
  1. neuroglia: small cells that surround neurons
  1. Neurons: excitable cells, transmit electrical signals

PNS

CNS

  1. satellite cells
  1. Astrocytes
  1. Microglial cells
  1. Epidymal cells
  1. oligodendrocytes
  1. Schwann cells

neuron cell body (soma)

neuron processes

cling to neurons, synaptic endings, capillaries

function: support neurons, guide migration of young neurons, respond to nerve impulses/neurotransmitters

small ovoid cells with thorny processes

migrate toward injured neurons

may be ciliated

lines central cavities of brain/ spinal column

forms preamble barrier between CSF in cavities/ tissues fluid bathing in CNS cells

branched cells

process wrap CNS nerve fibers forming myelin sheaths in thicker nerve fibers

surrounds neuron cell bodies in PNS

function similar to astrocytes in CNS

surround all peripheral nerve fibers and from myelin sheaths in thicker nerve fibers

vital for regeneration of damaged peripheral nerve fibers

contains nucleus with neucleolus

part of receptive region

most located in CNS

nuclei: clusters of neuron bodies in CNS

Ganglia: clusters of neuron bodies in PNS

armlike processes, extend from cell body

CNS contains both

PNS contains only processes

Tracts: bundles of neuron processes in CNS

Nerves: bundles of neuron processes in PNS

2 types of processes

  1. dendtrites
  1. axon

receptive (input) region of neuron

convey incoming messsages toward cell body as graded potentials

each neuron contains 1 axon that starts cone shaped area called axon hillock

long axon: nerve fibers

distal endings called axon terminals/ terminal boutons

functional characteristics

conducting region of neuron

generates nerve impulses, transmits them along axon axolemma to axon terminal

terminal: region that secrets neurotransmitters, released into extracellular space

Endoneurium: loose CT that encloses axons and their myelin sheaths/ schwann cells

perineurium: coarse CT that bundles fibers into fascicles

Epineurium: tough fibrous sheath around all fascicles to create the nerve