Nervous System- Alejandro Alvarez P2

Nervous System Divisions

Central Nervous System (CNS)

Peripheral Nervous System (PNS) (consists of cranial & spinal nerves)

Autonomic Nervous System (connects CNS to viscera, and controls subconscious activity)

Somatic Nervous System

Function: responsible for integration and decision making.

Structure: made up of brain and spinal cord

Sympathetic

Parasympathetic

Characteristics: enclosed in bony structures (skull and vertebrae) making it difficult to access.

connects CNS to skeletal muscles and the ski, and oversees conscious activities.

Cranial Nerves (12)

I Olfactory

II Optic

III Oculomotor

IV Trochlear

V Trigeminal

VI Abducens

Maxillary division

Mandibular division

Ophthalmic division

VIII Facial

VIII Vestibulocochlear

Cochlear branch

Vestibular branch

IX Glossopharyngeal

X Vagus

XI Accessory

XII Hypoglossal

spinal branch

Cranial branch

Type: Sensory

Function sense of smell

Type:Sensory

Function: sense of vision

Type: Primarily Motor

Function: move eyelids, eyes, focus lenses, light in the eyes

Type: primarily motor

Function: moves eyes in all directions

Type: miixed

Function: surface of eyes, scalp, forehead, and upper eyelid

Type: mixed

Function: upper teeth, upper gum,, upper lip, linning of palate, and skin of face

Type: mixed

Function: sensory fibers conduct impulses from skin of jaw, lower of jaw, teeth, upper gum, and lower lip. Motor fibers conduct impulses to muscles of mastication and floor of mouth.

Type: primarily motor

fucntion: move eyes laterally

Type: sensory

Function: balance and equalibrium

Type: sensory

Function: sense of hearing

Function: Sensory fibers conduct a sense of taste. Motor fibers impulse muscles of facial expressions, tear glands, and salivary glands.

Type: Mixed

Type: mixed

Function: conduct impulses from pharynx, tonsils, posterior tongue, and carotid arteries

Function: somatic motor fibers help with speech and swallowing. Sensory fibers conduct impulses from pharynx, esophagus, and viscera from thorax and adbdomen.

Function: motor fibers help with soft palate pharynx and larynx.

Type: primarily motor

Type: motor

motor fibers help move back and neck

Type: primarily motor

Function: muscle fibers help move tounge

Type: mixed

Function: prepares body for fight or flight siuuations

Target Organs: heart, lungs, joints, stomach, eyes

Characteristics: short preganglionic fibers arise from gray matter in thoracic/lumbar region of spinal cord. Axons leave spinal nerves and enter into the sympathetic ganglia where they. synapse with postganglionic neurons.

Functions: active under normal condidtions such as rest and digestion.

Target organs: salivary glands, esophageal glands, gastric glands, pancreas.

Characteristics: long preganglionic fibers arise from brainstem and sacral region of spinal cord. The fibers extend to cranial and sacral nerves where they synapse in terminal ganglia. Short postganglionic fibers continue to effector.

Neurotransmitters

PNS

CNS

Acetylcholine

Dopamine

(sympathetic) Norepinephrine

Acetylcholine

Dopamine

Serotonin

Histamine

(sympathetic) epinephrine

sympathetic postganglionic fibers release norepinephrine in fight or flight situations.

.stimulates skeletal muscle contraction at the neuromuscular junction, may excite or inhibit autonomic nervous system actions depending on receptors.

Limited actions in the autonomic nervous system; may excite or inhibit, depending on receptors.

released during fight or flight situations.

. leads to sleepiness, action is blocked by LSD, enhanced by selective serotonin reuptake inhibitor drugs.

. controls skeletal muscle actions

creates a sense of feeling good; deficiency in areas of the brain can lead to Parkinson disease.

. promotes alertness, released in hypothalamus.

General Functions

Sensory

Integrative

Motor

Functions: reponds to decisons made in the CNS

Characteristics: Nerve impulses are conducted along motor neurons to effectors

Detects internal and external change.

characteristics: provided by sensory receptors, information travels from receptors to sensory neurons which transports information into the CNS.

Function: Coordination of sensory information in the CNS

Characteristics: processing of information is the basis for decision making.

The Brain

Spinal Cord

Structure

Function

Cervical Enlargement

Lumbar enlargement

Cauda Equina (horse's tail)

Meninges

Ascending tracts

Descending Tracts

Spinal Reflexes:

Dura Mater (outermost), dense connective tissue, sheath around spinal cord is seperated by epidural space from vertebrae.

Arachnoid Mater (middle layer)

Subarachnoid Mater (in between pia and aracnoid) contains cerebrospinal fluid.

Pia Mater (Innermost layer)

thickened area near top of spinal cord, provides nerves to upper limbs

thickened area near bottom of spinal cord, provides nerves to lower limbs

structure where spinal cord tapers to a point inferiorly, consists of spinal nerves in the thoracic and sacral regions

carries sensory information to the brain

carries motor information from brain to muscles of glands

controlled by reflex arcs that pass through the spinal cord.

Cerebrum

Cerebellum

Diencephalon

Brainstem

Surface

Lobes

Matter

Basal Nuclei

Ventricles (connected cavites filled with cerebrospinal fluid)

Corpus Callosum

Temporal (sides)

Frontal (front)

Parietal (top)

Occipital (back)

Gyri

Sulci

Fissures

White Matter

Cerebral Cortex (Gray matter)

Lateral (1st and 2nd)

3rd Ventricle

4th ventricle

Cerebral aqueduct

Functional Areas

Association areas

Functional Areas

Association areas

Association Areas

Functional Areas

Association Areas

Cutaneous Senses

Auditory/hearing senses (posterior), sense of smell (deep in temporal lobe)

Visual senses.

controls planning and problem solving.

function in understanding speech and choosing proper words

help analyze visual patterns and combine visual images with other sensory info.

Wernickes area (left side) helps with understanding written and spoken language.

Functional Area

Broca's motor speech area controls muscle movements for speech.

Structure: deep grooves

Location: divides the cerebral hemispheres (longitudinal fissure), divides the cerebrum from cerebellum (transverse fissure)

Structure: grooves

Location: Central sulcus (separates frontal and parietal lobes), lateral sulcus (separates temporal lobe and parietal lobe)

Ridges located throughout cerebrum and cerebellum

Structure: made up of myelinated nerve fibers connecting cell bodies of the cerebral cortex with the rest of the nervous system

Location: lies beneath the cerebral cortex

Location: Lies on the outside of the cerebellum.

Structure: contains 75% if the neuron cell bodies in the nervous system.

Structure: masses of gray matter

Function: help facilitate voluntary movement

altered activity of these nuclei neurons produces the signs of Parkinson and Huntington Disease.

Structure: flat bundles of nerve fibers that connect the hemispheres

Thalamus

Hypothalamus

Limbic System

Midbrain

Pons

Medulla Oblongata

Cerebellar cortex

Arbor Vitae

Location: between the diencephalon and pons

Function: contains main motor pathways between cerebrum and lower portions of the nervous system

Location: between midbrain and medulla oblongata.

Function: contains centers that regulate the rate and depth of breathing

. transmits ascending and descending impulses between brain and spinal cord. houses nuclei that control visceral functions:

Cardiac Center

Vasomotor Center

Respiratory Center

alters heart rate

controls vasoconstriction and vasodilation of blood vessels, helps control blood pressure

controls rate and depth of breathing

. sorts and directs sensory info. to cerebral cortex, channels sensory impulses, except sense of smell. produces awareness such as pain, touch, and temperature.

produces hormones that cause pituitary gland to secrete its hormones, regulates heart rate, body temp, sleep, wakefullness, and digestive tract.

. controls emotional experience and expression. Modifies behavior by producing feelings of fear, anger, pleasure, and sorrow.

Function: integrates sensory info about the position of body parts, coordinates skeletal muscle activity, maintains posture

Characteristics:located beneth occipital lobes of cerebrum, made up of 2 hemispheres connected by vermis, communicates through cerebellar peduncles

layer of thin gray matter that lies outside of the arbor vitae.

core of white matter that branches like a tree

Spinal Nerves (31)(8 cervical, 12 thoracic, 5 lumbar, 1 coccygeal)

Brachial Plexuses (C5-T1)

Cervical Plexuses (C1-C4)

Lumbosacral Plexuses (L1-S4)

lie on either side of neck, supply muscles and skin of neck, include phrenic nerves which controls diaphragm.

arise from lower cervical and thoracic nerves, supply muscles and ksin of arms, forearms, and hands. upper limbs, include ulnar, median, radial, and axillary nerves

arise from lower spinal cord, supply muscles of abdomen skin, external genitalia, buttocks, legs, include obturator, femoral, and sciatic nerves.

Classification of Neurons

Functional

Structural

Multipolar

Bipolar

Unipolar

interneuron

Motor neuron

Sensory Neuron

.usually unipolar, conduct impulses from PNS to CNS

.multipolar, lies within CNS, forms links between other neurons

multipolar, conduct impulses from CNS to peripheral effectors (muscles or glands)

.many dendrites and 1 axon (most are in CNS)

2 processes extending from cell body, a dendrtie and an axon, found in special senses such as eyes, ears, and nose

have 1 process extending from cell body, outside cell body it splits into 2 parts that work as 1 axon

Tissues

Neurons

Neuroglia

Structure

Function

Soma

Dendrite

Axon

Myelin sheath

cells that communicate via electrical impulses, with neurons

Function

PNS

CNS

Microglia

Oligodendrocytes

Ependymalcytes

Astrocytes

Schwann Cells

Satellite cells

support neurons, fill spaces, protect, insulate

produce cerebrospinal fluid

small cells that are phagocytes for bacterial cells and produce scar tissue in sites of injury.

form myelin sheath around axons in brain and spinal cord.

structural support for blood vessels and neurons, formation of blood

myelin producing neuroglia

protective covering around cell bodies of neurons in the PNS

conducts impulses AWAY from cell body

conducts impulses TO cell body.

cell body, contains major organelles such as nucelus

increase conduction speed of axon, contains gaps called nodes of Ranvier

Connective Tissue Coverings

Epineurium

Perineurium

Endoneurium

outer covering of a nerve (superficial)

Covering around fasicles (bundles of nerve fibers)

covering around indivigual nerve fibers (axons)

Action potential and Impulse conduction

Action potential steps

  1. Now, both inside and outside of cell are positive (depolarization
  1. when at threshold potential Na+ channels open changing charge to +30 mv (action potential)
  1. Potential changes from -70mv to -55mv.
  1. outward flow of K+ ions allow the cell to become negative again (repolarization)
  1. stimulus opens Na+ channels allowing Na to enter the cell making it less negative
  1. After repolarization, hyperpolarization occurs where potential falls to -77mv
  1. Neuron remains rested

Types of Impulse Conduction

Continous Conduction

Saltatory Conduction

  1. Finally the Na/K pump moves Na out of the cell and K back in
  1. After action potential is finished, cells return to resting potential

Occurs in unmyelinated axons, conducts impulses sequently over the entire length of their membrane

occurs in myelinated axons, myelin sheath insulates axon, impulses jump from one node of ranvier to the next.

Disorders/Diseases

Cerebroascular Accident (stroke)

Autisum (erratic behavior non communative)

Alzhimers Disease (form of dimentia with old age)

Spinal Cord Injury

Meningitis (affects meninges on brain)

Multiple Sclerosis (autoimmnune disease, damages myelin sheath

Symptoms: nausea, vomiting, severe headache

Treatment: antibiotics, medication, vaccine

Causes/Risk factors: bacterial infection, tumors, fungi

Symptoms: memory loss, confusion, mood swings

Treatment: uncruable, medication, stem cells

Causes/Risk factors: hereditary, head tramua, family history

Symptoms: severe headache, confusion/memory loss, change in alertness

Treatment: hospitlization, blood thinners, surgery,

Causes/Risk factors: blood vessels burst, diabetes, high cholestral

Causes/Risk factors: hereditary, environmental, post medical issue

Symptoms: delay in learning, anxiety, depression

Treatment: anxiety management, medication, therapy.

Symptoms: paralysis, pain, numbness

Treatment: surgery, bed rest, phys. therapy

Causes/Risk factors: direct injury, disease, assult

Causes/Risk factors: hereditary, family history

Symptoms: muscle weakness, vision loss

Treatment: steroids, phys. therapy

Drug Abuse

Methamphetamines

Alcohol

Marijuana

Cocaine

Ecstacy

LSD

Heroine

Neurotransmitter Affected: Dopamine

Neurotransmitter Affected: Serotonin

Neurotransmitter Affected: Dopamine

Neurotransmitter Affected: Dopamine

Neurotransmitter Affected: GABA

Neurotransmitter Affected: Dopamine

Neurotransmitter Affected: Serotonin

Description: heroin mimics natural opiates and binds to opiate receptors allowing dopamine to be replaced

Description: confuses receptors for serotonin and acts like serotonin

Description: Cannaboid binds to receptors which turns off the release of inhibitory neurotransmitters allowing dopamine to be released. THC mimmics this allowing dopamine to squirt through into the synapse.

Description: meth mimics dopamine which allows it to be transported into the cell using dopamine receptors. As meth is entering the cell, its removing dopamine into the cleft which allows it to bind again to the receptors, overstimulating the cell.

Description: Alcohol makes GABA receptors even more inhibitory and binds to glutamine receptors preventing glutamine from exciting the cell.

Sensation: wakefulness, and evoking a startle to unexpected stimulus.

Sensation: makes user feel fidgety and unable to be still

Sensation: sedation, and well being

Sensation: mood, sleep, perception, and appetite

Sensation: calm, relaxed

Sensation: intense pleasure and exhilaration

Sensation: affects decison making, and impulse control

Description: LSD chemically resembles serotonin and elicits its effect by binding to serotonin receptors

Description: cocaine blocks dopamine transporters that remove it from synaptic cleft which allows it to bing again and again, over stimulating the cell.

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