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