Please enable JavaScript.
Coggle requires JavaScript to display documents.
Nervous System - Sandra Cortez P.1 - Coggle Diagram
Nervous System - Sandra Cortez P.1
Disorders/Diseases
3. Meningitis
Causes/Risk Factors:
Bacteria or viral infection, drug allergies, fungi or parasites, chemical irritations, tumors
Symptoms:
Nausea/vomiting, sensitivity to light, fever and chills, mental status change, stiff neck, severe headache, irritation
Description:
Infection in the meninges surrounding the brain
Treatment Options:
Bacterial - hospitalization, antibiotics, medication to treat symptoms, prevention with vaccination
4. Alzheimer´s Disease
Causes/Risk Factors:
Hereditary, family history, age: over 60, high insulin levels, past head trauma
Symptoms:
memory loss, confusion & disorientation, mood & behavior changes, difficulty preforming everyday functions, unfounded suspicions, difficulty speaking, swallowing, and/or walking
Description:
A form of dementia associated with age
Treatment Options:
Uncurable, medication, removing behavior triggers, psychological coping skills, herbal therapies, stem cells
2. Cerebrovascular Accident (Stroke)
Causes/Risk Factors:
(Certain types are hereditary) blood vessel is clogged by plaque or blood clot, blood vessel bursts, diabetes, high cholesterol or increasing age
Symptoms:
Severe headache, changing in hearing, taste, touch or vision, change in alertness, loss of coordination and balance, confusion or memory loss, muscle weakness
Description:
Occurs when blood flow to a portion of the brain is halted
Treatment Options:
Hospitalization, blood clot = clot busting drugs (thrombolytics), blood thinners, surgery to open clogged vessel, surgery to repair vessels or stroke rehabilitation
5. Multiple Sclerosis
Causes/Risk Factors:
Cause not well understood, hereditary, family history, diagnosed between 20-40, nerve damage caused by inflammation, possibly viral infection, environmental factors
Symptoms:
Very depending on location and severity, muscle weakness, spasms, tremors and numbness, incontinence and frequent urination, constipation/stool leakage vision and hearing loss, depression, dizziness, fatigue, and memory loss
Description:
Autoimmune disease that damages the myelin sheath
Treatment Options:
No known cure, medications to slow disease progress, steroid treatments, physical therapy, assistive devices and healthy lifestyle choices
1. Autism
Symptoms:
Delay in learning to talk/non-communicative, repeated behaviors, anxiety, depression, an unusual attachment to objects/routines
Treatment Options:
Medication, coping skills, specialized therapy, behavioral management or anxiety management
Causes/Risk Factors:
(Cause is not well understood) hereditary, past medical issues, family history,
mostly males
Description:
Brain disorder that makes it difficult to communicate
6. Spinal Cord Trauma
Causes/Risk Factors:
Direct injury or disease, assault, fall, accident, weakened vertebral column, fluid build-up around spinal cord, most common in men ages 15-35
Symptoms:
Weakness, loss of feeling below damaged site, spastic muscles, loss of bladder & bowel control, pain and/or numbness, paralysis
Description:
Damage to the spinal cord
Treatment Options:
Completely severed spinal cord cannot be cured, medication to reduce, swelling, surgery, bed rest, spinal traction, physical therapy
Major divisions and subdivisions of the nervous system
Central nervous system (CNS)
Spinal cord
1.Brain
{ Responsible for integration of information and decision making }
Peripheral nervous system (PNS)
{ Contains sensory (afferent) and motor (efferent) divisions }
Cranial nerves arising from the brain and brain stem
Spinal nerves arising from the spinal cord
Sensory fibers connecting peripheral sensory receptors to the CNS
Somatic fibers connecting to skin and skeletal muscles
Autonomic fibers connecting to viscera
Somatic fibers connecting to skin and skeletal muscles
Sensory fibers connecting peripheral sensory receptors to the CNS
Autonomic fibers connecting to viscera
Somatic nervous system
Connects the CNS to skeletal muscles and the skin, and oversees conscious activities
Autonomic nervous system
Connects the CNS to viscera and controls subconscious activities
Compare & contrast the autonomic nervous system
Parasympathetic division
Active under normal restful conditions (rest and digest)
Long preganglionic fibers in parasympathetic division arise from the brain stem and sacral region of the spinal cord
Preganglionic neuron
Leaves the CNS and synapses w/ one or more neurons which have cell bodies in an autonomic ganglion in the PNS
Sympathetic division
Active in conditions of stress or emergency (fight or flight)
Short preganglionic fibers in the sympathetic division arise from neurons in the gray matter in the thoracic and lumbar regions of the spinal cord
A postganglionic neuron
Whose fiber (axon) leaves an autonomic ganglion and innervates a visceral effector
Controls heart rate, blood pressure, breathing rate, body temperature and helps maintain homeostasis by responding to emotional stress / preparing the body for strenuous activity
Drugs of abuse (Mouse Party)
4. Methamphetamine
Dopamine molecules are forced out, the excess dopamine in the cell causes the transporters to start working backwards actively pumping dopamine out of the cell and into the synapse. The excess dopamine becomes trapped in the synaptic cleft, it binds again & again to the receptors (overstimulating the cell)
People feel intense pleasure and exhilaration
Interferes w/ dopamine neurotransmitters
Highly addictive
works directly on the brains reward pathway
5. Alcohol
Interferes w/ GABA inhibitory & glutamate neurotransmitters
Alcohol interacts w/ GABA receptors to make them even more inhibitory, it binds to glutamate receptors, preventing the glutamate from exciting the cell
Affects memory formation
Decision making and impulse control is affected
3. Marjuana
Cannabinoid receptors turn off the release of inhibitory neurotransmitters & without inhibition dopamine can´t be released. THC mimics anandamide & binds to cannabinoid receptors, inhibition is turned off & dopamine is allowed to squirt into the synapse
Slows down movement, makes people feel calm and relaxed
Interferes w/ both inhibitory and dopamine neurotransmitters
Involved in removing unnecessary short term memories
6. Cocaine
Interferes w/ dopamine neurotransmitters
Cocaine blocks transporters, leaving dopamine trapped in the synaptic cleft, as a result dopamine binds again and again to the receptors overstimulating the cell
Concentrates in the reward pathway, active in parts that control voluntary movement
Abusers are fidgety and unable to stay still
2. Ecstasy
Interferes w/ serotonin neurotransmitters
Serotonin receptors become confused & start to work backward, the transporter starts transporting serotonin out of the cell, and that excess serotonin is trapped in the synaptic cleft. Binding again & again to receptors - overstimulating the cell
Affects serotonin pathways / indirectly interacts w/ the reward pathway
Feel an increase in appetite, perception is altered, you feel moody and not tired
7.LSD
Excite locus cocruleus (LC)
Interferes w/ serotonin neurotransmitters
Interacts w/ particular receptors, but not always in the same way. Sometimes LSD may inhibit them and sometimes it may excite them, this is one reason why LSD has complex sensory effects.
People feel awake, have startled responses and unexpected stimulus
1. Heroine
Mimics natural opiates, binding to opiate receptors turning off dopamine inhibition. Dopamine is allowed to flood the synapse, producing immediate feelings of sedation and well being
Feel sedated and calm
Interferes w/ both inhibitory and dopamine neurotransmitters
Opiates are natural painkillers
Major parts and functions of the spinal cord
Cervical enlargement
A thickened area near top of the spinal cord
Provides nerves to upper limbs
Lumbar enlargement
A thickened region near the bottom of the spinal cord
Gives rise to nerves that serve the lower limbs
Cauda equina (horse´s tail)
Structure formed where spinal cord tapers to a point inferiorly
Consists of spinal nerves in the lumbar and sacral areas
{ Beginning at the base of the brain the spinal cord consists of 31 segments, each of which connects to a pair of spinal nerves }
Connective Tissue Coverings
The brain and spinal cord are surrounded by three membranes called ¨meninges¨ that lie between the skull bones, vertebrae, and the soft CNS tissues
Dura mater
Outermost layer of meninges
Made up of tough dense connective tissue (is very thick)
The sheath around the spinal cord is separated from the vertebrae by an epidural space
Arachnoid mater
The middle layer of meninges
Between the arachnoid and pia mater is the subarachnoid space which contains cerebrospinal fluid (CSF)
Pia mater
The innermost layer of meninges
Cranial nerves
12 pairs of cranial nerves arise from the underside of the brain
Most are mixed nerves, containing sensory and motor nerve fibers, but some are only sensory, and others are primarily motor
The first pair arises from from the cerebrum, and the second pair from the thalamus but most arise from the brainstem
The 12 pairs are designed by # and name the numbers are in order, from superior to inferior
Major parts and functions of the brain
a)
Cerebrum:
largest portion associated w/ higher mental functions and sensory/motor functions
b)
Diencephalon:
processes sensory input and controls many homeostatic processes
c)
Cerebellum:
coordinates muscular activity
d)
Brainstem:
coordinates and regulates visceral activities, and connects different parts of the nervous system
[Anterior parietal lobe]
cutaneous senses
[Posterior occipital lobe]
visual area
[Posterior temporal lobe]
auditory area
[Base of central sulcus and insula]
taste area
[Deep in temporal lobe]
smell area
Wernicke´s area:
(temporal lobe) helps with understanding written and spoken language
Broca´s motor speech area:
(frontal lobe) controls muscle movements for speech
e)
Thalamus:
sorts and directs sensory information, channels all sensory impulses and produces general awareness
f)
Hypothalamus:
maintains homeostasis by regulating a wide variety of visceral activities and by linking the endocrine system w/ the nervous system
g)
The brain-stem:
connects the cerebrum, diencephalon and cerebellum to the spinal cord
Spinal nerves
31 pairs of spinal nerves arise from spinal cord, all except the first pair are mixed nerves, grouped according to the level from which they arise
Numbered in sequence:
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 arises from two roots; a sensory dorsal root, and a motor ventral root
Each dorsal dorsal root contains a dorsal root ganglion which houses the cell bodies of sensory neurons entering the spinal cord
A ventral root & dorsal root unite to form a spinal nerve which extends out of the vertebral canal through the inter-vertebral foramen
Tissues
Neurons
Cell body (soma)
contains major organelles including nucelus
Dendrites
conduct impulses toward the cell body; they are short and branching, and they provide the receptive surface for communication w/ other neurons
A neuron contains a cell body, tubular cytoplasm-filled dendrites, and a tubular cytoplasm-filled axon
Axon
conducts impulses away from the cell body; it arises from a thickening extending from the cell body called the axon hillock (there is only one axon in each neuron)
Neuroglia
Cells that support neurons
Functions: fill spaces, structurally support, protect and insulate neurons (do not generate or conduct nerve impulses)
Peripheral nervous system
Schwann cells:
the myelin-producing neuroglia of the PNS
Satellite cells:
provide protective coating around cell bodies of neurons in the PNS
Central nervous system
Microglia:
small cells that function as phagocytes for bacterial cells and cellular debris, and produce scar tissue in sites of injury
Oligodendrocytes:
form the myelin sheath around around axons in the brain and spinal cord
Ependymal cells:
produce cerebrospinal fluid in CNS
Astrocytes:
lie between blood vessels and neurons, functions are structural support and the formation of the blood-brain barrier, which protects brain tissue from chemical fluctuation and prevents entry of many substances
Reflex arc (major parts & functions)
c) Inter-neuron
Description:
Dendrite, cell body, and axon of a neuron within the brain or spinal cord
Function:
Caries information from sensory neuron to motor neuron
d) Motor neuron
Description:
Dendrite, cell body and axon of a motor neuron
Function:
Carries instructions from brain or spinal cord out to effector
b) Sensory neuron
Description:
Dendrite, cell body, and axon of a sensory neuron
Function:
Carries information from receptor into brain or spinal cord
e) Effector
Function:
Respond to stimulation or inhibition by motor neuron and produces reflex or behavioral action
Description:
Muscle or gland
a) Receptors
Description:
Receptor end of a dendrite or a specialized receptor cell in a sensory organ
Function:
Senses specific type of external or internal change
Action potential & the Nerve Impulse
Action potential
Reaching action potential is all-or-none response
It occurs when the change reaches -55 mV
Action potential either occurs or does not
Action potentials of a neuron are all of the same strength
[Repolarization]
returns the polarized state and is accomplished by outward flow of potassium ions through potassium channels
[Depolarization]
change from negative to positive charge inside a neuron, the inside and outside would now both be positive
[Hyperpolarization]
at the end of repolarization a slight overshoot occurs in which potential dips below -70 mV
Nerve impulse
An action potential at the trigger zone cause an electrical current to flow to adjacent regions of the axon´s membrane
Sodium channels in the trigger zone of the axon open
Sodium ions diffuse inward, depolarizing the axon membrane
Threshold stimulus is received
Potassium channels in the axon membrane open
Neuron membrane maintains resting potential
Potassium ions diffuse outward, repolarizing the axon membrane
The resulting action potential causes a local electric current that stimulates the adjacent portions of the axon membrane
A series of action potentials occur along the axon
Saltatory conduction
Occurs in myelinated axons, the myelin sheath insulates axons from ion movement across the cell membrane, impulses ¨jump¨ from one Node of Ranvier to the next since sodium and potassium channels occur only @ the nodes
Continuous conduction
Occurs in unmyelinated axons and conduct impulses sequentially over the entire length of the membrane
Neurotransmitters
{ The chemical messengers in a synapse that convey an electrical impulse from a neuron to another cell, there are more than 100 }
Include...acetylcholine,amino acids, neuropeptides but their action depends on the type of receptors in a specific synapse
(Monoamines) Norepinephrine
CNS:
Creates a sense of feeling good; low levels may lead to depression
PNS:
May excite or inhibit autonomic nervous system actions, depending on receptors
Dopamine
CNS:
Creates a sense of feeling good; deficiency in some brain areas is associated w/ Parkinson Disease
PNS:
Limited actions in autonomic nervous system; may excite or inhibit, depending on receptors
Serotonin
CNS:
Primarily inhibitory; leads to sleepiness; action is blocked by LSD, enhanced by selective serotonin re-uptake inhibitor drugs (SSRIS)
Acetylcholine
CNS:
Controls skeletal muscle actions
PNS:
Stimulates skeletal muscle contraction at neuromuscular junctions: may excite or inhibit autonomic nervous system actions, depending on receptors
Histamine
CNS:
Release in hypothalamus promotes alertness
Classification of neurons
Inter-neurons (association/intern-uncial):
multi polar neurons lying within the CNS that form links between other neurons, the cell bodies of some inter-neurons aggregate in specialized masses called nuclei
Motor (efferent):
multi-polar neurons that conduct impulses from the CNS to peripheral effectors (muscles or glands)
Sensory (afferent):
conduct impulses from peripheral receptors to the CNS, usually uni-polar although some are bi-polar
Functional classification
Structural classification
Multi-polar neurons:
have many dendrites and one axon arising from their cell bodies; most neurons w/ cell bodies in the CNS (inter-neurons and motor neurons) are multi-polar
Uni-polar
have only one; outside the cell body, it soon splits into two parts that function as one axon. The peripheral process has dendrites near a peripheral body part, and the central process runs into the CNS. The cell bodies are found in ganglia outside the CNS, these are sensory neurons
Bi-polar:
have two processes extending from the cell body, a dendrite and an axon found in some of the special senses such as the eyes, nose and ears
:star:
Major functions of the nervous system
Major aspects
b) Integration and processing (decision making)
Coordination of sensory information in the CNS
Processing of this information is the basis for decision making
c) Motor output (response)
Nerve impulses (CNS) are conducted along motor neurons to effectors
Effectors are muscle or glands that respond to decisions made in the CNS
a) Sensory input
Provided by sensory receptors that detect internal or external changes
Information travels from receptors to sensory neurons which transport information into the CNS