Azucena Soto, period 5, Nervous system
Major parts and functions of the brain
Major divisions and subdivisions of the nervous system (sub of CNS and PNS)
It goes from the CNS to the PNS which is then divided into the Sensory and motor Division, the motor division is then broken down to the somatic NS and the Autonomic NS, the Autonomic NS is then broken down into the sympathetic and parasympathetic divisions
Tissues (structure and function of neurons and neuroglia
classification of neurons
Connective tissue coverings
Major parts and functions of the nervous system
action potential and the nerve impulse
Cranial nerves
spinal nerves
neurotransmitters
Compare & contrast the autonomic nervous system
Reflex arc (major parts and functions)
Disorders/ diseases
Drugs of abuse (Mouse Party)
Major parts and functions of the spinal cord
-Heroine-
Interferes with: dopamine
Effect on neurotransmitter: release of inhibitory neurotransmitters to shut down, dopamine does not release, also binds to opiate receptors.
Affect in person : Causes person to feel immediately sedated and well, affects pain signals and stress response.
-Ecstasy-
Interferes with: serotonin
Effect on neurotransmitter: serotonin transporters take up ecstasy instead of serotonin, serotonin goes out and transporter now does opposite job of what they need to do
Affect in person's mood: becomes addictive, changes brains chemistry, change in appetite and illusions.
(overstimulates the cell)
-Marijuana-
Interferes with: dopamine
Effect on neurotransmitter: THC (the active chemical in marijuana) turns off inhibition, causing dopamine to squirt into the synapse.
Affect on person: This drug causes a feeling of "high" and increases a persons appetite, alters their senses and creates a relaxed feeling.
-Methamphetamine-
Neurotransmitter it interferes with: dopamine
Effect on neurotransmitter:
Instead of dopamine being taken into the cell, meth is. It then enters the dopamine receptors and causes the transporters to start working in reverse. (cell is now overstimulated)
Effect on a person:
This drug becomes addictive, makes a person feel a lot of pleasure and exhilaration.
-Alcohol-
Neurotransmitters it interferes with:
inhibitory neurotransmitters of GABA and glutamate
Effect on neurotransmitters: it causes GABA receptors to be more inhibitory and prevents glutamate from exiting the cell.
Effect on person:
Alcohol effects areas of the brain that focus on memory formation, decision-making and impulse control. A person can feel more relaxed, but is now prone to have aggressive outbursts.
-Cocaine-
Neurotransmitter it interferes with: dopamine
Effect on neurotransmitters: cocaine blocks dopamine transporters, making dopamine bind again and again (overstimulates the cell)
Effect on person: causes a person to be fidgety, can not stay still (affects part of brain that controls voluntary movement)
-LSD-
Neurotransmitter it interferes with: seretonin
Affect on neurotransmitters: Drug binds itself to seretonin receptors, reacts differently can either inhibit or excite receptors.
Effect on person: Has complete sensory effects, can lead to paranoia, hallucinations, increased heart rate and more.
Cerebrovascular Accident (stroke):
Occurs when blood flow to a portion of the brain is halted
Cor RF:
-Diabetes
-High Cholesterol
-Increasing age
Symptoms:
-Severe Headache
-Confusion/ memory loss
-loss of coordination
Treatment:
-Hospitalization
-surgery to repair vessels
-Stroke rehabilitation
(most deaths occur in the EW)
Autism :
Brain disorder that makes it difficult to communicate.
C or RF:
-Causes not understood well
-Family history
-Hereditary
Symptoms: - delay in learning to talk
-anxiety
-repetitive behaviors
Treatment options:
medication
-coping skills
-specialized therapy
(increase of 11.3 from year 2000 to 2008)
-Alzheimer’s disease-
a form of dementia associated with age
C or RF :
-age over 60
-past head trauma
-Hereditary
symptoms
-memory loss
-confusion and disorientation
-unfounded suspicions
treatment options
-incurable
-medication
-stem cells
Spinal cord injury
Damage to the spinal cord
C or RF
-Direct injury/disease
-Assault, fall, accident
-weakened vertebral column
symptoms
-weakness
-loss of bladder / bowel control
-paralysis
treatment options
-surgery
-bed rest
-spinal traction
-physical therapy
(primary cause: motor vehicle accidents)
-Meningitis-
Infection in the meninges surrounding the brain
C or RF
-tumors
-fungi or -parasites
-drug allergies
symptoms:
Nausea/vomiting
stiff neck
irritation
Treatment options
-preventative with vaccination
-antibiotics
-medication to treat symptoms
-Multiple Sclerosis-
Autoimmune disease that damages the myelin sheath
C or RF
-cause not well understood
-family history
-Nerve damage caused by inflammation
Symptoms:
-vary depending on location and severity
-constipation and stool leakage
-memory loss
Treatment
-No known cure
-Assistive devices
-healthy lifestyle choices
(It is most prevalent in NA, especially the U.S., Greenland and in Canada.
I - Olfactory nerves: S
-nerves of smell
-fibers synapse in olfactory bulbs
-Pathway: terminates in primary olfactory cortex
-Purely olfactory function
II- Optic nerves: S
-Arise from retinas, a brain tract
-Pass through optic canals, coverage and partially cross over at OPTIC CHIASMA
-Synapse in Thalamus
-Optic radiation fibers run to occipital (visual) cortex
III-Oculomotor nerves
-Fibers extend from ventral midbrain through superior orbital fissures to 4/6 eye muscles (extrinsic)
-Function: raising eyelid, directing eyeball, constricting iris (parasympathetic), and control of lenses shape
IV- Trochlear nerves: M
-fibers from dorsal midbrain enter orbits via superior orbital fissures to innervate superior oblique muscle
-Primarily motor nerve that directs eyeball
V- trigeminal nerves: S
-Largest of these nerves, from pons to face
-(3 divisions) Ophthalmic, passes through superior orbital fissure, Maxillary,passes through foramen rotundum, Mandibular, passes through foramen ovale
-convey sensory impulses from areas of face, supply motor fibers for mastication
VI- Abducens: M
-from inferior pons, enter orbit via superior orbital fissures
-innervates lateral rectus muscle
VII- Facial: S
-fibers from pons travel to lateral aspect of face
-chief motor nerves of face, have five major branches
-M functions: facial expression, parasympathetic impulse to lacrimal and salivary glands
-s functions: taste from anterior two-thirds of tongue
VIII- Vestibulococlear: S
-Afferent fibers from hearing receptors (cochlear division), and equillibrium receptors (vestibular division) pass from inner ear and travel to enter the brain stem and pons-medulla border
-Mostly sensory function, small motor component for adjustment of sensitivity of reveptors
(was a auditory nerve)
IX- Glossopharyneal nerves
-fibers from medulla that leave the skull and run to the throat
-M functions: innervate part of tongue and pharynx for swallowing and provide parasympathetic fibers to parotid salivary glands.
-S functions: fibers conduct tate and general sensory impulses from pharynx and posterior tongue, impulses from carotid chemoreceptors and baroreceptors
X- Vagues
-only type of these nerves that extend beyond head and neck region
-fibers from medulla exit skull via jugular foramen
-most M fobers= parasympathetic that help regulate activities of heart, lungs and abdominal viscera
-S fibers: carry impulses from thoracic and abdominal viscera, barroreceptors, chemoreceptors and taste buds (posterior tongue and pharynx) .
XI-Accessory
-formed from ventral roolets from C1 to C5 region of spinal cord not brain
-rootlets pass through cranium via each foramen magnum
-exit skull via jugular foramina to innervate trapezius and sternoclenomastoid muscles
(were spinal cord accessory nerve)
XII- Hypoglossal
-Fibers from medulla exit skull via hypoglossal canal
-Innervate extrinsic and intrinsic muscles of tongue which contribute to swallowing and speech
The meninges
-Function:
- cover and protect CNS
- Protect blood vessels and enclose venous sinuses
- Contain CSF
- Form partitions in skull
-3 layers -
(external to internal)
1.dura mater (strongest)
2.arachnoid mater(spider web like extensions, separated by dura through subdural space, contains largest blood vessels and CSF)
3.pia mater (delicate, clings to brain, many tiny blood vessels that feed brain)
Adult brains: 4 regions
- Cerebral hemispheres (cerebrum)
- Diencephalon
- Brain stem, consisting of:
-Midbrain
-Pons
-Medulla - Cerebellum
Gray matter: short nonmyelinated neurons and cell bodies
White matter: myelinated and nonmyelinated axons
Parts: ventricles, cerebral aqueduct ,Gyri (bumps), sulci, fissures
Lobes: frontal, parietal, temporal, occipital, insula
Motor areas:
-primary motor cortex
-premotor cortex
-Broca's area (anterior to inferior premotor area)
-Frontal eye field; within anterior to promotor cortex, superior to Broca's
(brain is connected to the spinal cord via the brain stem)
Functions of the brain: Controls
-thought
-memory
-emotion
-all senses
-motor skills
-breathing
-Temperature (homeostasis)
-hunger
-all processes that regulate the body
(NS= master @ controlling and communicating system)
Three overlapping functions:
Sensory input: info gathered by sensory receptors about internal and external changes
Integration
Processing and interpretation of sensory input
Motor output:
activation of effector organs (muscle and glands) produce response
2 principal parts:
CNS: brain and Sc, integration and control center, directs sensory output
PNS: everything outside PNS, mainly of nerves that extend from brain and SC
CNS-PNS-Sensory division, motor division-somatic NS, autonomic NS-Sympathetic division, parasympathetic divisions
Job: transmit signals between brain and rest of body
"Language of the NS"
(only 50 + have been identified)
-most neurons make 2+ neurotransmitters
they are usually released at different stimulation frequencies
classified by: chemical structure and function
Acetylcholine: released @ NMJ, synthesized from acetic acid and choline by enzyme choline acetyltransferase
Dopamine: NE and E, made from amino acid tyrosine
Serotonin: made from the amino acid tryptophan
Histamine: made from amino acid histidine
Neurotransmitters:variety of functions
Effects: excitatory vs inhibitory, determined by receptors to which it binds, can be depolarizing or hyperpolarizing
Actions: direct vs indirect, direct= neurotransmitter binds directly to and opens channels
indirect=neurotransmitter acts through intracellular second messengers
Begins at the foramen magnum, ends in L1 or L2 vertebra
(cervical, thoracic, lumbar and sacral)
(contains spinal nerves part of PNS, attached by 31 paired roots)
+cervical and lumbosacral enlargements, nerves serving upper and lower limbs
Function:
- provides 2 way communication to and from brain and body
- major reflex center, reflexes are initiated and completed here
(protected by bone, meninges and CSF) - Terminates in conus medullaris
Divided into 2 parts
-Ventral (anterior) median fissure
-Dorsal (posterior) median sulcus
grey mater @ core, white outside, has central canal that runs through it
Horns:
Dorsal ( receive somatic and visceral sensory input)
Ventral (some interneurons, somatic motor neurons)
Lateral (only in thoracic and superior lumbar regions), sympathetic
-gray commisure-: bridge of gray matter, connect masses of gray matter, no matter what side
Roots:
-Ventral (bundle of motor neuron axons, exit spinal cord)
-Dorsal (sensory input to cord)
-Dorsal root (spinal) ganglia: cell bodies of sensory neurons
(spinal nerves: cause by fusion of dorsal and ventral roots)
-Major parts-
Stimulus
- receptor
- Sensory neuron
- Integration center
- motor neuron
- effector
Response
Function: maintain a balance and stable position, respond accordingly to body changes. (protect body from everything unplanned or that can cause harm)
Are formed by fusion of dorsal and ventral roots
-Part of PNS
-attach to SC by 31 paired roots
-Each spinal cord segment is designated by paired spinal nerves that arise from it
-directly interact to SC, modulate motor and sensory info from the body
Neuroglia: Nervous tissue, 2 principal cell types
Neuroglia (glial cells): small cells, surround and wrap delicate neurons
Neurons (nerve cells): excitable cells, transmit electrical signal
(4 main that support CNS)
Astrocytes: support and brace neurons, guide migration of young neurons
Microglial cells: touch and monitor neurons, migrate to injured neurons
Ependymal: range in shape, line central cavities of brain and spinal column
oligodendrocytes: processes wrap CNS nerve fibers, form myelin sheaths
(2 of PNS)
Satellite: surround neuron cell bodies, function alike as astrocytes
Schwann: surround peripheral nerve fibers, form myelin sheaths in thicker fibers.
Neurons: nerve cells, structural units of NS
-large, specialized cells, primarly conduct impulses
Characteristics:
-extreme longevity (last's a person's lifetime)
-Amitotic, few exceptions
-High metabolic rate: requires continuous supply of oxygen and glucose
(ALL HAVE CELL BODY = 1+ processes)
(neuron cell body = perikaryon or soma)
-Neuron processes:
CNS, contains both neuron cell bodies and processes
PNS, contains chiefly neuron processes
Action potentials
(generated by 4 steps: resting (all channels closed) depolarization(Na+ channels open), repolarization (Na+ channels inactivating, k+ channels open) and hyperpolarization (some K+ channels remain open, Na+ channels reset) )
Long distance signals of axons, it is the principal way that neurons send signals, long distance neural communication (only in muscle cells and axons of neurons
(do not decay over distance as graded potentials do, also known as nerve impulse)
+involves opening specific voltage gated channels
Nerve impulse: a signal that travels along a nerve fiber due to a stimulus, from receptor to effector) (through myelin sheaths)
CNS- Brain and SC, integrative and control centers (contains medulla, pons, cerebellum, midbrain and diencephalon + cerebral hemisphere
PNS- Contains cranial nerves and spinal nerves, communication lines between the CNS and the rest of the body
PNS:
1st divison
Sensory (afferent):
-somatic and visceral sensory nerve fibers
-conducts impulses from receptors to the CNS
Motor(efferent):
-Motor nerve fibers
-conducts impulses from the CNS to effectors: muscles and glands
Motor:
2 division
Somatic NS: voluntary motor nerve fibers, conducts impulses from the CNS to skeletal muscles
Autonomic NS: involuntary (visceral) motor nerve fibers, conducts impulses from CNS to cardiac muscle, smooth muscle and glands
Autonomic NS:
3 division
Sympathetic division: mobilizes body systems during activity
Parasympathetic: Conserves energy, promotes house keeping functions during relaxation
Three types of neurons groups by direction which nerve impulses travel to CNS
Sensory:
Transmits impulses from sensory receptors to CNS
99% almost all unipolar
Cell bodies: located in ganglia @ PNS
Motor:
-impulses from CNS to effectors
multipolar
most cell bodies located in CNS
Interneurons/ association neurons:
between motor and sensory
shutter signals through CNS pathways
most entirely in CNS
most of body ate interneurons
-Both have motor fibers, but are different in:
-effectors:
SNS = innervates skeletal muscles
ANS= innervates cardiac muscle, smooth and glands
-efferent pathways
SNS= cell body is in CNS, thick myelinated group, axon extends in spinal or cranial nerves (directly to SK muscles)
ANS = uses a 2 neuorn chain
Preganglionic: cell body in CNS is thin
Postganglionic= body synapses with preganglionic axon
-target neuroresponses to neurotransmitters
(overlap in function)