Brain and Spinal Cord
cranial and spinal nerves
- Cranial nerves 12
- Spinal nerves 31
- Pathways: afferent(ascending) sensory carry nerve impulses form sensory spots torward the CNS.
- Efferent: (descending)- motor carry sway from brain and spinal cord
Cells of the NS:
- Neuron: single unit it has dendrites- receptor arms of the neuron
- axon: delivery arm of the neuron
2. Glia- supportive cell to neurons create the myeline sheaths
- Cell body soma: evaluate/process mainly in the cns.
- Dendrite: receive, receptive portion of the neuron
- Axon: carries nerve impulses away from the cell body, one per neuron
Action potential begins here,
insulated layer of wrapped lipids, higher speed of conduction.
Neurons functional classifications'
- Sensory: afferent to the CNS
- Associational: interneurons sensory to motor
- Motor: Away from CNS to effector organ Efferent
Jelly bean producer in CNS make myelin.
Myelin in the PNS
make choroid plexus produce C.S. fluid= oxygen fuel(glucose)
Make B.B.B. blood brain barrier that filtrates circulating blood from the extracellular fluid in the CNS system, it is formed by capillary endothelial cells, which are connected by ight junctions
macrophage that lives in the CNS. Phagocytose only immunological cells allowed in the brain.
tight web of astrocytes around the brain capillaries that for the bbb. Selectivity only certain things can get in your brain.
- neurons generate and conduct electrical impulses by changing the electrochemistry of their membranes AP.
- -influence other nearby neurons and cells by the release of chemicals neurotransmitters.
inside of the cell high in K outside of the cell high in NA++
it goes from high to low through facilitated transport of NA++ in the cell.
Facilitated transporter of K out of the cell
is when everything has to get moved back to where it was ATP so K in and Na++ out.
Region between adjacent neurons synapse cleft, impulses are transmitted across the synapse by neurotransmitters. ACH first neurotrasnmitters acytocholine
- protective membranes surrounding the brain and spinal cord.
- Dura mater: external responsible for keeping in the cerebrospinal fluid
- Arachnoid: csf circulates through here
- Pia mater: thin fibrous tissue enclose csf it allows blood vessels to nourish the brain , when this gets inflamed it is called meningitis.
Produced by the choroid plexus(ependymal cells) within the ventricles, reabsorbed through the arachnoid villi, hydrocephalis is too much csf
- external cerebral cortex is Gray thinking ability to change
- Internal: White matter
- External: white matter/conduction
- Internal:Grey matter/thinking/evaluate
Functions of the brain:Temporal
temporal lobe: behavioral, hearing, memory,speech,vision
blood pressure, breathing, consciousness, heartbeat, swallowing
some say marry money but my brother says big brains matter most
- 1.afferent neuron
- 3.efferent neuron
- Sensory nerves enter spine through the back(dorsal)- motor comes out front (Ventril)
- 8 cervical
- =31 paired spinal nerves
Dorsal nerve route:
afferent sensation= sensory(dermatomes)-skin
Ventral nerve root:
efferent motor control(myotomes)-muscle
- involuntary control;
- sympathetic: flight or fight
- parasympathetic: rest
Flight or fight
- accelerates HR
- constricts smooth muscle-gut
- dilates blood vessel to skeletal muscles
- dilation of pupils
- increases epinephrine, sweat and slows down digestion parapalsis
- slows HB
- increases peristalsis
- increases secretion of digestive enzymes
Voluntary control of the motor nerves
Nerve injury and regeneration:
- -limited to myelinated axons
- -PNS schwann cells heal better
- -oligodendrocytes- is to provide support and insulation to axons in the CNS
Wallerian degeneration: PNS
process of healing
Nonciceptive: western medicine lidocaine
- A. somatic(joints, muscles)
- B.Visceral(organs tumors obstructions)
- Anti anxiety
- A. centeral or PNS
- B.peripheral neuropathies(DM/GB diseases)
Good Pain:Endorphins, encephalin, dynorphin
endorphisn, stimulate opiod receptor inhibit transmission of pain impulses in the spinals cord and brain by binding to mu
less potent but more potent than morphine
generally inhibits pain signals but can also incite pain.
Nociceptors: free nerve ending
- in skin, muscle, joints, arteries, viscera that respond to chemical, mechanical and thermal stimuli.
- Delta:touch, vibrations, thermal, and pain
Pain pathway: Injury, Transduction, Transmission, Perception, Modulation
- 2.nociceptor-prostagadins,kinins b.small c fiber(sending message) unmylenated
- 3.Transmission a.interneuron
- 4.Perception(grey matter) a. cerebral cortex
- 5.Modulation a. take sway pain decreased transmission opiod receptors >endorphins,serotonin,NE
Gate control: Pain
- Small C fibers-pain( diffuse,burning,aching) open the pain gate
- Large A fibers: touch, vibration or thermal inhibition of pain( close the gate)
is an increased sensitivity to pain
Pain without stimulation
- hypothalamus, exogenous pyrogens viruses
- Endogenous pyrogens: produced by phagocytic leukocytes which induces fever
Elevated body temperature due to failed thermoregulation that occurs when a body produces or absorbs more heat than it dissipates
rare inherited muscle disorder by inhaled anesthetics
Sleep: REM and Non-REM
- Rapid eye movement 20-25% of sleep time
- EEG pattern-awake-very active brain occurs every 90 min.
- NON-REM- 75-80% of sleep time initiate when inhibitory signals are released from the hypothalamus- higher parasympathetic tone 4 stages
obstructive sleep apnea syndrome:
Patterns of complete or partial blockage of the upper airway during sleep
Nocturnal paroxysmal dyspnea
attacks of severe shortness of breath
Vestibular Nystamus shaky eyes eyeball movement overstimulated of the semicircular canals
diffulculty with language, expressing onself when speaking,trouble understanding speech, and difficulty with reading or writing due to stroke
4 categories of Aphasia: Anomic/Amnesia:
least pathological, dementia, difficulty in using the correct names for particular objects, people, places, or events
- cant express but yes understand, difficulty in conveying thoughts through speech or writing, A. unilateral- patho/loss of verbal but express in writitng
- B. bilateral-loss of verbal and writing expression
Receptive Aphasia: Wernicke's
- express yes but understand no difficulty understanding spoken or written language
- A. unilateral: speak yes cant understand verbal but can understand written
- B. bilateral speak yes-cant understand both
to both broccas and wrenickes
state of awakeness mediated by the reticular activating system
Decoticate position :
severe brain damage rigidity with adduction and flexion of the arms with the wrists and fingers flexed on the chest, the legs are stiffly extended and internally rotated with plantar flexion of the feet.
rigidity with the arms adducted and extended with the wrist pronated and the fingers flexed, the legs are also stiffly extended with plantar flexion of the feet. damage to the upper brainstem.