Exam 3 (Neuro and EENT) Flashcards
Efferent
Motor.
Send signals from CNS to effector organs
Afferent
Sensory.
Sends signals to CNS
Visceral stimuli
Internal organs and mucosal surfaces
Sensory stimuli
External sources.
Like touching a hot stove
Somatic nervous system
Conscious, voluntary, controlled function.
Direct connection from CNS to skeletal muscle (no ganglia).
Myelinated
Autonomic nervous system
Automatic.
Unconscious, involuntary, regulatory functions.
Broken up into sympathetic and parasympathetic
Cholinergic and adrenergic neurons innervate various target organs.
Preganglionc neurons
Cell body originates in CNS from brainstem or spinal cord.
Form synaptic connection in ganglia.
Myelinated
Postganglionic neurons
Cell body begins in ganglia.
Ends on effector organ.
Nonmyelinated.
Ganglia
Synaptic relay station between neurons.
Sympathetic nervous system
Fight or flight.
Release energy.
Sympathetic nervous system neuron lengths
Short preganglionic and long postganglionic.
Is sympathetic or parasympathetic considered a complete system
Sympathetic
Sympathetic nervous system effects
Pupil dilation through contraction of iris radial.
Bronchiole dilation.
Secretion of epinephrine and norepinephrine.
Relaxation of detrusor, contraction of trigone and sphincter in bladder.
Blood vessels of skeletal muscle dilate.
Increased HR.
Thick secretion from salivary glands.
Decreased GI motility
Parasympathetic nervous system
Rest and digest.
Conserves energy.
Parasympathetic neuron lengths
Long preganglionic and short post ganglionic.
Where do parasympathetic neurons originate
Cranial nerves III, VII, IX, X, and sacral region of spinal chord.
Where do sympathetic neurons originate
Thoracic and lumbar regions (T1-L2)
Parasympathetic effects
Pupil contracts from contraction of iris sphincter.
Bronchioles constrict.
Detrusor contracts, trigone and sphincter relax of bladder.
Increased GI motility.
Decreased HR.
Watery secretion from salivary glands.
Production of tears
Glutamate
Most common excitatory neurotransmitter in the brain.
GABA
Major inhibitory neurotransmitter in the brain.
Uses Cl ligand gated channels to devrease cAMP and increase K channels
Glutamate and GABA relationship
Most and least excitatory neurotransmitters.
Balance each other
Epinephrine and norepinephrine receptors
alpha and beta adrenergic receptors
Dopamine receptors
D receptors
Serotonin receptor
5-HT receptors
GABA receptor
NMDA, AMPA
Acetylecholine receptors
Nicotinic and muscarinic cholinergic receptors
Glutamate receptor
NMDA, AMPA,mGLuR
Endorphin receptors
Opioid receptors
What are good drug targets
enzymes
Cholinergic nerve fibers in preganglionic autonomic neurons
Release ACh taht binds to nicotinic receptors
Cholinergic nerve fibers in somatic motor neurons
Release ACh whcih binds to nicotinic receptors on skeletal muscle cell.
Cholinergic fibers in parasympathetic postgalnglionic neurons
Release ACh that binds to muscarinic R
Adrenergic Nerve fibers
Release NE from sympathetic postganglionic neurons to adrenergic receptors on effector organ cells.
What releases epinephrine (a catecholamine) into blood
Adrenal medulla
Types of cholinergic receptors
Nicotinic and muscarinic
Nicotinic receptor
Ligand gated.
Ion channel
Faster than muscarinic
Ionotropic
Muscarinic receptors
G protein-coupled receptor.
Uses second messsenger system.
Slower than cholinergic
Matabotropic
Adrenergic receptor
On effector organs of sympathetic system.
G-protein coupled receptors
Uses secondary messenger system
Metabotropic.
Botulinum toxin
Block release of ACh.
Actions of acetylcholine
SLUDGE
Salivation
Lacrimation
Urination
Deification/diaphoresis
GI
Emesis
Acetylcholineesterase (AChE)
Breaks down ACh
What does nicotinic receptors bind to
Nicotine, ACh.
Weakly to muscarine
Three functionally characterized muscarinic receptors
M1 - on gastric parietal cells
M2 - cardiac cells and smooth muscle
M3 - on bladder , exocrine glands, and smppthe muscles
What does muscarinic receptors bind to
muscarine and ACh
Weak affinity for nicotine
Direct acting cholinergic agonists
ACh itself.
Little specificity
Quickly broken down
Not much clinical use
Indiract acting cholinergic agonists
AChE inhibitors.
Prevent ACh breakdown thus increasing ACh concentration
Antimuscarinics
Cholinergic antagonist that is selective for muscarinic receptors. (ex. Atropine)
Ganglionic blockers
Cholinergic antagonist that prefers nicotinic receptors, limited clinical use
Neuromuscular blocking agents
Cholinergic antagonist, mostly nicotinic antagonists that interrupt efferent impulses to skeletal muscles.
Used in surgery
Synthesis of epinephrine
Tyrosine –> DOPA –> Dopamine –> Norepinephrine –> Epinephrine
What is the rate limiting step of the creation of epinephrine
Hydoxylation of tyrosine by tyrosine hydroxylase
Reserpine
Stops the carrier system that transports dopamine into the synaptic vesicles to be treansformed into NE
COMT, MAO-
matabolize NE
Soma
Neuron cell body
Neurite
Process extending from cell body of neuron
Dendrite
Receives impulses from other neurons
Axon
carries action potentials away from soma
how many cranial nerves`
12 pairs
How many spinal nerves
31 pairs
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Cerebrum job
Generate motor function.
Process info.
Higher order thinking
Cerebellum job
equilibrium
coordination
muscle tone
achieve motor learning tasks.
Brainstem jobs
Flow of info between cerebrum and spinal chord.
Breathing,
Consciousness.
BP.
HR.
Sleep.
Cortex of brain
gray matter surface of brain
Gyri
Folds of brain
Sulci
Fissures of brain
Interneurons
In the gray matter of the spinal chord.
Translate between afferent and efferent nerves
White matter
Axons
Gray matter
cell bodies
What column of spinal chord is only sensory
Dorsal column
What column of spinal chord is both sensory and motor
Ventral and lateral
Three extracellular fluid compartments of CNS
Inside vascular system (blood plasma).
Between neural and glial cells (interstitial fluid).
In ventricular system and subarachnoid space (CSF)
Why is regulation of brain fluids important
Increased pressure leads to decreased perfusion.
Increased pressure can cause herniation.
Ionic environments effects neuronal firing.
Where does CSF come from
Derived from blood plasma.
Continuously secreted by choroid plexus.
Exits fourth ventricle into subarachnoid space and drains into venous system through arachnod granulations.
Functions of CSF
Protection
Homeostasis
Waste removal
Choroid Plexus
Network of blood vessels in each ventricle.
Made of pia mater CT and epithelial cells.
Filters blood plasma to make CSF.
Tight junctions to maintain blood-CSF barrier.
Similar to plasma but less protein
Where on the spine is a lumbar puncture done
Between L3 and L4
Blood brain barrier (BBB)
Highly selective semipermeable border of endothelial cells.
Small lipophilic substances can go through.
Glucose enters through facilitated diffusion with GLUT-1 protein
Things that can disrupt BBB
Hypertension
Hyperosmolality
Microwaves
Radiation
Infection
Trauma
Unipolar neuron
one neurite
Bipolar neuron
Two neurites
Multipolar neurons
Three or more neurites
Golgi Type I
Longer axon.
Connect different parts of system.
In pyramidal cells of cerebral cortex, motor cells of spinal chord
Golgi type II
Shorter axon.
In local v
Glial cells
Support cells that provide nutrients and energy to neurons.
10x more glial cells than neurons in brain.
Ependymal cells, astrocytes, microglia, and myelinating glia (oligodendrocytes and schwann cells)
Ependymal cells
Ciliated epithelial glial cells.
Line ventricles/central canal.
Produce CSF
Astrocytes
Glial cell that maintains BBB.
Provides structural scaffold for neurons.
Stores glycogen and provides neurons with lactate for energy.
Maintains stable K in brain.
Removes neurotransmitters from extracellular fluid.
Microglia
Glial cell that functions like macrophage in immune respnse of the brain
Oligodendrocyte
Glial cell that produces myelin sheaths in the CNS.
Myelinate multiple neurons
Schwann cell
Glial cell that produces myelin sheaths in the PNS.
Only myelinate one axon
necrosis
Cell lysis and inflammation usually a rapid process.
Seen in acute trauma or stroke
Apoptosis
Programmed cell death that does not cause inflammation
Gliosis
Proliferation of astrocytes secondary to CNS injury (scarring).
Long term effect of stroke, MS, Alzheimer’s
Gliosis
Scar tissue in brain
Generation of action potential steps
- Threshold met.
- Na channels open and Na goes into cell (depolarization).
- K channels open and K goes out of cell (repolarization).
- Voltage drops below resting potential (Hyperpolarization)
Glycine
Most common inhibitory neurotransmitter in the spinal cord.
Binds to Cl- ligand gated channels
Serotonin
Important in limbic function
Chatecholamines
Function as neurotransmitters and hormones.
Dopamine
Epinephrine
Norepinephrine
What releases norepinephrine
postganglionic neurons of sympathetic nervous system
Mu opiod receptor
Bind to beta endorphins causing inhibition of substance P protein (pain protein). Also inhibiting the release of GABA which results in excess dopamine
What are the attributes of stimulus
MILD
Modality (taste, smell touch, vision, hearing)
Intensity
Location
Duration
Merkel’s disk
Sense steady pressure.
Slowly adapting