Flashcards in Neurology Deck (38):
What are the FOUR STEPS that occur when ACTION POTENTIAL arrives at the synaptic knob?
1) AP arrives @ synaptic knob —> Ca2+ Voltage gated channels open —> Ca2+ enters synaptic knob.
2) Ca2+ causes Neurotransmitter to be expelled from synaptic knob.
3) Secretory vesicles binds to pre-synaptic membrane & Neurotransmitter expelled into synaptic cleft.
4) Neurotransmitter can bind to ligand-gated ion channel on post synaptic membrane & allow depolarization of another neuron.
What is the MOA for a benzodiazepine?
Benzodiazepine’s are positive allosteric modulator’s for GABA receptors —> bind to receptor site on Cl- channels and potentiates binding and effects of GABA (Increases intracellular Cl- concentration leading to hyperpolarization of cell.)
What do oligodendrocytes do?
Wrap around thicker neurons in CNS to form the myelin sheath.
What are Schwann cells? What do they do?
Surround nerve fibers in the PNS and form myelin sheaths around the thicker nerve fibers.
***vital in regeneration of damaged peripheral nerve fibers
What is graded potential?
Changes in membrane potential that are propagated in a graded & decremental fashion.
What are the steps of graded potential?
1) Neurotransmitter binds to Receptors on ligand gated channel. (Na+)
2) Na+ ions enter neuron, causes cell to become more POSITIVE(+) around axon hillock
3) Once axon hillock meets threshold of -60mV an action potential will be generated.
What is an action potential?
Propogated changes in membrane potential that affect the entire excited membrane.
****Think “all or none” “Point of no return”
What are the steps of action potential?
1) Resting state - all gated Na+/K+ channels are closed.
2) Depolarization - local currents depolarize the axon membrane, voltage gated sodium channels open & Na+ rushes in leading to depolarization.
3) Repolarization - Na+ channels are inactivating & K+ channels open.
4) Hyperpolarization - Some K+ channels remain open, Na+ channels reset. Na+/K+ pump returns cell to resting membrane potential.
What are mechanoreceptors?
Mechanoreceptors detect physical alteration such as in cell membrane including compression, bending, and stretching.
What are baroreceptors?
Baroreceptors detect stretch or recoil in elastic walls. Usually found in elastic tissue and distend-able organs.
What are chemoreceptors?
Chemoreceptors detect and respond to chemical changes. (Think blood alkalinity)
What are nociceptors?
Response/detect inflammation/cell damage & generates a sense of pain.
What are thermoreceptors?
Detect a change in temperature.
What are photoreceptors?
Detect changes in light (found in eyes)
Your Efferent PNS sends sensory info (like internal and external environment) to CNS.
True or false?
False; Afferent PNS sends sensory info TO THE CNS.
Somatic- outside world/temp/touch/pressure.
Visceral- organs & internal.
Your Efferent Somatic nervous system consists of you Parasympathetic/sympathetic nervous systems. True or False?
False; Efferent Somatic is skeletal muscle. Both voluntary/involuntary.
Your Efferent Autonomic nervous system holds your parasympathetic/sympathetic nervous system. What do the Parasympathetic/sympathetic NS control?
Cardiac Muscle, smooth muscle, glands. (EVERYTHING YOU DO NOT CONTROL)
Your Efferent nervous system is responsible for relaying signals from the CNS (effector) usually in the form of motor responses. True or False?
What are the 3 types of synapses?
Neuron to neuron
What are the two ways in which neurons communicate?
1) chemical synapse - NT released into synaptic cleft
2) electrical synapse - Gap junctions
What does the Frontal Lobe do?
- primary motor cortex
- personality & emotions
- voluntary control of skeletal muscle
-Speech (Broca’s area)
What does the Parietal lobe do?
-sensory motor cortex
-conscious perception of sensory info
What does the Temporal lobe do?
What does the occipital lobe do?
-recognize visual stimuli (color, form, movement)
What does the Thalamus do?
-relay sensory info to cerebral cortex
-relay motor impulses brown cerebellum/cerebrum
-plays a role in learning/memory
What does the hypothalamus do?
-Autonomic NS control center (flee, fight, feed, fuck)
-regulated body temp, sex drive (hormones)
-H2O balance & thirst
-endocrine system functions
-produces ADH & oxytocin
What does the cerebellum do?
-maintains balance & posture
-allows smooth coordination of movements
—> ataxia: disturbed balance.
What does the midbrain do?
-Reticular activating system (awake/asleep)
-depressed by drugs
-visual/auditory reflex center
What does the Pons do?
Helps relay info from PNS to cerebrum + cerebellum
What does the medulla oblongata do?
-Makes alligators ornery, cuz mama said so.
-control HR, Blood valve diameter, RR, vomiting/cough center
Layers from Spinal cord out.
Spinal cord to the...
Subarachnoid space to the...
Arachnoid matter to the...
Subdural space to the...
Dura matter to the...
What are the three meninges?
Duramater: outermost layer attached to inner surface of the skull.
Arachnoid Mater: middle layer between dura/pia
Pia Mater: softest layer, contains BV and layer clings to brain.
What is an ionotropic mechanism?
Neurotransmitter binds to receptor on ion channel and allows ions to enter cell.
What is a metabotropic mechanism?
NT (1st messenger) binds to GCPR; G protein coupled with receptor causes a cascade of reactions and generates a second messenger that affects cell activity.
Excitatory neurotransmitters are different from inhibitory neurotransmitters how?
Excitatory: more POSITIVE charges go into cell. Cell ‘gets excited’
Inhibitory: more NEGATIVE charges go into cell. Cell doesn’t wanna party.
What are the two types of cholinergic receptors?
Nicotinic and muscarinic (CIGARETTES AND MUSCLES)
What neurotransmitter is associated with cholinergic receptors?