NEURO PHYSIO Flashcards
AXON TERMINAL to SOMA (CELL BODY)
Recycles synaptic vesicle membrane for lysosomal degradation
Retrograde Axonal Transport
What do you call the death of the axon distal to the site of injury after an axon is transected?
ANTEROGRADE/ORTHOGRADE DEGENERATION
What do you call the changes to the soma after an axon is transected?
AXONAL REACTION/ CHROMATOLYSIS
Axonal regeneration occurs better in the CNs or PNS?
PNS
Used by a neuron to communicate with another neuron across a SYNAPSE
Maybe excitatory, inhibitory or both
NUEROTRANSMITTERS
Secreted by neurons in many areas:
- LARGE PYRAMIDAL CELLS IN MOTOR CORTEX
- BASAL GANGLIA (NUCLEUS BASALIS OF MEYNERT)
- SKELETAL MUSCLES
- ALL PREGANGLIONIC NEURONS OF ANS
- POSTGANGLIONIC NEURONS OF PARASYMPATHETIC NS
- SOME POSTGANGLIONIC NEURONS OF SYMPATHETIC NS
ACETYLCHOLINE
Synthesis: uses ACETYL COA and CHOLINE
Enzyme: CHOLINE ACETYLTRANSFERASE
Degradation: produces ACETATE and CHOLINE
Enzyme: ACETYLCHOLINESTERASE
CHOLINE is recycled
Is deficient in ALZHEIMER’s DISEASE
Acetylcholine (Ach)
Found mainly in the SUBSTANTIA NIGRA PARS COMPACTA AND VENTRAL SEGMENTAL AREA
Dopamine
Degraded by MAO (IN PRESYNAPTIC NERVE TERMINALS), COMT (IN TISSUES INCLUDING LIVER)
Dopamine
Dopamine deficiency
PARKINSON’s DISEASE
Dopamine excess
SCHIZOPHRENIA
Secreted by many neurons: BRAIN STEM HYPOTHALAMUS LOCUS CERULEUS IN THE PONS POSTGANGLIONIC NEURONS OF SYMPATHETIC NS
Norepinephrine and Epinephrine
Control overall activity and mood of the mind, such as increasing the level of WAKEFULNESS
may be EXCITATORY or INHIBITORY
NE and Epi acts on ADRENERGIC RECEPTORS
NE and Epi
ILOCUS NORte
LOCUS ceruleus = NORepinephrine
Phenylalanine derivatives
“PARE, TRUE LOVE DOES NOT EXIST to ME”
Phenylalanine Tyrosine L-Dopa Dopamine NE Epinephrine Thyroxine Melanin
Tryptophan derivatives
“TRIP MO SYA NOH?”
Tryptophan
Melatonin
Serotonin
Niacin
Secred mainly by the MEDIAN RAPHE OF THE BRAIN STEM
Serotonin
Inhibitor of pain pathways in the spinal cord
Serotonin
“happy hormone”
Low levels seen in clinical depression
Serotonin
From Tryptophan (W)
Serotonin
In the pineal gland, it is converted to MELATONIN
Serotonin
Serotonin
“Si MRS mahilig sa Dark na Tsokolate”
Median Raphe: Serotonin
converted to Melatonin (Dark)
comes from Tryptophan
Secreted in areas of the brain responsible for long term behavior and memory
Nitric Oxide
From Arginine
Nitric Oxide
Short acting inhibitory neurotransmitter
Nitric Oxide
Differences from other NTs:
not performed and stored in vesicles
- synthesized almost instantly as needed
- PERMEANT GAS THAT DIFFUSES TOWARDS ITS TARGET CELL
Nitric Oxide
From Histidine
HISTAMINE
Located mainly within the TUBEROMAMMILLARY NUCLEUS OF THE HYPOTHALAMUS
Histamine
Involved in control of AROUSAL, SLEEP AND CIRCADIAN RHYTHM
Histamine
INHIBITORY nuerotransmitter usually found in SPINAL INTERNEURONS
GLYCINE
Increases CHLORIDE INFLUX
GLYCINE
The number one INHIBITORY neurotransmitter in the brain (spiny neurons of striatum, Purkinje cells of cerebellum)
GABA
Comes from GLUTAMATE
GABA
Increases chloride influx (GABAs) or Potassium Efflux (GABAs)
GABA
The number one EXCITATORY neurotransmitter in the brain
GLUTAMATE
ENKEPHALINS, ENDORPHINS, DYNORPHINS
OPIOID PEPTIDES
Inhibit neurons in the brain involved in the perception of pain
OPIOID PEPTIDES
In specific areas of the BRAIN, PRIMARY SENSORY NEURONS, GI PLEXUS NEURONS
SUBSTANCE P
Involved in pain transmission
Substance P
SOMA (CELL BODY) to AXON TERMINAL
Replenishes synaptic vesicles and enzymes for NT synthesis
Anterograde Axonal Transport
Potential difference that exist across the membrane
Resting Membrane Potential
Exhibited by ALMOST ALL CELLS
Resting Membrane Potential
By convention, refers to the INTRAcellular charge
Resting Membrane Potential
Typically -70mV
Resting Membrane potential
Caused by:
NERNST POTENTIAL FOR Na and K DIFFUSION
Na-K LEAK CHANNELS OR K LEAK CHANNELS
Na-K-ATPase (-4mV)
Resting Membrane Potential
Exhibited by EXCITABLE CELLS ONLY
Action Potential
Basis for RMP and AP
Ion channels
Opening of Na-activation gates that causes SODIUM INFLUX
DEPOLARIZATION
Closure of Na-Inactivation gates that STOPS SODIUM INFLUX
REPOLARIZATION
Opening of potassium gates that CAUSES POTASSIUM EFFLUX
REPOLARIZATION
SODIUM CHANNEL BLOCKERS OF NEURONS
TETRADOTOXIN (puffer fish)
SAXITOXIN (red-tide)
POTASSIUM CHANNEL BLOCKER OF NEURONS
TETRAETHYLAMMONIUM
What stimulates nerve depolarization in the first place?
MECHANICAL DISTRUBANCE, CHEMICALS, ELECTRICITY
Time periods in an action potential during which a new stimulus cannot be readily elicited
REFRACTORY PERIOD
Another action potential cannot be elicited no matter how large the stimulus
ABSOLUTE REFRACTORY PERIOD
Coincides with almost the entire duration of e action potential
ABSOLUTE REFRACTORY PERIOD
Inactivation gates of the Na channel are closed when the membrane potential is depolarized and remain closed until repolarization occurs
IONIC BASIS OF ABSOLUTE REFRACTORY PERIOD
NO ACTION POTENTIAL CAN OCCUR UNTIL THE Na-INACTIVATION GATES OPEN
IONIC BASIS OF ABSOLUTE REFRACTORY PERIOD
Begins at the end of the absolute refractory perriod and continues until the membrane potential returns to the resting level
RELATIVE REFRACTORY PERIOD
Action potential can be elicited ONLY IF A LARGER THAN USUAL INWARD CURRENT IS PROVIDED
RELATIVE REFRACTORY PERIOD
During RRP, K+ conductase is elevated (opposes depolarization
IONIC BASIS OF RELATIVE REFRACTORY PERIOD
Membrane potential is closer to the K+ equilibrium potential and farther from threshold
IONIC BASIS OF RRP
MORE INWARD CURRENT is required to bring the membrane to threshold
IONIC BASIS OF RRP
When a cell is depolarized so SLOWLY such that the THRESHOLD POTENTIAL IS PASSES WITHOUT FIRING AN ACTION POTENTIAL
ACCOMODATION
In an excitable cell such as the heart muscle, what is the effect of hyperkalemia and hypokalemia respectively?
HYPERKALEMIA - depolarizes the ❤️
HYPOKALEMIA- hyperpolarizes the ❤️
Synaptic inputs that depolarize the postsynaptic cell
EXCITATORY POST-SYNAPTIC POTENTIAL
Synaptic inouts that hyperpolarize the post-synaptic cell
INHIBITORY POST-SYNAPTIC POTENTIAL
Two or more presynaptic inputs arrive at postsynaptic cell simultaneously
SPATIAL SUMMATION
Two or more presynaptic inputs arrive at postsynaptic cell in rapid succession
TEMPORARY SUMMATION
Repeate stimulation causes response of postsynaptic cell to be greater than expected
NERVE FACILITATION
Increase released of NT and increased sensitivity to the NT
LONG-TERM POTENTIATION
Repeated stimulation causes decreases response of postsynpatic cell
SYNAPTIC FATIGUE
Some sensory signals need to be transmitted at different speeds (slow or fast)
NERVE FIBERS
Type A nerve fibers VS Type C nerve fibers
Thicker
More myelinated
Faster
Which is more powerful in creating new memories (takes precedence over the other)
PUNISHMENT AND FEAR - powerful
PLEASURE AND REWARD
Regulate activity of many physiological processes including heart rate, blood pressure, body core temperature and blood levels of hormones
BIOLOGICAL CLOCK
MASTE CLOCK of all biological clocks in the human body
Suprachiasmatic Nucleus (SCN)
Neurons retain synchronized, rhythmical firing patterns even though they are isolated from the rest of the brain
Suprachiasmatic Nucleus (SCN)
Destuction causes loss of circasian functions
Suprachiasmatic Nucleus (SCN)
REGULATES circadian rhythms
Pineal gland
Secretes a hormone MELATONIN that is synthesized by SEROTONIN
Pineal gland
Increased during darkness
Melatonin
Inhibited by daylight
Melatonin
Controlled by sympathetic nerve activity, which is regulated by light signals from the retina
Melatonin
Recording of neuronal electrical activity
EEG
Important diagnostic tool in clinicak neurology
EEG
Awake
Eyes closed (8-13Hz)
RELAX STATE
ALOHA WAVES
Awake
Eyes open (13-30Hz)
ALERT STATE
BETA WAVES
Brain disorders and degenerative brain states (4-7Hz)
THETA WAVES
Deep sleep, organic brain disease, infants (0.5-4Hz)
DELTA WAVE
Total amount of CSF in the brain
150ml
Amount of CSF produced per day
500ml
Function of CSF
CUSHIONING
CSF PATHWAY
Lateral ventricles Foramen of Monroe Third ventricle Aqueduct of Sylvius, fourth ventricle Foramen of Magendie (1) and Luschka (2) Subarachnoid space over the brain and spinal cord Arachnoid granulations Dural venous sinus blood