lecture 6: chemical & electrical signal transformation Flashcards
neurons are specialized and terminally differentiated _______ cells
- sensory:
- motor:
- interneurons:
epithelial cells
- afferent
- efferent
- integration/coordination
cellular organs:
- condensed, lost replicative functions, no centriole
- protein/peptide synthesis
- lipid synthesis
- modification of synthesized protein/peptide and lipid for sorting
- degrade metabolic wastes
- power plant
- neurofilaments, unique shape
- nucleus
- rough ER/ nissl body
- smooth ER
- golgi apparatus
- lysosome and peroxisome
- mitochondria
- cytoskeletal structures
what is a nissl body?
helps with protein synthesis in the rough ER
What is neuron reception and summation of signals?
reception: 1st step in communication, dendrites catch neurotransmitters
summation: neurons sum up all signals received (inhibitory & excitatory)
MOST neurons have only ______ axon, may or may not be ________
Neurons can have _____ of axon terminals
one; myelinated
hundreds
What are enzymes for neurotransmitter synthesis and activation:
Mitochondria, lysosome/peroxisome
Where axon form and extending out, the initiation of AP:
hillock
What is unique about pseudounipolar neurons:
initiation of action potential by peripheral process (touch, pressure, temp.)
Neuron axons form synapses with ______ cells through _______
The release of neurotransmitters = transformation from _________ to _______
target; terminals
electrical to chemical
Which neuron in the cerebellar cortex is the only one providing afferent axons to other brain structures and which neurotransmitter does it release?
Purkinje cell; GABA
Types of Neurons:
1. multiple dendrites from the soma:
2. dendrites mainly on one end of the soma:
3. one hillock with dendrites on the axon
4. one hillock then divides the axon into 2 branches
- multipolar
- bipolar
- unipolar
- pseudounipolar
Where are MOST of the sensory neurons?
pseudounipolar
Neurons: dendrites = limited cellular organs like axons but have ______ extension
Golgi apparatus
Transportation of molecules in the neurons —> rapid delivery = _______
(a) anterograde transportation:
(b) retrograde transportation:
active transportation
(a): from soma to dendrites/axons
(b): from dendrites/axons back to soma
Transportation of Molecules in the Neurons:
_________ elongating unidirectional to the plus direction (+)
_______ can be either way ( + or -) but only to the terminal in the axon
Tubulins
Dendrites
Transportation of Molecules in the Neurons:
Golgi apparatus extension directly delivers the ______ proteins in the tip
Differentiation of dendrites and axons:
tubulin
dendrites: both directions (+/-)
axons: uniform only (+) direction
Kinesin =
Dynein =
anterograde transportion
retrograde transportation (die*)
Which transportation can be hijacked by virus and bacterial toxins:
retrograde transporttaion, dynein
Is neuron cellular membrane is selectively permeable?
yes - allows some molecules to pass through while blocking others
- Facilitate the transport of water molecules; maintain water balance________
ion channels: _____ or ______
ion pumps:
water channel: aquaporin
leaking or gated
Na/K, atp dependent
The ion pumps consists of _______ and _____ dependent
Na+ (sodium) and K+ potassium); ATP
The polarity of the neuron cell membrane
-Osmotic:
-Electric:
Inside the neuron cellular membrane is more ______ due to the 2 potentials: _____ to _____, rest membrane potential
numbers of ions and molecules- related to movement of water
positive and negative charges- electrical potential for signaling
negative; -40 to -90 mV
Which cellular organs are located in the axons?
Mitochondria, lysosomes/peroxisomes, and enzymes
Ligand-gated: Lignad as _________, ion channel as _________ –> change in _________ potential
Voltage-gated: resting membrane potential increased to the _______ no ______ needed. Only opens when membrane potential ________
Modality gated: open or close based receptors such as:
neurotransmitters; receptors; membrane
threshold; ligand; reaches threshold
touch, pressure, heat, cold, light, sound wave
K+ can freely move cross membrane through _______ channel and is in charge of _______ membrane potential: polarized
leaking
resting
List the 5 phases of initiation of AP:
resting potential
slow depolarization/graded potential
fast depolarization/ action potential
repolarization
hyperpolarization
-70 mV =
> -70mV, ligand/modality gated Na+ =
> -55mV, threshold, voltage gated Na+
back to -70mV, voltage gated K+ and pumps
resting potential
slow depolarization/graded potential
fast depolarization/action potential
Hyperpolarization
Is the following statement True or False?
The voltage-gated sodium channels 2 gates open and close separately at different phases this means that both gates can close at the same time.
false; BOTH gates CANNOT close at the same time
Resting state =
AG:
IAG:
below threshold
closed
open
Activated state =
AG:
IAG:
fast depolarization
both gates are open
Inactivated state =
AG:
IAG:
repolarization + hyperpolarization
open
closed
Which proteins oversee anterograde and retrograde transportation along the axons separately?
Anterograde: kinesin
Retrograde: dynein
Is the following statement True or False? During the absolute refractory period, voltage-gated sodium channel APs will respond to any stimulus.
False: APs WILL NOT respond to any stimulus no matter how strong
Why can APs be induced in the relative refractory period but not in the absolute refractory period?
The IAG is engaged/closed during the absolute refractory period but is open in the relative.
_______ defines unidirectional conduction of APs by preventing immediate re-excitation
Refractory period