Nerves 1-5 Flashcards
What are the 4 lobes of thee brain ?
Frontal, temporal, parietal and occipital
The spinal cord is __ surrounded by ___ ?
Grey mater and white mater
What Glial cell maintains the homeostasis of the environment and surrounds blood vessels ?
Astrocytes
What glial cell poduces the blood brain barrier ?
Astrocytes
What glial cells act as hoovers ?
Microglia
What glial cells form myelin sheaths ?
Oligodendrocytes
How many cervical vertebrae ?
7
How many thoracic vertebrae ?
12
How many lumbar vertebrae ?
5
How many sacral vertebrae ?
5
What are the names for the grooves and the folds of the brain ?
Grooves: Sulcus
Folds: Gyrus
Where in the brain is the thalamus and the hypothalamus found ?
Diencephalon at the top of the brainstem
What are the three components of the top of the brain stem from superior to inferior ?
Mid brain
pons
Medulla Oblongata
What is the name for the mini brain found at the back of the cerebrum ?
Cerebellum
What kind of neuron detects things in the environment ?
Afferent neurons
What kind of neurons decide what to do with the info from the environment ?
Inter neurons
What kind of neurons send the signal to carry out the request ?
Efferent neurons
What part of the neuron receives information ?
Dendrites
Which part of the neuon triggers the action potential ?
Initial segment
Which part of the neuron sends the action potential ?
The axon
Which part of the neuron releases the neurotransmitter ?
Axon (pre-synaptic terminals)
Inter-neurons are found in the ____ nervous system
Central
Afferent and efferent neurons are found in the _____ nervous system
Peripheral
Describe the ionic basis of the resting membrane potential
The leaky potassium channels constantly leaking positive charge out of the cell is what maintains the cell’s -70mV charge
What is the figure for resting membrane potential ?
-70mV
What does the resting membrane potential do ?
Keeps the cell ready to respond
Define the equilibrium potential
The membrane potential at which the concentration gradient is exactly equal and opposite to the concentration gradient
What equation deals with the equilibrium potential of single ion species ?
Nernst equation
What equation deals with the equilibrium potential of multiple ion species ?
Goldman equation
What does the nernst equation state that the RMP should be ?
-90mV
Why is the RMP closer to -70mV than -90mV ?
There are other leaky channels (Na, Cl and Ca)
Action potentials send signals over ___ distances
Long
What are four examples of graded potentials ?
1: Post synaptic potentials
2: Generator potentials
3: End-plate potentials
4: Pacemaker potentials
What kind of potential is found at a sensory receptor?
Generator potential
What kind of potential is found at a synapse ?
Post-synaptic potential
What kind of potential is found at the NMJ ?
End-plate potential
What kind of potential is found within pacemaker cells ?
Pacemaker potential
Graded potentials are useful over ___ distances
Short
Graded potentials are propogated/non-propogated ?
Non-propogated
What increases the amplitude of graded potentials ?
Increased signal stimulus
What kind of potential can both excite and inhibit a cell ?
Graded potential
How is a fast IPSP generated ?
By opening chlorine channels and hyperpolarising the cell (Cl into cell)
How are slow IPSPs generated ?
By opening more Potassium channels and making the inside of the cell more negative (K into cell)
How are fast EPSPs generated ?
By opening channels so that Na can enter the cell depolarising the cell
How are slow EPSPs generated ?
Closing Potassium channels and allowing a positive charge to build up in the cell
How are postsynaptic potentials produced ?
By a neurotransmitter binding to a ligand-gated channel
What is synaptic integration and what does this mean for graded potentials ?
Where many synapses (inhibitory and excitatory) synapse onto one neuron and can add up to inhibit or excite that neuron.
Graded potentials can summate therefore this gives them a larger input meaning stronger potential which can reach threshold
In order for an action potential to happen it must reach a ____ , which is around ___mV
Threshold
55mV
What is the rapid depolarizing phase of an action potential due to ?
Influx of Na ions into the cell
What is the rapid re-polarization phase of an action potential due to ?
rush of potassium out of the cell
Action potentials are encoded by their ____ where as graded potentials are encoded by their____
Frequency
Amplitude
Action potentials are mediated by what kind of ion channel ?
Voltage gated ion channel
What kind of potential has a refractory period and what kind doesn’t ?
Action Potential: Refractory period
Graded potential: No refractory period
What forms myelin sheaths in the PNS ?
Schwann cells
What forms myelin sheaths in the CNS ?
Oligodendrocytes
The gaps in the myelin sheaths are called ?
Nodes of ranvier
What triggers the pre-synaptic voltage gated Ca channels to open ?
Action potential in the motor neuron
What kind of receptors does the Ach bind onto on the post synaptic cleft ? what does this generate ?
Nicotinic receptors
Local graded potential due to opening of Na and K ligand gated channels
What removes Ach from the synaptic cleft ?
Acetylcholinesterase
What is the mechanism of action of Tetrodotoxin ?
Blocks Na channels therefore blocks action potential generation
What is the mechanism of action of Joro spider toxin ?
Blocks Ca channel in pre-synaptic cleft therefore no Ach vesicles generated
What is the mechanism of action of Botulinum toxin ?
Blocks machinery that generates Ach vesicles so neurotransmitter not released
What is the mechanism of action of Curare ?
Blocks Ach receptors therefore no end-plate potential
What is the mechanism of action of Anticholinesterase ?
Stops the breakdown of Ach therefore increased transmission at NMJ
The synapses in the CNS have a range of post synaptic potentials, true or false ?
True
IPSPs and EPSPs fast and slow
