Nerve cells and Connections 2 Flashcards
What systems are in the PNS
Autonomic nervous system and Somatic Nervous system
What systems are in the Autonomic Nervous System
Sympathetic, Parasympathetic and Enteric
What are Gyrus and Sulcus
lumps and bumps of the brain
What is the cerebellum and what is the purposeof it
smaller part at the back of the brain and it does motor control
where is the cerebrum
the larger part at the back of the brain
what does the frontal lobe control
speech and movement
what does the temporal lobe do
controls hearing
what does the parietal lobe do
somatic sensory cortex –> sensation
what does the occipital lobe do
involves in vision
difference between thalamus and hypothalamus
thalamus is where most sensory inputs go
hypothalamus is the control of basic function
what does the presynaptic terminal do
releases neurotransmitter into the synaptic cleft
what do neurotransmitters do after diffusing into the synaptic cleft
it will bind onto the receptors of the target cell or bind onto other neurons
what are the types of neurons
bipolar, pseudounipolar, multipolar and anaxonic
bipolar and pseudounipolar are classed as what type of neurons
afferent (sensory) neurons
multipolar and anaxonic are classed as what types of nerons
interneurons
describe the difference in multipolar neurons in interneurons and motor neurons
in interneurons, there is a large number of dendrites, to receieve inputs from a large number of neurons
in motor neurons, they have long axons so they can get to their target
what do astrocytes do
maintain external environment for the neurons
how do astrocytes maintain external environment for the neurons
regulating the water and potassium concentrations in the intracellular fluid
what are oilgodendrocytes
they form myelin sheaths on many axons in the CNS
what are microglia
immune cells (hoover up infections)
what do ependymal cells do
produce the cerebrospinal fluid that protects the brain
what are the glia cells in the PNS
schwann cells and satellite cells
what do schwann cells do
forms myelin sheaths on ONE axon
what do satellite cells do
support neuron cell bodies
what are the three types of potentials
resting, graded and action
what do action potentials do
transmit electrical signals over long distances
what do graded potentials do
decide when an action potential should be fires - by depolarizing the cell to threshold
what does the resting membrane potential do
keeps cell ready to respond
what is a potential difference
the difference of charge between inside and outside the cell
how does a resting membrane potential happen
when the electrical gradient is equal and opposite to the concentration gradient - equilibrium is reached
what is the charge of the resting membrane potential for a typical neuron
-70mV
charges of potassium, sodium and chlorine inside and outside of a cell
K+ - 150, 5
Na+ - 15, 150
Cl- - 10, 110
what voltage does the cell have to reach to fire an action potential
-55mV
where do end plate potentials happen
NMJ
where do generator potentials happen
at the sensory receptors
where do postsynaptic potentials happed
at synapses (at the end - after the diffusion of the neurotransmitter from the presynaptic cleft)
what are the 4 types of graded potentials
generator, postsynaptic, end plate and pacemaker
what does it mean if graded potentials are decremental
electrical signal become smaller as they travel along the axon
what are the characteristics of graded potentials
they are decremental (decay as they travel)
they can summate (be added together)
hyperpolarizing or depolarizing (can excite or inhibit a cell)
what channels can you open/close to depolarize the cell
the opening of sodium channels and closing of potassium channels
what channels can you close/open to hyperpolarize the cell
the opening of potassium channels and the opening of chloride channels and the closing of sodium channels
what types of channels are used for fast IPSPs and EPSPs
integral ion channels
what kind of receptors are used for fast IPSPs and EPSPs
ionotropic receptors
what kind of receptors are used for slow IPSPs and EPSPs
G-coupled proteins - metabotropic receptors
why are metabotropic receptors slow
G-protein is used and it takes them a while to find the potassium channels to open/close them
in fast EPSPs what type of channel is used
non-specific monovalent cation channel (+1)
what is the difference between temporal and spatial summation
temporal involves in single presynaptic neuron rapid fire signal
spatial involves multiple presynaptic neurons simultaneously
what does it mean if the permeability is high/low
high - a lot of channels are open
low - few channels are open
what is the term called when a cell absolutely cannot generate another action potential
the refractory period
what is an axial resistance
when electrical current flows more easily down a large diameter axon than a small axon
what is saltory conduction
action potentials spread passively from node to node and still reach threshold
what is Guillain-Barré syndrome
demyelination in the PNS
the largest type of axons to the smallest
A-alpha, A-Beta, A-gamma, A-???, C
where does the NMJ synapse
between a motor neuron and skeletal muscle
what is a the skeletal muscle membrane called
sarcolemma
what triggers the diffusion of ACh in the NMJ
the opening of voltage-gated calcium channels in the presynaptic terminals
ACh diffuses across the NMJ synaptic cleft and binds to what
ACh (nicotinic) receptors
what is the enzyme that breaks down acetylcholine after an end plate potential happens
acetycholinesterase
what is the most common excitatory neurotransmitter
glutamate
most common inhibitory neurotransmitter in the brain
GABA
most common inhibitory neurotransmitter in the spinal cord
glycine
all the classes of neurotransmitter in the CNS
amines, amino acids, peptides, purines and gases
axo-somatic synapses are usually …
inhibitory
axo-dendric synapses are usually …
excitatory
how do polysynaptic reflexes differ from a monosynaptic reflexes
instead of sensory neurons directly synapsing onto the motor neuron, they synapes on interneurons
what do interneurons do
they influence the behaviour of the motor neurons
muscle spindle (stretch) reflex is an example of what type of reflex
monosynaptic reflex
what is the bulk of the muscle called
extrafusal muscle
what is the purpose of the muscle spindle (stretch) reflex
to keep you muscles the same length
what does it mean if a neuron is tonically active
its always firing action potentials
when muscles get stretched, what happens to the rate of action potential
it increases
scenario: what happens to your muscle when you get more load on you biceps
when your arm goes down a bit, that’s when your muscles are being stretched, which causes more firing of action potential to bring the extrafusal muscle back to original length
muscle spindle (stretch) reflex is what type of feedback
negative
how are extrafusal fibers innervated
by alpha motor neurons
how are intrafusal fibers innervated
by gamma motor neurons
what is the purpose of the golgi tendon organ
a mechanism to ensure that excessive tension does not damage the cell
what type of reflex does the golgi tendon organ use
polysynaptic
what is the nociceptor known for
detecting a damaging or potentially damaging stimuli
what does the flexion (and crossed extensor) reflex do
a mechanism to remove a limb from a damaging/potentially damaging stimuli, and not fall over
in flexion (and crossed extensor) reflex, what type of receptors detect the stimulus
nociceptors
what is the purpose of the basal ganglia
it details the exact movements
what does dopeminergic mean
the neurons release are dopamine
what happens if there is an over activity of dopaminergic neurons
schizophrenia
what does L-DOPA do
its to treat patients with Parkinson’s disease
how does L-DOPA treat parkinson’s disease
L-DOPA can cross the blood-brain barrier and then it gets converted into dopamine which will then stimulate dopaminergic pathways
what is the fiber that comes before the ganglion in the autonomic nervous system
preganglionic fiber
what is the fiber that comes after the ganglion in the autonomic nervous system
postganglionic fiber
what can the postganglionic fibers innervate
skeletal muscle, cardiac muscle, glands and GI neurons
NMJ is in what system
somatic nervous system
what are the bumps called on the postganglionic fibers
variscosities
where are the neurotransmitter release in the ANS
interstitial fluid
what is the sympathetic nervous system used for
fight or flight
what is the parasympathetic nervous system used for
rest and digest
what receptors does acetylcholine act on
cholinergic, nicotinic and muscarinic receptors
what receptors does noradrenalin act on
adrenergic, alpha and beta receptors
