Nervous System Flashcards
What is the name of the cell body of a neuron?
soma
What is the function of sensory neurons?
detect changes in external and internal environment (CNS and PNS, light, sound, odours, touch
What is the function of motor neurons?
- controls muscle contraction and also gland secretion (CNS and PNS)
What is the functions of interneurons?
- lie entirely within the CNS and are involved in cognition (i.e.,perceiving, learning, remembering and executive functioning such as decision making)
What is a multipolar neuron?
neuron with one axon and many dendrites attached to its soma
what is a bipolar neuron?
neuron with one axon and many dendrites attached to its soma
what is a unipolar neuron?
neuron with one axon attached to its soma; the axon divides, with one branch receiving sensory information and the other sending the information into the central nervous system.
what are astrocytes?
Type of glial cell. The support cells imbetween neurons
what do astrocytes do?
- Provide physical support to neurons
- Provide nourishment
- When neurons die they clean up debris and form scar tissue
- Control chemical composition of fluid surrounding neurons
what are Oligodendrocytes
cells that support axons and produce myelin sheath, in the CNS - they wrap around several adjacent axons
what are nodes of Ranvier?
the parts of neurons not covered by myelin sheaths
what are schwann cells?
Found in PNS, single Schwann cell wrapped around the PNS axon (kinda myelin sheath for PNS)
What is the name for the weakest part pf the blood-brain barrier?
area postrema
where is the area postrema located?
the medulla
which neuron plays the inhibitory role in the role of inhibition?
the interneuron
what is a membrane potential?
electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell.
what is the resting potential of a neuron?
-70mV
what is depolarisation?
reduction of negative charge (toward zero) of the membrane potential when we stimulate neuron
what is an action potential in a cell?
– brief electrical impulse that provides the basis for conduction of information along an axon
what is the threshold of excitation?
The value of the membrane potential that must be reached to produce an action potential
what is hyperpolarisation?
– decrease in the membrane potential of a cell
summarise a cell action potential cycle
Starts at -70 as this is the baseline.
Reaches the threshold of excitation.
Fully action potential causes massive +ve spike in cell charge
The action +ve cahrge decreases after a peak and they after enters hyperpolarisation dips below -70 briefly before depolarising back to -70.
CHECK SLIDE 21 ON WEEK 2
what is electrostatic pressure?
When substances dissolve in water, they split into 2 parts with opposing electrical charge have attraction & repulsion (Na + and Cl− ions)
Revisit and draw flow diagram of NaK pump
CHECL SLIDE 21 OF WEEK 2
what is the all-or-none law?
– once the action potential begins, it proceeds without decrement to the terminal buttons (it either occurs, or it doesn’t occur)
how do you measure speed of conduction?
delay between stimulus and action potential
what is the rate law?
variations in the intensity of a stimulus are represented by
variations in the rate at which that axon fires
what is saltatory conduction?
Conduction of action potentials by myelinated axons. The action potential appears to jump from one node of Ranvier to the next, speeding up signalling.
what is the name for the gap between neurons?
synaptic cleft
can action potentials jump over the synaptic cleft?
no- that why we have neurotransmitters dummy
where are neurotransmitters kept before firing?
in the synaptic vesicles
what does lock and key binding mean in regards to nerve impulses?
The membrane of the post-synaptic neuron has chemical-gated ion channels called neuroreceptors. These have specific binding sites for neurotransmitters. The chemical messenger fits the binding site like a lock and key.
Is opening transmitter-dependant ion channels direct of indirect?
It can be both
indirect = metabotropic
direct = ionatropic
(go over slide 31/32 of week 2)
What is Excitatory Postsynaptic Potential (EPSP)
excitatory depolarization (+ve) of the postsynaptic membrane.
What us the Inhibitory Postsynaptic Potential (IPSP)?
inhibitory hyperpolarization (-ve) of the post synaptic membrane.
what are the 3 main types of ion channel?
Na+, K+ and Cl-
how do neurotransmitters cause hyperpolarisation or depolarisation of the post-synaptic cell?
The neurotransmitters bind to ion channels to cause influx of Na, Cl or K ions to enter the cell.
what is neuronal integration?
Process by which inhibitory and excitatory postsynaptic potentials summate and control the rate of firing of a neuron.
what is temporal summation?
sensory summation that involves the addition of single stimuli over a short period of TIME. (a few small depolarisations that don’t meet threshold for excitation can combine together if they arrive at similar times)
what is spatial summation?
Spatial summation involves simultaneous signals coming from multiple presynaptic neurons being received by a single postsynaptic neuron.
what are glial cells?
glue cells that hold neurons together, split into astrocytes and oligodendrocytes.
briefly describe how you study the resting potential of an axon
apply a +ve stimulation to an axon placed in saltwater with 1 electrode in the water and another on the axon & use an oscilloscope/voltmeter to measure the AP
which lobe is the motor cortex in?
frontal
which lobe is the somatosensory cortex in?
parietal
which lobe is the visual cortex in?
occipital
which lobe is the auditory cortex in?
temporal
