Introduction Flashcards

1
Q

Describe 3 breakthrough studies in neuroscience.

A

Imprinting - Konrad Lorenz on the greylag goose. Exposure during critical period causes young to follow mother or substitute.
Waggledance - Karl Von Frisch on the honeybee.Honeybees communicate direction of food source by a specific behaviour.
Sign Stimuli - Niko Tinbergen on the stickleback. A specific feature will trigger the release of an innate behaviour.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the ways in which physiology of nervous systems can be studied?

A

Electrophysiology - recording electrical activity.
Optical imaging - Voltage/calcium-sensitive dye
Brain scans.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the three types of brain scans that can be used to study physiology of nervous systems? Describe what each ca be used for.

A

NMR - Anatomy
PET - Activity
fMRI - Activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can the anatomy of nervous systems be studied/observed?

A

Staining of neurones:
Golgi stain
Backfilling
Intracellular filling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is immunocytochemistry?

A

Study of specific biochemical components of nervous systems by using antibodies raised against the neurotransmitters.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is molecular biology used to study nervous systems?

A

Examination and manipulation of gene expression allows to determine time and location at which the components of nervous systems are formed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the theoretical study of nervous system involve?

A

Predictions based on computer models and theoretical analysis of behaviour.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Briefly describe the structure of the nervous system of Hydra.

A

Net-like

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Briefly describe the structure of the nervous system of jellyfish.

A

Nerve rings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Briefly describe the structure of the nervous system of Flatworms.

A

Ladder-like

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Briefly describe the structure of the nervous system of insects.

A

Simple networks

340,000 neurones in the brain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Briefly describe the structure of the nervous system of humans.

A

Extreme cephalisation.

100,000,000,000 neurones in the brain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can behaviour of complex nervous systems be studied?

A

Simple behaviour can be studied on simple nervous systems and the principles can be applied to more complex systems.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the functional classes of neurones?

A

Sensory neurons
Motor neurons
Interneurons
Modulatory neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the types of sensory neurons? Give examples.

A

Exteroceptor - stimulated by external environment
Proprioceptor - carry positional/movement information about the body
e.g.:
Touch sensitive SN
Odour sensitive SN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the types of motor neurons? Give examples

A
Excitatory
Inhibitory
e.g.:
Extensor MN
Leg MN
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the types of interneurons?

A

Sensory

Pre-motor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are neurons classified morphologically?

A

According to shape, location and branching regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the common shapes of neurons?

A

Bipolar

Multipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Give examples of neuron locations.

A

Cortical
Spinal
Metathoracic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Give examples of types of branching regions of neurons.

A
Local
Intersegmental
Ascending
Descending
Supraspinal
22
Q

Desctibe the structure of a neuron.

A

Cell body - contains a nucleus and intracellular organelles.
Dendrites - branches which allow incoming neurons to make connections on.
Axon - Extension which may branch and transmit the signal onto other parts of the body.

23
Q

What is the function of Dendrites?

A

Receive excitation or inhibition

Convey informaton from dendritic synapses onto soma (nucleus).

24
Q

How do neurons convey signals?

A

Via action potentials enabled by opening and closing of voltage gated channels that span the length of the axon.

25
Q

What is the resting potential?

A

Difference in voltage between the inside and outside of the axon when no signal is being transmitted.

26
Q

Describe the properties of the neuron during a resting potential.

A

Relatively impermeable membrane - slightly to potassium.
Potassium channels open
Sodium channels closed

27
Q

How is the equilibrium of an axon set up?

A

Potassium is drawn out of the cell down a concentration gradient but then back in when the charge left behind by potassium is too negative (electrical gradient).
Once the two forces balance, an equilibrium is set up - no net charge flow.

28
Q

Describe the activity of the sodium-potassium pump.

A

Pumps 3 sodium ions out for every 2 potassium ions drawn in.
Each transaction removes one negative charge from the outside.
Moves ions against their potential gradient using ATP.

29
Q

What is depolarisation?

A

A stimulus which causes the inside of the neuron to be more positive than in resting potential.

30
Q

What is hyperpolarisation?

A

Anything that causes the inside of the axon to be more negative than at resting potential.

31
Q

Describe how the action potential is mediated by Voltage Gated Channels (VGCs)

A

Depolarising voltage raises the membrane potential to threshold (-55mV) which causes sodium channels to open.
Sodium flows into the axon down its electrochemical gradient.
Once the membrane potential reaches the threshold necessary for activation of potassium VGCs (~30mV), potassium channels openb more slowly and sodium channels close.
Potassium starts rushing out of the cell down its electrochemical gradient.
Membrane potential decreases and hyperpolarises the membrane.
Hyperpolarisation causes inactivation of potassium channels and the axon enters a refractory period until it recovers to resting potential.

32
Q

What is the refractory period? What is its function?

A

Period after hyperpolarisation where sodium and potassium channels are inactivated and the sodium/potassium pump restores the membrane potential.
It stops the action potential from going backwards and prevents exhaustion of the axon by disabling action potentials that are too frequent.

33
Q

Describe how the action potential propagates.

A

Local current spreads along the axon away from the soma
Action potential depolarises the membrane within its proximity.
If the depolarisation is strong enough, an action potential will be generated.
Refractory period causes the local current to not be sufficient in that part of the axon which means the AP can only propagate in one direction.

34
Q

Describe signal transmission in myelinated axons.

A

Myelinated axons are covered in Schwann cells - insulatory lipid cells.
Gaps - nodes of Ranvier - conduct electricity.
Signal transmission in myelinated axons is quicker because the only resistance the signal is exposed to is at the nodes of Ranvier which are a small proportion of the axon.

35
Q

What is the function of sensory receptors?

A

Transduction of sensory input into an electrical signal

36
Q

Described how a specialised sensory epithelium transduces stimulus signal.

A

Stimulus bends hair follicle causing distortion of the attached dendrite.
Distortion leads to opening of ion channels causing depolarisation.
Depolarisation leads to a generator/receptor potential which, if greater than threshold, initiates an action potential.

37
Q

Describe the grading of generator potentials.

A

Amplitude of generator potential is proportional to the size of the stimulus.
Generator potential amplittude must be high enough to reach threshold.

38
Q

What are the types of synapses?

A

Electrical

Chemical

39
Q

What are the properties of electrical synapses?

A

Do not use neurotransmitters
Allow direct transmission of signal from cell to cell - faster.
Ionic current flows passively through gap junctions

40
Q

How is signal transmitted at a chanical synapse?

A

AP reaches nerve terminal causing calcium influx channels to open.
Calcium binds to neurotransmitter vesicles causing them to fuse with the presynaptic membrane.
Fusion causes release of neurotransmitter into the synaptic cleft where it attaches to receptors on the postsynaptic membrane.
Activation of receptors causes ion channels to open causing either an excitatory or inhibitory potential in the postsynaptic axon (EPSP/IPSP). Type depends on receptor type.
Slower.

41
Q

What are the types of neurotransmitters used by chemical synases?

A

Amines
Amino acids
Peptides
Soluble gasses

42
Q

Give examples of amine neurotransmitters.

A
ACh
Dopamine - DA
Serotonin - 5-HT
Histamine
Octopamine
43
Q

What is ACh?

A

Excitatory neurotransmitter of CNS in invertebrates and vertebrates and the muscles of vertebrates.

44
Q

What is 5-HT?

A

Serotonin - Excitatory/inhibitory/modulator

45
Q

What is octopamine?

A

Modulator of muscles and neuronal function in invertebrates.

46
Q

Give examples of amino acid neurotransmitters.

A

Gamma-aminobutyric acid - GABA - inhibitory
Glycine
Glutamate - excitatory
Aspartate

47
Q

Give examples of peptide neurotransmitters.

A

Proctolin
Substance P
Prolactin

48
Q

Give example of soluble gas neurotransmitters.

A

Nitric oxide - NO

Carbon monoxide - CO

49
Q

Describe summation of postsynaptic potentials.

A

Summation can either be spatial - multiple PSPs firing at once - or temporal - single inputs in quick succession.

50
Q

What is facilitation of PSPs?

A

Summation of EPSPs leading to them becoming larger.

51
Q

What is depression of PSPs?

A

Summation of IPSPs leading to them becoming smaller/more negative.

52
Q

Describe the knee-jerk reflex pathway.

A

Happer tap stretches tendon
Tendon stretches sensory receptors in leg extensor (quadriceps)
Sensory neuron symapses with/excites the motor neuron in the spinal cord.
Sensory neuron also excites spinal interneuron which inhibits the motor neuron to the flexor muscle (hamstring)
Motor neuron conducts AP to synapses on extensor muscle fibers causing contraction.
Flexor relaxes because the activity of its motor neuron has been inhibited.
Leg extends.