Week 5 - Neurons

Question 1

Camillo Golgi (1843)

Answer 1

• reticular theory, which was an idea that the nervous tissue was one continuous net-like structure.
• developed the ‘Golgi staining technique’, which colours the cell bodies of the neurons, easier to see the branch-like structures.
• discover the Golgi apparatus, an organelle in cells.

Question 2

Santiago Ramón Y Cajal (1852)

Answer 2

• using Golgi’s method, investigated neural tissue, to create technical illustrations of human and animal samples.
• discovered that neural tissue was made up of individual cells, which are distinguishable processing units rather than continuous structures.

Question 3

soma

Answer 3

central part, contains the nucleus, which holds genetic information, and directs protein synthesis and provides the energy for cells to function.

Question 4

Dendrites

Answer 4

how the cells receive inputs. On them are dendritic spines, which are protrusions that form synapses with terminal buttons of the presynaptic axon.

Question 5

axon

Answer 5

the primary output. It extends off of the soma, splitting several times to connect with other neurons. There are numerous branches to allow it to connect with other cells.

Question 6

action potential

Answer 6

“all or nothing” electrical current that is conducted down the axon when the membrane potential reaches the threshold of excitation. It allows messages to be sent from one area of the brain to another.
When the signal propagates all the way down the axon, it reaches the synapse.

Question 7

synapse

Answer 7

junctions between the presynaptic terminal button of one neuron and the dendrite, axon, or soma of another postsynaptic neuron.

Question 8

myelin sheath

Answer 8

substance surrounding the axon that serves as insulation, allowing the action potential to conduct rapidly.

Question 9

nodes of Ranvier

Answer 9

small gaps between myelin sheath of insulation, to speed up electrical currents

Question 10

intracellular fluid

Answer 10

slightly negatively charged relative to the outside of the cell, which forms the resting membrane potential.

Question 11

Ion channels

Answer 11

proteins that span the cell membrane, forming channels that specific ions can flow through between the intra and extracellular space.

Question 12

action potential

Answer 12

electrostatic pressure repels anions such as Chloride (Cl-) and attracts cations such as Potassium (K+). The differences in concentration of molecules can cause ions to either be pushed out of or into the cell, in a process known as diffusion.

Question 13

Anions

Answer 13

negatively charged ions in high concentration within cells.

Question 14

Potassium (K+)

Answer 14

high concentration inside cells. The cell membrane is highly permeable to K+.

Question 15

Chloride (Cl-)

Answer 15

high concentration outside cells. The cell membrane is highly permeable to Cl-.

Question 16

Sodium (Na+)

Answer 16

high concentration outside cells. The cell membrane is not very permeable to Na+.

Question 17

resting membrane potential

Answer 17

-70mV, result of the interactions between these molecules and the subsequent difference in charge between the inside and outside

Question 18

sodium-potassium pump

Answer 18

ion channel that uses the neuron’s energy (adenosine triphosphate, ATP) to pump three Na+ ions outside the cell in exchange for bringing two K+ ions inside the cell.

Question 19

Excitatory postsynaptic potential (EPSPs)

Answer 19

depolarizing current that causes the membrane to become more positive and closer to the threshold of excitation.

Question 20

Inhibitory postsynaptic potential (IPSPs)

Answer 20

hyperpolarizing current that causes the membrane to become more negative and further from the threshold of excitation.

Question 21

threshold is met

Answer 21

Voltage-dependent sodium (Na+) channels are opened.
Na+ rushes inward due to electrostatic pressure and diffusion pushing it inside the cell, making it highly depolarized.
Because the inside of the cell is positive, voltage-gated potassium (K+) channels are opened.
K+ rushes outside of the cell due to diffusion and electrostatic pressure.
Na+ channels close as the cell becomes more negative, due to the potassium quickly decreasing. This combines with the sodium-potassium pump and the K+ channels gradually closing to cause the charge to drop lower than the resting membrane potential.
This slight drop below the resting membrane potential leads to a short refractory period. A higher increase in charge is required to reach the threshold of excitation during this period.

Question 22

saltatory conduction

Answer 22

action potential travels down the axon, the myelin sheath protects it from losing significant cellular energy, this allows it to quickly travel

Question 23

synaptic vesicles

Answer 23

presynaptic terminal button, package together groups of chemicals called neurotransmitters

Question 24

motor neurons

Answer 24

to initiate movement and behaviour

Question 25

interneurons

Answer 25

process the sensory input from our environment in order to be represented, and to plan and execute behavioural responses.

Question 26

Unipolar neurons

Answer 26

one axon and no dendrites; they relay information forward, such as communicating body temperature through the spinal cord to the brain.

Question 27

Bipolar neurons

Answer 27

one axon and one dendrite; they are involved in sensory perception and allow for the acquisition and passing of information.

Question 28

Multipolar neurons

Answer 28

most common, with one axon and many dendrites allowing for communication with other neurons; they communicate sensory and motor information in the brain.

Question 29

Glial cells

Answer 29

forming myelin sheaths, digesting debris of dead neurons, carrying nutrients from the blood to neurons, etc. They support the neurons but do not communicate between cells.

Question 30

electrochemical action

Answer 30

electrical conduction of dendritic input to the initiation of an action potential within a neuron, and chemical transmission across the synaptic gap to the postsynaptic neuron.

Question 31

Diffusion

Answer 31

force on molecules to move from areas of high concentration to low concentration.

Question 31

Diffusion

Answer 31

force on molecules to move from areas of high concentration to low concentration.

Question 32

Electrostatic pressure

Answer 32

force on two ions with similar charges to repel each other, and with opposite charges to attract one another.

Question 33

depolarization

Answer 33

change in the charge or potential of the cell from its resting membrane potential (-70 mV) in a more positive direction.

Question 34

threshold of excitation

Answer 34

-50mV, specific membrane potential that the neuron must reach to initiate an action potential

Question 35

Behavioural endocrinology

Answer 35

scientific study of the interaction between hormones and behaviour. This interaction is bidirectional.

Hormones are chemical messengers that influence the nervous system to regulate behaviours (released by specialized endocrine glands through the bloodstream, and can travel over great distances and temporal ranges)

Question 36

Psychopharmacology

Answer 36

study of how drugs affect behaviour (psychoactive or psychotropic drugs)

• change the way you feel do this by altering how neurons communicate with each other.
• all psychoactive drugs interfere or alter the process of neurotransmission.
• can either increase activity at the synapse (agonists) or reduce activity at the synapse (antagonists).
• have effects on other neurotransmitters

Question 37

Acetylcholine (ACh)

Answer 37

related to learning and memory, as well as muscle movement in the peripheral nervous system and Alzheimer’s disease.

Question 38

Dopamine (DA)

Answer 38

related to our brain’s reward circuits, and Schizophrenia.

Question 39

Norepinephrine (NE)

Answer 39

related to arousal and depression.

Question 40

Serotonin (5HT)

Answer 40

related to depression and aggression, as well as Schizophrenia.

Question 41

Glutamate (GLU)

Answer 41

related to learning. It is the major excitatory neurotransmitter in the brain.

Question 42

GABA (GABA)

Answer 42

related to anxiety disorders and epilepsy. It is the major inhibitory neurotransmitter in the brain.

Question 43

Endorphins

Answer 43

related to pain, reward, and analgesia (loss in a sensation of pain).

Question 44

Pharmacokinetics

Answer 44

how the body handles a drug that we take.
-Psychoactive drugs alter neuronal communication in the brain, by traveling in the blood.
-ADME is used to describe this process:
Absorption, Distribution, Metabolism, Excretion.

Question 45

Motor Neurons

Answer 45

Allow us to initiate movement and behaviour.

Found in the cerebrum.

Question 46

brain stem

Answer 46

Regulates basic behaviours such as breathing, circulation, digestion.
Sorts information going up and down (motor and sensory).
Attached to the spinal cord.

Question 47

cerebellum

Answer 47

Controls motor function, balance, and motion memory (remembering to ride a bike).
Small lobe at the back of the brain, behind the brain stem.

Question 48

thalamus

Answer 48

Acts as a router, sorting and sending information to where it needs to go.
In the middle of the forebrain, sitting on top of the brain stem.

Question 49

hypothalamus

Answer 49

Maintains homeostasis; Body temperature, appetite, circadian rhythm, etc.
Sits just below the thalamus, right above the roof of the mouth.

Question 50

pituitary gland

Answer 50

Sends out hormones to maintain hormone balance.

Hangs below the hypothalamus.

Question 51

cerebrum

Answer 51

Integration - making sense of all of the data and information which is received.
The large, upper portion of the brain.

Question 52

right hemisphere

Answer 52

Facial recognition, expression.

The right side of the cerebrum.

Question 53

left hemisphere

Answer 53

Mathematical reasoning, logic.

The left side of the cerebrum.

Question 54

corpus callosum

Answer 54

A connection of nerves between the two hemispheres, allowing them to communicate.
Connects the two hemispheres of the cerebrum.

Question 55

basal ganglia

Answer 55

Made up of nuclei (groups of neurons that have the same function). Regulates our motor control.
Directly below the corpus callosum.

Question 56

cerebral cortex

Answer 56

Makes up 80% of the brain. Controls the functions of the cerebrum.
Makes up 80% of the brain. Is the main portion of the cerebrum.

Question 57

frontal lobe

Answer 57

Controls executive function and emotional control. Damage to the frontal lobe can cause large emotional swings.
Front of the cerebrum.

Question 58

parietal lobe

Answer 58

Dealing with and reacting to environments; lots of neurons bringing sensory input.
Upper-back of the cerebrum.

Question 59

occipital lobe

Answer 59

Primarily controls vision.

Back of the cerebrum.

Question 60

temporal lobe

Answer 60

Language, hearing, and memory.

Lower sides of the cerebrum.

Question 61

somatosensory cortex

Answer 61

Where sensory information is coming into the brain. There are large areas devoted to primary sensory tools, such as the fingers and the tongue.
Inside the parietal lobe, bordering the frontal lobe.

Question 62

motor cortex

Answer 62

Where motor output is released from the brain.

Inside the frontal lobe, bordering the parietal lobe.