Lecture 2

Question 1

4 principal parts of the brain?

Answer 1

Brain stem,
Cerebellum,
Diencephalon,
Cerebrum.

Question 2

What does the brainstem continue from?

Answer 2

Spinal cord.

Question 3

What does the brainstem control?

Answer 3

Respiratory and cardiovascular systems, swallowing, vomiting.

Question 4

Where is the cerebellum located in relation to the brain stem?

Answer 4

Behind the brain stem.

Question 5

What does the cerebellum coordinate?

What does it maintain?

Answer 5

movement, balance, posture.

Muscle tone.

Question 6

What are the 2 principal parts of the diencephalon?

Answer 6

Thalamus and hypothalamus.

Question 7

Where is the diencephalon located in relation to the brain stem?

Answer 7

Above brain stem.

Question 8

Where is the diencephalon located in relation to the brain stem?

Answer 8

Above brain stem.

Question 9

What does the diencephalon detect?

Answer 9

Touch/pressure/pain, hot/cold, sound, taste, smell, thirst, sleep patterns.

Question 10

Where is the cerebrum located, and how well is it developed in humans?

Answer 10

Surrounding the diencephalon.

Very well developed in humans.

Question 11

What four areas does the cerebrum feature?

Answer 11

Sensory, motor, association areas, and visual cortex.

Question 12

What 3 things is the association area responsible for?

Answer 12

Intelligence, memory, emotions.

Question 13

What does the outside of the cerebrum consist of? What about the inside?

Answer 13

Grey matter/cortex (neuronal cell bodies, dendrites).
White matter (myelinated axons).

Question 14

The cerebrum is divided into 2 hemispheres, but what connects them?

Answer 14

Corpus callosum.

Question 15

What 2 words describe the cerebral cortex’s physical features?

Answer 15

sulci, gyri.

Question 16

How many lobes is each hemisphere divided into? And what are they?

Answer 16

4. Frontal, parietal, occipital, temporal.

Question 17

Where are the Somatosensory areas located?

Answer 17

Anterior parietal lobe of the cerebral cortex.

Question 18

Where are the Motor areas located?

Answer 18

Posteror frontal lobe of the cerebral cortex.

Question 19

Are the association areas limited to one lobe in the cerebral cortex?

Answer 19

No, several.

Question 20

Where do neurons receive information?

Answer 20

Dendrites.

Question 21

How is information transmitted along axons?

Answer 21

Electrochemical signals/action potentials.

Question 22

Is the lipid bilayer impermeable to Na+ and K+?

Answer 22

Yes.

Question 23

2 types of ion channels?

Answer 23

Always open,

Gated.

Question 24

3 types of gated ion channels?

Answer 24

Mechanically-gated, ligand-gated, voltage-gated.

Question 25

What are voltage-gated ion channels involved in?

Answer 25

Generation and propagation of nerve impulses.

Question 26

What are ligand-gated ion channels involved in?

Answer 26

Neurotransmission at the synapse.

Question 27

What are mechanically-gated ion channels involved in?

Answer 27

Perception of touch.

Question 28

2 types of molecules that could be a ligand?

Answer 28

Hormone or neurotransmitter.

Question 29

What 2 forces move ions through membrane channels?

Answer 29

Chemical driving force (diffusion from region of high concentration to low) Electrical driving force (retention of positive cations and expulsion of negative anions from negatively charged interior of cell).

Question 30

What is the electrochemical driving force a combination of, and therefore, what does it give us?

Answer 30

Chemical and electrical driving forces acting on any particular ion. Gives us nett force.

Question 31

What is resting membrane potential of axon w.r.t. exterior?

Answer 31

-70mV.

Question 32

What is the resting membrane potential (Vm) of a nerve cell?

Answer 32

Difference in voltage across plasma membrane when cell is at rest.

Question 33

What were resting nerve potential studies initially carried out on?

Answer 33

Giant squid axon.

Question 34

What does resting membrane potential depend on?

Answer 34

Concentration gradients for multiple ions across membrane, and the relative permeability of the membrane to those ions.

Question 35

Why will Na+ enter the cell at rest?

Answer 35

15mM Na+ on the inside, 150mM Na+ on the outside, so chemical driving force acts towards the cell. Interior of the cell is negative, so electrical driving force acts towards the cell.

Question 36

What is the equilibrium potential (E)?

Answer 36

Membrane potential required to exactly counteract chemical forces acting to move one particular ion across the membrane.

Question 37

What is the Nernst equation? | And what does E, z, Co and Ci mean?

Answer 37

E=(61/z)*log(Co/Ci) ``` E = equilibrium potential (mV) z = charge (valence) of ion Co = outside concentration of ion Ci = inside concentration of ion ```

Question 38

What is ENa? And why does this

Answer 38

+60mV.

Question 39

What is ENa? And why does this cause sodium to try and enter the cell?

Answer 39

+60mV. | Greater than resting Vm. Both chemical and electric driving force act in same direction.

Question 40

What is Ek? And why does this cause potassium to try and leave the cell?

Answer 40

-94mV. | Less than resting Vm. Although chemical and electrical force act in opposite directions, chemical force is greater.