lecture 3

Question 1

Histology

Answer 1

Make thin slices of cells to see morphology
Preserve
Staining of nerve tissue

Question 2

Types of stains

Answer 2

Golgi (red, silhouette neuron)
Nissl (purple, only colors cell bodies)
Fluorescent
HRP (horseradish peroxidase, show where dendrites and axons are going)

Question 3

Neuronal morphology

Answer 3

Dendrite (afferent)
Axon (efferent)
Soma (genetic and metabolic processes)

Question 4

Cell organelles

Answer 4

Mitochondira
Endoplasmic reticulum
Cell membrane
Ribosomes
Nucleus
Golgi complex
Mitochondria

Question 5

Dendritic spine

Answer 5

Receives the presynaptic terminals/boutons

Question 6

Protein from soma to axon

Answer 6

Protein made in the nucleus
Packaging and shipping in golgi bodies
Transport (active process instead of diffusion)
Uptake into axon membrane
Exocytosis (exit the axon membrane)

Question 7

Channel

Answer 7

Always lets K+ flow through
Diffusion
Permeability depends on number of channels

Question 8

Gate

Answer 8

Gated channel
Opens or closes
Change depends on voltage or chemical stimulus

Question 9

Pump

Answer 9

Active transport
Requires energy
Creates membrane potential

Question 10

Neuron classification by structure

Answer 10

Multipolar
Bipolar
Pseudounipolar

Question 11

Neuron classification by location/connectivity

Answer 11

Projection neuron

Interneuron

Question 12

Projection neuron

Answer 12

Have myelinated axons outside of the structure they belong to
Eg sensory neuron

Question 13

Interneuron

Answer 13

Short axons
Transmits to neurons nearby
Not myelinated

Question 14

Neuronal metabolism

Answer 14

Glucose as fuel (passes through blood brain barrier)

Brain consumes a lot of oxygen due to glucose consumption

Question 15

Glucose synthesis

Answer 15

Glucose can be synthesized in the liver

Vitamin B1 enables glucose use (deficiency = Korsakoff syndrome)

Question 16

Glial cells

Answer 16

Astrocytes
Microglia
Oligodendrodendrocytes
Schwann cells

Question 17

Astrocytes

Answer 17

Provide structure and solidity to NS

Help blood brain barrier by maintaining tight junctions

Question 18

Microglia

Answer 18

Immune system of the brain

Question 19

Oligodendrocytes

Answer 19

Make myelin sheath

Cell body is away from axons, send out projections to dendrites that roll around dendrite as a fatty layer

Question 20

Schwann cells

Answer 20

Makes myelin sheath

Single cell that wraps its membrane around the axon

Question 21

Axonal regeneration

Answer 21

Axons can generate
Schwann cells point to where the axon was supposed to run
New axon is formed
Schwann cells envelop the axon again

Question 22

Blood brain barrier

Answer 22

Border between blood and brainfluid
Maintains composition of brainfluid by precenting toxic substances from entering the brain
Selectively permeable
Passive to lipophilic substances and small molecules
Active to glucose and amino acids

Question 23

Functions of glial cells

Answer 23

Forming myelin
Insulate nerve fiber
Remove dead neurons/waste transport
Uptake/release of ions/neurotransmitters
Forming tight junctions
Guiding migration of neurons

Question 24

Active transport of sodium potassium pump

Answer 24

Pumps out 3 sodium ions
Pumps in 2 potassium ions
So more positive on the outside and more negative on the inside of the membrane

Question 25

Electrochemical potential

Answer 25

``` Electrical gradient Chemical gradient (stronger) ```

Question 26

Chemichal gradient

Answer 26

Inside rich in K | Outside rich in Na

Question 27

Graded potentials

Answer 27

EPSP and IPSP

Question 28

EPSP

Answer 28

``` Na channels open Positive charge (Na ions) flows into cells and diffuses along membrane Cell membrane depolarizes locally ```

Question 29

IPSP

Answer 29

Cl channels open Negative charge flows in Membrane hyperpolarizes locally

Question 30

Conduction of graded potentials

Answer 30

The current fades away over distance due to; 1. diffusion of charge over an increasingly large surface 2. outward leakage of K+ ions (positive current) through open K+ channels

Question 31

Graded local de-/hyperpolarization

Answer 31

Amplitude is proportional to stimulus strength Amplitude reduction as a function of distance to the stimulus On dendrites and soma

Question 32

Action potential

Answer 32

High concentration of Voltage dependent Na channels in axon hillock Massive influx of Na Membrane potential shoots up Action potential only in axon

Question 33

Start of action potential

Answer 33

Dendrites and soma receive stimulation from other cells These graded potentials spread along the cell membrane Voltage dependent Na channels at the axon hillock respond to local membrane potential When the critical threshold for the votlage dependent Na channels is reached the channels open and an action potential is triggered

Question 34

Termination of action potential

Answer 34

2 processes Opening of voltage dependent K channels (delayed opening) Slow inactivation of voltage dependent Na channels (slowly close)

Question 35

Refractory period

Answer 35

Because Na channels close and K channels open 1 ms Neurons can't fire

Question 36

All or none law of action potentials

Answer 36

``` Equal amplitude Equal shape Equal duration Equal propagation speed Larger stimulation = more action potentials ```

Question 37

CSN synapses

Answer 37

Axodendritic Axosomatic Axoaxonic

Question 38

Synaptic potentials

Answer 38

Resting membrane potential Graded potentials (excitatory/inhibitory) Action potentials