Lecture3

Question 1

First known reference to the brain?

Answer 1

Egyptian papyrus

Question 2

Functions of the Diencephalon

Answer 2

vegetative functions - breathing, HR, BP, pH of blood, digestive, immune, nervous, body temp, hunger/thirst (involuntary)

Question 3

Functions of the Telencephalon

Answer 3

think, feel, dislike (this), ability to do calculatons (cognitive functions, you do not need a telencephalon to live)

Question 4

Typical Size of a Neuron

Answer 4

10 microns - 120 microns in diameter

Question 5

Describe the basic historic review of neuroscience research

Answer 5

Philosophy (Psychology)–>Anatomy (Histology-Embryology)–>Physiology–>Molecular Biology (where it’s at now)

Question 6

What is responsible for “head functions?”

Answer 6

pons, medulla, midbrain (brain stem)

Question 7

Two Classes of Nerve Cells

Answer 7

neurons and glia

Question 8

Anatomical Characteristics of Neurons

Answer 8

size (10-120 microns), shape (bi-, uni-, multi-), transmitter, intracellular organelles (highly metabolic)

Question 9

Physiological Characteristics of Neurons

Answer 9

polarity/excitability, signal morphing, signal spread (AP), signal communication

Question 10

Signal Morphing (Transduction)

Answer 10

using excitability, neurons can transduce physical stimuli into neural stimuli (touch, pressure, stress, temp, sound), neurons can change stimuli into ELECTRICITY

Question 11

Signal Spread (Action Potential)

Answer 11

spread info over long distances through action potentials, membrane properties allows this communication to occur

Question 12

Signal Communication (Synaptic Transmission)

Answer 12

communication between cells through neurotransmitters or neuromodulators

Question 13

Four Zones of Basic Neuronal Morphology

Answer 13

input zone, integration zone, output zone, synaptic zone

Question 14

Integration Zone

Answer 14

integrating information from other neurons, cell body (soma) is where most intracellular organelles are located, can get communications from 10,000 other neurons

Question 15

Input Zone

Answer 15

dendritic tree, where synapses put in information, more branches = more synapses = more info, not myelinated

Question 16

Output Zone

Answer 16

axon, each neuron only has one axon but may have many branches (collateral branches), <1 micron in diameter, may be myelinated

Question 17

Synaptic Zone

Answer 17

synaptic bouton, will have connections with other neurons

Question 18

Multipolar Neuron

Answer 18

large number of dendrites, large input zone, can be myelinated or not

Question 19

Bipolar Neuron

Answer 19

two poles, one will act as a dendrite and one as axon, not myelinated, these are more rare

Question 20

Unipolar Neuron

Answer 20

rounded cell body without dendrites, single bifurcated axon, central (axon) and peripheral (dendrite) branch, found in sensory ganglia, can be myelinated

Question 21

Betz Cells

Answer 21

some of the largest in the brain (multipolar), give us control over the main functions in our body

Question 22

Anatomical Characteristics of Glia

Answer 22

astrocytes, oligodentrocytes, microglia, schwann

Question 23

Astrocytes

Answer 23

type of glia found in CNS, may be protoplasmic (gray matter) or fibrous (white matter)

Question 24

Responsible for Formation of the Blood Brain Barrier

Answer 24

astrocytes (protoplasmic and fibrous)

Question 25

Oligodentrocytes

Answer 25

myelin making cells in the CNS

Question 26

Microglia

Answer 26

scavenger cells of the CNS, clean up dead cells

Question 27

Schwann Cells

Answer 27

in the PNS, make myelin and clean up, basal lamina forms conduit which allows for regeneration

Question 28

Which cells make myelin?

Answer 28

oligodentrocytes (CNS) and Schwann cells (PNS), they make myelin based on diameter of axon

Question 29

Physiologocial Characteristics of Glia

Answer 29

structure/protection (primary), ion homeostasis, myelin formation, debris clearance

Question 30

Why can PNS potentially regenerate but not CNS?

Answer 30

Schwann cells, PNS can regenerate through basal lamina (oligodentrocytes do not make a basal lamina)

Question 31

Basic CNS Functions

Answer 31

collect and analyze information (transduction), react to information, store information as memory (protein), recall memories as appropriate, modify behaviors

Question 32

Two Types of Axoplasmic Transport

Answer 32

anterograde (away from cell body) and retrograde (towards cell body) transport

Question 33

Slow Anterograde Transport

Answer 33

"bulk flow," 1 mm/day (same speed as regeneration in PNS), maintenance (no ATP)

Question 34

Fast Anterograde Transport

Answer 34

specific membrane-bound organelles, 400 mm/day, synaptic/trophic functions (ATP needed)

Question 35

Retrograde Transport

Answer 35

specific molecules, 200 mm/day, metabolic turnover, trophic interactions (ATP needed)

Question 36

Axonal Transport Mechanism

Answer 36

kinesin with vesicles rolls down microtubules witin axon

Question 37

1780 Luigi Galvani

Answer 37

animal electricity

Question 38

1849 Emil Dubois-Reymond

Answer 38

nerve conduction

Question 39

1925 Edgar Adrian

Answer 39

all-or-nothing principle

Question 40

1938 Kenneth Cole and Howard Curtis

Answer 40

ionic fluxes

Question 41

1945 Alan Hodgkins, Andrew Huxley, & Bernard Katz

Answer 41

NA+/K+ pumps-sliding filament theory

Question 42

Resting Membrane Potential

Answer 42

-70mV is average, in reality it is constantly fluctuating, based on concentration gradient of all ions

Question 43

Threshold

Answer 43

occurs when potential raises to -50mV, conformational change in NA+/K+ pump, opens and NA+ rushes in

Question 44

Spike Peak

Answer 44

NA+ stops coming in (approx. +30-35mV), K+ starts leaving, begins repolarization process

Question 45

Repolarization

Answer 45

K+ leaving cells

Question 46

Hyperpolarization

Answer 46

overshoot in repolarization to about -90mV

Question 47

Depolarizaton

Answer 47

positive after potential, back to -70mV

Question 48

Action Potential Components

Answer 48

resting potential, threshold, spike peak, repolarization, hyperpolarizing (negative after potential), depolarizing (positive after potential)

Question 49

Refractory Period

Answer 49

cannot have another AP, limit to spread of excitation due to this (can only have so many per unit time)

Question 50

Approximately how long is one action potential?

Answer 50

4 msec

Question 51

Membrane Cable Properties

Answer 51

AP gets weaker as it travels down the length of the axon as potential leaks out (myelin can allow for better conduction velocity)

Question 52

Lambda

Answer 52

distance between where 100% current and enough leakage occurs for current to die out (37%)

Question 53

Saltatory Conduction

Answer 53

counter current of flow down the axon, some ions are flowing in at one node and out at another, can only occur in myelinated axons