BIO 360 - Exam 2 - Chapter 8 Nervous System SP 2023 PowerPoint

Question 1

sliding filament mechanism

Answer 1

Andrew Huxley and Hugh Huxley (no relation!)

Question 2

2004 Nobel Prize in Physiology or Medicine -
Olfactory sensory cells that express the same receptor
project to the same area (glomerulus) in the olfactory bulb.

Answer 2

Linda Buck, Fred Hutchinson, Richard Axel

Question 3

Reduced silver staining technique
(July 7, 1843 – January 21, 1926)
Nobel Prize in Physiology or Medicine in 1906

Answer 3

Camillo Golgi

Question 4

Neuron Doctrine
(May 1, 1852 – October 17, 1934)
Nobel Prize in Physiology or Medicine in 1906

Answer 4

Santiago Ramón y Cajal

Question 5

The Brain: Phineas Gage (1823 – May 21, 1860)
* Association of frontal lobes and personality

Question 6

Signaling in neurons
Basis of the Action Potential
Nobel Prize in Physiology or Medicine in 1963

Answer 6

Sir Alan Hodgkin, Sir Andrew Huxley

Question 7

Signaling in neurons
Graded local potential
Nobel Prize in Physiology or Medicine in 1963

Answer 7

Sir John C. Eccles

Question 8

Synaptic Transmission
Chemical - synapse & Electrical - gap junction
Nobel Prize in Physiology or Medicine in 1970

Answer 8

Julius Axelrod, Ulf S. von Euler & Sir Bernard Katz

Question 9

What five things constitute the Neuron Doctrine?

Answer 9

• CELLS ARE DISCRETE UNITS
• PRINCIPLE OF DYNAMIC POLARIZATION
  Information flows in one direction
  Input->Integration->Output
• PRINCIPLE OF CONNECTIONAL SPECIFICITY
  Connections determine function

Question 10

Fig. 8.1 ESSENTIALS The Organization of the Nervous System

Question 11

What are the three specializations of the cerebral cortex?

Answer 11

(1) Sensory areas (Input): Sensory input translated into
perception
(2) Association areas (Integration): Integrate information
from sensory and motor areas. Can direct voluntary
behaviors.
(3) Motor areas (Output) Direct skeletal muscle or glandular movement.

Question 12

General layout of the nervous system

Answer 12

Diagrams showing: frontal lobe, central sulcus, parietal lobe, occipital lobe, temporal lobe, and lateral (Syvian) fissure.

Frontal lobe (prefrontal association area): coordinates information from other association areas and controls some behaviors.

Temporal lobe (auditory association area and auditory cortex): hearing.

Occipital lobe (visual association area and visual cortex): Vision

Parietal lobe (sensory association area and primary somatic sensory cortex): information from the skin, musculo-skeletal system, viscera and taste buds.

Diagram showing: cerebrum, diencephalon, midbrain, pons, cerebellum, medulla, spinal cord, cervical enlargement, lumbosacral enlargement, Cauda equina.

Question 13

Spinal Cord – External and Internal Anatomy

Which part is the white matter and which part is the grey matter.

Answer 13

Cerivical, Thoracic, Lumbar, Sacral areas.

White matter is tissue in the brain composed of nerve fibers. The fibers (called axons) connect nerve cells and are covered by myelin (a type of fat). The myelin is what gives white matter its white color.

Grey matter contains most of the brain’s neuronal cell bodies. The grey matter includes regions of the brain involved in muscle control, and sensory perception such as seeing and
hearing, memory, emotions, speech, decision making, and self-control.

Question 14

Autonomic Nervous System

What is the difference between parasympathetic and sympathetic?

Answer 14

Parasympathetic
* Cranio-sacral “rest and digest” (output).

• Second stage neurons are near the target organ.
• Cholinergic then cholinergic.

Sympathetic
* Thoraco-lumbar “fight or flight” (output).

• Second stage neurons are far from the target organ.
• Cholinergic then noradrenergic.

Question 15

Cell type 1: Neurons

• Neurons have ______ and ______ signaling properties.
• ______ ______ divide mitotically in adult.

What are the input, integration, & output?

Answer 15

• Neurons have ACTIVE and PASSIVE signaling properties
• DO NOT divide mitotically in adult

Input: Dendrites receive chemical information from presynaptic neuron.

Integration: Axon hillock

Output: Axons carry signal electrically over distance. Chemicals released from presynaptic bulb into synapse.

Question 16

Neurons - classification

What are the three different classes based on FUNCTION?

Answer 16

• SENSORY - translate physical stimulus into electrical signals
• INTERNEURON - processing
• MOTOR NEURON - activate muscles and other target organs
  (e.g. glands)

Question 17

What is the difference between bipolar, anaxonic, and multi-polar neurons?

Answer 17

(sensory) Bipolar neurons have two relatively equal fibers extending off the central cell body.

(interneuron) Anaxonic CNS interneurons have no apparent axon.

(interneuron) Multi-polar CNS interneurons are highly branched but lack long extensions.

(efferent) A typical multipolar efferent neuron has 5-7 dendrites, each branching four to six times. A single long axon may branch several times and end at enlarged axon terminals.

Question 18

Cells of Nervous System (NS): Axonal Transport

• Slow axonal transport
  Moves material by axoplasmic flow at 0.2–2.5 mm/day
• Fast axonal transport
  Moves organelles at rates of up to 400 mm/day
  Forward transport: from cell body to axon terminal
  Backward transport: from axon terminal to cell body
• Vesicles and organelles are moved by the cytoskeletal system
• Two proteins (dynein & kinesin)
  Requires ATP!

Question 19

Fig. 8.3 Fast axonal transport

How does the axonal transport move proteins and organelles between cell body and axon terminal?

Answer 19

(1) peptides synthesized and packaged
(2) Fast axonal transport along microtubule network
(3) vesicle contents released by exocytosis
(4) synaptic vesicles recycling
(5) Retrograde fast axonal transport
(6) oldest membrane components digested in lysosomes

Question 20

What are the 5 functions of Glial cells?

Answer 20

(2) BUFFER extracellular space and maintain concentrations of ions - Remove NT’s
(3) GUIDE DEVELOPING neurites - so they make the right
connections!
(4) give rise to MYELIN
(5) SCAVENGERS: Debris/waste and transmitter removal.
(1) SUPPORT ELEMENTS: Lend firmness and structure to
brain

Question 21

______ form ______ ______.

Answer 21

Oligodendrocytes / myelin sheaths

Question 22

Fig. 8.5(c) ESSENTIALS Glial cells

Answer 22

Locate the cell body, nodes of ranvier, schwann cell nucleus, myelin and axon.

Question 23

Blood brain barrier is formed by ______ cells. The blood–brain barrier protects the brain from chemicals in the blood and maintains the ionic environment crucial for signaling.

Answer 23

glial

Question 24

Electrical Signals: Nernst Equation

Membrane potential is influenced by what three things?

Answer 24

• Concentration gradient of ions
• Valence (z)
• Membrane permeability (P) to those ions

Question 25

Electrical Signals: GHK Equation

What does the GHK Equation predict?

Answer 25

Predicts membrane potential using multiple ions

Vm is E - electrical (equilibrium) potential

Question 26

Electrical Signals: GHK Equation

___&raquo_space;> ___ at rest
* So ___ ______ and the resting potential is closest to the ______
Nernst potential
Ex., PNa/ PK > 1/1000; e.g. permeability to ___ is 1,000 fold higher
* But still not quite accurate! What’s the problem?
The sodium-potassium pump stabilizes the RMP and lowers it
by 5-8 mV

Answer 26

Pk / PNa

Pk dominates / K+

K

Question 27

Table 8.3 Comparison of Graded Potential and Action Potential in Neurons

• Action potentials are not degraded over distance.
• Regenerated in each patch of membrane along an
  axon by action of ______ ______ ______ channels.

Answer 27

voltage gated ion

Question 28

Fig. 8.7 ESSENTIALS Graded potentials

Question 29

Electrical Signals: Ion Movement

______ channels control ion permeability
* Mechanically gated
* Chemical gated
* Voltage gated
Two voltage gated channels are important for the Action
Potential!
* ______ voltage gated ______ channel.
Responds ______ to depolarizing membrane potential
* ______ voltage gated ______ channel
Responds ______ to depolarizing membrane potential

Answer 29

Gated

Fast / sodium (Na+)
rapidly

Slow / potassium (K+)
slowly

Question 30

Na+ channels have two gates: ______ and ______ gates.

Answer 30

activation and inactivation

Question 31

Fig. 8.9 ESSENTIALS the action potential

Question 32

Fig. 8.10 The voltage-gated channel

Answer 32

(a) At resting membrane potential, the activation gate closes the channel.
(b) depolarizing stimulus arrives at the channel - activation gate opens.
(c) Sodium enters the cell
(d) Approx EQUILIBRIUM POTENTIAL for sodium (Na) +30 - The inactivation gate closes and Na+ entry stops.

Question 33

Fig. 8.11 Positive feedback

Answer 33

The addition of positive charge further depolarizes the inside of the cell and starts a positive feedback loop [p. 16] (Fig. 8.11). More Na+ channels open, and more Na+ enters, further depolarizing the cell. As long as the cell remains depolarized, activation gates in Na+ channels remain open.

Question 34

Fig. 8.12 Refractory periods following an action potential

Action potentials will not fire during an ______ ______ period.

Answer 34

absolute refractory

Question 35

Electrical Signals: Trigger Zone

______ ______ enters trigger zone.
* Voltage-gated ______ channels open and ______ enters axon.
* Positive charge spreads along adjacent sections of
axon by local current flow.
* Local current flow causes new section of the membrane to depolarize.
* The ______ period prevents ______ ______; loss of ______ repolarizes the membrane.

Answer 35

Graded potentials / Na+ / Na+ / refractory / backward conduction / K+

Question 36

A ______ stimulus releases little neurotransmitter.
A ______ stimulus causes more action potentials and releases more neurotransmitter.

Answer 36

weak / strong

Question 37

Speed of action potential in neuron influenced by what two things?

Answer 37

(1) Diameter of axon - Larger axons are faster.
(2) Resistance of axon membrane to ion leakage out of the cell - Myelinated axons are faster.

MS is autoimmune disease where the immune system attacks myelin.

Question 38

Electrical synapses, or gap junctions, are different
from chemical synapses because they couple
neurons electrically.
* The two neurons are connected by membrane
proteins called connexons that form a tunnel
through which ions (current!) and small molecules
can pass.
* Transmission at electrical synapses is very fast and
bidirectional.
* Can synchronize cells so they “act as one.”

Question 39

Fig. 8.19(a) ESSENTIALS Synaptic communication

Question 40

Fig. 8.23 ESSENTIALS Fast and Slow Postsynaptic Responses

Answer 40

Ionotropic: Chemically gated ion channel

Metabotropic: G-protein coupled receptor

Question 41

Fig. 8.20 Synthesis and recycling of acetylcholine

Question 42

Dopamine mediates sense of pleasure and “reward”
* Cocaine elevates dopamine by blocking reuptake.
* Methamphetamines reduce dopamine.