Sensory Systems I & II

Question 0

I. Sensory Information

parts

Answer 0

A. Transduction Machinery

B. Modalities

Question 1

Sensory Systems I

Answer 1

I. Sensory Information
II. Mammalian Eye
III. Visual Systems Pathways
IV. Receptive Field (RF)

Question 2

I. Sensory Information

A. Transduction Machinery

Answer 2

-GPs in sensory neurons

Question 3

I. Sensory Information

B. Modalities

Answer 3

pain, pressure, heat, cold, touch, taste, smell vision
-all mediated by G protein - coupled receptors (GPCRs)
metatrophic receptors - see pg 108-113

Question 4

II.Mammalian Eye

parts

Answer 4

A. Anatomy
B. Light transduction
C. Retina: 5 cell layers - inverted

Question 5

II. Mammalian Eye

A. Anatomy

Answer 5

Figure 38.25 a overview of eye structure

Question 6

II. Mammalian Eye

B. Light Transduction

Answer 6

1. Cell Types: photoreceptors -
2. Molecular Mechanisms -

Figure 38.25 c&d photoreceptor cells & visual pigments

Question 7

1. Cell Types: photoreceptors

Answer 7

a) Rods - white/ black (very sensitive)
b) Cones- color (blue / red / green)
-outer segments contain RHODOPSIN
= protein (opsin) + light absorbing pigment
RETINAL (from vitamin A)

Question 8

2. Molecular Mechanism

Answer 8

a) In the dark: CGMP (cyclic GMP) holds Na+ channels open
-> increase inward ion flow
=> dark current

b) In the light: pathway that closes these channels

diagram: flow chart
Figure 38.26 production of receptor potential in rod cell
Extra Figure: effect of light at rod cell synapses onto their downstream targets

Question 9

2. Molecular Mechanism

diagram

Answer 9

cis-retinal - trans-retinal - release of G protein subunit (transductin) - inactive phosphodisterase - active p-diesterase
cGMP - GMP

Question 10

II. Mammalian Eye

C. Retina - 5 cell layers inverted

Answer 10

1. Photoreceptors (back of eye)
   2. Horizontal cells
2. Bipolar Cells
   4. Amacrine Cells
3. Retinal Ganglion Cells (RGCs)
   - >project (via optic nerve) to the brain

Figure 38.25 Eyes compostion &Retinal Call Layers

Question 11

III.Visual System Pathways

Answer 11

Retina -> Lateral Geniculate Nucleus ->Primary Visual Cortex

Diagram: (left & right eye crossing)
ExtraFigure: Neural Pathways for vision

Question 12

IV. Receptive Field (RF)

definition

Answer 12

Concept: that part of sensory field that affect the cell in the pathway

Example: in the visual system, that part of the visual field -> alters firing of neuron

Question 13

IV. Receptive Field (RF)

part

Answer 13

A. RGCs (Retinal Ganglion Cells)
- RFs are “center-surround” configuration
Diagram

B. Cells in the Visual Cortex
1. Best RF: Oriented bar of light & optimum length & position
diagram
2. Hypothesis: diagram