sensory system

Question 1

flow of information in the nervous system

Answer 1

Sensory neuron brings in information we have an interneuron that brings about an action

Not every sensory input needs a response

Question 2

All stimuli represent___

Answer 2

forms of energy

Question 3

what is necessary to convert stimulus energy into a change in the membrane potential in the nervous system

Answer 3

sensory receptor

Question 4

all sensory pathways have four basic functions in common

Answer 4

Sensory reception

Transduction

Transmission

Perception

Question 5

Sensory reception

Answer 5

Capture the energy of sensory signal → sense it
receptor

Question 6

Transduction

Answer 6

Puts the sensory signal into the language of the nervous system

Changes in membrane potential

Question 7

transmission

Answer 7

Send sensory signal to our brain

Question 8

Perception

Answer 8

Become aware of input so that you can respond to it

Question 9

Types of sensory receptors

Answer 9

Ionotropic sensory receptors

Metabotropic sensory receptors

Question 10

Ionotropic sensory receptors

Answer 10

A pressure receptor
Transmembrane protein that responds to pressure by changing conformation
Push→ opens→ lets ions in (+ charges)

Question 11

Metabotropic sensory receptors

Answer 11

Channel that open and close
Chemoreceptor and photoreceptor
Have different receiving molecules
Taste molecules & light molecules

Question 12

process of smelling steps overview

Answer 12

Step 1: sensory reception
Step 2: transduction
Step 3: transmission
Step 4: perception

Question 13

Step 1: sensory reception

Answer 13

There are only a few dozen taste receptor genes
Odorants enter nose
There are different chemoreceptors for different odorants
Odorant receptors are largest gene family in the genome of mammals
Odorant receptors are sensitive to specific odorants

Question 14

Step 2: transduction

Answer 14

Odorants bind to odor receptors
Causes change in resting potential
If it changes membrane potential enough the active potential occurs

Question 15

Step 3: transmission

Answer 15

Get signal to brain to become aware of it
Olfactory receptor cell travels to brain → olfactory bulb of brain

Question 16

Step 4: perception

Answer 16

We perceive that smell

Question 18

Weak vs strong smell

Answer 18

Weak smell is a lower frequency of action potentials per receptor but a strong smell is a higher frequency of action potentials per receptor
More of the molecules you are smelling are coming into your nose→ more of the odor receptors will bind to molecule and you will more frequently set off action potentials

Question 19

how do we sense heat

Answer 19

Heat is sensed by an ion channel called TRPV1

Question 20

why do we snese heat when we eat peppers

Answer 20

Peppers have Capsaicin which binds to TRP channel and you get the sensation of hot from hot peppers
Messing with your head
Nothing is actually hot

Question 21

:
Both olfaction(taste/smell) and vision(light) use
whta kind of receptors

Answer 21

metabotropic receptors

Question 22

when we perceive vision what are we doing

Answer 22

Turning light into electrical signals

Question 23

Objects in our environment will emit light or reflect light at different wavelengths
This gives us information on

Answer 23

the chemical composition of the object → what we call color

Question 24

Specialized cells called photoreceptors are modified ___ that can detect ____. they turn light into ___

Answer 24

neurons
that can detect light
Turning light into electrical signals

Question 25

human eye composition

Answer 25

Just inside the choroid(thin layer that nourishes the neurons) are the interneurons and photoreceptors of the retina

The lens is a transparent disk of protein

In front of the lens is the clear and watery aqueous humor and behind it is the jellylike vitreous humor

The iris is a muscular structure that controls the diameter of the pupil and thus how much light enters the eye

Visual information leaves the eye and goes to the brain via the optic nerve

Question 26

The cells that are detecting light and turning light into neural signals is t

Answer 26

the rods and cones

Question 27

Light passes through ___before reaching the ____cells

Answer 27

interneurons
light detecting

Question 28

difference between rods and cones

Answer 28

Rods are more sensitive to light but don’t distinguish colors
Low light vision
Cones provide color vision
Different sensitivity to different colors

Question 29

Photoreceptors synapse onto:

which then synapse onto

Answer 29

Bipolar cells → these then synapse onto ganglion cells (link ganglion cells w photoreceptor cells)

Question 30

It is the axons of the ganglion cells that make up

Answer 30

the optic nerve(bundle of axons)

Question 31

Horizontal cells

Answer 31

involved in processing the visual image even before it goes to the brain
They sharpen edges through lateral inhibition

Question 32

Amacrine cells

Answer 32

have varied roles in visual processing such as detecting the direction of motion
Amacrine cells help detect motion

Question 33

How does the retina convert light into membrane potential that your brain can use

Answer 33

It uses light receptor molecules called rhodopsin

Question 34

Rhodopsin

Answer 34

transmembrane proteins that undergo changes in conformation as they absorb light
This sets off an event that leads to a membrane potential

consist of a protein called opsin and a light-absorbing group, 11-cis-retinal

Question 35

11-cis-retinal

Answer 35

is covalently bound in the center of the opsin molecule
When 11-cis-retinal absorbs a photon, it changes to all-trans-retinal, which changes the conformation of the opsin
This change detects light

Question 36

In rods and cones there are disks of membrane components (disks have lipid bilayer component on the outside and an internal compartments)
The transmembrane proteins that span the disks are the

Answer 36

opsin

Question 37

Retinal absorbs light and goes from ___ to ___ configuration

Answer 37

cis
trans

Question 38

Put retinal back to ___configuration so that your eye can detect light again
Enzymes in your eye do this

Answer 38

cis

Question 39

Retinal is derived from ___

Answer 39

vitamin A

Question 40

why does Consuming more vitamin A not make your eyes better

Answer 40

Once all your opsin have retinol in it it’s as good as it gets

Question 41

How do we convert light into membrane potential

Answer 41

Photoreceptor in the dark has a membrane potential of about -40

Partially depolarized in the dark
To have the membrane potential go from the more typical -70 to -40 we have a sodium current going into the cell
This channel opens and closes depending on the presence of cyclic GMP (cGMP)

Question 42

in the dark what process occurs

Answer 42

cGMP is produced and it binds to the sodium channel allowing sodium to come in
Releases glutamate
Signals to bipolar cells

Question 43

in the light what occurs

Answer 43

It activates the rhodopsin by conversion of the cis-retinal to trans-retinal
This activated the molecule transducin which activates an enzyme called phosphodiesterase

Question 44

what does phosphodiesterase do

Answer 44

This enzyme breaks cGMP to GMP
GMP doesn’t bind to the sodium channel
Closes sodium channel
Hyperpolarizes
Becomes more negative
When we absorb light our rods and cones become more negative
No glutamate released

Question 45

In signal transduction in the eye, cyclic GMP:

Answer 45

Binds to a Na+ channel and opens it