nov 8 23 ad

Science Sections 3 & 4

senses and whatever

touch + pain + pressure + temperature, etc.

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somatosensation

Multiple Choice

vision is part of somatosensation

• true

• false

sense of balance and position

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vestibular system

Multiple Choice

which applies the most: riding a bike involves the ___________

• vestibular system

• smell

• parasympathetic nervous system

CLOSE YOUR EYES
HOLD OUT YOU HAND TO THE SIDE
TOUCH YOUR NOSE
TOUCH YOUR EAR
that's proprioception: your body knows where it is and where its parts are

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​proprioception

sensory nerves turn stimuli into chemicals (remember section 2?) => nerve signals

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​sensory transduction

Multiple Choice

Sensory transduction...

• is how your body remembers the position of its limbs, joints, and how they are moving

• is how your body turns light, sound, pressure, temperature, and other stimuli into chemical signals

• is how signals travel across the synaptic cleft

- turn external signals into neural signals
- input is called "receptive field"
- There is "local processing" done near the sight of transduction that eliminates extra signals

sensory receptor

Labelling

what are these

Drag labels to their correct position on the image

receptive field

soma

Match

Match the following

• Sensory Transduction
• Sensory Receptor
• Receptive Field

• Vestibular System

• Proprioception

stimulus => chemical signal

Neurons that tranduce

Part of neuron that recognizes stimulus

Sense of balance/position

Sense of relative location of body parts

• stimulus => chemical signal

• Neurons that tranduce
• Part of neuron that recognizes stimulus

• Sense of balance/position

• Sense of relative location of body parts

Multiple Choice

Are you aware of all stimuli that your sensory receptors transduce?

• Yes; sensory signals are only excited, not inhibited by local processing.

• Yes; after sensory transduction, signals are locally processed before being sent to the central nervous system.

• No; sensory signals are only excited, not inhibited by local processing.

• No; after sensory transduction, signals are locally processed before being sent to the central nervous system.

Opposite direction of senses

cerebral cortex
v
spine
v
muscles

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Motor systems

VISUAL SYSTEM
yes, like your eyes

Back part of the eye that performs sensory transduction (turns light into neural signal)

Retina

Front part of the eye that refracts (bends) light. This is the part that is altered during Lasik.

​​Cornea

You prob (hopefully) know what this is already, the iris is the color part, the pupil is the hole that can change size to let in more/less light

Iris / Pupil

An actual lens... refracts light to focus it onto the retina.

Lens

Light from one point ends up in one point (it would be bad if all the light from an object ended up on more than one point on the retina)

Focusing

​myopia (nearsightedness) - light is focused in front of the eye, so blurry

Multiple Choice

What is this, then?

• Nearsightedness

• Myopia

• Farsightedness

• Perfect Vision

arranged "inside out"
- connecting neurons
- to brain
- photoreceptors
- transduce light
- pigmented epithelium
- absorb excess light
- choroid
- feed retina

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Retina

Made up of disks which sense light

Rods -
- have more disks, sense in lower light levels
- peripheral/night vision
Cones -
- color vision in bright light
- clustered in the center

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Photoreceptors

Labelling

label

Drag labels to their correct position on the image

Soma

Disks

Axon

Good in bright

Good in dark

Pigments called opsins
- absorb different colors
- color = wavelength
- rods have rhodopsin
- 3 types of cones =
3 types of color opsins

Light causes LESS neurotransmitter to be released (opposite of normal)

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Light Transduction

3 different cones (opsins) respond differently to different colors (wavelengths). your brain interprets the different signals and merges them into a single color. Some animals have more types of cones

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​Trichromatism

photoreceptor releases glutamate

bipolar cells are activated

they synapse retinal ganglion cells

goes to the brain through the optic nerve (you have a blindspot there!)

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Circuitry

horizontal cells inhibit other photoreceptors

bipolar cells either flip or don't flip signals from a receptive field of photoreceptors

their receptive field is "center-surround" which helps sense contrast and sharp edges

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Circuitry

Dropdown

Select answer

have three types corresponding to blue, green, and red.

retino - retina
fugal - leave
how signals leave the retina
nerves cross in the optic chiasm (decussation)
get mixed to make the optic tract
allows for depth perception and binocular vision

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​Retinofugal pathway

retino - retina
fugal - leave
how signals leave the retina
nerves cross in the optic chiasm (decussation)
get mixed to make the optic tract
allows for depth perception and binocular vision

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​Retinofugal pathway

Categorize

Options (10)

Cone Cells

Rod Cells

Bipolar Cells

Horizontal Cells

Optic Nerve

Optic Chiasm

Optic Tract

LGN

Pigmented Epithelium

Choroid

Organize these options into the right categories

Photoreceptors

Retinal circuitry neurons

Parts of the Retinofugal Pathway

Pigment layer

AUDITORY SYSTEM
yes, like your ears

Pinna - external
Sound goes down the auditory canal

vibrates tympanic membrane (ear drum)

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​Ear anatomy

After the ear drum is the middle ear
Vibrated ossicles (smallest bones in the human body, act as a lever)
- malleus (hammer)
- incus (anvil)
-stapes (stirrup)

​convert eardrum vibration into inner ear fluid vibration

​Ear anatomy

After the ossicles are the inner ear: Cochlea (sound transduction) and semicircular canals (movement of the head)

enters through the only flexible membrane of the cochlea, the oval window

​Ear anatomy

travels down the spiral cochlea and pressure is relieved at the round window

​Ear anatomy

cochlea has three chambers
- scala vestibuli
- scala media
- scala tympani
(top to bottom VMT vomit)

Basilar membrane separates scala tympani from scala media

​Ear anatomy

Organ of Corti is above Basilar membrane is where auditory transduction takes place (turning sound into electrochemical signals)

Basilar membrane is stiffer on the outside and floppier on the inside of the spiral => different frequencies of sound

​Ear anatomy

Tectorial membrane goes along Organ of Corti but does not move -- hair cells in OoC get shifted back and forth by the unmoving tectorial membrane

Hair cells have stereocilia (look like hairs) which sense vibrations

​Ear anatomy

When the stereocilia of INNER HAIR CELLS move they open the hatch for K+ to go in (normal neurons would let Na+ go in; this is abnormal)

​Auditory transduction

​- Name of Author

Outer hair cells receive signals that cause them to move the tectorial membrane up and down, sharpening or dampening certain pitches

Chemical Senses
taste, smell

sweet - sugars
umami - proteins
sour - vitamins/minerals
bitter - toxins
salty - ...salt

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salt and sour depolarize the cells themselves;

Na+ and H+ are both positive AND are the targets of taste

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Cranial nerves are the nerves from the mouth and face that don't go through the spinal cord
#7, 9, 10
Goes to the thalamus and then to the primary gustatory cortex

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Pathways

olfactory epithelium - consists of structural cells + receptors lining nasal cavity

humans - ~12million receptors
rabbits - ~100million
dog - ~1 billion
bloodhound - ~4billion

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Smell

thousands of different genes that code for different types of olfaction

each neuron only has one receptor on it

signals travel through the cribriform plate and synapse in the olfactory bulb

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Smell

glomeruli are where the receptors terminate onto the next neuron in the olfactory bulb

cranial nerve 1 goes to the brain

any given smell activates many receptors, encoding smell data over many values

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Smell

Categorize

Options (8)

cranial nerve 7

cranial nerve 9

cranial nerve 10

cranial nerve 1

tastant

odorant

olfactory blub

cribiform plate

Organize these options into the right categories

taste

smell

Today we skipped...

• Lateral Geniculate Nucleus, Visual Cortex, Dorsal Extrastriate Pathway,

  Ventral Extrastriate Pathway

• Auditory Pathway, Auditory Cortex

• Somatosensory system

• Motor system

• Memory and neuroplasticity

• Section V