Sensory Information: Chapter 14

• Chapter 14 covers pages 444-467.

Sensory Information

• Chapter 13 explored functional pathways in which neurons generate electrical impulses and supply the CNS with information about the external environment.
• The chapter explores how biological sensory receptors interface with the environment and codify information that travels through the nervous system
• Sensory neurons are explored.

Sensory Neurons

• Sensory Neurons supply the central nervous system with information about the environment with sensory receptors.
• Light-sensitive receptors in retinas perceive space.
• Heat receptors in the skin provide temperature information.
• Chemoreceptors identify blood carbon levels.
• Membranes sense sound vibrations.

Receptor/Stimulus Types

• A stimulus is any form of energy change; sensory receptors convert energy sources, leading to action potentials interpreted by the brain.
• The tongue is a chemoreceptor that creates action potentials unique to chemicals, interpreted as taste.
• Capsaicin is interpreted as heat and dangerous.

Sensory Types

• The tongue detects the presence if specific chemicals.
• Smell detects the presence of chemicals.
• Pressure detects the movement of skin.
• Proprioceptor detects the movement of limbs.
• Balance detects body movement.
• Audio detects sounds waves
• Visual detects changes in light intensity and movement.
• Thermoreceptor detects the flow of heat.

Sensory Organs

• Sensory receptors have highly specialized dendrites.
• The body groups specialized cells into synergistic organs like the eyeball.
• Human eyes contain all major light sensory receptors for synergistic effect and binocular vision.
• The goal is to see how to localize special receptors

Skin Receptors

• The skin has the following receptors cold, hot, touch, pressure, and pain.
• Each receptor's structure accommodates its function.
• Pain receptors are “naked' dendrites throughout the skin; pain is critical as it forces a person to move if they are in danger.

All in Your Head

• All skin receptors process information in the CNS.
• Pain sensation is only in the brain.
• Neurotransmitters or electric probes can create or remove pain if the processing location is known.

What Do We Miss

• The universe is physically lost, even with extremely precise perception.
• Many senses that are lacked were not critical to our survival.
• Sharks detect Electromagnetic Fields.
• Snakes sense thermal wavelengths of EMR.

Sensory Adaptation

• Senses can be fooled, especially regarding temperature.
• Senses do not operate as thermometers but as signalers of change
• Thermoreceptors can depolarize when temperature rapidly changes.
• Bodily receptors can be tricked into not noticing if conditions change slowly enough; this highlighted in a boiled frog experiment.
• Sensory Adaptation occurs when a sensory receptor is accustomed to a stimulus level.
• Neurons do not fire when sensory receptors are accustomed to the stimulus.
• The body communicates that the environmental condition does not feel dangerous.
• Everyday sensory adaptation occurs when we put clothes on or off; we do not get a constant “wearing clothes" stimulus.

Taste Receptors

• Taste receptors react with dangerous chemicals to prevent ingestion of dangerous plants/animals.
• Tongues check for specific ion concentrations.
• Salty food contains Sodium with a positive ion.
• Sodium-rich food is associated as salty, even without table salt.
• Chemical that are dissolved enter a taste pore where the receptor cells wait.
• There are about 10,000 buds are in the human mouth.

Food/ Taste

• The taste of food is chemical irritation of the chemoreceptors in the mouth.
• Chemoreceptors in the nose capture airborne particles from food.
• Smell plays a critical role in tasting food.
• Flavor is perceived via combined input from mouth and nose cells, creating information about what you are ingesting.
• Humans tend to like things they should not - like spicy chilis.
• Taste does a good quality job at discerning humans from true poison.

The Eye

• After exploring how receptors work.
• Eyes are look at a highly complex sensory system.

Parts of The Eye

• The eye comprises many components which are easy to understand
• The intention is from the outside in

Sclera

• The sclera is fibrous and white external, which is the eye’s tough, external covering.
• The sclera maintains eye shape and protects from puncture and impact.
• The eye is the called "white of the eyes" and protects the insides.

Cornea

• The cornea is the outermost layer and transparent part of the sclera.
• Light passes through to enter the sensing region.
• The cornea absorbs oxygen directly from the air, not supplied blood.

Aqueous Humor

• The aqueous humor is the fluid that makes up the cavity directly behind the cornea.
• The aqueous humor provides nutrients to the cornea and the lens.
• The humor maintains constant pressure to help the eye retain its shape.

The Choroid Layer/Iris

• The second layer of the eye is the choroid layer.
• The frontmost part is the iris.
• The iris is the circular muscle that controls entering light.
• The iris controls pupil dilation.
• The iris is where eye color is stored, melanin is colored pigment that makes an opaque barrier.

The Pupil

• The pupil is the opening in the eye that allows light to travel into the eye.
• The iris controls pupil diameter for varied light conditions.
• Wide pupils is for low lights and small is for bright ones.

The Lens

• The lens operates much like a glasses lens, that focuses the image onto the retina (back) and to create the sharpest image possible
• The lens is contorted and bent by ciliary muscles attached to ligaments to help focus the light.
• The lens is dense and strong.

Ciliary Body

• Includes the ring-shaped ciliary muscle.
• When the muscle contracts, the lens becomes thicker.
• When the muscle ceases to contract, the lens becomes thinner and stretched.

Vitreous Humor

• The large chamber behind the lens is the vitreous humor.
• This cloudy jelly like material maintains eye shape and permits light the reach the retina to the back.
• The vitreous fluid makes up the bulk of the eyeball.

Retina

• The innermost layer of the eye in the retina.
• The retina has four additional layers of cells: pigmented epithelium, light-sensitive cells, bipolar cells, and cells of the optic nerve.
• The retina is the layer that those cells reside upon that interpret light.

Retinal Layers

• Pigmented Epithelium is between the choroid layer and the light sensitive cells.
• Pigment granules prevent light scattering.
• Two light-sensitive cells consists of the rods that have a low intensity of light and the cones which have a high intensity of light and that can identify light.
• Both types of cells act as a sensory receptor becoming excited as light hits them.
• Bipolar cells act as interneurons in the eye.
• Bipolar cells transfer information from rods/cones sensory receptors and communicate the information to a series of ganglia.
• Ganglions for the retina, is the final layer that transmit the information received from the eye to the brain.
• Rods and cones are layered back of the eye, but with the bipolar cells in front and the ganglions are in front of them.
• This phenomenon may be related to the high oxygen requirements of the rods and cones, however, it makes placing the light sensors behind other material an unusual order.

Rods

• The Rod is the low light intensity photoreceptor in the eye, and can operate in low light conditions.
• The rod do not detect color.
• Rods are distributed around the fovea for peripheral vision, though colorless

Cones

• The Cone requires much more intense light.
• Therefore they do not activate in low-light conditions
• They are placed in the fovea, and are largely used for direct viewing.

Fovea Centralis

• The Fovea Centralis is a small depression on the back of the eye that process our directed vision.
• It has the highest density of photoreceptors, tightly packed with cones.
• Rods surround the fovea, the actual depression is full of cones.

Cones

• The perception for brain combines the information from multiple cone
• Humans have 3 types of cones, that consist of Red, Blue, and Green.
• Dogs have more rodes.
• Mantis shrimp have 16 cones that they can likely see UV and IR light.

Afterimage Effect

• Afterimages will occur for one of two reasons
• Positive afterimages occur after bright light.
• Negative after images uses sensory adaptation. After looking an image for a long time, the sensory adaption will make the cones exhausted and will fire only red cones creating an image of the flag

Blind Spot

• Due to how the eye layout is, the nerves need to find a way to get out, meaning there is a spot where the optic nerve connects.

The Chemistry of Sight

• Rods contain Rhodopsin formed from vitamin A and opsin.
• Light strikes the Rhodopsin and it breaks apart into retinen (pigment) and opsin (protein).
• Cones have less-light-sensitive chemicals similar to Rhodopsin.
• The division of rhodopsin alters the cell membrane potential and This produces an action potential.
• The pathway releases neurotransmitters at the axon end plate that communicates the message across the synapse toa bipolar cell.
• The impulse is conducted from the bipolar cell to the optic nerve.
• The extreme sensitivity of rhodopsin means that bright light will remain broken down.
• Less sensitive cones work better in high intensity situations.
• As the lens are contorted that as it is bends, it will slow down and to accommodate light and objects.
• The light slows when the lens first hits the cornea then the vitreous humor and lastly the lens.

Accommodation

• The edges are thickest because they are for allowing more light bending to take place.
• The lens is also contorted by the ciliary muscles to become thicker.
• A thicker lens allows for more light drastically then a thin one.

Aging

• As we age, the protective coding is built on the lens.
• As, the lens will eventually require surgery or corrective lens to further accommodate vision.
• If, the object is over 6 mins away than it won't require any accommodation

Vision Defects

• Consider the development and maintenance of vision.
• Apply understanding of vision to a few diseases with proposed solutions.

Vision Eye Diseases

• Glaucoma is a caused by the buildup of Aqueuous humor in Anterior chamber, that in turn blocking and stops the drainage which inturn causes the pressure in the eye

Propose Eye Diseases Solutions

• Laser Surgery
• Tube insertion
• Specialized eye drops

Cataracts

• The lens can become opaque and prevent light from passing.
• Onset of the Cataract caused by hardening of protein & clumping of tissues.

Cataracts Solutions

• There is no way to reverse the fix but we can can slow it.
• The only fix can be to reverse the lens.

Astigmatism

• A common ocular issue will be Astigmatism, which can be treated with surgery or corrective lenses.
• Lens or the cornea have become irregularly shaped

Myopia

• Myopia is where the image will stop in short of the retinal photoreceptors
• The correction is of course corrective lenses.

Hyperopia

• Correction lens or laser surfacing of the cornea to focus of the image.

Mid Chapter Review

• The slides are designed to test knowledge
• What structures the sclera.
• What's the difference between Cone and rod.
• How the rhodopsin leads to an impulses.
• What's the function of Vitreous humor
• Why is pain receptors called “Naked”
• Why does Human is the the blind spot
• When the ciliary muscle is contracted what happened to the lens?

The Human Ear

• Human ear
• Functions
• We tend to think it as a container of wax where that's double as a listening device. that has the other job if maintaining the equilibrium.
• The ear is not a auditory reception but also a role of balance and perception of up and done
• The auditory ossicles: contain the smallest bines in the body.

The Ear

• The 3 sections: We will split this three section the outer, the middle and Inner ear.
• This the other air includes the pinna and the autitory canal
• The pinna and focuses on some and the carry it to processing special sweat it ear wax where us capturing foreign particles.

The Ear Drum

• Starts At tympanic
• Sound vibrations which can Strike drum symphitacly

The Inner and outer parts of the ear

• Includes: Hammer Anvil Stirrups
• The vibrations of the tympanic are ampfly and connected by the connected by the 3 ossicle bones
• Includes: Malleus,Incus are each to serve to focus the sound and energy is being passed.

Air canals

• We're that will strike structure is called a oval structure

Inner and Outer ear

• This structure can permits for equalization of air and two sides of the memphane.
• This will case the plane pop on the plane

Quick recap inner ear

• Sound where the pinna and travels which is connected through canal
• Where sounds strikes against of the tympanic membrane.
• The tympanic are focus of the malleus and then incus.
• From that the focus one will strikes the oval membrane.

Inner Ear

• Then has a dichotomy of structuring, for some and hearing and establishing with equilibirn.
• Then finish explored then we are then going to move with equilibrium and then going to describe.

A snail like shell

• This inner air which is connected with a snail,
• Where interior will be lined with a hair cells.

Hearing

• When where by the stapes then the vibrate sounds will flow into the inner ear.
• This will transmit the the auditory that will sounds has a mechanical, The these are sensed that contains like cell.

More hearing in detail

• Where that can create for the bulges,
• This with where by move and create.

Organ Control

• The organ comes from structures where house the sense where the and the holding apparatus inside the cochlea.
• This structure where with to membrane when sandwiching cells. The waves are moving, This is also where brush the tech with the membrane,
• Which also contains the potential and will be sent back along.

Data for interpreting data

• To this the where we are sensing the time.

Inner ear

• Each hair cell is a part of a sound each sound is
• To The end of the cell from any and what there with damage if they die then it will affect the frequency,
• To that is there a cell is there it will contain. This which called Tinnitus.

Equilibrium

• There where a few more structures and the air to require discussion
• These structures are being noted for hearing. Where to maintain the the body balance.
• This contains canals and vestibule.

How The Body Can Be Balanced

• That is structure one which will static equilibrium from in the body. One is that for singular that what to the the vertical orientation.

Static is one where

• This and the body to to be the where with monitor two fluid set which are with the tristle.
• A small circle where the outer one and where is contained the set with will fire.

Outer fluid

• This will help move the the otoliths with slowly move is internal fluid. That this well help cause the action potential inform the brain.

Semi canals

• Where arranged in right or a circle pattern.

Body Movement in Three Formats

• Body movements or 3 d
• They Are with dynamic which is contained. What is dynamic is information, which is for moving,

Hair Cells

• Where also there are lined each cell.
• This also comes up with a body which are the movement .

Quick Reacap

• For this where we have do feel the recap question and inner air Then we will ask all these
• This structured with is that the with Snail?
• This The purpose or what is the window there for, with the rounded win.
• This what do you know do with the inner Membrane or how?
• What is the tectorial of inner air with it.
• What if that's a with
• What does what are all is 2 primary
• This the function system.

Hearing Loss

• If each with in each complex argument, will be that, a,
• Way by what we can keep in maintaining hearing and equilibrium.

Sensorineuran

• Then for hearing loss can be to to fix all which as in air is.
• Where then can be damage to the and we are connecting.

Hearing Solutions

• There where two solutions This where that are the currently use.

This solutions

• Hearing Aids.
• The implant called to be used. And this the device that can.