Something To Settle The Nerves!!

(An in depth look into the nervous system through recipes!)

Marisa, Courtney, Nathan, Lindsey, Victoria, & Braxten

Volume 3

In this section: • Sensory Receptors • Special Senses

Ingredients: Types, distribution, and functions of receptors

1. Location: 1. Exteroceptors 2. Visceroceptors 3. Proprioceptors

2. Stimulus Detected: 1. Mechanoreceptors 2. Chemoreceptors 3. Thermoreceptors 4. Nociceptors 5. Photoreceptors

3. Structure: 1. Free Nerve Ending 2. Root Hair Plexuses 3. Merkel Disks 4. Meissner Corpuscle 5. Pacinian Corpuscles 6. Muscle Spindles 7. Golgi Tendon Organs

Recipe: Sensory Receptors

Directions: LOCATION

1. Exteroceptors: Are located on or very near the body surface and respond most frequently to stimuli that are external to the body. Examples: Include those that detect pressure, touch, pain, and temperature.

2. Visceroceptors: Also called interceptors. Located internally, often within the substance of body organs (viscera), and when stimulated provide information about the internal environment. Examples: Include mediating sensations such as hunger an thirst.

3. Proprioceptors: Special type of Visceroceptors. Located in skeletal muscles, joint capsules, and tendons. Provide us with information about body movement, orientation in space, and muscle stretch. Activated by two types of proprioceptors, called tonic and phasic receptors.

STIMULUS DETECTED 1. Mechanoreceptors: Activated by mechanical stimuli that is some way “deform” or change the

position of the receptor, resulting in the generation of a receptor potential. Examples: Pressure applied to the skin or to blood vessels, or cause be stretch or pressure in muscle, tendon, or lung tissue.

2. Chemoreceptors: Activated by either the amount or the changing concentration of certain chemicals. Examples: Sense of taste and smell.

3. Thermoreceptors: Activated by heat or cold. 4. Nociceptors: Activated by intense stimuli of any type that results in tissue damage. 5. Photoreceptors: Found only in the eye. Respond to light stimuli if the intensity is great enough

to generate a receptor potential.

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Directions Continue: STRUCTURE

1. Free nerve ending- simplest, most common, and most widely distributed sensory receptors. They are located both on the body surface and in the deep visceral organs (1) 2. Root hair plexuses- delicate, web like arrangements of free nerve endings that surround the hair follicles and detect hair movement (1) 3. Merkel disks- flattened or disk shaped variation of free nerve ending, responsible for mediating sensations of light or discriminate touch (1) 4. Meissner Corpuscle- relatively large and ovoid- or egg-shaped mechanoreceptors located close to the skin and detect light touch. They are most numerous on hairless areas of the shin like the nipples, fingertips and lips. (1) 5. Pacinian Corpuscles- large mechanoreceptors, which are found deep in the dermis of the skin, especial in the hands and feet, are also numerous in joint capsules. They respond quickly to the sensation of deep pressure, high frequency vibration, and stretch. Although they are quick to respond these receptors adapt quickly, and the sensation they evoke rarely lasts for long. (1) 6. Muscle Spindles- a type of stretch receptor that consists of a discrete grouping of about 5 – 10 modified muscle fibers, which are surrounded by a delicate capsule. (1) 7. Golgi tendon Organs- located at the point of junction between muscle tissue and tendon. Consists of dendrites of sensory nerves called type Ib nerve fibers. These receptors work opposite the muscle spindles, they are stimulated but excessive muscle contraction and when activated, cause the muscle to relax. (1)

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Ingredients: 1. Smell:

1. Olfactory Receptors 2. Olfactory Pathways 3. Compare Olfaction in a Human and with a canine

2. Taste: 1. Taste Buds 2. Neural Pathway

3. Hearing: 1. Describe Mechanism of hearing 2. Detail Neuronal Pathway of hearing

4. Balance: 1. Sense of balance 2. Dynamic equilibrium

5. Vision: 1. Structure of eye 2. Cavities and humors 3. Muscles 4. Accessory structure

6. Process of Seeing: 1. Formation of retinal image 2. Role of phototpigments

1. Rods 2. Cones

3. Answer the quesitons 1. Why don’t deer see Hunters who wear bright orange? 2. What is the difference between “nearsighted” and farsighted”? How are each of these

corrected?

Recipe: Special Senses

Directions SMELL

1. Olfactory Receptors (11): The olfactory receptor, also called the smell receptor, they are proteins that group odor molecules and play a central role in the sensce of smell. Olfactory receptors group on Olfactory receptor cells in groups in small areas in the back of the nasal cavity.

2. Olfactory Pathways (1): If the level of odor-producing chemicals dissolved in the mucus surrounding the olfactory cilia reaches a threshold level, a receptor potential and, then, an action potential will be generated and passed to the olfactory nerves in the olfactory bulb. From there, the impulse passes through the olfactory tract and into the thalamic and olfactory centers of the brain for interpretation, integration, and memory storage.

3. Olfaction in a Human and with a canine (12): Dogs possess a highly developed Olfactory Lobe in their brains, they also have an extra olfactory chamber called the vemeronasal organ, this gives the canine the upper hand when sniffing even the slightest scent out of the air.

TASTE 1. Taste Buds (13): A small organ located on the tongue that functions in the perception

of taste. taste receptor cells occur on the tongue in groups of 50-150 each group forms a taste bud.

2. Neutral Pathway (14): Sensory nerve cells feed information to the brain from every part of the body, external and internal. The brain evaluates the data, then sends directives through the motor nerve cells to muscles and glands, causing them to take suitable action.

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Directions Continued: HEARING

1. Description of mechanism of hearing: The ear is comprised of three portions: an outer ear (external), a middle ear and inner ear. Each part performs an important function in the process of hearing. 2. Detailed neuronal pathway of hearing: begins in the cochlear nerve, which is a division of the acoustic nerve that conducts auditory stimuli to the brain. • The outer (external) ear consists of an auricle and the ear canal. These structures

gather the sound and direct it towards the eardrum (tympanic membrane). 3. Mechanism Of Hearing- Sound is created by vibrations that may occur in air, fluid, or

sold material. When we speak, for example, the vibrating vocal cords create sound waves by producing vibrations in air passing over them.

BALANCE

1. Describe sense of balance: Sense of balance, which is a sensory system located in the structures of the ear that registers as the orientation of the head. 2. Describe dynamic equilibrium: the condition of balance between varying, shifting, and opposing forces that is characteristic of living processes.

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Directions Continued: VISION

1. Structure of Eye: Coats of the eyeball contain three layers of tissues that make up the eyeball. Sclera(outer coat)- tough, white, fibrous tissue; contains the cornea(transport anterior portion) and the canal of schema(found deep in the sclera.) Choroid(middle coat)-contains many blood vessels and a large amount of pigment. Retina (incomplete innermost coat of the eyeball) three layers make up the sensory retina; Photoreceptor neurons, bipolar neurons, and ganglionic neurons.

2. Cavities & Humors: Cavities eyeball has a large interior space that divided into two

cavities. Anterior Cavity-lies in front of the lens and also has to subdivisions, the anterior

and posterior chambers. Posterior Cavity-occupies all the space posterior to the lens,

ligament, and ciliary body. Humors: Aqueous humor- fills both chambers of the anterior

cavity; a clear watery fluid that leaks when the eye has an injury. Vitreous humor-fills the

posterior chamber; helps to maintain intraocular pressure and works with the aqueous

humor to give the eye its shape.

3. Muscles: There are two types of eye muscles. Extrinsic eye muscles-skeletal muscles that attach to the outside of the eyeball and to the bones of the orbit; the muscles are named according to their position in the eyeball, such as superior, inferior, medial, etc. Intrinsic eye muscles- smooth muscles in the eye such as, iris (regulates pupil size) and ciliary muscle (controls shape of lens)

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Directions Continued: PROCESS OF SEEING:

4. Accessory Structures Description of formation of Retinal Image: Refract light rays- deflecting or bending of light rays produced by light rays passing one medium into another; cornea, aqueous, humor, lens, and vitreous humor are the refracting medias. Accommodation of lens- it increase in curvature of the lens to give a better refraction for near vision. Constriction of pupil-muscles of iris are important it the formation of retinal images; the constriction prevents divergent rays from object from entering the eye through the cornea and lens. Convergence of eyes-movement of the two eyeballs inward so their visual axes come together at the object viewed; for convergence to occur, a balance must exist between opposing extrinsic muscles.

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Detailed Image &

Structure of the eye!

Photo pigments Rods Cones Hunters in orange Nearsighted Farsighted

PROCESS OF SEEING: Ingredients:

Directions:

First add the Photo pigments: light-sensitive pigmented compounds that are found in the outer (distal) are of both types of photoreceptors near the pigmented retina Can be broken down into glycoprotein called opsin and vitamin a derivative called retinal, which acts light absorbing portion of all photo pigments The photo pigments contain Rods-single photo pigment found in rods is named rhodopsin. Highly light sensitive that even in dim light causes a rapid breakdown of the photopigment into its opsin and retnil components. Light causes the retnil to change shape and opsin to expand.

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Directions Continued:

Be sure the photo pigment contains Cones- 3 types in retina. Primary colors (red green and blue) reflect light rays of a different wave length each wave length initiates an impulse and breaks down. Less sensitive to light, so brighter light is necessary for breakdown Make sure that your ingredients do not include: Near sighted- can only see objects up close Far sighted- can only see objects clearly in the distance. If you do have either of these ingredients, they can be removed by: Treatment near sighted- refractive surgery, glasses, and contact lenses Treatment far sighted- glasses, contacts, and Lasik eye surgery *fun fact: Deer have no red sensitive cone cells in their eyes, therefore they cannot tell red or orange from green or brown

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Directions Continued: