Anatomy and Physiology Honors | Control and Coordination - Senses

Sensing

It is when sensory cells translating stimuli (chemical, electromagnetic, mechanical) into action potentials that our nervous system can integrate.

General Sensory Receptors

They are found in our bodies and are typically modified nerve endings of sensory neurons.

Touch

It is considered a general (somatic) sense

Touch, general sensory receptors

__________ relates to our ability to detect pressure, pain, temperature, and tension through a variety of

__________.

Special Senses

= vision, smell, taste, hearing, and equilibrium.

sensory organs, epithelial structures.

Special senses utilize special sensory receptors in

__________ (like in your ear and eye) and/or

__________ (like your taste buds and olfactory epithelium) in your head.

Vision

The most dominant sense of humans.

Light

= electromagnetic waves

Photoreceptors in the eyes

They convert the light energy → electrical energy (APs) that then travel to the brain.

Eye

The visionary sensory organ.

Protective fat and bony orbits

The eye is surrounded by what?

Eyelids

Eyelashes

Lacrimal apparatus

Eyebrows

Extrinsic eye muscles

What are the accessory structures of the eye?

Eyebrows

They help keep sweat and sunlight out of the eye.

Eyelids and eyelashes

They trigger reflexive blinking to keep the eyes moist.

Lacrimal apparatus

It consists of the lacrimal gland that produces and secretes tears and the ducts that drain the secretions.

Extrinsic eye muscles

They are located on each eyeball and control the eye’s movement.

Fibrous Layers

Vascular Layer

Retina

What are the three layers of the eyeball’s wall?

Fibrous layers

Outermost layer of the eyeball’s walls.

Sclera and cornea

What are part of the fibrous layer?

Sclera

it is the white stuff and the anchoring site for extrinsic eye muscles.

Cornea

The window that lets light into the eyes.

Vascular layer

Middle layer of the eyeball’s wall.

Choroid

Suspensory ligaments (ciliary zonule)

intrinsic eye muscles

What are part of the vascular layer?

Choroid

It supplies all the layers of the eyeball with blood.

Ciliary body

Iris

What are the intrinsic eye muscles?

Ciliary body

rind of muscle tissue around lens

Iris

(colored part of the eye) the ring of smooth muscle between the cornea and lens that contracts and expands to change the size of pupil.

Retina

inner layer of the eyeball

Outer pigmented layer

pigment cells that help absorb light so it doesn’t scatter.

inner neural layer

has tons of neurons and neuroglia which help create pathways for light.

Millions of photoreceptors that convert light energy → APs that travel through the optic nerve to the thalamus, and the visual cortex of the brain.

What does the retina do?

Rods

register black and white

Cone

detect fine detail and color

Lens

It is the convex transparent disc that focuses the light that is allowed in and projects it onto the retina in the inner layer.

Vitreous humor

clear gel that fills the posterior segment of the eye behind the lens.

Aqueous humor

clear fluid that fills the anterior segment in front of the lens.

Chemoreceptors

What does smell (olfaction) and taste (gustation) use to detect molecules in the air and our food?

Odor

Gaseous molecule we smell

Olfactory epithelium

What do molecules hit in the roof of the nasal cavity which has olfactory sensory neurons.

Taste buds

sensory organ of taste

papillae (bumps on tongue)

Where are the taste buds located?

Gustatory epithelial cells

taste receptor cells

Basal epithelial cells

stem cells that make new gustatory epithelial cell

sensory receptor cells → APs → signal to the gustatory cortex of the brain → release digestive enzymes to break down food → ENERGY

How do you taste?

Molecules bind to receptors → APs down the olfactory nerve into the ethmoid bone, eventually to the olfactory bulb that connects to our brain

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travels down the olfactory tract to the olfactory complex

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signal gets sent to the frontal lobe to be identified and to the emotional pathway in our limbic system.

How do we smell?

Ear

sensory organ for hearing and balance (equilibrium)

Mechanical waves

Our ears our designed to receive what kind of waves?

Sound creates vibrations in the air that hit our eardums and cause tiny bones to move internal fluid against the membrane which trigger tiny hair cells to stimulate neurons → APs to the brain.

How do we hear?

Outer Ear

Middle Ear

Inner Ear

What are the three parts of the ear?

Pinna (auricle)

Part of the outer ear and the part we see made out of cartilage.

External acoustic meatus

Part of the outer ear and is called the auditory canal.

External (Outer) Ear

Its function is to catch sound waves and pass them deeper into the ear through the auditory canal eventually hitting the eardrum.

Tympanic Membrane (Eardrum)

It is the connective tissue boundary between the external and middle ear.

Middle Ear

Also known as the tympanic cavity and is a relay station between the outer and inner ear

Malleus (hammer), Incus (anvil), Stapes (stirrup)

What are the three tiny bones of the middle ear?

Amplify sound waves to make them stronger for the inner ear.

What is the function of the middle ear?

Auditory ossicles

They conduct vibrations to the oval window to get the inner ear fluid moving.

Eustachian tube

It is a passage from the middle ear to the pharynx that aids in equalizing pressure around the eardrum.

Inner ear

Also known as a labyrinth (bony and membranous)

Turn physical vibrations into electrical impulses (APs) to travel to the brain.

What is the function of the inner ear?

Vestibule

Semicircular Canals

Cochlea

What are the three parts of the inner ear?

Vestibule

key structure for maintaining balnace

\
head movements cause fluid to stimulate hair cells → send AP through the vestibular nerve.

Semicircular canals

They aid in maintaining balance when head rotates

Cochlea

They contain hair cells that vibrate at different frequencies → stimulating the organ of Corti to send AP through cochlear nerve to the auditory cortex in the brain.