Chapter 16 – The Special Senses Flashcards

Flashcards covering the key concepts from the lecture notes on Chapter 16 – The Special Senses.

What is the general function of sensory receptors?

Detect and respond to stimuli and send the info to CNS which is done via a sensory neuron

What role does the thalamus play in sensation?

The thalamus filters the stimuli and go to where it needs to go. Also decides if we should feel these sensations.

What is the difference between tonic and phasic receptors? Provide examples.

Tonic receptors adapt slowly (e.g., muscle spindle), while phasic receptors adapt quickly (e.g., root hair plexus).

Define “adaptation”

A diminished sensitivity of a sensory receptor to a continuous stimuli.

Where are the following receptors located: general, somatic, visceral, and special senses?

General senses are all around our bodies, somatic senses are in our skin and mucous membranes, visceral senses are in our organs and blood vessels, and special senses are in localized areas in the head.

What is the difference between exteroceptors, interoceptors, and proprioceptors?

Exteroceptors detect stimuli in the environment, interoceptors detect stimuli inside our bodies, and proprioceptors detect limb movement in our bodies.

What modality does each of the following receptor types respond to: chemoreceptors, thermoreceptors, photoreceptors, mechanoreceptors, nociceptors?

Chemoreceptors detect chemicals, thermoreceptors detect temperature, photoreceptors detect changes in light, mechanoreceptors detect changes in the cell membrane, and nociceptors detect pain.

What type of receptor are tactile receptors and where are they located?

Tactile receptors are tonic and are found throughout the skin.

What is the difference between unencapsulated and encapsulated receptors?

Unencapsulated receptors don't have a capsule, while encapsulated receptors have a capsule.

Which receptors are unencapsulated? What do each of these receptors sense?

Free nerve endings (detect temperature, pain, and light pressure), root hair plexuses (hair movement), and tactile discs (light touch).

Which receptors are encapsulated? What do each of these receptors sense?

End bulbs (light touch, vibration), lamellated corpuscles (deep touch, coarse), bulbous corpuscles (continuous pressure), and tactile corpuscles (discriminative touch).

List three types of proprioceptors and their functional significance.

Muscle spindle (detects the stretch of skeletal muscle), tendon organ (stretch of the tendon), and joint kinesthetic receptor (stretch of the joint).

What type of receptor is used to detect odorants? What must the odorants do in order to be sensed?

The chemoreceptor detects odorants and odorants must dissolve in our mucus in order to be detected.

What is the sensory organ for olfaction?

Olfactory epithelium

Name the three cells that are a part of the olfactory sensory organ and define each of their roles.

Olfactory receptor cells (detect odor), supporting cells (support olfactory receptor cells), and basal cells (divide and make new cells).

What is the lamina propria

Its made of loose CT and located underneath or deep in the olfactory epithelium

What is located on the dendrite of an olfactory receptor cell and what is its function?

Olfactory hairs which have chemoreceptors responsible for detecting chemicals/molecules aka help in process of detecting smells

When the axons of multiple olfactory receptor cells are bundled together what do they form? What opening do they travel through and which cranial bone are those openings located in? Where do they synapse?

The axons form our olfactory nerve (CN I) and they go through the olfactory foramina (next to the cribiform plate on ethmoid bone) then they enter(synapse) on the olfactory bulb

What is within the olfactory glomeruli of the olfactory bulb?

Mitral cells and tufted cells

Some axons from olfactory bulb go to the primary olfactory cortex in order for us to perceive smell. What lobe is this cortex located in?

Temporal lobe

Why is it functionally significant that some axons from the olfactory bulb go to the hypothalamus and amygdala (limbic system)?

It goes to the limbic system. Its functionally significant because this system is associated with emotions

What structure is NOT seen in the pathway of olfaction?

THALAMUS

Is the sense of smell tonic or phasic?'

Its phasic because the constant exposure diminishes its strength over time at a fast rate

What type of receptor is used to detect tastants? What other receptor types are also associated with the sense of taste?

Gustatory cells primarily use chemoreceptors. Mechanoreceptors detect texture, thermoreceptors detect temperature.

Describe the shapes and locations of fungiform, foliate, and vallate papillae.

Fungiform: mushroom-shaped, tips and sides of tongue, few taste buds. Foliate: leaf-shaped, posterior and lateral tongue, few taste buds (mostly in children). Vallate: posterior tongue, least numerous, most taste buds.

Name the three cells that are within the taste buds and define each of their roles.

Gustatory cells (sensors of taste), supporting cells (keep gustatory cells alive), and basal cells (replace gustatory cells).

Which cranial nerves are providing taste sensation and what location are they specific to?

Facial nerve (CN VII)- anterior 2/3 of tongue, Glossopharyngeal Nerve (CN IX)- posterior 1/3 of tongue, Vagus Nerve (CN X)- throat

The cranial nerves that control taste travel to the medulla oblongata and synapse there. What is the specific part of the medulla oblongata that they synapse in?

Nucleus solitaris

What type of reflexes occur due to the taste pathway synapsing in the medulla oblongata?

Reflexive salivation and stomach secretions. This can cause the gag/vomiting reflex.

After the medulla oblongata, the taste pathway travels to what part of the brain for processing?

Thalamus

After the thalamus, the taste pathway travels to the primary gustatory cortex where in the brain is that?

Insula

What are the 5 basic tastes?

Sweet, salty, sour, bitter, umani

For each of the extrinsic eye muscles, state what direction they move the eye.

Medial rectus (moves eye medially), lateral rectus (moves eye laterally), inferior rectus (moves eye inferiorly), superior rectus (moves eye superiorly), inferior oblique, superior oblique.

What is the functional significance of the eyebrows?

Nonverbal communication and protection

The eyelids are also called palpebrae. What is their functional significance?

Protective covering aka blink

What reflex is triggered by the receptor at the base of the eyelashes? What type of secretion comes out of the gland associated with the eyelashes?

Blinking reflex which prevents things from entering eyes. They also have a oil glands which secrete oil

What does the conjunctiva cover? Why is it important that the conjunctiva does NOT cover the cornea?

It covers the sclera and internal eyelid which prevents things from moving further into the eye. Because it would hinder our ability to see

Where are tears drained?

Its drained through the lacrimonasal ducts and into the nose

The following structures are a part of this layer: the sclera and the cornea. Describe each of them

Sclera (the white of the eye around the eye), Cornea (clear covering over the eye)

What is the functional significance of melanocytes in the choroid?

Absorbs extra light

How does the pupil react to bright light?

constricts (turns small)

How does the pupil react to low light?

dilates (turns big)

What is in the inner neural layer of the retina?

Inner layer that contains photoreceptor cells

What is the function of the lens?

To focus light in order to see a clear image

What type of fluid is in the anterior cavity?

Aqueous humor

What structure separates the anterior cavity into the two chambers?

The iris separate the two chambers

What type of fluid is in the posterior cavity?

Vitreous humor

What is the main function of photoreceptor cells?

Main function is to absorb light and generate an action potential to see an image

What do Rods photoreceptor cells detect?

Detect dim light

What do Cones photoreceptor cells detect?

detect bright light and color

What do the axons of the ganglion cells form?

Forms the optic nerve

Where in the neural layer are there no photoreceptors?

No photoreceptor cells

Where in the neural layer is there the best vision?

Fovea centralis

Which structures are responsible for refraction?

Cornea and lens can change shape to bend light

What shape is the lens for vision far away?

Flatten the lens

What shape is the lens for vision up close?

Curves the lens

What size is the pupil for far sightedness?

dilates

What size is the pupil for near sightedness?

constrict

What does Rods= rhodopsin do for the photoreceptors?

perceives dim light or black and white colors

What does Cones= photopsin do for the photoreceptors?

Perceives bright light or color

Blue cones, green cones, and red cones

What color cones are there

After the thalamus the axons will go to the primary vision cortex. What lobe is this cortex in?

Occipital lobe

What is the functional significance of having visual input go to the midbrain?

Allows us to make reflexive movements to respond to vision

Hyperopia is farsightedness which means you can see and is due to the eyeball being too _.

Far, short

Myopia is farsightedness which means you can see and is due to the eyeball being too _.

Far, long

Auricle:

outside part we can visibly see

What is the functional purpose of cerumen?

Protects our tympanic membrane

tympanic membrane:

the ear drum

What is the functional significance of the auditory tube?

Region where we equalize pressure in the ear

Malleus:

1st bone

Incus:

2nd bone

Stapes:

3rd bone

What type of fluid is found in the cochlear duct?

Endolymph

Where is the sensory structure for hearing?

The spiral organ

The hair cells are resting on the membrane.

basilar

The hair cells will contact the membrane to send signals to the brain.

tectorical

The external ear is filled with ___, the middle ear is filled with __, and the inner ear is filled with .

Air, air, fluid

What does the pitch of sound depends on?

Higher frequency sounds = high pitch. Lower/lesser frequency sounds= low pitch

What is does the loudness of sound depends on?

More movement= louder. Less movement=softer

Which inner ear structure is associated with the awareness and monitoring of the position of the head?

Vestibular apparatus

Which specific structures are involved in detecting static equilibrium?

The utricle and saccule are involved in the detection of this movement

Where is the sensory receptor involved in Static equilibrium located?

The macula is the sensory receptor. Its in the vestibule

What leads to neurotransmitter release when the head moves during Static equilibrium?

The otolith(gelatinous layer) will move with the momentum which signals to the brain we are moving

Which specific structures are involved in detecting dynamic equilibrium?

The semicircular ducts are involved

Where is the sensory receptor involved in dynamic equilibrium located?

The ampulla is the sensory receptor. It is @ the base of the semicircular canals

What leads to neurotransmitter release when the head moves during Dynamic equilibrium?

When the endolymph leads to the bending of the hair cells in the ampulla it releases a neurotransmitter