Exam 4: Ch. 16

Question 1

Types of Touch Receptors

Answer 1

Pacinian Corpuscle - Deep Pressure sensing
Messiner’s Corpuscle - Light Pressure sensing (fingertips reading braille)
Free Nerve Endings - Primary Pain Detectors & Temperature Sensing
Merkel Discs - Epidermal structures that stimulate Merkel Cells to relay pain signals
End Bulb - Possible Temperature sensing
Ruffini Corpuscle - Stretch sensing receptors that give a sense of control and position

Question 2

Wilhelm Krause

Answer 2

A German anatomist whom the Krause End Bulb was named after

Question 3

Angelo Ruffini

Answer 3

An Italian histologist whom the Ruffini Corpuscle was named after

Question 4

Two-Point Discrimination Test

Answer 4

Two points of stimuli are placed on the skin and moved away from each other until the recipient can tell that there are two stimuli. In areas where neurons are less abundant and are used to detect touch over large areas (Shoulders), the stimuli will be farther apart. In areas with a greater density of neurons (fingertips), the stimuli will be relatively close together.

Question 5

Four Universal Taste Receptors

Answer 5

Sweet
Salty
Sour
Bitter

Question 6

Where are the Taste Receptors Distributed?

Answer 6

Sweet - Tip of the tongue
Salty - Sides of the tongue just proximal to the sweet receptors
Sour - Proximal to the salty receptors, along the sides of the wider tongue body
Bitter - Along the base/back of the tongue

Question 7

Chemoreceptive Senses

Answer 7

Taste & Smell are chemoreceptive senses because they detect CHEMICALS.

In taste, chemicals are detected as liquids

In smell, chemicals are detected as gasses

Question 8

What are the two taste receptors only seen in a percentage of the population?

Answer 8

Umami & Fat/Savory

Question 9

What structures make up the Gustatory Pathway?

Answer 9

The brain (thalamus), Cranial Nerves (Facial, Glossopharyngeal, & Vagus), & the tongue/oral cavity

The Facial Nerve is responsible for taste in the anterior 2/3 of the tongue

The Glossopharyngeal & Vagus Nerves are responsible for taste in the posterior 1/3 of the tongue

Question 10

What is the olfactory epithelium?

Answer 10

The small patch where sensory structures for smell are located

Question 11

Cribriform Plate

Answer 11

A thin bony plate (Ethmoid Bone) between the olfactory epithelium & the olfactory bulb/nerve.

Question 12

Retronasal Aroma

Answer 12

A method of sensing the smell of food by which gasses enter the nasal cavity through the pharynx when we chew. The warmth of the oral cavity in combination with the saliva and mechanical chewing causes gasses to be released.

Question 13

Common Odorant Categories

Answer 13

Flowery - flowers
Spicy - curry
Camphoraceous - Vapo-rub
Musky - body odor
Putrid - decay
Ethereal - gasoline

Question 14

Olfactory Gland

Answer 14

A gland that resides in the lamina propria connective tissue, just above the olfactory epithelium. These glands produce mucus that replaces the mucus lining the olfactory epithelium so that new scents can be detected.

Lingering scents occur when chemicals heavily saturate the mucus or when not enough mucus is formed

Question 15

George Wald

Answer 15

He received the Nobel Prize in 1967 for his discoveries concerning the physiological and chemical visual processes in the eye

Question 16

Important Accessory Structures of the Eye

Answer 16

Eyebrow - Helps to shunt away moisture that would otherwise enter the eye (rain or sweat)

Eyelashes - Helps to deflect particles from reaching the surface of the eye (like a broom)

Medial Commussure - Houses the lacrimal caruncle

Eyelids - Tissues that are crucial for cleaning the surface of the eye

Question 17

The Journey of Lacrimal Fluid

Answer 17

Tears are produced in the lacrimal gland and flow diagonally across the eye and into the lacrimal punctum. From the lacrimal punctum, lacrimal fluid flows through the lacrimal canaliculus and into the lacrimal sac until it drains into the nasolacrimal duct.

Question 18

Which Cranial Nerves control which Extrinsic Eye Muscles?

Answer 18

Abducens - Lateral Rectus
Oculomotor - Medial, Superior, and Inferior Rectus & the Inferior Oblique
Trochlear - Superior Oblique

Question 19

Which muscles cause the pupil to shrink in bright light?

Answer 19

The Circular Muscles parasympathetically contract to shrink the pupil

Question 20

Which muscles cause the pupil to dilate in dim light?

Answer 20

The Radial Muscles sympathetically contract to dilate the pupil

Question 21

Emmetropic Eye Shape

Answer 21

Normal Eye Shape, Normal Vision

Question 22

Hyperopic Eye Shape

Answer 22

The eye is too short front to back, thus light is focused on a place outside of the eye entirely, Farsighted Vision, Remedied via Convex Lenses

Question 23

Myopic Eye Shape

Answer 23

The eye is too long front to back, thus light is focused in the center of the eye, Nearsighted Vision, Remedied via Concave Lenses

Question 24

Photoreceptive Sense

Answer 24

Vision is the only photoreceptive sense. Photoreception is the ability to detect photons of light energy

Question 25

Photoreceptive Cells

Answer 25

Rods - Detect light/dark
Cones - Detect colors & allow for color vision

Question 26

Structures within Rod Photoreceptive Cells

Answer 26

Discs are stacked within the cell membrane.

A single disc is composed of PLB with Opsin proteins along it.

Opsin is a pigment molecule that contains Retinal (a molecule that comes in 2 forms)

Cis-Retinal is the bent version of Retinal that allows humans to see better in the dark
Trans-Retinal is the straight version of Retinal that allows humans to see better in areas with lots of light

Question 27

Classifications of Cones

Answer 27

Blue - Short wavelength
Green - Medium wavelength
Red - Long wavelength

Question 28

Red-Green Colorblindness

Answer 28

The most common form of colorblindness, this condition makes it difficult to tell the difference between red and green. ~8% of the male population has at least some form of red-green colorblindness. <1% of females have red-green color blindness. This is because the gene for the condition is X-linked

Question 29

Binocular Vision

Answer 29

When an animal has two eyes that “face forward,” allowing the perception of a single, 3D image of its surroundings.

Binocular vision is important for Depth Perception

Question 30

Mechanoreceptive Senses

Answer 30

Touch & Hearing are mechanoreceptive senses because they rely on other structures to detect movement and provide feedback/stimulus

Question 31

Structures of the Outer Ear

Answer 31

Lobule - Earlobe
Pinna - Funnel-shaped “flap” of the ear
Helix - The outer border/curve of the pinna

Question 32

What are the three zones of the ear & their border indicators?

Answer 32

Outer Ear - From the pinna to the tympanic membrane

Middle Ear - From the tympanic membrane to the oval window

Inner Ear - From the oval window to the Vestibulocochlear Nerve

Question 33

What is the purpose of the Auditory (Eustachian) Tube?

Answer 33

Pressure regulation

In infants, the tube is nearly horizontal. In adults, the tube runs diagonally. This is because infants are more prone to ear infections and need better/faster drainage because fluid collects more rapidly.

Question 34

What are the three bones of the ear?

Answer 34

Malleus - The hammer
Stapes - The stirrup
Incus - The anvil

Question 35

Muscles of the ear

Answer 35

Tensor Tympani Muscle - Attaches to the malleus
Stapedius Muscle - Attaches to the stapes

Question 36

Structures of the Inner Ear

Answer 36

Cochlea - The spiral cavity of the inner ear containing the organ of Corti. Produces nerve impulses in response to sound vibrations

Vestibule - A chamber/opening into another, the central cavity of the inner ear labyrinth. Contains patches of tissue called maculae

Semicircular Canals - Three fluid-filled bony channels in the inner ear. They are positioned at right angles to one another in order to cover all planes of space. They provide the brain with orientational information and are used to maintain balance

Question 37

Sound Measurements

Answer 37

Wavelength - The measure between two peaks of a sound wave, correlates to the pitch (low or high) of a sound

Amplitude - The height of a sound wave, correlates to the strength/volume of the sound

Question 38

Structure of the Macula of the Ear

Answer 38

A layer of columnar support cells contains Vestibular Nerve endings & Hair Cells

Hair Cells contain one Kinocilium (a strand w/ a bulbous end) and several Stereocilia (uniform, straight strands)

On top of the hair bundles lays the Otolithic Membrane

Atop the Otolithic Membrane lays an array of Otoliths (aka Otolithic Crystals)

Question 39

How does the Macula of the Ear function?

Answer 39

When the head is positioned straight up and down, the gravitational pull is equal along the Otolithic Crystals, thus Action Potentials are generated at the same frequency across the Macula.

When the head tilts to one side, the Otolithic Crystals fall differently, applying more pressure to some of the Vestibularcochlear Nerves, causing those nerves to generate action potentials at a different rate

Question 40

Crista Ampullaris

Answer 40

The ends of the Semicircular Canals are connected to Vestibular Nerves via structures called Cupulas. Each cupula detects the flow of endolymph within the semicircular canals. These structures are present in each of the 3 canals per ear, allowing the brain to discern movement in all three dimensions

Question 41

Types of Papillae

Answer 41

Fungiform - The majority of the papillae on the tongue surface

Circumvallate - The “V” shaped papillae located on the back of the tongue

Foliate - The “gill” shaped taste receptors on the sides of the tongue

Question 42

Papilla/Taste Bud Structure

Answer 42

Each papilla is composed of epithelium and connective tissue

Gustatory cells are embedded in the epithelium of the papillae

Sensory Nerve Fibers innervate the gustatory cells

Gustatory cells have gustatory hairs emerging from the taste pores, allowing liquids to enter for taste sensations

Question 43

What is the function of the tensor tympani & Stapedius muscles?

Answer 43

These muscles work together to help the ear bones modulate sound waves

Question 44

Hair Cells of the ear

Answer 44

Kinocilia - Longer, bulb-shaped ends, connects the otolithic membrane to the hair cells, only one present.

Stereocilia - Shorter, cylindrical, transduces the pressure regulation stimuli to the vestibular nerves, several present per bundle.