Chapter 11- senses

What are the two major classifications of sense organs?

General and Special.

What distinguishes general senses from special senses?

detected by simple receptors throughout the body

What distinguishes special senses from general senses?

detected by complex receptors in specific areas.

What are the major functions of general senses?

Pain, temperature, touch, pressure, and body position.

What are the major functions special senses?

smell, taste, vision, hearing, equilibrium

What are the five types of sensory receptors?

Photoreceptors, Chemoreceptors, Pain receptors, Thermoreceptors, and Mechanoreceptors.

What type of stimulus does photoreceptors respond to?

light (vision)

What type of stimulus does chemoreceptors respond to?

chemical substances (taste and smell)

What type of stimulus does pain receptors respond to?

injury

What type of stimulus does thermoreceptors respond to?

temperature changes (heat and cold)

What type of stimulus does mechanoreceptors respond to?

physical deformation (pressure, touch, vibration)

What is the pathway for general senses detection?

Receptors → Nerve impulse → Spinal cord → Thalamus (or cerebellum) → Brain interpretation.

Which receptors are for the Eyes?

Rods/Cones, organ of Corti, Crista ampullaris, Macula

What is proprioception?

located in tendons/ muscles, The ability to detect the position and movement of body parts.

What are rods responsible for?

Vision in dim light and black-and-white vision.

What is the function of cones in the retina?

They allow color vision and function in bright light.

What are the layers of the eyeball?

Fibrous, Vascular, Inner layer.

What happens to pupils in dim light?

Radial muscles contract, and pupils dilate to let more light in.

What happens to pupils in bright light?

The circular muscles contract, and pupils constrict to limit light entry.

What are the primary components of the eye's fibrous layer?

sclera, cornea, and conjunctiva.

What is the function of the cornea?

To bend light for focusing and act as a transparent window.

What is inflammation of the Cornea?

Keratitis

what is the thin mucous membrane that lines the eyelids and covers the sclera?

Conjunctiva

What gland keeps the conjunctiva moist?

Lacrimal gland (tear production)

What is part of the Vascular Layer of the eye?

Choroid, ciliary muscle, Iris, Lens

What does the iris do?

colored part of the eye, controls pupil size

What does the Choroid do?

contains blood vessels and pigment melanin

What controls lens shape for focusing?

Ciliary Muscle

Where are the lens of the eye? What does it do?

located behind the iris; focuses light on retina

What is part of the inner layer of the eye?

Retina (rods +cones),, Macula Lutea, Fovea Centralis

What is the macula lutea?

A yellowish area near the retina's center, associated with sharp vision.

What medical device is used to view structures like the macula and fovea in the eye?

Ophthalmoscope

What type of cells send information to the brain about da/night cycles, helping regulate the internal clock?

Ganglion cells

What is glaucoma?

A condition where increased pressure in the eye may lead to blindness.

What is the Aqueous humor?

watery fluid in front of lens; provides nutrients and maintains intraocular pressure.

What is the Vitreous Humor?

jelly-like fluid behind lens; maintains shape

What is myopia?

Nearsightedness, where images focus in front of the retina.

What is hyperopia?

Farsightedness, where images focus behind the retina.

What is astigmatism?

Distorted vision due to unequal curvature of the cornea or lens.

What is Presbyopia?

Age-related loss of lens elasticity → inability to bulge for near vision. Corrected with reading glasses

What causes cataracts?

Hardening and loss of transparency in the lens, often due to UV exposure.

What is conjunctivitis also commonly known as?

Pink eye.

What is strabismus?

Condition where eyes fail to align properly, disrupting binocular vision.

What is a convergent squint?

eyes turn toward nose (cross-eyed)

What is a divergent squint?

eyes turn outward

What is retinal detachment?

Separation of the retina from the underlying tissue supporting it.

What is diabetic retinopathy?

A disease caused by diabetes that leads to damage of retinal blood vessels.

What is Galucoma?

excessive intraocular pressure from accumulation of aqueous humor.

A Vitamin A deficiency can cause what condition?

Retinal Degeneration

What is the leading cause of permanent blindness in older adults?

Age- Related Macular degeneration

What condition is inherited, caused by genes on the X chromosome producing abnormal photopigments in cones.

Color Vision Deficiency

What is Nyctalopia?

Night blindness

Pinna is another name for?

Auricle

Auricle (pinna) is what?

The outer ear structure that directs sound waves into the ear canal.

Where is the tragus?

small projection just anterior to the canal opening

What is the medical device used to the view the external canal and the outer surface of the tympanic membrane?

Otoscope

What is the auditory (Eustachian) tube?

A tube connecting the throat to the middle ear that equalizes air pressure.

What is otitis media?

Ear infection causing inflammation and pus in the middle ear.

The middle ear contains which three auditory ossicles?

Malleus, Incus, Stapes

What is the function of the cochlea?

To convert sound vibrations into nerve impulses.

What structure in the ear vibrates when sound waves travel through the acoustic canal?

tympanic membrane

Why does an infection of the throat often spread and cause middle ear infection called otitis media?

the auditory (Eustachian) tube connects throat ↔ middle ear, infections spread and cause otitis media.

What fluid fills the bony labyrinth and the membranous labyrinth of the inner ear?

Perilymph (bony labyrinth) and endolymph (membranous labyrinth).

What are the two types of equilibrium?

Static equilibrium and dynamic equilibrium.

What is static equilibrium?

The sense of gravity when the body is at rest.

What is dynamic equilibrium?

The sense of balance when the head is moving.

What is the primary taste that detects sugars?

Sweet.

Which cranial nerves are primarily involved in taste?

CN VII (facial) and CN IX (glossopharyngeal).

What is the role of olfactory receptors?

To detect chemicals that trigger nerve impulses for smell.

What is adaptation in olfactory receptors?

Decreased sensitivity to odor after prolonged exposure.

What is the process of the visual pathway?

Light enters eye → pupil → refracted → retina → nerve impulse → optic nerve → brain.

What does vision heavily rely on?

The correct functioning of light processing, nerve impulses, and brain interpretation.

What is presbycusis?

Progressive hearing loss associated with aging.

What common condition may cause temporary equilibrium impairment?

Motion sickness.

What is Ménière's disease?

A chronic inner ear disease marked by vertigo and tinnitus.

What does the sense of flavor combine?

Taste, smell, touch, pain receptors, and temperature sensations.

What part of the brain processes olfactory information?

Thalamic and olfactory centers of the brain.

What is nystagmus?

Involuntary eye movement that may be caused by inner ear issues.

What is tinnitus?

Ringing or buzzing in the ears, often related to hearing issues.

What conditions may cause hearing impairment?

Conduction impairment and nerve impairment.

What might changes in the tympanic membrane indicate?

Otitis media due to infection.

What can cause chronic hearing loss?

Noise-induced hearing loss from repeated exposure to loud sounds.

What does the lacrimal gland do?

Produces tears to keep the conjunctiva moist.

What is color vision deficiency?

A genetic condition that impairs the perception of colors.

What is the function of supportive cells in taste buds?

To provide structure and support for the gustatory cells.

What are the main types of gum used in sweetener formulations?

Sugar-free gum typically contains artificial sweeteners.

How do loud sounds affect the ear?

They can damage hair cells in the cochlea, leading to hearing loss.

What is the role of the ciliary muscle?

To change the shape of the lens for focusing.

What type of vision do cones provide?

Color vision in bright light.

What role does taste play in reflex actions like breathing?

It influences to avoid dangerous or harmful substances.

What could changes in visual acuity indicate?

Possible damage or disorders affecting the eye's structures.

What structural changes in the ear can occur due to aging?

Degeneration or decreased sensitivity of mechanoreceptors.

What test measures touch sensitivity on the skin?

Two-point discrimination test.

What is sensory integration?

Combining stimuli from different senses for cohesive perception.

What is the function of the vestibular system?

To provide the brain with information about motion, head position, and spatial orientation.

What is the threshold for sensory perception?

The minimum stimuli level needed to be perceived by the senses.

What is the purpose of the external acoustic canal?

To direct sound waves toward the tympanic membrane.

How does the ear amplify sound?

Through the vibration process involving the ossicles.

What ensures proper drainage of the aqueous humor?

Open channels that allow fluid movement in the eye.

What does light refraction in the eye focus onto?

The retina.