Chapter 9 senses

General & Special Senses

Q: What is a sense?
A: The ability to perceive stimuli.

Q: What is sensation?
A: The conscious awareness of stimuli received by sensory neurons.

Q: What are the two main types of senses?
A: General senses (touch, pain, temperature) and special senses (smell, taste, vision, hearing, balance).

Types of Sensory Receptors

Q: What do mechanoreceptors detect?
A: Movement (touch, pressure, vibration).

Q: What do chemoreceptors detect?
A: Chemicals (e.g., odors, tastes).

Q: What do photoreceptors detect?
A: Light (vision).

Q: What do thermoreceptors detect?
A: Temperature changes.

Q: What do nociceptors detect?
A: Pain.

Touch & Pain Receptors

Q: What do Merkel’s disks detect?
A: Light touch and pressure.

Q: What do Meissner corpuscles detect?
A: Localizing tactile sensations.

Q: What do Pacinian corpuscles detect?
A: Deep pressure, vibration, and position.

Q: What are the two types of pain?
A: Localized (sharp, fast) and diffuse (burning, slow).

Q: What is referred pain?
A: Pain perceived in a different location than the source (e.g., heart attack causing arm pain).

Olfaction (Smell)

Q: What type of receptors are involved in olfaction?
A: Chemoreceptors.

Q: What cranial nerve carries olfactory information?
A: Cranial Nerve I (Olfactory nerve).

Q: Where is smell processed in the brain?
A: The frontal and temporal lobes.

Gustation (Taste)

Q: Where are taste buds located?
A: Tongue, hard palate, throat.

Q: What are the five basic tastes?
A: Sweet, sour, salty, bitter, umami.

Q: Which cranial nerves carry taste information?
A: Facial (CN VII), Glossopharyngeal (CN IX), Vagus (CN X).

Vision – Eye Structures

Q: What protects the eye from sweat and sunlight?
A: Eyebrows.

Q: What produces tears?
A: Lacrimal glands.

Q: What are the three layers (tunics) of the eye?
A: Fibrous (sclera & cornea), Vascular (choroid, ciliary body, iris), Nervous (retina).

Q: What is the function of the cornea?
A: Focuses light onto the retina.

Q: What controls the amount of light entering the eye?
A: The pupil.

Q: What part of the retina is responsible for sharp vision?
A: The fovea centralis.

Q: What is the blind spot of the eye?
A: The optic disc (where the optic nerve exits).

Photoreceptors & Vision Pathways

Q: What are the two types of photoreceptors?
A: Rods (black & white vision, low light) and Cones (color vision, bright light).

Q: What is rhodopsin?
A: A photosensitive pigment in rods.

Q: What causes color blindness?
A: A lack or deficiency of certain cones.

Q: What is myopia?
A: Nearsightedness (image focused in front of retina).

Q: What is hyperopia?
A: Farsightedness (image focused behind retina).

Hearing – Structures of the Ear

Q: What are the three regions of the ear?
A: Outer ear, middle ear, inner ear.

Q: What structure separates the outer and middle ear?
A: The tympanic membrane (eardrum).

Q: What are the three auditory ossicles?
A: Malleus (hammer), Incus (anvil), Stapes (stirrup).

Q: What structure transmits sound waves into the cochlea?
A: The oval window.

Q: Where does hearing take place?
A: The cochlea.

Hearing & Balance

Q: What cranial nerve is responsible for hearing and balance?
A: Vestibulocochlear nerve (CN VIII).

Q: What is static equilibrium?
A: Detects head position relative to gravity (vestibule).

Q: What is dynamic equilibrium?
A: Detects head movement (semicircular canals).

Q: What part of the ear is responsible for detecting rotational movements?
A: Semicircular canals.

Ear Disorders

Q: What is presbycusis?
A: Age-related hearing loss.

Q: What is otitis media?
A: Middle ear infection.

Q: What is tinnitus?
A: Ringing in the ears.

Q: What is Meniere’s disease?
A: Inner ear disorder causing vertigo and hearing loss.