Sense organs Flashcards
→ listing the sense organs → detailed anatomy of each organ → cover basic physiology of sense and how that links to nervous system
What is the primary function of sense organs?
To take information from the external environment and convert it into neural signals for the nervous system
What is transduction in sensory systems?
The conversion of external stimuli (light, sound waves, chemicals) into electrical signals for the nervous system
What are the five primary sensory systems?
Sight, Taste, Touch, Smell (Olfaction), and Hearing
How do sensory organs convert external information?
Through transduction, where stimuli like light and sound waves are converted into electrical signals
What is another name for the eyeball?
The globe
What structures provide support to the eye?
Ocular adnexa (muscles, eyelashes, eyelids).
Lacrimal apparatus (tear glands).
Extraocular muscles.
What is the function of photoreceptors in the eye?
To detect light and convert it into electrical signals for vision
What is the function of the ocular adnexa?
To protect the cornea and keep the eye moist
What are the components of the ocular adnexa?
- Palpebrae (eyelids): Includes three eyelids (upper, lower, and third eyelid).
- Eyelashes: Help protect the eye from debris.
- Tear glands: Keep the eye moist.
What is the third eyelid, and what is its function?
A mucous membrane that helps protect the eye and contributes to 50% of the tear film
What are the three eyelids in animals?
Upper eyelid.
Lower eyelid.
Third eyelid (a mucous membrane from the ventromedial conjunctival sac).
What are the three layers of the tear film?
Oily layer (superficial).
Aqueous layer (middle).
Thin glycoprotein layer (deep).
How does lacrimal drainage differ in species?
Dogs → Have large puncta (tear ducts).
Horses → Have small puncta.
What is the pertorbita?
A conical fibrous membrane that lines the orbit of the eye
What are the three layers of the globe (eyeball)?
Fibrous tunic.
Vascular tunic.
Nervous tunic.
What is the fibrous tunic, and what are its components?
Sclera → Dense network of collagen and elastic fibers.
Cornea → Transparent collagen fibers in lamellar form.
How does the cornea shape differ in species?
Carnivores → Rounded cornea.
Herbivores → Oval cornea.
What is the vascular tunic, and what is its function?
- Contains pigment cells and blood vessels.
- Functions include:
Blood supply to the eye.
Regulation of lens suspension and pupil size.
Aqueous humor production.
What are the three key components of the vascular tunic?
- Choroid → Inner layer with reflective properties.
- Iris → Controls pupil size via melanin and muscles.
- Ciliary body → Produces aqueous humor and supports the lens.
What muscles control pupil size?
Miosis → Pupil constriction.
Mydriasis → Pupil dilation.
What is the nervous tunic, and what does it contain?
Neurons and glial cells.
Photoreceptive layer (rods and cones).
Pigmented layer → Absorbs light, reduces scatter.
What is the function of the outer ear?
Captures and directs sound waves into the middle ear
What are the three parts of the outer ear?
Pinna/Auricle → Shape depends on auricular cartilage.
External auditory canal → Contains sebaceous and ceruminous glands.
Tympanic membrane (eardrum) → Converts sound waves into mechanical impulses.
What are the three structures of the middle ear?
Tympanic cavity.
Auditory ossicles (bones).
Auditory tube.
