ANATOMY - Term Test 1 (Sensory Organs) Flashcards
Where are photoreceptors found?
Only in the eye (sensory retina)
How are photoreceptors stimulated?
activated by light stimuli (if intensity is great enough to create a receptor potential)
What are nociceptors?
Primary sensory receptors for pain
Where are nociceptors found?
all over the body except for in brain tissue
How are nociceptors activated?
- activated by powerful/intense stimuli of any kind that results in tissue damage
- produces pain sensation
What are thermoreceptors and where are they located?
Free nerve ending receptors
- Warm receptors located deep in the dermis
- Cold receptors located in the deepest layer of the epidermis
How are thermoreceptors activated?
- by changes in temperature
- warm receptors: Activated above 25 deg C
- cold receptors: most active at ~10-40 deg C
What are mechanoreceptors and where are they found?
- receptors that respond to physical movement in the environment
- found in skin, ear
How are mechanoreceptors activated?
by mechanical stimuli that “deforms” or changes the position of the receptor resulting in a receptor potential
What are chemoreceptors and where are they located?
- receptors that respond to chemicals
- responsible for taste and smell and monitoring concentration of specific chemicals in the blood
- located in the nose (olfactory epithelium), taste buds (excluding other ones in the body that are outside of general senses)
How are chemoreceptors activated?
Activated by amount or changing concentration of certain chemicals
What is cerumen?
Ear wax; wax-like substance secreted by modified sweat glands in auditory canal
What is the auricle?
outer portion of the ear: visible appendage on side of head surrounding opening of external acoustic meatus
What is the external acoustic/auditory meatus?
Ear canal; ends at tympanic membrane
What is the tympanic membrane?
ear drum - stretches across inner end of canal separating outer ear from the middle ear
Presbyopia
- inability to focus the lens properly as we age (lenses lose elasticity and thus ability to bulge and accommodate for near vision)
- can be compensated with reading glasses when near vision is needed
Glaucoma
- excessive intraocular pressure caused by abnormal accumulation of aqueous humor
- reduced blood flow occurs due to increased pressure which causes degeneration of the retina and eventual loss of vision (slow progression)
- extensive damage can cause “halos” in bright lights
- one of the most common characteristics: swelling or “cupping” of optic disks
Cataracts
- cloudy spots in eye’s lens that develop with age
- associated with difficulties with night vision (due to weak beams from dim light not being able to pass through the cloudy spots)
Presbycusis
- progressive hearing loss due to nerve impairment (degeneration of nerve tissue in the ear and the vestibulocochlear nerve)
- associated with aging
- First to go is usually high-pitch/frequency sounds
Ménière’s disease
- chronic inner ear disease with unknown cause, may lead to nerve damage
- Characterized by tinnitus, progressive nerve deafness, and vertigo (sensation of spinning)
Myopia
- nearsightedness
- caused by elongated eyes causing the image to focus in front of the retina
- can be corrected with concave contact lenses/glasses, or refractive eye surgery
Otosclerosis
- inherited bone disorder that impairs the conduction of sound waves by structural irregularities in the stapes
- Usually first appears during childhood or early adulthood as tinnitus
Tinnitus
ringing in the ears
