Ch.15 Flashcards
What is general sense and not a special sense?
Touch
Special Senses
- Smell
- Taste
- Sight
- Hearing
- Equilibrium
- Each have specialized receptors that send sensory information to the brain
* Receptors are highly localized for their function
Smell-Olfactory Receptors
- Receptors located in epithelium covering cribriform plate and superior nasal concha
- 10-100 million Bipolar neurons
- Receptors on hairs
Basal Cell
- Stem cell
- to make more olfactory Neurons (30-60 dys)
Supporting cells
- Insulate the olfactory cells
- Have cilia to move mucus
Physiology of Smell
Ordorant binds receptor
→ Axons of olfactory neurons send axons through cribiform plate → synapse in olfactory bulb → olfactory tract → olfactory cortex (and limbic system)
Sensory adaptation
within a sec of stimulation intensity drop 50%, in a min receptors are insensitive ex living with a smoker
Taste
Function:
- Triggers reflexes that prepare the GI tract for activity
- Induce vomit if food is bad
Taste Anatomy
- Receptor = Taste buds
- Located on tongue and oral cavity
- Tongue has 3 type of raised projections (papillae)
Taste Physiology
Tastant binds receptor → gustatory cells transmit signal to neurons (of cranial nerve VII, IX, X) → medulla → thalamus → gustatory cortex (and limbic system)
5 primary taste sensations:
- sweet: carbs
- sour: acids
- salt: inorganic salts
- bitter: organic/inorganic salts
- unami: amino acids - glutamate
Eyelids
Vision Anatomy
- Protection
- Shade eyes for sleep
- Spread lubricant
- Anchor orbicularis oculi
Eyelash
Vision Anatomy
Trigger blink reflex
Lacrimal Apparatus
Vision Anatomy
Produces tears = mixture of mucus, antibodies, lysozyme
Conjunctiva
Vision Anatomy
- Thin mucous membrane lines inner side of lids and whites of the eyeball
- For protection
Extrinsic eye muscles
Vision Anatomy
- originate from bony orbit and insert on eyeball
- Superior, inferior, lateral, and medial rectus: Enable eye to follow moving objects, maintain shape of eyeball, and hold it in orbit
– names indicate movements - Superior and inferior oblique muscles: move eye in vertical plane and rotate eyeball
Lateral rectus
Extrinsic Eye Muscle
- moves eye laterally
- VI (abducens)
Medial rectus
Extrinsic Eye Muscle
- moves eye medially
- III oculomotor