Human Anatomy CH 16 Flashcards
What are the special senses?
- Taste
- Smell
- Sight
- Hearing
- Balance
Define Touch
A large group of general senses
What two types of cells are taste bud cells? BE SPECIFIC
- Gustatory epithelial cells
- Basal epithelial cells
Where are special sensory receptors located?
They are localized and confined to the head region
What are special receptor cells and what do they do?
They are neuronlike epithelial cells or small peripheral neurons. They transfer sensory information to other neurons in an afferent pathway.
What is taste called?
Gustation
What is smell called?
Olfaction
What are receptors that respond to chemical substances called?
Chemoreceptors
How are chemoreceptors able to respond to smell?
Airborne chemicals dissolve in fluids of the nasal mucosa
What are the two types of tongue papillae?
- Fungiform papillae
- Vallate papillae
Where are taste receptors found? BE SPECIFIC
Taste buds, more specifically mostly on the surface of the tongue within tongue papillae
How many cells are in the taste buds?
50-100
How often are taste bud cells replaced?
Every 7-10 days
What are the five basic qualities of taste?
- Sweet
- Sour
- Salty
- Bitter
- Umami
What is umami drawn out by?
It is elicited by glutamate
What extends from the gustatory epithelial cells and where do they extend to?
Long microvilli extends through a taste pore to the surface of the epithelium
Where are taste modalities elicited from?
All areas containing taste buds
What is elicited from areas containing taste buds?
Taste modalities
Where does taste information travel through to reach the cerebral cortex?
Facial (VII), Glossopharyngeal (IX), and Vagus (X) nerves
Out of the 3 taste nerves, which one is NOT one of the primary taste nerves?
Vague Nerve (X)
What does synapse mean?
A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter
Where do sensory neurons synapse?
Solitary nucleus of the medulla
From the solitary nucleus, where are impulses transmitted to?
The thalamus and ultimately to the gustatory area of the cerebral cortex in the insula
Where are olfactory receptors part of?
Olfactory epithelium
What type of tissue is the olfactory epithelium made of?
Pseudostratified columnar
What are the 3 main cell types of the olfactory epithelium?
- Olfactory sensory neurons
- Supporting epithelial cells
- Olfactory stem cells
Where are cell bodies of olfactory neurons located?
Olfactory epithelium
Describe the cell bodies of olfactory sensory neurons
They have an apical dendrite that projects to the epithelial surface and ends in a knob from which olfactory cilia radiate
What do olfactory cilia do?
Act as receptive structures for smell
What does mucus do?
Captures and dissolves odor molecules
What are the bundles of axons of olfactory sensory neurons called?
Filaments of the olfactory nerve
What do filaments of the olfactory nerves do?
- Penetrate the cribriform plate of the ethmoid bone
- Enter the olfactory bulbs and synapse with mitral cells
What do mitral cells do?
They transmit impulses to the olfactory tract
Where do mitral cells transmit impulses to?
- Limbic System
- Piriform lobe of the cerebral cortex
- Primary olfactory cortex in piriform lobe
What disorder is the absence of the sense of smell?
Anosmia
What is anosmia caused by?
Injury, colds, allergies, or zinc deficiency
What is the distortion of smells or olfactory hallucinations?
Uncinate Fits
What do Uncinate Fits result from?
Irritation of olfactory pathways after brain surgery or head trauma
From what does the olfactory epithelium derive from?
Olfactory placodes
When do taste buds develop?
Upon stimulation by gustatory nerves
What is the dominant sense in humans?
Vision
What’s the percentage of all sensory receptors in the eyes?
70%
What’s the percentage of the cerebral cortex involved in processing visual information?
40%
How much of the eye’s surface is visible?
Anterior one-sixth
Define Eyebrows
Coarse hair on the superciliary arches
What’s another name for eyelids? What are they separated by?
Palpebrae; Separated by the palpebrae fissure
Where do the eyelids meet?
Medial and lateral angles (canthi)
What is the reddish elevation at the medial canthus?
Lacrimal caruncle
What is the connective tissue within the eyelids?
Tarsal plates
What are modified sebaceous glands called?
Tarsal glands
What is transparent mucous membrane called?
Conjunctiva
What are the parts of the conjunctiva called?
- Palpebral conjunctiva
- Bulbar conjunctiva
- Conjunctival sac
What keeps the surface of the eye moist?
Lacrimal apparatus
What produces lacrimal fluid?
Lacrimal gland
Where does the lacrimal fluid drain into?
Empties into the lacrimal sac, then the nasal cavity
How many muscles control the movement of the eye? What are they?
Six muscles;
1. Lateral and medial rectus
2. Superior and inferior rectus
3. Superior and inferior oblique
Where do the 4 rectus muscles originate from?
Annular ring
Where do the extrinsic eye muscles originate and insert into?
Originates in the walls of the orbit and inserts on outer surface of the eyeball
What do the components of the eye do?
- Protect and support the photoreceptors which gather, focus, and process light into precise images
What are the external walls composed of and how many? What are their names?
3 tunics
What are the 4 parts of the fibrous layer?
- Sclera
- Cornea
- Limbus
- Scleral venous sinus
What is the most external layer of the eyeball called?
Fibrous Layer
What is the fibrous layer composed of?
2 regions of connective tissue