Lecture #10 - The Senses Flashcards
(28 cards)
The Chemical Senses
Name the chemical senses and its contents.
- taste (gustation)
- smell (olfaction)
- contain chemoreceptors that respond to chemicals (ex. food dissolved in saliva; airborne chemicals that dissolve in nasal mucosa)
Smell (olfaction)
Olfactory receptors are a part of what type of tissue?
olfactory epithelium
Smell (olfaction)
Name the specific epithelia the olfactory epithelium is made of.
What are the three main cell types in the olfactory epithelium?
- pseudostratified columnar epithelium
SOO
- supporting epithelial cells
- olfactory sensory neurons
- olfactory stem cells
Smell (olfaction) - CELL BODIES
Where are the cell bodies of the olfactory sensory neurons located?
Describe the cell bodies of the olfactory sensory neurons.
Describe function of olfactory cilia.
- location: olfactory epithelium
- contain apical dendrite -> projects to epithelial surface; ends in knob where olfactory cilia radiate
- olfactory cilia act as receptive structures for smell -> mucus captures and dissolves odor molecules
Smell (olfaction) - AXONS
What is the name of a bundle of axons of olfactory sensory neurons?
filaments of the olfactory nerve
Smell (olfaction) - AXONS
Describe the direction of the filaments of the olfactory sensory nerve
What do mitral cells do?
- penetrate cribriform plate of ethmoid bone -> enter olfactory bulbs -> synapse with mitral cells
- transmit impulses along olfactory tract to the limbic system and primary olfactory cortex
The Eye - Fibrous Layer
What layer of the eye does the fibrous layer make up?
What regions of connective tissue make up the fibrous layer?
- most external layer of the eyeball
SCS
- sclera
- cornea
- scleral venous sinus
The Eye - Fibrous Layer
Describe the sclera
Describe the cornea
Describe the scleral venous sinus
SCLERA
- posterior 5/6 of fibrous layer
- white, opaque region
- provides shape and an anchor for eye muscle
CORNEA
- anterior 1/6 of fibrous layer
- transparent; clear
SCLERAL VENOUS SINUS
- allows aqueous humor to drain
The Eye - Vascular Layer
What layer of the eye does the vascular layer make up?
What is the components is the vascular layer made of?
middle layer
- choroid
- ciliary body
- iris
The Eye - Vascular Layer
Describe the choroid
Describe the ciliary body
CHOROID
- vascular, darkly pigmented membrane
- brown color (from melanocytes)
- prevents scattering of light rays
- (corresponds to arachnoid and pia maters)
CILIARY BODY
- thickened ring of tissue; encircles lens
- composed of ciliary muscle
-> ciliary processes - posterior surface of ciliary body
-> ciliary zonule - attached around entire circumference of lens
The Eye - Vascular Layer
Describe the iris
What is the round, central opening of the iris? Describe this structure
IRIS
- visible, colored part of eye
- attached to ciliary body
- made of smooth muscle
PUPIL
- contains sphincter and dilator pupillae muscle
-> acts to vary size of pupil - pupillary light reflex - protective response; pupil constricts in bright light
The Eye - Retinal Layer
What part of the eye does the retinal layer make up?
What layers make up the retinal layer? Describe them and the types of neurons found here (if applicable)
- innermost/deepest layer
- pigmented layer: single layer of melanocytes
- neural layer: sheet of nervous tissue
-> photoreceptor cells
-> bipolar cells
-> ganglion cells
The Eye - Retinal Layer
Describe how the neural layer of retinal layer works
- photoreceptor cells signal bipolar cells
- bipolar cells signal ganglion cells to generate nerve impulse
- axons from ganglion cells run along internal surface of retina -> converge posteriorly to form optic nerve
The Eye - Retinal Layer - Photoreceptors
What are the two main types of photoreceptors? Describe them
- rod cells: more sensitive to light; allow vision in dim light
- cone cells: operate best in bright light; enable high-acuity, color vision
photoreceptors
- vulnerable to damage by light or heat
- cannot be regenerated if destroyed
Regional Specializations of the Retina
Name the different types of regional specilizations of the retina
FOMO
- fovea centralis: contains only cones (region of highest visual activity)
- optic disc: blind spot
- macula lutea: contains mostly cones
- ora serrata: neural layer ends at the posterior margin of ciliary body; pigmented layers covers ciliary body and posterior surface of iris
Internal Chambers and Fluids
What divides the eye into anterior and posterior segments?
lens and ciliary zonules
Internal Chambers and Fluids
Describe the posterior segment of the eye
- filled with vitreous humor (clear, jellylike substance)
-> vitreous humor transmits light and maintains intraocular pressure
Internal Chambers and Fluids
Describe the anterior segment of the eye
- divided into anterior and posterior CHAMBERS
-> anterior chamber: between cornea and iris
-> posterior chamber: between iris and lens - filled with aqueous humor
-> renewed consistently
-> supplies nutrients to the lens
The Lens
Describe what the lens is
Define lens epithelium
Define lens fibers
- thick, transparent, biconvex disc that is held in place by ciliary zonule (help change size)
- lens epithelium: covers anterior surface of lens
- lens fibers: form bulk of lens
-> new lens fibers are continuously added
-> lens enlarges throughout life
The Ear
What are the three main regions of the ear?
Describe what each region functions in
- external ear: hearing
- middle ear: hearing
- internal ear: hearing and equilibrium
The External Ear
- What structures is the external ear composed of?
- What do the structures in the external ear do?
- auricle: helps direct sound
- external acoustic meatus: channels sound to eardrum (hairs, sebaceous glands, ceruminous glands)
- tympanic membrane (eardrum): thin cone-shaped connective tissue that transmits sound from air to ossicles
-> forms boundary between external and middle ear
The Middle Ear
- What structure is the middle ear composed of?
- What do the structures in the middle ear do?
TTOP
- tympanic cavity: small, air-filled cavity that’s located within temporal bone
- tensor tympani and stapedius: two tiny skeletal muscles in middle ear cavity
- ossicles:
-> malleus: attaches to eardrum
-> incus: between malleus and stapes
-> stapes: vibrates against oval window - pharyngotympanic tube (auditory tube): links middle ear and pharynx
What part of the ear is also called the labyrinth and lies within the petrous part of the temporal bone?
internal ear
The Internal Ear
- What parts make up the bony labyrinth?
- Describe the membranous labyrinth. What parts make up the membranous labyrinth?
- bony labyrinth: semicircular canals, vestibule, cochlea
- membranous labyrinth: series of membrane-walled sacs and ducts; filled with endolymph
- semicircular ducts (in semicircular canals)
- utricle and saccule (in vestibule)
- cochlear duct (in cochlea)
