Week Six: Sense Organs Flashcards
What are some examples of mechanical stimuli?
Touch, hearing, balance
What are some examples of thermal stimuli?
Hot and cold
What are some examples of electromagnetic stimuli?
Vision
What are some examples of chemical stimuli?
Taste and smell
What are visceral sensations?
Sensations of hunger and thirst
Also include visceral stretch receptors in GI tract and urinary system
What is tactile sense?
Sensation of something being in contact with the surface of the body
What is the definition of pressure?
Sensation of something pressing on the body surface
What are superficial temperature receptors?
Detect upward or downward changes in skin temperatures
What are central temperature receptors?
(In hypothalamus)
Monitor the temperature of the blood
_____ can activate mechanisms (like sweating, piloerection) to correct hypothermia or hyperthermia
CNS
What are nociceptors?
Pain receptors
Pain receptors are not present in the…
Brain
Pain receptors detect what?
Mechanical forces, temperature, ect.
What does transduction mean?
Conversion of painful stimulus into nerve impulse
What does transmission mean?
Conduction of nerve impulse to the spinal cord
What is modulation?
Changes the sensory nerve impulse
Can amplify or suppress sensory impulses
What is perception?
Conscious awareness of painful stimuli
Where does modulation usually occur?
Spinal cord
What is proprioception?
Sense of body position and movements
Drunk driving test
What are the chemical receptors called in the oral cavity?
Taste buds
What is papillae?
Small elevated structures on the tongue
Why is the external ear important?
Acts as a funnel to collect sound wave vibrations and direct them to the eardrum
What does the middle ear do?
Amplifies and transmits the vibrationsfrom the eardrum to the inner ear
Describe the inner ear?
Contains the sensory receptors that conver the mechanical vibrations to nerve impulses, along with receptors for the equilibrium sense
What is the pinna?
Elastic cartilage and skin
What is the external auditory canal?
Membrane-lined tube
What is the tympanic membrane?
Sound wave vibrations strike this and cause it to vibrate
Three ossicles (small bones) link the ______ with the cochlea of the inner ear
Tympanic membrane
______ ______ connects the middle ear cavity with the pharynx
Eustachian tube
What is the malleus?
Outermost bone, attached to tympanic membrane
What is the incus?
Middle bone
What is the stapes?
Medial-most bone; attached to membrane that covers the oval window of the cochlea
What are the middle ear ossicles
Malleus, incus, stapes
What is the cochlea?
Shell-shaped spiral cavity in the temporal bone
What is the organ of corti?
Fluid-filled portion that makes up the receptor organ of hearing
Consists of hair cells, supporting cells, and tectorial membrane
Where is the organ of corti?
Runs along the cochlear duct on the basilar membrane
What causes the tympanic membrane and ossicles in the middle ear to vibrate?
Sound wave vibrations
What causes the cochlear duct to move?
Fluid vibration
What is the mechanical sense of the equilibrium?
Helps maintain balance by keeping track of the position and movements of the head
Where are the receptors of the equilibrium located?
In the vestibule and semicircular canals in the inner ear
Where is the vestibule located?
Between the cochlea and semicircular canals
What is the vestibule composed of?
Utricle and saccule
_____ causes otoliths and the gelatinous matrix to put pressure on the hairs
Gravity
What generates nerve impulses that give the brain information about position of the head?
Vestibule
What is the ampulla?
Enlarged area near the utricle end of each semicircular canal
What is the crista ampullaris?
Receptor within ampulla
What generates nerve impulses that give the brain information about motion of the head?
Semicircular canals
Most components of the eye function to help form an accurate visual image, not ________ it.
Detect
What detects the image and generate visual nerve impulses?
Photoreceptors in the retina
What are the layers of the eyeball?
Outer fibrous layer, middle vascular layre, and inner nervous layer
What is the cornea?
Transparent; admits light to interior of the eye
Arrangement of collagen fibers, no blood vessels
What is the sclera?
“white” of eye
Dense fibrous connective tissue
What is the limbus?
Junction of the cornea and the sclera
What type of tissue is in the cornea?
Modified epithelial tissue
What is choroid?
Between the sclera and the retina
Pigment and bloodvessels
In most animals, choroid forms the ______ which is a highly reflective area in the rear of the eye
Tapetum
better for night vision
What is the iris?
Pigmented muscular diaphragm
Controls amount of light that enters the posterior part of the eyeball
What is the pupil?
Opening at center of iris
The iris is involuntary except in…
Reptiles
What is cilliary body?
Ring-shaped structure behind the iris
Muscles that adjust shape of the lens to allow near and far vision
What is the retina?
Lines the back of the eye
Contains sensory receptors for vision
Contains rods and cones
What is the aqueous compartment?
Contains a clear watery fluid (aqueous humor)
Produced in the posterior chamber by cells of the cillary body
What is the vitreous compartment?
Contains a clear gelatinous fluid called vitreous humor
______ _____ fills the whole back of the eyeball behind the lens and cillary body
Vitreous humor
What is the lens?
Front surface is in contact with aqueous humor; back surface is in contact with vitreous humor
Helps focus a clear image on the retina
What is accommodation?
Process by which the shape of the lens is changed to allow close up and sitant vision
Relaxation of cilliary muscles causes tension on ________ ligaments; flattens the lens
Suspensory
Contraction of ______ muscles releases tensions on the suspensory ligaments
Ciliary muscles
Layers of the retina:
Pigment layer Photoreceptor layer Bipolar cell layer Ganglion cell layer Layer of nerve fibers
What is the optic disc?
Site where nerve fibers on the inside surface of the retina converge and leave the eye to form the optic nerve
What are photoreceptor cells?
Neurons with modified dendrites
What are rods?
More sensitive to light
What are cones?
More sensitive to color and detail
What are the photoreceptors cells?
Rods and cones
What is conjunctiva?
Thing transparent membrane
Covers the front portion of the eyeball and lines the interior surfaces of the eyelids
What is the conjunctival sac?
Space between the bulbar and palpebral portions of the conjunctiva
What are eyelids?
Upper and lower folds of skin lined by the thin, moist conjunctiva
What are the lateral and medial canthus?
Corners where the eyelids come together
What are the tarsal glands?
Produce waxy substance the helps prevent tears from overflowing onto the face
What is the nictitating membrane?
Third eyelid
What is the lacrimal apparatus?
Structures that produce and secrete tears and drain them away from the surface of the eye
