Chapter 9 Flashcards
All begin with a stimulus, physical or chemical.
Sensory receptor converts stimulus to a change in resting potential
Signals (action potentials) are sent to the CNS
Unconsciously or consciously perceived.
Sensory Pathway
Mechanoreceptors Thermoreceptors Nociceptors Chemoreceptors Photoreceptors
Types of Sensory Receptors
mechanoreceptors involved in reflex actions that maintain muscle tone, tell us limb positions
Proprioceptors
receptors in skin and skeletal muscles. Respond to mechanical, thermal, electrical or chemical damage
Somatic Nociceptors
Respond to excessive stretching of internal organs (stomach too full), oxygen deprivation, and chemicals (prostaglandins) released by damaged tissues. Deep Receptors
Visceral nociceptors
Pain originates at different point than actual source (heart attack)
referred pain
Somatic pain receptors are on _____ nerve pathway(s) as visceral pain receptors.
same
oval structures on tongue papillae, pharynx, palate, epiglottis.
taste buds
5 flavors taste buds can detect.
sweet, sour, salty, bitter, and umami
What cranial nerves send taste signals
Cranial nerves VII, IX, and X
Sense of smell
olfication
Specialized cells (modified neurons) with cilia lie on roof of _____
nasal cavity
Odors dissolve in _____ and bind to specific receptors on cilia.
mucus
1000 different types of ______ that can detect at least 10,000 smells.
olfactory receptors
humans can detect how many smells?
10,000
Sense of taste is called?
Gustation
Total number of receptors in human is
6 million
What cranial nerve goes to the temporal lobe?
Cranial Nerve I
What system does olfaction have direct connections to?
limbic system for emotion and memory
Outer layer of eye, white and fibrous except for transparent cornea region in front of eye (window)
sclera
Middle, vascular layer. Becomes iris in the front which regulates the pupil size.
Choroid
Inner layer - with photoreceptors. Covers the posterior portion of the eye.
retina
Detect light
rod cells
detect color and are important in fine/ high resolution vision
cone cells
attached to ciliary body, divides eye into anterior and posterior compartments
lens
In front of lens – filled w/ aqueous humor. Provide nutrients for eye surface, holds lens in place
anterior compartment
filled with vitreous humor, contains retina. Holds retina in place.
posterior compartment
What is the function of the eye
sensory receptor, focuses light on light sensitive surface. opening can be adjusted to change amount of light
Where is the light appropriately focused on the eye
retina
What is the function of the vitreous humour
keeps eyeball in place
What disease occurs when there is too much aqueous humor
Glaucoma
What happens to the lens and the ciliary muscle when objects are viewed up close?
Ciliary muscle contracts and rounds
the lens when viewing close up
objects (accomodation)
pinna, auditory canal, produce ear wax
outer ear
begins at tympanic membrane and ends at body wall containing two small openings covered by membranes
middle ear
Semicircular canals and vestibule.
inner ear
Where is there fluid located normally in the ear?
Inner ear
Where is air located normally in the ear>
Outer and middle ear
What is the purpose of semicircular canals?
detect rotational and angular movements of head
What is the purpose of the vestibule
detect lineral movement of the head in any direction.
What happens to the lens and the ciliary muscle when objects are viewed far away
Ciliary muscle relaxes when viewing
distant objects
Sensory receptor for pressure and movement
Mechanoreceptors
Sensory receptor for temperature
Thermoreceptors
Sensory receptor for pain
Nociceptors
Sensory receptor for chemicals
Chemoreceptors
Sensory receptor for light
Photoreceptors
Cones are primarily located in the
fovea centralis
Point of clearest vision on retina
Macula lutea
Area of greatest visual acuity, lots of cones
fovea centralis
Nearsightedness, rays focus in front of retina
myopia
farsightedness, rays focus behind retina
hyperopia
Uneven cornea, rays don’t focus evenly
astigmatism
in rods a chemical change in _____ leads to nerve impulses
rhodopsin
Rods are important for
peripheral and night vision
Which vitamin helps make rhodopsin components
Vitamin A
Cones allow us to detect
fine detail and color
Color vision depends on three different
cones containing pigments called
B (blue)
R (red)
G (green)
where optic nerve exits the retina, no rods and cones here.
optic disc
Inside the _____ fluid movement causes stereocilia to bend, which activates hair cell to transmit action potentials to cranial nerve VIII
cochlea
