Chapter 10- Sense organs Flashcards
List the four general types of stimulus that can trigger a response from sensory receptors
Chemicals (chemoreceptors)
Temperature (thermoreceptors)
Pressure (mechanoreceptors)
Light (photoreceptors)
List and describe visceral senses
Miscellaneous category of interior body sensations
hunger
thirst
Visceral stretch
- bladder
-Gi tract
List and describe the processes that contribute to nociception
transduction, transmission, modulation, and perception.
nociception
Pain perception
Describe the structure of taste buds
Tiny, rounded structures made up of gustatory cells and supporting ells
taste pores allow dissolved substants to enter taste bus and contact sensory receptors
the sensory receptors are tiny hairlike processes
Touch
Touh and pressure are sometimes classified as different senses
Touch is known as tactile sense
Pressure is something pressing on body surface (gives a sense of where we are)
Both senses operate largely unconscious
- unless contact is abrupt.
Temperature
maintains temperature homeostasis
Touch receptors can be superficial or central
-central in hypothalamus, monitors temp of blood. we can shiver or sweat as a result
General senses
Distributed throughout the body
Don’t have special sense organ
Tend not to be associated with disease
Visceral
Touch
Temperature
Pain
Proprioception
Pain
Nociceptors are pain receptors
widely distributed inside and on the surface of the body. Not in the brain
may be simple free nerve endings (dendrites) or more specialized structures
purpose - protect the brain
unpleasant sensory and/or emotional experience associated with actual or potential tissue damage
Proprioception
Sense of body position and movement
-movement of limbs
-position of joints
-state of contraction of muscles
-tension on ligaments and tendons
Stretch receptors located in skeletal muscles, tendons, ligaments and joint capsules
List special senses
Transduction occurs in an organ
Taste
Smell
Hearing
Equilibrium
Vision
Taste
Also called gustatory sense
Chemical sense
Receptors are located in taste buds
-majority are located in elevated structure in tongue- papilae
- some in lining of mouth and throat (pharynx)
Smell
Also called olfactory sense
Chemical
more important to non-human animals
two patches of olfactory epithelium located high up in both nasal passages
hair like processes project up from olfactory cells into the mucus layer that covers the nasal epithelium
Odor molecules dissolve in mucus and contact the sensory processes (dendrites)
Hearing anatomy (big picture)
Auditory sense
Mechanical
converts vibrations in the air to nerve impulses
impulses interpreted as sound
External
-acts as a funnel, collects sound wave and funnel towards middle ear
Middle
-amplifies and transmit vibrations from ear drum to inner ear
Inner
-contains the sensory receptors that convert the mechanical wave to nerve impulses - transduction
Equilibrium
Balance and head position
A mechanical sense
Helps animal maintain
balance by keeping track
of head’s position and
movements
* Equilibrium receptors in
inner ear
* Vestibule
* Semicircular canals
* Information from eyes
and proprioceptors
around the body
Vision
Electromagnetic
Describe the structures of the ear
External ear/Pinna
- external auditory canal
-tympanic membrane/ear drum
Middle ear - hollowed out area in temporal bone
Ossicles
Eustachian tube
Cochlea
Malleus
Incus
Stapes
Inner ear
Organ of corti
Cochlear duct
Oval window
basilar membrane
tetcorial membrane
Cochlear duct
Filled with endolymph
Near Vestibule
receptors for hearing
external auditory canal
Connected to the Pinna
funnels sound
-tympanic membrane/ear drum
Thin connective tissue stretched tightly between opening for external auditory canal and middle ear
Sound waves strike tympanic membrane and make it vibrate
paper thin
Eustachian tube
Called the auditory in
Connects the middle ear with the pharynx
equalizes are pressure in ear
Cochlea
Receptors for hearing, transduction occurs
Shell shaped spiral cavity in temporal bone
Contains organ of corti
Ossicles
Amplify sound and bring cochlea
Ossicles act as a system of levers to transmit sound wave vibrations from tympanic membrane
- vibrations decreased in size, increased in force
Malleus - outermost, attached to tympanic membrane
Incus - middle
Stapes - attached to the membrane covering the oval window of cochlea
Organ of corti
fluid filled portion that makes up receptor organ of hearing
- consists of hair cells, supporting cells and tectorial membrane
filled with endolymph
runs length of cochlea
Oval window
Membrane covered opening at the end of the cochlear duct
- filled with perilymph
-stapes is attached
basilar membrane
Shelf in the organ of Corti it contains hair cells , supporting cells and the tectorial membrane
tectorial membrane
A membrane located ABOVE the basilar membrane; serves as a shelf against which the cilia of the auditory hair cells move.
Describe the process that contributes to the sense of equilibrium
Vestibule
The vestibule is the central part of the bony labyrinth in the inner ear, and is situated medial to the eardrum, behind the cochlea, and in front of the three semicircular canals.
used for equilibrium
Semicircular canals
Located on other side of the vestibule from the
cochlea
Contain fluid-filled membranous tubes
Three layers of eye
Fibrous
Vascular
Nervous
List the structures of the eyeball
Two comparments
Aqueous and vitreous
Sclera.
Cornea.
Iris.
Pupil.
Lens.
Retina.
Optic nerves.
Conjunctiva
Lines the inner surface of the eye lid and the corner of the eyes
Eyelids
Sense organs
Sensation
any stimulus the body is aware of
Perception
conscious awareness and interpretation
Nociceptors
pain receptors
Pain pathways-
transduction - conversion of stimulus into impulse
transmission - nerve impulse moves up nerve fiber (axon)
modulation - changing of nerve impulse can occur at spial column. Can influence the info the brain receives
perception - conscious perception
3 sensory neurons
Hearing physiology
Pinna/outer ear funnel sound
Sound wave vibrations cause tympanic membrane and ossicles in middle ear to vibrate
Perilymph around cochlear duct vibrates
Cochlear duct moves
Tectorial membrane and hair cells of organ of Corti rub against each other
Nerve impulses are generated in the cochlear (vestibule-cochlear) nerve
Impulses travel to brain and are interpreted as sound
Vision
Most components of the eye function to help form an accurate visual image, not detect it
Photoreceptors that detect the image cand generate visual nerve impulses are in a single layer of ccells in the retina
Fibrous layer eye
Cornea: transparent; admits light to interior of the eye
* Sclera: “white” of the eye
* Limbus:
Cornea
Fibrous layer of eye
Arrangement of collagen fibers; no blood vessels
light is refracted (bent)
Sclera
Fibrous layer of eye
Dense fibrous connective tissue
White of eye
Limbus
Fibrous layer of the eye
junction of the cornea and the sclera
Sense of motion
The head moves
Fluid movement lags in one
plane of semicircular
canals
Fluid movement pulls on
cupula
Hairs are bent
Nerve impulse is generated
Brain receives information
about motion of the head
Iris
Vascular layer of eye
pigmented muscular diaphragm
* Controls amount of light that enters the posterior p
Pupil
Vascular layer of eye
opening at center of iris
Choroid
Vascular layer of the eye between the sclera and the retina
*Pigment and blood vessels
*In most animals, choroid forms the tapetum
tapetum
Vascular layer of eye
highly reflective area in the rear of the eye
(the surface that reflects light at night)
Iris
Vascular layer of eye pigmented muscular diaphragm
* Controls amount of light that enters the posterior part of the eyeball
Ciliary body
Vascular layer of eye
Ciliary body: ring shaped structure behind the iris
* Muscles that adjust shape of the lens to allow near and far vision
Retina
Nervous layer of eye
Lines most of the vitreous compartment (the back of the eye)
*“Movie Screen” or “Film in Camera”
* Where visual image is formed
Contains the sensory receptors for vision, the rods and cones
Less important
Multilayered:
*Pigment layer
*Photoreceptor layer - rods (night vision) and cones (color)
*Bipolar cell layer
*Ganglion cell layer
*Layer of nerve fibers
Compartments of the eye
Aqueous - interior to the lens
-subdivided into anterior and posterior by iris
- posterior aqueous produces aqueous humor. (And where it drains).
– Drained by canal of
Schlemm
-has ciliary body
Bends light
Vitreous - posterior to the lens
Contains a clear gelatinous fluid called vitreous humor
Vitreous humor fills the whole back of the eyeball behind the lens and ciliary body
Bends light
Lens
Soft, translucent layers of fibers
Elastic and biconvex
Front surface in contact with aqueous humor; back surface in contact with vitreous humor
Helps focus a clear image on the retina through accommodation process
Bends light
Refraction of the eye
Occurs in the:
cornea, Aqueous humor, lens, vitreous humor
Lens accommodation
Lens Accommodation
Accommodation: process by which the shape of
the lens is changed to allow close-up and distant
vision
* Relaxation of ciliary muscles causes tension on
suspensory ligaments; flattens the lens
* Contraction of ciliary muscles releases tension on
the suspensory ligaments
Conjunctiva
Conjunctiva
* Thin, moist, transparent
membrane
* Covers front portion of eyeball
* Bulbar conjunctiva
* Lines interior surfaces of
eyelids
* Palpebral conjunctiva
Conjunctival sac
* Space between bulbar and
palpebral portions of conjunctiva
Extraocular structures
Eyelids
* Upper and lower folds of skin, lined by conjunctiva
Lateral and medial canthus
* Corners where the eyelids come together
Tarsal glands = meibomian glands
* Their tiny openings are found along eyelid margin
*Produce waxy substance to prevent tears from
overflowing onto the face
Eyelashes
Eyelashes
* Prominent on upper lid of most
animals
Third eyelid = nictitating
membrane
* T-shaped plate of cartilage
covered by conjunctiva
* Located medially between
eyelids and eyeball
* No muscle attachment; passive
movements
* Lymph nodules and accessory
lacrimal gland on ocular
surface
Lacrimal Apparatus
*Structures that produce and secrete tears and drain tears away from the surface of the eye
Lacrimal glands are the primary source of tears
Tear drainage system
* Lacrimal puncta
* Lacrimal sacs
* Nasolacrimal duc
Tears
Liquid film that moistens and protects the surface
of the eye
3 main layers of tears
*Inner mucous layer – from cells in conjunctiva
* Contains antibacterial substances
* Middle tear layer – from lacrimal glands and
accessory lacrimal glands of the third eyelid
*Keeps the cornea moist
* Outer oily layer – from tarsal or meibomian glands
* Reduces evaporation of underlying tear layer
*Prevents tears from flowing over the lid margin
