Lecture 6 – Somatic and Special Senses Flashcards
Olfaction
Sense of Smell
receptors for olfaction and the olfactory pathway to the brain.
Olfaction (sense of smell)
Gustation
Sense of Taste
receptors for gustation and the gustatory pathway to the brain.
Gustation (sense of taste)
accessory structures of the eye, the layers of the eyeball, the lens, the interior of the eyeball, image formation, and binocular vision. It describes the receptors for vision and the visual pathway to the brain.
Vision
structures of the external, middle, and internal ear. It describes the receptors for hearing and equilibrium and outline their pathways to the brain.
Hearing and Equilibrium
Somatic senses and Visceral senses
General Senses
Tactile (touch, pressure, vibration); Thermal (warm and cold); Pain; Proprioceptive
Somatic senses
conditions within internal organs
Visceral senses
Smell, Taste, Vision, Hearing, and Equilibrium (balance)
Special Senses
conscious or subconscious awareness of changes in the external or internal environment.
Sensation
Must satisfy the four conditions
Sensation
stimulus getting to the brain
Sensation
- Stimulus must occur and activate a receptor. 2. Receptor must convert the stimulus into nerve impulses. 3. Nerve impulse must be conducted to the brain. 4. Brain must receive and integrate the nerve impulses into a SENSATION.
FOUR Conditions for SENSATION to Occur
conscious awareness and interpretation of sensations and is primarily a function of the cerebral cortex
Perception
how the cerebral cortex interprets the sensation
Perception
Characteristic of MOST sensory receptors
Adaptation
Decrease in the strength of sensation during prolonged stimulus because of decrease in responsiveness of receptors.
Adaptation
Perception of a sensation may _____________ even though the stimulus persists.
fade or disappear
Rapidly Adapting and Slowly Adapting
Two Variations of Adaptation
pressure, touch, smell
Rapidly Adapting
pain, body position, chemical composition of the blood
Slowly Adapting
detect mechanical pressure; provide sensations of touch, pressure, vibration, proprioception, and hearing and equilibrium; also monitor stretching of blood vessels and internal organs
Mechanoreceptors
detect changes in temperature.
Thermoreceptors
respond to painful stimuli resulting from physical or chemical damage to tissue
Nociceptors
detect light that strikes the retina of the eye
Photoreceptors
detect chemicals in mouth (taste), nose (smell), and body fluids
Chemoreceptors
sense the osmotic pressure of body fluids
Osmoreceptors
allow us to know where our head and limbs are located and how they are moving even if we are not looking at them.
Proprioceptive Sensation
the eye and its disorders
Ophthalmology
the science that deals with the ears, nose, and throat and their disorders.
Otorhinolaryngology (ENT)
where gustatory receptor cells are located.
Taste Buds
substance to be tasted
Dissolved in Saliva
salty, sweet, sour, bitter, and umami.
Five Primary Tastes
taste receptors are located
Taste buds
taste buds are located
Tongue Papillae
found 10,000 taste buds
Tongue
pharynx, epiglottis
Roof of the Mouth
about 12 that contain 100- 300 taste buds
Vallate papillae
scattered over the tongue with about 5 taste buds each
Fungiform papillae
located in lateral trenches of the tongue—most of their taste buds degenerate in early childhood.
Foliate papillae
cover the entire surface of the tongue. Contain tactile receptors but no taste buds.
Filiform papillae
dissolved in the saliva and enter taste pores.
Tastant
shade the eyes during sleep, protect the eyes from excessive light and foreign objects, and spread lubricating secretions over the eyeballs.
Upper And Lower Eyelids or Palpebrae
more movable than the lower and contains in its superior region the levator palpebrae superioris muscle.
Upper Eyelid
space between the upper and lower eyelids that exposes the eyeball.
Palpebral Fissure
narrower and closer to the temporal bone
Lateral Commissure
broader and nearer the nasal bone
Medial Commissure
contains sebaceous (oil) glands and sudoriferous (sweat) glands. The whitish material that sometimes collects in the medial commissure comes from these glands.
Lacrimal Caruncle
thick fold of connective tissue that gives form and support to the eyelids.
Tarsal Plate
is a thin, protective mucous membrane that lines the eyelids and covers the sclera.
Conjunctiva
cornea and sclera
Fibrous Tunic
choroid, ciliary body and iris
Vascular Tunic
colored portion of the eyeball and controls the size of the pupil based on autonomic reflexes.
Iris
Inner coat of the eyeball and beginning of the visual pathway
Retina
Pigmented layer and Photoreceptors
2 layers of Retina
Contains melanin and Absorbs stray light
Pigmented layer
Rods and Cones
Photoreceptors
shades of gray in dim light; 120 million; absent in fovea, more numerous in the periphery of the retina; 6-600 : 1 bipolar cell
Rods
stimulated by brighter light; highly acute color vision; blue, green, red cones; 6 million; most dense in fovea centralis (area of highest visual acuity); 1:1 bipolar cell higher acuity
Cones
Divided into an anterior chamber and a posterior chamber by the iris (colored portion of the eyeball).
Anterior Cavity
Both chambers are filled with aqueous humor (a clear, watery liquid)
Anterior Cavity
Aka vitreous chamber
Posterior Cavity
Filled with vitreous humor (transparent, gelatinous substance)
Posterior Cavity
focus image on the retina
Cornea and Lens
total refraction occurs at the cornea
75%
further refracts the light rays so that they come into exact focus on the retina
lens
Images focused on the retina are inverted and right-to-left reversed due to
refraction
The brain corrects the
image
to properly focus the object.
lens must accommodate
site of sharpest vision
Central fovea
refract light correctly and focus a clear image on the retina.
Normal (Emmetropic eye)
Emmetropic eye
Normal eye
sufficiently refract light rays from an object 6 m (20 ft)
Normal (Emmetropic eye)
near sightedness
Myopia
eyeball is longer than it should be and the image converges (narrows down to a sharp focal point) in front of the retina.
Myopia
people see close objects better
Myopia
concave lens is used to correct the vision
Myopia
farsightedness, hypermetropia
Hyperopia
eyeball is shorter than it should be and the image converges behind the retina.
Hyperopia
individuals can see distant objects better
Hyperopia
convex lens is used to correct this abnormality
Hyperopia
lens use in Myopia and Hyperopia
Concave and Convex lens
irregular curvature. Condition where either the cornea or the lens (or both) has an irregular curve and causes blurred or distorted vision
Astigmatism
auricle (pinna), external auditory canal, and tympanic membrane (eardrum).
External ear
captures sound
auricle
transmits sound to the eardrum
external auditory canal
secrete cerumen (earwax) to protect the canal and eardrum
ceruminous glands
auditory (eustachian) tube, ossicles, and oval window
Middle ear
malleus, incus, stapes
3 auditory ossicles
transmitted from the eardrum through these 3 bones to the oval window into which the stapes fits.
sound vibrations
extends from the middle ear into the nasopharynx to regulate air pressure in the middle ear
eustachian tube
AKA Bony labyrinth and Membranous labyrinth.
Internal ear
contains the spiral organ (organ of corti), the organ of hearing.
Internal ear
translates vibrations into neural impulses that the brain can interpret as sound.
Cochlea
contains utricle and saccule
Vestibule
work with the cerebellum for balance and equilibrium
Semicircular canals
Utricle and Saccule
Static Equilibrium
linear horizontal motion
Utricle
linear vertical motion
Saccule
Semicircular Canals and rotational acceleration or deceleration
Dynamic Equilibrium
