12 Somatic And Special Senses Flashcards
The somatic sensations of touch, pressure, vibration, warmth, cold, and pain arise from sensory receptors in the __, subcutaneous layer, and the __ __.
Skin; mucous membranes
__ are present in almost every tissue of the body.
Nociceptors
The __ epithelium consists of olfactory receptor cells, supporting cells, and basal cells.
Olfactory
__ receptor cells are located in taste buds.
Gustatory
What are the accessory structures of the eye?
Eyebrows Eyelashes Eyelids Extrinsic eye muscles Lacrimal apparatus (tears)
The wall of the eyeball consists of 3 layers:
The fibrous tunic
The vascular tunic
Retina (nervous tunic)
Contraction of the __ muscles causes constriction of the pupil; contraction of the __ muscles causes dilation. Of the pupil.
Circular; radial
In the __, visual signals pass from photoreceptors to bipolar cells to ganglion cells.
Retina
__ is the bending of light rays.
Refraction
In uncorrected __ distant objects can’t be seen clearly.
Myopia
In uncorrected __ nearby objects can’t be seen clearly.
Hyperopia
At the __ chiasm, half of the retinal ganglion cells axons from each eye cross to the opposite side of the brain.
Optic
The ear has 3 principal regions:
The external ear
The middle ear
The internal ear
The 3 channels in the cochlea are:
The scala vestibuli
Scala tympani
Cochlear duct
Sound waves originate from __ objects.
Vibrating
Movements of the __ membrane stimulate the hair cells.
Otolithic
The positions of the membranous semicircular ducts permit detection of __ movements.
Rotational
Which cells in the taste buds provide the sense of taste?
Gustatory receptor cells
What are corpuscles of touch (Meissner’s corpuscles), and where are they located?
They are discriminate touch receptors located in the dermal papillae of the skin.
Define photopigment.
A substance that absorbs light and undergoes structural changes that lead to the development of a generator potential.
How are cutaneous sensations generated?
Cutaneous sensations result when the surface of the skin is stimulated.
Name and describe the pain receptors.
Nociceptors are the branching ends of the dendrites of some neurons. They are free nerve endings.
Describe the olfactory tracts.
Are axons of olfactory neurons that lead from the olfactory bulbs to the cerebrum. A second pathway extends to the thalamus and then to the cerebral cortex.
Identify the location of the tastebuds.
Located on the tongue, soft palate, and walls of the pharynx.
What are proprioceptors?
Are receptors located in muscles, tendons, and joints that provide information about position and movement.
Identify the auditory ossicles and describe their function.
Are the 3 bones if the middle ear - the malleus, incus, and stapes - which conduct vibrations from the ear drum to the oval window.
Name the 3 areas of the bony labyrinth.
Vestibule
Cochlea
Semicircular canals
Contrast sensation and perception.
Sensation is the conscious or unconscious awareness of stimuli.
Perception is the conscious awareness and interpretation of sensations.
What is the function of the cones?
To enable vision in bright light and the perception of colour.
List the 4 tactile sensations:
Touch
Pressure
Vibration
Itch and tickle
Name the 2 parts of the ciliary body and describe the function of each:
Ciliary processes - secrete aqueous humor
Ciliary muscle - changes the shape of the lens
List the 4 conditions that must be satisfied for a sensation to occur:
Stimulation of a sensory receptor
Conversion of the stimulus into graded potential
Conduction of the impulse
Translation of the impulse by a region of the brain
Name, from the inside to the outside, the 3 layers of neurons found in the retina:
Ganglion layer
Bipolar layer
Photoreceptor layer
Identify the specific locations where the receptors of the olfactory sense are found.
In the nasal epithelium in the superior region of the nasal cavity on either side of the nasal septum.
What is the optic tract?
A collection of axons of ganglion cells from the retina after they pass through the optic chiasm.
What are the 5 primary taste sensations?
Sour Salt Bitter Sweet Umami
What are the functions of the eyelids?
To shade and protect the eyes, and to spread lubricating secretions over the surface of the eye.
What is rhodopsin?
Is a photopigment found in rod cells; it consists of opsin (a protein) and retinal.
Describe the meaning of accommodation of the lens.
Refers to changes in the curvature of the lens of the eye, which changes focus from near to distant objects and vice versa.
Define mechanoreceptors, and give 3 examples of the stimuli they detect.
Detect deformation in response to stimuli such as touch, pressure, vibration, proprioception, hear, and blood pressure.
Identify the location of the receptors that function in the maintenance of static equilibrium.
They are located in the walls of the utricle and saccule, the 2 sacs of the vestibule.
Describe the role of the organ of Corti in hearing.
The hair cells on the basilar membrane move against the overlying tectorial membrane and initiate a signal that causes nerve impulses, which are interpreted as sounds by the auditory area of the cerebrum.
List in order, from outside to the inside, the 3 layers of the eyeball.
Fibrous tunic (sclera and cornea) Vascular tunic (choroid, ciliary body, iris) Nervous tunic (retina)
What is meant by the term adaptation to sensations?
Adaptation to sensations is a decreased sensitivity to the same stimulus.
What is referred pain?
A pain sensation that the brain projects back to some location other than that from which the pain originates.
Describe the cells that act as the olfactory sensors.
The olfactory cells are first order neurons. The olfactory hairs are cilia projecting from the end of the neuron. These hairs detect inhaled compounds.
What is the function of the lacrimal glands?
To produce tears - a watering solution containing salts, mucus, and lysozyme.
Name cutaneous sensations.
Cold Pain Hot Touch Vibration
What structure directly alters the shape of the lens for far and near vision?
Ciliary muscle
The external (outer) ear:
Has hair cells in its auditory canal a d specialized glands called ceruminous glands.
Name the accessory structures of the eye:
Eyebrows
Eyelashes
Eyelids
Lacrimal apparatus
Which of the following is a tactile sensation?
Cold, heat, pain, vibration
Vibration
The spiral organ of Corti is:
A coiled sheet of supporting cells and hair cells.
Chemoreceptors detect what?
Smell and taste
In humans, both eyes focus on only one set of objects; this characteristic is known as:
Binocular vision
The vestibular membrane separates the cochlear duct from the scala vestibuli.
This is a statement that is true of what?
The membranous labyrinth
It is separated from the internal ear by a bony partition containing the oval and round windows.
Is a statement of what area of the ear?
The middle ear
Cristae in semicircular ducts is the sense organ for __ equilibrium only.
Dynamic
What are otoliths, and what role do they play in the maintenance of equilibrium?
Otoliths are crystals of calcium carbonate that lie on a gelatinous layer of the macula and move in response to changes in the position of the head.
Since the nervous system does not replace neurons, all olfactory epithelial cells gradually decrease in number as we get older.
Olfactory epithelium
For vision to occur what is the correct sequence?
Photoreceptors > bipolar cells > ganglion cells > optic nerve > thalamus
