15CHAPTER 16: SOMATIC AND SPECIAL SENSES Flashcards
1
Q
What are the special senses?
A
- smell,
- taste,
- vision
- hearing
- and equilibrium
2
Q
What are the general senses?
A
Both somatic and visceral senses.
3
Q
What do general senses provide?
A
Information about conditions within internal organs.
4
Q
What is sensation?
A
a conscious or unconscious awareness of external or internal stimuli.
5
Q
What is perception?
A
the conscious awareness and interpretation of sensations.
6
Q
On a microscopic level, what are sensory receptors?
A
- free nerve endings,
- encapsulated nerve ending at the dendrites of first-order sensory neurons,
- or separate cells that synapse with first order sensory neurons.
7
Q
On the basis of the type of stimulus detected, how are receptors classified?
A
- Mechanoreceptors,
- Thermoreceptors,
- Nocieceptors,
- Photoreceptors,
- Chemoreceptors,
- and Osmorereceptors.
8
Q
What are tactile sensations?
A
touch, pressure, vibration, itch and tickle.
9
Q
What are tactile receptors?
A
- corpuscles of touch
- hair root plexuses
- type I and type II cutaneous mechanoreceptors
- lamellated corpuscles
- free nerve endings
10
Q
What does Crude Touch refer to?
A
the ability to perceive that something has simply touched the skin.
11
Q
What does Disciminative Touch refer to?
A
ability to recognize exactly what point of the body is touched.
12
Q
What results from the stimulation of tactile receptors in the deeper tissues?
A
pressure sensation
13
Q
What is pressure?
A
a sustained sensation that is felt over a larger area than touch.
14
Q
What receptors are for pressure?
A
- Type I mechanoreceptors and
2. Lamelleared (Pacinian) corpuscles.
15
Q
What does vibration sensation result from?
A
rapidly repetitive sensory signals from tactile receptors.
16
Q
What receptors are for vibration sensation and what do they detect?
A
- corpuscles of touch
- lamellated corpuscles
they detect low-frequency and high-frequency vibrations
17
Q
What are the receptors for itch and tickle sensations?
A
free nerve endings
18
Q
Why is pain a vital sensation?
A
it provides us with info about tissue damaging stimuli, and with signs that can be used for the diagnosis of disease or injury.
19
Q
What are pain receptors?
A
(nociceptors) - free nerve endings in almost every body tissue.
20
Q
What are the two types of pain?
A
- fast
2. slow
21
Q
Where are the receptors located that convey nerve impulses related to muscle tone, movement of body parts, and body position?
A
Located in skeletal muscles, tendons, around joints, and in the internal ear.
22
Q
What does Proprioceptive or Kinesthetic sense provide?
A
awareness of the activities of muscles, tendons, and joints, and
balance or equilibrium.
23
Q
Where are the receptors for olfaction located?
A
nasal epithelium in the superior portion of the nasal cavity..
24
Q
What do basal stem cells produce?
A
new olfactory receptors
25
Where do olfactory receptors convey nerve impulses to?
1. olfactory nerves,
2. olfactory bulbs,
3. olfactory tracts,
4. the cerebral Cortex,
5. and the limbic system.
26
What are the different classes for taste stimuli?
sour, sweet, bitter, salty, and umami.
27
What are the receptors for gustation and where are they located?
- Gustatory receptor cells
| - located in taste buds.
28
What do taste buds consist of?
1. supporting cells,
2. gustatory receptor cells,
3. and basal cells.
29
Where are taste buds found?
in the papillae, which appear as elevations on the tongue.
30
What are the different classifications of papillae?
circumvallate, fungiform, or filiform
31
Receptor potentials developed in gustatory hairs cause the release of what?
Neurotransmitters, which give rise to nerve impulses.
32
What is the taste threshold?
Bitter being the lowest, then sour and finally salty and sweet.
33
Where do gustatory receptor cells convey impulses to?
1. cranial nerves V, VII, IX, and S;
2. the medulla
3. the thalamus,
4. and the parietal lobe of the cerebral cortex.
34
What are the functions of the eyelid?
1. shade the eyes during sleep,
2. protect the eyes from excessive light and foreign objects
3. and spread lubricating secretion over the eyeball.
35
What is conjunctiva?
a thin mucous membrane that lines the inner aspect of the eyelids and is reflected onto the anterior surface of the eyeball.
36
The lacrimal apparatus consists of structures that do what?
produce and drain tears,
37
The eyeball is constructed of what three layers?
1. Fibrous tunic (outer most),
2. vascular tunic,
3. and retina (inner most)
38
The fibrous tunic of the eyeball is divided into what two regions?
the posterior sclera and anterior cornea
39
What is sclera?
"white of eye' -a white coat of dense fibrous tissue that covers the entire eyeball except iris (most anterior portion).
40
What is the function of sclera?
it gives shape to the eyeball and protects its inner parts.
41
What is the cornea and what is its function?
a nonvascular, transparent, fibrous coat through which the iris can be seen.
function= reflects light
42
the vascular tunic of the eyeball is composed of what 3 parts?
1. choroid
2. ciliary body
3. iris
43
What does the choroid do?
absorbs light rays so that they are not reflected and scattered within the eyeball.
and
provides nutrients to the posterior surface of the retina.
44
What ciliary body consists of what 2 parts>
ciliary processes and ciliary muscle.
45
What does the ciliary processes consist of?
protrusions or folds on the internal surface of the ciliary body where epithelial cells secrete aqueous humor.
46
What is the ciliary muscle?
a smooth muscle that alters the shape of the lens for near or far vision.
47
What is the iris? what does it include?
the colored portions seen through the cornea.
includes circular iris and radial iris smooth muscle fibres (cells) that are arranged to form a doughnut-shaped structure.
48
What is the principal function of the iris?
to regulate the amount of light entering the posterior cavity of the eyeball.
49
Where does the beginning of the visual pathway start?
retina
50
What is the optic disc?
the site where the optic nerve enters the eyeball.
51
The retina consists of what 2 layers?
1. a pigmented layer (nonvisual portion)
| 2. a neural layer (visual portion)
52
The pigment layer of the retina aids the choroid to do what?
absorb stray light rays.
53
The neural portion of the retina contains 3 zones of neurons that are names in the order in which they conduct nerve impulses. What are they called?
1. photoreceptor layer
2. bipolar cell layer
3. ganglion cell layer
54
Where is the lens located?
behind the pupil and retina
55
What are photoreceptor layers called?
cones and rods
56
What do rods do?
- specialized for black-and-white in dim lighting
- enable discrimination between different shades of dark and light
- permit us to see shapes and movement
57
What do cones do?
-specialized for color vision and sharpness of vision (high visual acuity) in bright light
58
Where are cones most densely concentrated?
in the central fovea,
| a small depression in the center of the macula lutea.
59
What is the macula lutea?
the exact center of the posterior portion of the retina.
| -corresponds to the visual axis of the eye.
60
How come the fovea is the area of sharpest vision?
because of its high concentration of cones.
61
Where are rods most densely concentrated?
the periphery of the retina.
62
Why do we have a blind spot?
the optic disc does not contain rods or cone, therefore when light strikes this area of the eye, an image is not formed.
63
The interior of the eyeball is a large space divided into what 2 parts?
1. Anterior cavity
| 2. Vitreous chamber.
64
The anterior cavity is subdivided into the anterior chamber and the posterior chamber. Where do these chamber lie?
Anterior chamber - lies behind the corner and in front of the iris.
Posterior chamber - lies behind the iris and in front of the suspensory ligaments and lens.
65
What is the water fluid called that fills the anterior cavity of the eyeball?
aqueous humor.
66
What are the ciliary processes behind the iris continually secreting?
Aqueous humor
67
The aqueous humor is mainly responsible for producing what?
pressure in the eye called the Intraocular pressure.
68
the Intraocular pressure and the vitreous body do what together?
maintain the shape of the eyeball and keep the retina smoothly applied to the choroid to produce clear images.
69
What is glaucoma?
Excessive intraocular pressure,
| causes a degeneration of the retina and blindness.
70
What is the gel called found inside the vitreous chamber (posterior cavity)?
vitreous body.
| which is formed during embryonic life and is not replaced thereafter
71
Image formation on the retina involves what?
- refraction of light rays by the cornea and lens,
- accommodation of the lens, and
- constriction of the pupil.
72
What is refraction?
the bending of light rays at the interface of two different media.
73
What is accommodation and how is it initiated?
an increase in the curvature of the lens,
| initiated by ciliary muscle contraction that allows the lens to focus on near objects.
74
What is presbyopia?
the inability to read print at close range.
75
What is myopia?
nearsightedness
76
What is hypermetropia?
farsightedness
77
What is astigmatism?
a refraction abnormality due to an irregular curvature of either the cornea or lens.
78
The constriction of the pupil narrows the diameter of the hole through which light enters the eye. This process occurs simultaneously with what and what does it function to prevent?
- the accommodation of the lens.
| - functions to prevent light rays from entering the eye through the periphery on the lens.
79
When does convergence occur?
when both eyes focus on a single object.
80
What does the inner ear do?
transduces fluid motion into action potentials
81
What does the inner ear house?
The bony labyrinth (tunnels within temporal bone)
82
What is the bony labyrinth lines with?
Fleshy tubes called membranous labyrinth filled with fluid
83
What are the subdivisions of the bony labyrinth?
vestibule (equilibrium), 3 semicircular canals (equilibrium), and cochlea (hearing)
84
What is the function of the cochlea?
converts physical vibrations of sound waves into electrical impulses
85
What are the three fluid-filled tubes separated by membranes within the cochlea and how are they arranged?
Superior tube = vestibular duct
Middle tube = cochlear duct
Inferior tube = tympanic duct
Coiled like a snail
86
What is the basilar membrane of the cochlea separate?
separates cochlear duct from inferior tube
87
What is the tectorial membrane of the cochlea separate?
separates cochlear duct from superior duct
88
Where is the spiral organ located?
located within the cochlear duct on top of basilar membrane
89
Where are the hair cells in the spiral organ?
The location of auditory receptors
90
What occurs due to the stiff microvilli (stereocilia) of the hair cells of the spiral organ?
ion channels open and depolarization occurs
91
When the basilair membrane moves up and down, what happens?
hair cells press against tectorial membrane and bend – triggering an action potential
92
What does the inner hair cells do?
Most of the ‘hearing'
93
What does the outer hair cells do?
The fine tuning
94
What does the loudness of a sound depend on?
Depends on number of hair cells that are stimulated
95
What do high and low pitches depend on?
which hair cells are stimulated
