1. Senses

2. Two categories of sensory receptors:
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Two categories of sensory receptors:
somatic-touch, pressure, temperature, pain
Special senses that are important for smell, taste, hearing, equilibrium, and vision

3. -chemoreceptors-sense changes in chemicals -pain-sense tissue damage
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Types of Receptors
-chemoreceptors-sense changes in chemicals
-pain-sense tissue damage
-thermoreceptors-change in temperatures
-mechanoreceptors-change in pressure or movement
-photoreceptors-light stimuli

4. Sensations vs. Projection
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Sensations vs. Projection
-Sensations are feelings that occur when the brain interprets sensory impulses.
-projection allows a person to figure out where that sensation came from
ex: ears hear, nose smells
-You have the ability to ignore certain stimuli
-sensory adaptation
-unresponsive receptors or signal does not get to cerebral cortex

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Type 1: Somatic Senses
A. Associated with receptors in the skin, muscles, joints, and viscera (organs within the body cavities)
B. Touch/Pressure, Temperature, and Pain

6. Free nerve endings-in skin
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Touch and Pressure Senses-Receptors
Free nerve endings-in skin
Meissner’s corpuscles-flattened connective tissue
Abundant in hairless areas/very sensitive
Pacinian corpuscles- They function to detect deep pressure.
Muscle, tendons, joints, subcutaneous layer

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8. -warm receptors and cold receptors (free nerve ending types)
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Temperature Senses
-warm receptors and cold receptors (free nerve ending types)
-adapt very rapidly
-respond in different temperature ranges

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Sense of Pain
Visceral pain receptors are the only receptors in the viscera that produce sensations.
a. Referred pain-pain may feel like it is coming from one area other than the area that is stimulated.
b. occurs because of the common nerve pathways leading from skin and internal organs.

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Pain Nerve Fibers
a. Fibers conducting pain impulses away from their source are either acute pain fibers or chronic pain fibers.
b. Acute pain fibers are thin, myelinated fibers that carry impulses rapidly and cease when the stimulus stops.
c. Chronic pain fibers are thin, unmyelinated fibers that conduct impulses slowly and continue sending impulses after the stimulus stops.

11. d. Pain impulses are processed in the gray matter of the spinal cord.
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d. Pain impulses are processed in the gray matter of the spinal cord.
e. Pain impulses are conducted to the thalamus (first to be aware of pain), hypothalamus, and cerebral cortex (determine pain intensity, locate source, mediate response..

12. Sense of Smell A. Olfactory Receptors 1. chemoreceptors
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Sense of Smell
A. Olfactory Receptors
1.      chemoreceptors
2. Smell and taste work together-food selection

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14. 1. are located in the upper nasal cavity.
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Olfactory Organs
1. are located in the upper nasal cavity.
2. The receptor cells are bipolar neurons with hairlike cilia covering the dendrites. The cilia project into the nasal cavity.

15. Olfactory Stimulation
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Olfactory Stimulation
1. Scientists are uncertain of how olfactory reception operates but believe that each odor stimulates a set of specific protein receptors in cell membranes.
2. The brain interprets different receptor combinations as an olfactory code.
3. Olfactory receptors adapt quickly but selectively.

16. Headaches
Tension headache-due to stress, fatigue, emotional tension, anxiety
Caused contraction of skeletal muscles in forehead, side of head, and back of neck
Vascular headache-constriction and dilation of cranial blood vessels
Migraine-form of vascular headache
BV constrict and produce blood deficiency

17. Taste
Taste buds are the organs of taste and are located within papillae of the tongue and are scattered throughout the mouth and pharynx.
-papillae-tiny elevations

18. Taste Receptors
1. Taste cells are modified epithelial cells that function as receptors. (Each taste bud has of these) 2. Contain the taste hairs that are the portions sensitive to taste.
Sweet-near the tip Sour-lateral edges Salt-tip and upper portion of tongue Bitter-back of tongue -this is up for debate