10.1-10.5 Senses

Two categories of sensory receptors: CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. Two categories of sensory receptors: somatic-touch, pressure, temperature, pain Special senses that are important for smell, taste, hearing, equilibrium, and vision

-chemoreceptors-sense changes in chemicals -pain-sense tissue damage CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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

Sensations vs. Projection CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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

CopyrightThe McGraw-Hill Companies, Inc CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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

Free nerve endings-in skin CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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

CopyrightThe McGraw-Hill Companies, Inc CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.

-warm receptors and cold receptors (free nerve ending types) CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. Temperature Senses -warm receptors and cold receptors (free nerve ending types) -adapt very rapidly -respond in different temperature ranges

CopyrightThe McGraw-Hill Companies, Inc CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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.

CopyrightThe McGraw-Hill Companies, Inc CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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.

d. Pain impulses are processed in the gray matter of the spinal cord. CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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..

Sense of Smell A. Olfactory Receptors 1. chemoreceptors CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sense of Smell A. Olfactory Receptors 1.      chemoreceptors 2. Smell and taste work together-food selection

CopyrightThe McGraw-Hill Companies, Inc CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.

1. are located in the upper nasal cavity. CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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.

Olfactory Stimulation CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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.

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

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

Taste Receptors 1. Taste cells are modified epithelial cells that function as receptors. (Each taste bud has 50-150 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