Download Notes for Ch. 10 (Somatic and Special Senses) Introduction

Notes for Ch. 10 (Somatic and Special Senses)
Introduction
• General senses
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Receptors that are widely distributed throughout the body
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Skin, various organs and joints
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Special senses
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Specialized receptors confined to structures in the head
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Eyes, ears, nose and mouth
Receptors, Sensation, and Perception
• Sensory receptors
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Specialized cells or multicellular structures that collect information from the environment
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Stimulate neurons to send impulses along sensory fibers to the brain
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_______________________ – A feeling that occurs when brain interprets sensory impulses.
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_______________________ – A person’s view of the stimulus; the way the brain interprets the information
Receptor Types
• _______________________ – Respond to changes in chemical concentrations
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_______________________– Respond to tissue damage
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_______________________–Respond to changes in temperature
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_______________________–Respond to mechanical forces
• _______________________–Respond to light
Touch and Pressure Senses
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_______________________
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Common in epithelial tissues (most common receptor in the body)
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Simplest receptors
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Sense itching
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_______________________
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Abundant in hairless portions of skin and lips
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Detect fine touch; distinguish between two points on the skin
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_______________________
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Common in deeper subcutaneous tissues, tendons and ligaments
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Detect heavy pressure and vibrations
Temperature Senses
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_______________________
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Sensitive to temperatures above 25oC (77o F)
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Unresponsive to temperature above 45oC (113oF)
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_______________________
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Sensitive to temperatures between 10oC (50oF) and 20oC (68oF)
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_______________________
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Respond to temperatures below 10oC
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Respond to temperatures above 45oC
Sense of Pain
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Detected by _____________________________________, Widely distributed
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Nervous tissue of _____________________ lacks pain receptors – brain surgery does not hurt!
Stimulated by tissue damage, chemical, mechanical forces, or extremes in temperature
Adapt very little, if at all
Visceral Pain
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____________________________ are the only receptors in viscera whose stimulation produces sensations
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Pain receptors may feel as if coming from some other part of the body -- known as _______________________________
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This convey information that includes the sense of fullness after eating a meal as well as the discomfort of intestinal gas and
the pain that signals a heart attack
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Referred pain may occur due to sensory impulses from two regions following a common nerve pathway to brain
Pain Nerve Pathways
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_______________________________
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Thin, myelinated, Conduct impulses rapidly, Associated with sharp pain, Well localized
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_______________________________
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Thin, unmyelinated , Conduct impulses more slowly, Associated with dull, aching pain, Difficult to pinpoint
Regulation of Pain Impulses
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_____________________________ – Allows person to be aware of pain
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Judges intensity of pain
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Locates source of pain
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Produces emotional and motor responses to pain
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Pain inhibiting substances:_____________________________________________________________________
Special Senses
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Sensory receptors are within large, complex sensory organs in the head
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_____________________ in olfactory organs
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_____________________ in taste buds
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____________________________________ in ears
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_____________________ in eyes
Sense of Smell
• _________________________________
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Chemoreceptors
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Respond to chemicals dissolved in liquids
• _________________________________
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Contain olfactory receptors and supporting epithelial cells
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Cover parts of nasal cavity, superior nasal conchae, and a portion of the nasal septum
• Once olfactory receptors are stimulated, nerve impulses travel through:
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Olfactory nerves  _________________________  olfactory tracts  ________________________________
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(for emotions) and ____________________________________ (for interpretation)
Olfactory Stimulation
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Olfactory organs located high in the ________________________________ above the usual pathway of inhaled air
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Olfactory receptors undergo sensory adaptation rapidly
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Sense of smell drops by _____% within a second after stimulation
Sense of Taste
• _____________________________
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Organs of taste
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Located on papillae of tongue, roof of mouth, linings of cheeks and walls of pharynx
• ________________________________
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Chemoreceptors
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___________________________ – modified epithelial cells that function as receptors
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___________________________ –microvilli that protrude from taste cells; sensitive parts of taste cells
Four primary taste sensations
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___________________ – stimulated by carbohydrates
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___________________ – stimulated by acids
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___________________ – stimulated by salts
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___________________ – stimulated by many organic compounds
• Spicy foods activate ______________________________
Taste Nerve Pathways
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Sensory impulses from taste receptors travel along
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Cranial nerves_______________________________ ________________________Gustatory cortex (for interpretation)
Sense of Hearing
• Ear – Organ of hearing
• Three (3) sections:
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External ear
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Middle ear
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Inner ear
External Ear
• ____________________________ – Collects sounds waves
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External auditory meatus
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Lined with __________________________ glands
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Carries sound to ___________________________________
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Terminates with tympanic membrane
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____________________________ –Vibrates in response to sound waves
Middle Ear
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____________________________ – Air-filled space in temporal bone
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____________________________ –Vibrate in response to tympanic membrane
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______________________________________________(smallest bones in the body)
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Oval window
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Opening in wall of tympanic cavity
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Stapes vibrates against it to move fluids in inner ear
• Auditory Tube
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Also known as the _____________________________
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Connects middle ear to throat
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Helps maintain equal pressure on both sides of ____________________________________
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Usually closed by valve-like flaps in throat
Inner Ear
Three (3) parts of labyrinths:
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____________________________ – Functions in hearing
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____________________________ – Functions in dynamic equilibrium
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____________________________ – Functions in static equilibrium
Sense of Equilibrium
• __________________________________________
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Vestibule
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Senses position of head when body is not moving
• __________________________________________
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Semicircular canals
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Senses rotation and movement of head and body
Sense of Sight
• Visual accessory organs
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Eyelids
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Lacrimal apparatus
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Extrinsic eye muscles
• Eyelid
• Palpebra – Composed of four (4) layers: (Skin, Muscle, Connective tissue, Conjunctiva)
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___________________________ – closes eyelid
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______________________________________ – opens eyelid
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___________________________– secrete oil onto eyelashes
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___________________________ – mucous membrane; lines eyelid and covers portion of eyeball
Lacrimal apparatus
____________________________ – Lateral to eye and secretes tears
____________________________ – Collect tears
____________________________ – Collects from canaliculi
____________________________ – Collects from lacrimal sac and empties tears into nasal cavity
Extrinsic eye muscles
_____________________________ – Rotates eye up and medially
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_____________________________ – Rotates eye down and medially
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_____________________________ – Rotates eye medially
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_____________________________ – Rotates eye laterally
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_____________________________ – Rotates eye down and laterally
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_____________________________ – Rotates eye up and laterally