Body Senses

Body Sensations: Messages About Myself Sensation and Perception Body Sensations: Messages About Myself Orientation and movement Vestibular organ – 2 sets of sensory structures Semicircular canals Saccule and utricle Kinesthetic receptors – throughout body Skin senses Pressure sensitivity Temperature sensitivity

Touch Skin Sensations pressure warmth cold pain only skin sensation with identifiable receptors warmth cold pain Touch localization demonstration, concentrate on where the sensations of touch are felt: Touch two index fingers together, feel it in both Touch finger to bottom lip, light taps, felt mostly in lip even though both are being stimulated Touch ankle, now its felt mostly in finger Touch localization depends on the relative lengths of the pathways from the stimulated parts to the brain

Skin Senses Only pressure has identifiable receptors. All other skin sensations are variations of pressure, warmth, cold and pain. Pressure Vibration Vibration Burning hot Cold, warmth and pain

The Skin Senses Pressure Temperature Free nerve endings hair Tactile discs hair Specialized end bulbs basket cell around hair Temperature

Braille Alphabet A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Ashley Blocker (right) feels neither pain Pain tells the body that something has gone wrong. Usually pain results from damage to the skin and other tissues. A rare disease exists in which the afflicted person feels no pain. AP Photo/ Stephen Morton Ashley Blocker (right) feels neither pain nor extreme hot or cold.

Pain Nerve endings in body act as nocioceptors Sensation and Perception Pain Nerve endings in body act as nocioceptors Neural messages transmitted along two distinct pathways Rapid – detects first pain sensation Slow – detects second long-lasting pain Endorphins and endogenous morphine

Gate-Control Theory Melzack and Wall (1965, 1983) proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed. Gary Comer/ PhototakeUSA.com

Gate-control theory of pain Direction of pain message neuro-transmitter molecules in axon of slow-pain neuron Endorphin receptor Axon of inhibitory pain gate neuron endorphin Neuron in slow-pain fiber Inhibitory pain gate neuron Stimulation of endorphin receptors inhibits firing of axon of slow-pain neuron Close-up view of inhibitory pain gates Somatosensory area of cortex Limbric system Area of pain gates Pathway of fast-pain fibers Pathway of slow-pain fibers

Pain Control Pain can be controlled by a number of therapies including, drugs, surgery, acupuncture, exercise, hypnosis, and even thought distraction. Todd Richards and Aric Vills, U.W. ©Hunter Hoffman, www.vrpain.com

Chemical Senses: The Flavors and Aromas of Life Sensation and Perception Chemical Senses: The Flavors and Aromas of Life Senses of gustation (taste) and olfaction (smell) differ from all other senses Taste cells and papillae on tongue Taste buds detect Sweet Sour Salty Bitter Umami (Fresh Chicken)

Sensory Interaction When one sense affects another sense, sensory interaction takes place. So, the taste of strawberry interacts with its smell and its texture on the tongue to produce flavor.

Taste Surface of tongue Receptor cells Pore Bitter Sour Salty Sweet and fatty Sensory nerve fiber Taste

Chemical Senses: The Flavors and Aromas of Life Sensation and Perception Chemical Senses: The Flavors and Aromas of Life Olfactory nerve to brain Olfactory epithelium Nasal cavity Olfaction Olfactory epithelium – top of nasal cavity Pheromone detection of sweat and urine Vomeronasal organ Influence human female reproductive cycles Inhalation of male sex hormone and mood changes Males may respond to sex hormones

Smell Like taste, smell is a chemical sense. Odorants enter the nasal cavity to stimulate 5 million receptors to sense smell. Unlike taste, there are many different forms of smell. Preview Question 15: How do we experience smell?

Smell and Memories The brain region for smell (in red) is closely connected with the brain regions involved with memory (limbic system). That is why strong memories are made through the sense of smell.

Age, Sex and Sense of Smell Women Men 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 Age Group 4 3 2 Number of correct answers Women and young adults have best sense of smell Smell can be used to identify gender The phenomenon of women in the same home having the same menstrual cycle is related to smell—researcher Martha McClintock discovered this 30 years ago while at Wellesley College; now a researcher at the U of Chicago found that smell can stimulate ovulation Citrus odors make people more alert, spiced apple helps relaxation Pumping certain pleasant food odors cut by 40 percent shoving, pushing in New York subways People in New York mall were more likely to help strangers when there was the aroma of roasting coffee or baking cookies Good and Plenty licorice combined with cucumber increased female blood flow by 14 percent (anything over 10 percent was considered stimulating), baby talc 13 percent, lavender + pumpkin pie 11 percent Cherry cut flow by 18 percent, charcoal barbecue 15 percent, men’s cologne by 1 percent Women seem to be excited by things that remind them of childhood, or are fresh smelling, relating to safety and security needed in order to feel sexual

Body Position and Movement The sense of our body parts’ position and movement is called kinesthesis. The vestibular sense monitors the head (and body’s) position. http://www.heyokamagazine.com Bob Daemmrich/ The Image Works Whirling Dervishes Wire Walk

Sense Example of Sensation Example of Perception Sight Hearing Smell   Hearing Smell Touch Taste

Sight Hearing Smell Touch Taste Balance Kinesthesis Senses Organ Responsible Stimuli each sense responds to How stimuli is changed into neural impulses Sight Eye Light waves Light- pupil- lens- retina/ Rods and cones change light energy into neural impulses Hearing Ear Vibrations Sound waves- inner ear- hair cells- auditory nerve/ Change sound vibrations into neural signals Smell Nose Gaseous molecules Gaseous molecules- smell receptors in nose- olfactory nerve/ Changes molecules into neural impulses Touch Skin Pressure, warmth, cold, pain Begins with stimuli affecting nerves in the skin. They send the message to the brain. The brain identifies the sensation as pressure, warmth, cold, or pain. Taste Tongue Chemicals Liquid chemicals must stimulate receptors in taste buds on your tongue. Brain gets data about texture and temperature Balance Inner Ear Movement Inertia causes fluid in the canals to resist changes in motion. Bends receptor cells projecting into the fluid Kinesthesis Muscles, joints, tendons Movement and body position the vestibular organ provides information about body orientation, and the kinesthetic sense reports bodily position and movement