DO NOW

• Get into a group of 3 with the people who have the same Case # as you on their Do Now paper.

• Read the article and summarize it as a group. Choose someone to speak for your group!

OBJECTIVES

• Identify and explain the different types of sensory receptors.• Explain referred and phantom pain.• Compare and contrast acute and chronic pain.

1 0 . 1 - 1 0 . 4

SPECIAL SENSES

PHANTOM PAIN

• The sensation of pain in a limb that has been amputated.• Causes aren’t completely understood• damaged nerve endings, scar tissue at the site of the

amputation and the physical memory of pre-amputation pain in the affected area

http://www.youtube.com/watch?v=YL_6OMPywnQ

DO NOW

• What is phantom pain?• What causes it?• What is mirror therapy?• How else could someone alleviate this pain?

OBJECTIVES

• Identify and explain the different types of sensory receptors.• Explain referred and phantom pain.• Compare and contrast acute and chronic pain.

PHANTOM PAIN

• http://www.youtube.com/watch?v=hlQZmNlPdHQ

RECEPTORS & SENSATIONS

Sensation• formed based on the sensory input from receptors• how brain interprets it

• Projection • Brain sends the sensation back to its point of origin• person can pinpoint the area of stimulation

RECEPTIVE FIELDS

• Remember the 2 point discrimination in the lab? • Which part of your body had a larger receptive field?

SENSORY ADAPTATION

• Before reading this sentence, could you feel your clothes on your skin? • The ability to ignore unimportant stimuli is called

sensory adaptation.

RECEPTOR CATEGORIES

• Somatic senses • touch, pressure, pain

Specialized senses

smell, taste, hearing, equilibrium, vision

SOMATIC RECEPTORS

• Chemoreceptors• Thermoreceptors• Photoreceptors• Mechanoreceptors• Pain receptors (Nociceptors)

CHEMORECEPTORS

• respond to changes in chemical concentrations• Ex: Monitor CO2 levels in blood and pH

THERMORECEPTORS

• Respond to changes in temperature

THERMORECEPTOR ACTIVITY

• Place your pointer finger on your right hand in cold water and the same finger on your left hand in warm water. • Leave them in there for 1 minute• Now place them both in the room temperature

water.•

PHOTORECEPTORS

• Responds to light• Rods- respond to light• Cones- respond to colors

PHOTORECEPTOR ACTIVITY

• Hold the ends of a pencil, one in each hand. Hold them horizontally facing each other at arms-length from your body. • 2. With one eye closed, try to touch the end of

the pencils together. • 3. Now try with two eyes.• What did you experience?

MECHANORECEPTORSFree nerve endings• common in epithelial tissues• simplest receptors• sense itchingMeissner’s corpuscles• abundant in hairless portions of

skin; lips• detect fine touch; distinguish

between two points on the skinPacinian corpuscles• common in deeper subcutaneous

tissues, tendons, and ligaments• detect heavy pressure and

vibrations

PAIN RECEPTORS

• “Nociceptors”- • found on free nerve endings • Respond to tissue damage

Pain receptor clip: http://www.nlm.nih.gov/medlineplus/ency/anatomyvideos/000054.htm

ACUTE VS. CHRONIC PAIN

• Acute pain fibers: • Relatively thin, myelinated• Rapid impulse conduction, causing sharp pain

• Chronic pain fibers:• Thin, unmyelinated• Conduct impulses slowly, produce a dull aching sensation

REFERRED PAIN

• may occur due to sensory impulses from two regions following a common nerve pathway to brain • Ex:• Someone experiencing

a heart attack may feel pain in their left shoulder

REVIEW

• What receptors detect deep pressure?• What is the difference between acute and chronic

pain?• Where do you have the most receptive fields?

**Monday- bring your books and notes to class! We are going to start reviewing for midterms.