Receptors and General Senses Lab 30 Receptors and General Senses

Materials Needed Direction packet Lab Report 30 worksheet (1 per person) Textbook Pen (washable) Ruler (mm) Sharp pencil/sharp point of lead/ or paper clip point Blunt metal probe Forceps Warm water Ice water Paper towel

Procedure B 1. Investigate the distribution of touch receptors in your lab partner’s skin. Draw a 2.5 x 2.5 cm square on your partner’s inner wrist, near their palm Draw a 2.5 x 2.5 cm box Then draw a line every .5 cm Horizontally Vertically 2.5 cm x 2.5cm

Procedure B Investigate the distribution of touch receptors in your lab partner’s skin. c. Ask your partner to rest their wrist on the table and to CLOSE THEIR EYES 2.5 mm x 2.5mm

Procedure B Investigate the distribution of touch receptors in your lab partner’s skin. Press the end of a sharp pencil in a square on the grid, using light pressure Ask your partner to report whenever the touch is felt. Record in lab report. + if felt 0 if NOT felt Continue until you test all 25 locations on the grid. GO IN RANDOM ORDER. 2.5 mm x 2.5mm

Procedure B Investigate the distribution of touch receptors in your lab partner’s skin. Test two other areas of exposed skin. Palm Your choice 2.5 mm x 2.5mm

Procedure B Investigate the distribution of touch receptors in your lab partner’s skin. Answer questions in part B of lab report. 2.5 mm x 2.5mm

Procedure C Test your partner’s ability to recognize the difference between one and two points of skin being stimulated simultaneously. a. Have your partner place a hand with the palm up on the table and close eyes.

Procedure C Test your partner’s ability to recognize the difference between one and two points of skin being stimulated simultaneously. b. Hold the tips of the forceps tightly together and gently touch the skin of your partners index finger. c. Ask your partner to report if it feels like one or two points are touching their finger

Procedure C Test your partner’s ability to recognize the difference between one and two points of skin being stimulated simultaneously. d. Allow the tips of the forceps or the points of the tips to spread so they are 1 mm apart. Press both points against the skin simultaneously, and ask your partner to report.

Procedure C Test your partner’s ability to recognize the difference between one and two points of skin being stimulated simultaneously. e. Repeat, allowing the tips of your forceps to spread more each time UNTIL YOUR PARTNER CAN FEEL BOTH TIPS This is called the two-point threshold. As soon as you can feel this, two receptors are being stimulated, instead of one! f. Record results

Procedure C Test your partner’s ability to recognize the difference between one and two points of skin being stimulated simultaneously. Repeat on: Palm Back of hand Leg Sole of foot –or ankle if you want Answer the questions in part C

Procedure D Investigate the distribution of warm receptors in your partner’s skin Using the grid on your palm from procedure A, have your partner rest their hand on the table and close their eyes

Procedure D Investigate the distribution of warm receptors in your partner’s skin d. Heat the blunt metal probe by placing it in your cup of hot water (BE CAREFUL!!!) for a minute or so. e. Wipe probe dry and touch it to the skin on some part of the grid

Procedure D Investigate the distribution of warm receptors in your partner’s skin f. Ask your partner to report if the probe feels warm. Record in part D. Keep the probe warm, and repeat until you have RANDOMLY tested all 25 squares + if felt 0 if NOT felt

Procedure D Investigate the distribution of cold receptors in your partner’s skin Repeat using ice water. Answer the questions in part D of the lab report

Other Directions: WORK IN PARTNERS Share materials with another set of partners NO ICE OR HOT WATER WILL BE AVAILABLE TOMORROW!!!!! So you MUST complete procedure D today. You will have limited time in class tomorrow to finish Lab report 30 Approx 15 mins (MAX)