1. Ch 13 – PNS & Reflex Activity Learning Objectives 1.Describe the major responsibilities of the PNS. 2.Recognize that reaction times are controlled with the assistance of the PNS. 3.Discuss the 5 types of sensory receptors and what they do. 4.Identify and explain the structures and function of the eye. The brain of an average-sized adult weighs about three pounds, yet the amount of information it contains is amazing! Read 442, 445 – 464. Review eye anatomy & learn structures and functions (complete 11 terms last slide).

2. Reaction Time Need 2 Volunteers – 1 is the “catcher”; 1 drops ruler between their partner’s fingers (the “dropper”) Instructions for Volunteers: The “Catcher” - Hold your thumb and index finger two inches apart while your partner drops a ruler between them. The “Dropper” – hold ruler vertical and drop it between your partner’s thumb and index finger. The distance the ruler falls before he/she stops it with his thumb and finger indicates their reaction time. Repeat twice. Record the results. Challenge: Try the experiment again while the catcher recites addition or multiplication facts. Compare the results. What happened to the reaction time? Why? NOTE: Our reaction time increases when we are distracted. With all of our senses, an __________ ______ is passed between neurons and travels through the nerves, spinal cord, and brain.

3. PNS Sensory (afferent) division Motor (efferent) division PNS Provides links to and from the _________ environment Conducts these impulses from receptors to the _____

4. PNS The peripheral nervous system includes the _______ that extend from the brain and the spinal cord. ("Peripheral" means "by the surface or the edge“) Our skin has receptors called ________________ that that allow us to feel pressure and touch, and __________ that allow us to feel heat and cold

5. Other Receptors We also have receptors that respond to light such as those in the retina of the eye called ________________ Those that allow us to smell or taste called __________________ Some that tell indicate potentially dangerous stimuli (i.e., searing heat, extreme cold, excessive pressure) that could result in pain called ___________

6. Sensation versus Perception Survival depends upon sensation and perception. _________ is the awareness of changes in the internal and external environment __________ is the conscious interpretation of those stimuli

7. The Eye and Vision Vision is our dominant sense because ___ of all sensory receptors are in the eyes and nearly ____ of the cerebral cortex is involved in some aspect of visual processing http://lightisreal.com/lightillusion.html?gclid =CJPjl7Sx5I8CFQdEFQodan3R6whttp://lightisreal.com/lightillusion.html?gclid =CJPjl7Sx5I8CFQdEFQodan3R6w

8. Eye Anatomy Label your practice diagram cornea pupil iris lens aqueous humor blind spot optic nerve vitreous humor sclera choroid retina

9. Homework & Study Practice 1.cornea 2.pupil 3.iris 4.lens 5.aqueous humor 6.vitreous humor 7.sclera 8.choroid 9.retina 10.optic nerve 11.blind spot Instructions: Describe each structure and explain its function