1. Sensation and Perception part 3 Chapter 4 November 2014

2. Sensation: Touch Cutaneous refers to touch Human skin contains three types of cutaneous receptors: Pressure Pain Temperature

3. Sensation: Touch Different cutaneous receptors in skin:

4. Sensation: Smell Olfaction – the sense of smell Depends on ability to detect chemicals Humans have weaker sense of smell than many other animals Deer and sharks Odors can recreate emotional memories of when that odor was previously encountered

5. Sensation: Smell Cilia – tiny hairs that receive odor molecules. Some act as receptors in the nose. Cilia collect molecules of odor, which sends electric signal to olfactory bulb Structurally similar to those in the ear, but different function Olfactory bulbs – units that receive odor molecules and communicate their nature to the brain.

6. Sensation: Smell

8. Smell intended to send information about food If food smells spoiled, you will be discouraged from eating it, and you will avoid getting sick. Smell is more important in eating than taste Maybe I shouldn’t eat this… Get in my belly!

9. Sensation: Smell Pheromones – odor chemicals that communicate a message Animals communicate sexual interest w/pheromones

10. Sensation: Smell Difficult to study whether pheromones play a part in human sexual attraction, because it is so complex

11. Sensation: Taste Taste receptors – chemical receptors on the tongue that decode molecules of food or drink to identify them “taste buds”

12. Sensation: Taste Four types of taste receptors : salt, sweet, sour, bitter

13. Sensation: Taste Salt – needed for chemical balance. Used for muscle contraction Low-salt  dizzy, sick Healthy people remove excess salt through urination

14. Sensation: Taste Salt – Newborn babies do not need salt, so they do not crave it Children (a few months and older), and pregnant women crave lots of salt because they need it Elderly people use lots of salt because receptors have dulled with age.

15. Sensation: Taste Sugar– most animals need sugar for energy Not enough sugar  tremble, feel faint, mental confusion

16. Sensation: Taste Sourness and bitterness – we need to be able to detect sourness and bitterness because spoiled foods or poisonous plants tend to have bitter flavors. Spoiled food usually detected by odor before it reaches taste buds, but some poisonous plants are odorless http://www.youtube.com/watch?v=3P8EDpoONl8