1. Unit 4: Sensation & Perception
Module 15:
Other Important Senses

2. Touch

3. TOUCH (SOMATOSENSATION)
Somatosensation: the skin sensations, or the sense of touch.
Made up of four skin senses:
Pressure
Warmth
Cold
Pain
Touch is also linked to your brain!
Rubber hand illusion

4. Rubber Hand Illusion

5. TOUCH (SOMATOSENSATION)
These parts can combine to create different touch sensations. For example, burning is pain, warmth, and cold.
Itching is gentle stimulation of pain receptors.

6. Touch – Pain Pain is your body telling you something is wrong.
Pain is important because it alert you to injury and often prevents further damage.
Those born without the ability to feel pain usually die by early adulthood.
Hyperalgesia – increased sensitivity to pain.

7. Touch – Pain
Pain follows a slower and less defined pathway, and requires a psychological and physical explanation.
Gate-Control Theory: pain is experienced only if the pain messages can pass through a “gate” in the spinal cord on their way to the brain.

8. Touch – Pain
Massage, electrical stimulation, acupuncture, ice, and the natural release of endorphins can close the gate.

9. Touch – Pain
The gate is opened by small nerve fibers that carry pain signals, and is kept open by things like anxiety, depression, and focusing on the pain.
The gate is closed by neural activity of larger nerve fibers, which conduct most other sensory signals, or by information coming from the brain.

10. Touch – Pain Pain is also in the brain!
When we are distracted from the pain, it is lessened.
Ex. Athletes often can play through the pain until after the game is over.
People also feel more pain if others around them feel pain.
“I can feel your pain!” – LITERALLY

11. Taste

12. Taste
Gustation: the chemical sense of taste with receptor cells in taste buds in fungiform papillae (tissue) on the tongue, on the roof of the mouth, in the throat.
There are three kinds of tasters: nontasters, tasters, and supertasters.
Molecules must dissolved in saliva or a liquid to be sensed.

13. Taste Five basic taste sensations are: Sweet Sour Salty Bitter
Umami (Meaty Taste)
Taste is a chemical sense.
Taste buds catch food chemicals.

14. Taste
Flavor is the interaction of sensations of taste and odor with contributions by temperature and texture.
Babies show a preference for sweet and salty foods, both necessary for survival; and disgust for bitter and sour, which are characteristic of poisonous and spoiled food.

15. Taste Taste receptors reproduce every week or two.
If you burn your tongue, you might lose taste buds, but they grow back.
As you get older, you lose taste buds and taste sensitivity.
Smoking and alcohol also kill buds.
Sensory Interaction – one sense may influence another.
Ex. We need to smell food to taste it.

16. Smell

17. Smell
Olfaction: the chemical sense of smell with receptors in a mucous membrane on the roof of the nasal cavity.
Molecules must reach the membrane and dissolve to be sensed.
Only sense that does not go through the thalamus.

18. Smell Odors evoke memories and feelings.
We can recognize odors from past experiences and recall those experiences.
Pheromones – chemicals released by animals that triggers a social response by another animal.
Role of pheromones in humans are not clear.

20. Our Senses
See
Hear
Smell
Taste
Touch

21. BODY SENSES
Kinesthesis: body sense that provides information about the position and movement of individual parts of your body with receptors in muscles, tendons, and joints.
e.g. close your eyes and touch your nose.

22. BODY SENSES
Vestibular sense: body sense of equilibrium with hair like receptors in semicircular canals and vestibular sac in the inner ear.
If we spin around, we get dizzy because the fluids in your semicircular canals and your kinesthetic receptors have not returned to normal.