1. Taste

2. Papillae
Bumps that cover the tongue surface

3. 10,000 taste buds are crammed into the tongue
Found in grooves, detect taste
10,000 taste buds are crammed into the tongue

4. Saliva
Water-like fluid that dissolves chemicals in food making them detectable
We produce 2-3 pints a day

5. Types of Taste

6. Bitter
At back of tongue

7. Sour
On sides of tongue

8. Salty
Along sides and tip of tongue

9. Sweet
At tip of tongue

10. Umami
Savory taste of foods like steak and cheese

11. Review

13. Smell

14. Nose Main organ of smell
What’s the difference between smelling and breathing?

15. Nose
Receptor cells in the top of the nose detect chemicals in the air

16. Smell
Humans have 5-6 million receptor cells in the nose and can recognize 10,000 different smells
Rabbits have 100 million
Dogs have 220 million

17. Nose
Olfactory nerves send messages to brain

18. Smell 80% of what we “taste” is actually smell
Foods can lose their “flavor” when we get sick

19. Smell The nose and mouth are linked at the throat
We can smell food as we chew it

20. Why is smell important?

21. Touch

22. Skin
The sense organ for touch
Largest organ of the body

23. Two layers:

24. Epidermis
Outside layer made of dead cells

25. Dermis
Inside layer made of living cells

26. Receptors Most are in the dermis Allow us to feel: Heat Cold Touch
Pressure
Pain

27. Heat Receptors
Detect heat

28. Cold Receptors
Detect cold

29. Touch Receptors
Detect light touch

30. Pressure Receptors
Detect deep pressure

31. Pain Receptors
Detect pain, found very close to surface of skin

32. Hair Movement
Can feel hairs moving without touching skin

33. Nerves Receptors connect to nerves throughout the body Sensory Nerves
Motor Nerves

34. Nerves
Sensory nerves – collect information and send it to the brain

35. Nerves
Motor nerves – sends messages from brain to body to respond

36. Try It Receptors, Sensory Nerves, Spinal Cord, Brain, Spinal Cord, Motor Nerves, Muscles

37. Not worth noticing
Brain receives messages all the time, but filters out the less important ones

38. Sensitivity
depends a lot on how close together the receptors are and how deep they are

39. Sensitive areas
Fingertips – about 3,000 touch receptors

40. Sensitive areas
Lips – skin is very thin

41. Other areas
Tongue – lots of pain receptors but not so many hot or cold receptors

42. Other areas
Feet – calluses can make them less sensitive

43. Not so much…
Middle back, legs, elbows

44. Using our sense of touch

45. Braille
Using raised dots to represent letters and numbers

46. Braille

47. Braille
M a l i a K u n d e