The senses “generalized senses” “special senses” What are they? What are the structures associated with the senses? Wha

1. The senses “generalized senses” “special senses” What are they? What are the structures associated with the senses? What is adaptation? Some respond to external environment Some are internal and monitor body conditions such as?

3. General senses touch receptors in skin (free nerve endings, also special structures many receptors in some parts of the body, very few in others pressure, vibration- in deeper layers of skin temperature- cold and heat receptors capsaicin- heat AND pain sense of body and limb position in muscles and joints along with inner ear, helps determine balance and coordination

6. Pain receptors where in the body are they? what causes pain? tissue damage release of chemicals bradykinin histamine prostaglandin capsaicin- activated by heat How does aspirin relieve pain What are the benefits of pain?

8. Chemical receptors Smell Taste Substances have odor or taste because of chemical receptors in our noses and mouths

10. Any one “taste bud” can sense all of the tastes Some are more sensitive to certain tastes than others Sense of taste can be very complex some salts are saltier than others acids tend to taste sour many toxic substances taste bitter

11. Olfaction (smell) Odorants must be dissolved in mucus Bind to specific receptors (many different types) Receptor can amplify signal; one item (such as a flower) can release many different odorants Signal is sent directly to cerebrum limbic system also activated

14. Hearing and equilibrium What do we hear? Sound waves how high are the sound waves? (loudness) what is their frequency? (pitch) How do we hear with our ears?

16. Outer ear- collection of sound waves Middle ear- amplification Inner ear- connects to neurons, transmits information to brain two structures here cochlea (hearing) vestibular apparatus (balance)

17. In the cochlea

18. Hearing loss Conductive deafness Nerve deafness What causes it? infection injury aging drugs What can be done about it?

19. Equilibrium and balance Mechanoreceptors are bent in response to movement Rotational (side to side) Gravitational (up and down) Also involved: receptors in joints and muscles vision

20. rotational (ro gravitational

21. Vision Light receptors How does the eye focus light? How do we see images? Why do we have two eyes? Why do we sometimes not see clearly, and what can we do about it?

23. Focusing an image requires bending light cornea and lens do this cornea cannot adjust its shape; lens can (accommodation) Problems with lenses aging cataracts

25. Image is focused on the retina Many photoreceptors Light is focused on fovea Problems with focusing myopia (nearsightedness) hyperopia (farsightedness) astigmatism (irregularities in cornea or lens)

27. Rods and cones (photoreceptors) Rods enable us to see in dim light Cones enable us to see color; also to see most clearly (lots of cones in fovea) What is color, anyway?

28. Having two eyes allows us to see depth Brain identifies image, also our position relative to it Image is inverted; brain corrects it

30. Summary Each type of sensory receptor detects a different stimulus Equilibrium and balance Cutaneous receptors Chemical receptors (taste and smell) Mechanoreceptors (hearing and equilibrium) Light receptors (vision)