1. Animal Form & Function Physiology AP Biology

2. Nerve Impulse Transmission  Resting potential  More negative inside cell than outside Why? Large negatively charged proteins & nucleic acids Na+/K+ pumps maintain high [Na+] outside cell and high [K+] inside cell

3. Nerve Impulse Transmission  Resting potential  Membrane potential = -70 mV

4. Nerve Impulse Transmission  Depolarization  Stimulus causes Na+ gates to open  Na+ rushes into cell

5. Nerve Impulse Transmission  Repolarization  Na+ gates close & K+ gates open  K+ rushes out of cell  High [Na+] inside cell  High [K+] outside cell

6. Nerve Impulse Transmission  Hyperpolarization  K+ gates slow to close  More K+ moved out than necessary

7. Nerve Impulse Transmission  Refractory period  Na+/K+ pumps move Na+ out of cell K+ into cell  Restores resting potential distribution of Na+ and K+

8. Transmission Across a Synapse  Synapse  Gap between neurons

9. Transmission Across a Synapse  Stimulus reaches synaptic end bulb

10. Transmission Across a Synapse  Ca 2+ gates open  Ca 2+ enters end bulb

11. Transmission Across a Synapse  Vesicles with neurotransmitter migrate to presynaptic membrane

12. Transmission Across a Synapse  Vesicle fuses with presynaptic membrane

13. Transmission Across a Synapse  Neurotransmitter released into synaptic cleft

14. Transmission Across a Synapse  Neurotransmitter diffuses across cleft

15. Transmission Across a Synapse  Neurotransmitter binds to receptor protein

16. Transmission Across a Synapse  Postsynpatic neuron depolarizes

17. Muscle Contraction  Sliding filament model

18. Muscle Contraction  Sliding filament model  Depolarization of muscle causes sarcoplasmic reticulum to release Ca 2+

19. Muscle Contraction  Sliding filament model  Ca 2+ exposes binding sites on actin  Myosin heads bind to actin  Cross bridges form

20. Muscle Contraction  Sliding filament model  Myosin heads lose ADP + P  Myosin heads change shape  Actin pulled toward center of sarcomere  Muscle contracts

21. Muscle Contraction  Sliding filament model  ATP binds to myosin heads  Cross bridges break  Muscle relaxes

22. Muscle Contraction  Sliding filament model

23. Steroid Hormone  Steroid hormone enters cell

24. Steroid Hormone  Steroid hormone enters cell  Binds to receptor

25. Steroid Hormone  Steroid hormone enters cell  Binds to receptor  Hormone- receptor complex enters nucleus  Causes transcription DNA transcribed RNA translated

26. Protein Hormone  Protein hormone too big to enter cell

27. Protein Hormone  Protein hormone too big to enter cell  Binds to receptor

28. Protein Hormone  Protein hormone too big to enter cell  Binds to receptor  Activates enzyme

29. Protein Hormone  Protein hormone too big to enter cell  Binds to receptor  Activates enzyme  Enzyme used to make cyclic AMP

30. Protein Hormone  Protein hormone too big to enter cell  Binds to receptor  Activates enzyme  Enzyme used to make cyclic AMP  Cyclic AMP targets cell responses

31. Kidney  Filtration  Formation of filtrate  Waste, nutrients, water, ions, proteins move from the blood into the Bowman’s capsule

32. Kidney  Reabsorpton  Nutrients, ions, & water move from filtrate back into blood

33. Kidney  Secretion  Ions & wastes more from the blood into the filtrate

34. Kidney  Bowman’s capsule  Filtrate production  Blood pressure forces small solutes, water & ions from blood into capusule

35. Kidney  Proximal convoluted tubule  Reabsorption of water, ions, and all organic nutrients

36. Kidney  Loop of Henle  Descending limb  Water reabsorbed  Wall permeable to water but not solutes

37. Kidney  Loop of Henle  Ascending limb  Wall impermeable to water and solutes  Cells actively pump Na+ and Cl - out of tubular fluid

38. Kidney  Distal convoluted tubule  Secretion of ions, acids, drugs, toxins  Variable reabsorption of water and Na+

39. Kidney  Collecting duct  Variable reabsorption of water and ions  Variable secretion of water and ions  Balancing act - homeostasis