1. Slap Hands Game!

2. In the slap hands game, if your hands were on top what did you have to respond to?

3. Stimulus
- any internal or external change or event that causes a response in an organism

4. In the slap hands game, what body structures allowed you to detect and respond to the stimulus?
Sense organs
(eyes, skin)
Nerves
Brain
Muscle

5. The Human Nervous System

6. What are some examples of stimuli that an organism might have to respond to?
External
Predator
Prey
Food, Water
Mates, Rivals
Sunlight
Temperature
Internal
Hunger
Full bladder
Full rectum
Blood sugar level
Infection
Temperature

7. Why is it important to be able to respond to stimuli?
Survival
Homeostasis - the maintenance of a stable internal environment in an organism

8. To maintain homeostasis, the activities performed by various structures have to be controlled and coordinated.
Regulation - the coordination and control of all the life activities

9. How does our nervous system function? (How do nerve cells work?)

10. Neuron - the basic structural and functional unit of the nervous system
Specialized cell for receiving and transmitting impulses (stimuli)

11. The Neuron
Axon
Axon
Terminal Branches

12. 1 - Soma (cell body) 5 - Node 2 - Axon 6 - Dendrites 3 - Myelin Sheath8.
1 - Soma (cell body)
5 - Node
2 - Axon
6 - Dendrites
3 - Myelin Sheath
7 - Nucleus
4 - Axon
8 - Terminal Branches

13. Describe the direction in which impulses (stimuli) are transmitted along a neuron.

14. 2. What is a synapse?
- the space between two neurons
Synapse

15. How do neurons receive and send impulses? (How do nerve cells work?)

16. Sodium ions are like Black Friday shoppers
The membrane of a neuron (its dendrite) before the stimulus is polarized
Sodium ions are like Black Friday shoppers

17. Stimulus opens ion channels
Outside cell
Inside cell

18. What happened to the charges? Membrane is depolarized
Before Stimulus
After Stimulus

19. How does a nerve impulse travel down the neuron?

20. axon

21. Krazy George Henderson
A High School teacher
Became a professional cheerleader
1st time was an accident delayed response of one section to his direction

23. Nerve impulse
- a moving area of electrical and chemical change on the nerve cell membrane

24. The Myelin Sheath

26. Saltatory conduction - (leaping) - influx of ions in one node causes next node to become permeable to sodium (sodium channels open)

27. Speed of a Nerve Impulse
unmyelinated myelinated axons axons
3 mm/sec M/sec
(200,000mm/sec)

29. How does the nerve impulse get across the space between neurons?
Synapse (the space between two neurons)

30. Animation of Synaptic Transmission

31. 3. What is the chemical substance that transmits impulses across the synapse called?
neurotransmitters

33. A Neuromuscular Junction
Neurotransmitter
Receptors

34. Slap Hands Activity

35. How does the nerve reset itself so it can fire another impulse?

36. The Sodium-Potassium Pump

37. acetylcholinesterase

38. Sarin Nerve Gas
Sarin nerve gas inhibits the activity of an enzyme that is supposed to break down the neurotransmitter acetylcholine. This neurotransmitter makes skeletal muscles contract. Acetylcholine also acts at sites made of smooth muscle (the iris, respiratory and gastrointestinal tract, bladder, and blood vessels), cardiac muscle, as well as the salivary and sweat glands.
Predict what would happen to the concentration of acetylcholine in the synapse and on postsynaptic receptors as a result of exposure to Sarin.
Predict the effects of Sarin on the body.

39. Immediate signs and symptoms of sarin exposure
Runny nose
Watery eyes
Small, pinpoint pupils
Eye pain
Blurred vision
Drooling and excessive sweating
Cough
Chest tightness
Rapid breathing
Diarrhea
 Nausea, vomiting, and/or abdominal pain
Increased urination
Confusion
Drowsiness
Weakness
Headache
Slow or fast heart rate
Low or high blood pressure

40. Cyanide
Cyanide is a fast-acting poison that can be lethal. In large doses, cyanide quickly binds with iron in cytochrome a3, a protein in the mitochondria essential for the process of aerobic cellular respiration.
Predict the effect of cyanide on ATP production and the kind of cellular respiration taking place in cells.
Predict the effect of cyanide on nerve cell activity (e.g. sodium- potassium pump; impulses traveling down the axon).

42. Synapse - space between two neurons
synaptic knobs - secrete neurotransmitters into the synapse
Neurotransmitters - chemicals that transmit impulses across a synapse

43. Myelin sheath -
wraps around axon
insulates axon

45. The Neuron

47. Nerve Impulse 1. sodium ions (Na+) flow into the cell
2. Inside of cell becomes positively charged
3. This change stimulates adjacent membrane to become permeable to sodium
4. More sodium flows into the cell in this adjacent area of membrane (step 1)
5. Repeat step 2 etc...

48. +++++++ - - - - - - - - - - ++++++++
outside neuron
__________________________________________________________________
inside neuron impulse

51. What structures on the membranes of our cells detect (receive) stimuli?
Receptors - structures specialized to detect stimuli

52. Dendrites - receive stimuli (impulse) and conducts impulse to cell body, cyton (cell body)
in a sensory neuron, the impulse comes from a stimulus

53. Axon - transmits or conducts impulses away from cell body toward terminal branches
Terminal branches - conducts impulses to different synaptic knobs and then to different cells