1 / 17

Objective 4

Objective 4. Outline the steps of a nerve impulse, and its conduction from one neuron to the next. Action Potential. A nerve impulse, signal, electrical impulse… Is correctly called an “Action Potential” “Potential” is from the chemistry…the potential charges of the + and – ions involved

penn
Download Presentation

Objective 4

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Objective 4 Outline the steps of a nerve impulse, and its conduction from one neuron to the next.

  2. Action Potential • A nerve impulse, signal, electrical impulse… • Is correctly called an “Action Potential” • “Potential” is from the chemistry…the potential charges of the + and – ions involved • Are received from the dendrites…pass down an axon…to the axon terminals.

  3. Starting a Nerve Impulse • Resting State – all ion gates closed… Na+ outside, K+ inside • Depolarizing - membrane allows sodium (Na+) to flow inside the membrane Figure 7.9a–c

  4. Nerve Impulse Propagation 3. Repolarizing – Na channels close. K+ channels open 4. “Undershoot” – K+ channels are open too long, there is a ‘dip’ in the charge 5. Sodium/Potassium Pump – energy is used to pump Na & K back to normal state Figure 7.9d–f

  5. The Action Potential • If the action potential (nerve impulse) starts, it is passed over the entire axon (“all or none”) • Potassium ions rush out of the neuron after sodium ions rush in, which repolarizes the membrane • The sodium-potassium pump restores the original configuration • This action requires ATP

  6. How Neurons Communicate at Synapses Figure 7.10

  7. Continuation of the Nerve Impulse between Neurons • Impulses are able to cross the synapse to another nerve 1. Ca+ Gates open when action potential (nerve impulse) reaches the axon terminal

  8. How Neurons Communicate at Synapses 2. Ca+ causes vesicles (vacuoles) to dump Neurotransmitters into the synapse (gap)

  9. How Neurons Communicate at Synapses (Ignore the numbers!)

  10. How Neurons Communicate at Synapses 3. Neurotransmitters bind to the receptors of the next cell (can be another neuron, a muscle, or a gland)

  11. How Neurons Communicate at Synapses

  12. How Neurons Communicate at Synapses 4. Binding causes Na+ ion channels to open so … - (if neuron) action potential can continue - (if muscle/gland) trigger the appropriate response

  13. The Neurotransmitter can “hang around” causing ‘after-effects’ after the stimulus is removed. • Some medications work on this process… • Pain killers can prevent neurotransmitters from binding to receptors • Depression medication can take the place of neurotransmitters

  14. Objective 5 List the main components of a reflex arc.

  15. The Reflex Arc • Reflex – rapid, predictable, and involuntary responses to stimuli • Reflex arc – direct route from a sensory neuron, to an interneuron, to an effector Figure 7.11a

  16. Simple Reflex Arc Figure 7.11b–c

  17. Types of Reflexes and Regulation • Autonomic reflexes • Smooth muscle regulation • Heart and blood pressure regulation • Regulation of glands • Digestive system regulation • Somatic reflexes • Activation of skeletal muscles

More Related