 You are walking from school and suddenly a huge, ferocious dog jumps from behind the bushes and starts barking at you and begins to chase you. You are filled with so much fear that you scream and run away from the dog as quickly as possible. Eventually, you reach home, run inside and pass out from exhaustion. Example of How Nervous Regulation Works

Nervous Regulation  Allows an organism to detect changes in their environment and respond quickly to these changes.  Human Nervous System consists of…. Brain, Spinal Cord and Nerves Brain, Spinal Cord and Nerves

A. Stimulus Any change in environment such asAny change in environment such as temperature, sound, light…. temperature, sound, light…. that causes a response that causes a response

B. B.What allows an organism to detect stimuli?  Receptors - Human receptors include eyes, ears, skin, tongue, and nose. - Human receptors include eyes, ears, skin, tongue, and nose.

C. C.What allows an organism to respond to stimuli?  Effectors - Structures that produce a response - Structures that produce a response -Human effectors include muscles and endocrine glands -Human effectors include muscles and endocrine glands

D. How are messages transmitted from receptors to the brain and then to effectors  Messages (Impulses) are carried over nerve cells called….. NEURONS NEURONS

Structure of Neuron

1.Dendrites - Receive impulse - Receive impulse 2.Cell Body (Cyton) - Contains nucleus & cell organelles - Contains nucleus & cell organelles 3.Axon - Carries impulse away from cell body toward terminal branches - Carries impulse away from cell body toward terminal branches A. Parts of Neuron

4. Schwann Cell - Surrounds axon and produces a fatty substance called myelin. - Surrounds axon and produces a fatty substance called myelin. - Myelin insulates the axon & causes the impulse to move faster down axon - Myelin insulates the axon & causes the impulse to move faster down axon 5.Nodes of Ranvier - Gaps between Schwann Cells…no myelin - Gaps between Schwann Cells…no myelin - Impulse moves faster over myelin, so impulse jumps from node to node. - Impulse moves faster over myelin, so impulse jumps from node to node.

6.Terminal Branches - End of neuron - End of neuron - Contain synaptic knobs which secrete neurotransmitters into synapse which bring impulse to next neuron or effector. - Contain synaptic knobs which secrete neurotransmitters into synapse which bring impulse to next neuron or effector. -Example of a neurotransmitter - Acetylcholine -Example of a neurotransmitter - Acetylcholine

B.What happens when impulse reaches end of neuron? Space between Neurons urotransmission.htmscience.education.nih.gov/supplements/nih2/Addiction/activities/lesson2_ne urotransmission.htm

 Space between neuron and muscle

Types of Neurons in Human Nervous System 1.Sensory Neurons - Transmit impulses from receptors to - Transmit impulses from receptors to spinal cord and brain. spinal cord and brain. 2.Interneurons - Located in the brain & spinal cord - Located in the brain & spinal cord - Interpret stimulus. - Interpret stimulus. - Relay impulses between sensory & motor neurons. - Relay impulses between sensory & motor neurons. 3.Motor Neurons - Carries impulses from brain and spinal cord to effectors (muscles/glands) - Carries impulses from brain and spinal cord to effectors (muscles/glands)

Directions for Tonight’s HW  You are to outline the packet titled, “Adaptations for Nervous Regulation.”  Set up the outline as follows on loose-leaf: Regulation in Lower Organisms A.Protists (Information) B. Hydra (Sketch and information) C. Earthworm (Sketch and information) D. Grasshopper (Sketch and information) After the outline, write out and answer the questions on the last page of the packet.

The Nerve Impulse A.Resting Neuron No transmission of impulse across neuronNo transmission of impulse across neuron Called_______________Called_______________ When not transmitting an impulse, outside of cell has a positive charge and inside has a negative chargeWhen not transmitting an impulse, outside of cell has a positive charge and inside has a negative charge Resting Potential -70 millivolts

1. Why is there a positive charge on the outside and a negative charge on the inside?  Animation: Sodium-Potassium Pump Animation: Sodium-Potassium Pump Animation: Sodium-Potassium Pump

Sodium-Potassium Pump  Uses ATP to pump 3 Na + (ions) out of neuron and 2 K + into neuron.  Potassium channels are open, so some K+ diffuses out.  Sodium gates closed, so Na+ stays outside.  Results on + charge on outside.

B.Active Neuron - Impulse travels over neuron - Impulse travels over neuron -Called _____________ -Called _____________ -As impulse travels, sodium gates -As impulse travels, sodium gates open, and Na+ flow into neuron and charges reverse. open, and Na+ flow into neuron and charges reverse. -Diagram -Diagram Animation: Action Potential Action Potential +40 mV

Human Nervous System  Human N.S. has 2 main parts: 1. Central N.S. 1. Central N.S. 2. Peripheral N.S 2. Peripheral N.S -Contain brain and spinal cord. -Contain nerves outside brain and spinal cord.

Human Nervous System A.Central Nervous System -Brain and spinal cord. -Brain and spinal cord. 1. Brain – 1. Brain – - 3 Major Divisions: (Cerebrum, Cerebellum &Medulla) a. Cerebrum -Largest part. -Thinking, memory, reasoning, learning -Interpret impulses from senses. -Voluntary movement. Surrounded by membranes called meninges.

b. Cerebellum - Coordinates movement of muscles, so - Coordinates movement of muscles, so movements are smooth. movements are smooth. -Maintains balance. -Maintains balance. c. Medulla - Involuntary activities like: - Involuntary activities like: heartbeat, breathing, blinking heartbeat, breathing, blinking

2.Spinal Cord -Extends downward from base of brain. -Extends downward from base of brain. -Protected by backbone (vertebrae) and meninges. -Protected by backbone (vertebrae) and meninges. -Relays impulses toward brain and away from brain to effectors. -Relays impulses toward brain and away from brain to effectors. -Center for reflexes: -Center for reflexes: Knee Jerk and Withdrawal

B.Peripheral Nervous System -Nerves outside brain & spinal cord. -Nerves outside brain & spinal cord. Peripheral Nervous System Somatic N.S. Autonomic N.S. Nerves that control voluntary activities. Nerves that control Involuntary activities.