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Topic: The Nervous System. Aim : What is the function of the nervous system? Do Now : Make a K-W-L Chart. Fill in the first two columns. What is the function of the Nervous System?. Receive and send information about activities within the body
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Topic: The Nervous System Aim: What is the function of the nervous system? Do Now: Make a K-W-L Chart. Fill in the first two columns.
What is the function of the Nervous System? • Receive and send information about activities within the body • Monitor and respond to changes in the environment • Changes in the environment that cause a response are called STIMULI (STIMULUS – singular) • Nervous system tells other parts of the body what to do • Interpret (make sense of) various information
What is the stimulus? What is the response? 1. An insect flies toward your eye and you blink to avoid danger. • Flying insect = stimulus • Blinking = response 2. You put your hand on a hot stove and quickly remove it. • Hot stove (heat) = stimulus • Removing your hand from the stove = response • A child runs into the street while you’re driving a car, and you slam on the brakes. • Child running in the street = stimulus • Slamming on the brakes = response
What controls a response? • Responses are a result of nerve impulses • An IMPULSE is a message sent by a neuron (nerve cell) • Responses to stimuli can be both voluntary or involuntary
Topic: The Nervous System Aim: What is a neuron? Do Now: Identify the stimulus and response in the following scenario: You’re sleeping. The alarm clock buzzes and you awaken.
What structures are part of the nervous system? 1. Neurons: nerve cells 2. Spinal cord 3. Brain
Topic: The Nervous System Aim: What is a reflex arc? Do Now: Draw and label a neuron.
Topic: The Nervous System Aim: What is a reflex arc? Do Now: Give an example of a receptor.
Describe a Neuron. • Neurons can never be replaced • Neurons contain: • Cell body (1) • Dendrites (2) • Nucleus (3) • Axon (4) • Axon terminals (5) 3 4 5
A Neuron Dendrites: branches at the beginning of a neuron; RECEIVEIMPULSES and carry messages TO the cell body Nucleus: control center Axon Terminals: branches at the end of the neuron that pass IMPULSES (messages) on to dendrites of other neurons Cell body: largest part of the neuron; contains the nucleus. Axon: long tail-like fiber; Carries IMPULSES (messages) AWAY from cell body to the end of the neuron
How many different types of neurons are in the body? • Three different types: • Sensory neurons • Interneurons • Motor neurons
What are receptors and sensory neurons? • Receptor cells: receive information from surroundings • Impulses begin at receptors • Sense organs are receptors • Eyes – Nose • Ears – Skin • Tongue • Messages travel from receptors to the spinal cord and brain through SENSORY NEURONS
What are interneurons? • Interneurons are found in the spinal cord and brain • Connect sensory neurons to motor neurons
What are motor neurons? • Carry impulses from interneurons (in brain and spinal cord) to EFFECTORS • EFFECTORS: muscles or glands that carry out a response
Topic: The Nervous System Aim: What is a synapse? Do Now: Substitute words for numbers in the following reflex arc: Stimulus→1 →2 →3 →4 →5 →Response
Describe the path of a nerve impulse. • Reflex arc = path of an impulse • stimulus → receptor → sensory neuron → interneuron → motor neuron → effector → response interneuron
How does an impulse get from one neuron to another neuron? • Impulses travel from one neuron to another neuron in the form of an ELECTRICAL and CHEMICAL SIGNAL • Electrical impulses enter neurons at the dendrites, to cell body, through the axons, and out the end of the axon terminal
What is a Synapse? • Tiny gap between two neurons • Nerve impulse “jumps” the gap (synapse) between two neurons with a CHEMICAL SIGNAL • Chemical signal called a NEUROTRANSMITTER carries the impulse from one neuron to another
Topic: The nervous system AIM: What are the two divisions of the nervous system? Do Now: 1. Messages (impulses) are sent in the form of __________ and ___________ signals across neurons. Describe the path of an impulse along one neuron.
Topic: The nervous system AIM: What are the two divisions of the nervous system? Do Now: Describe the path of an impulse along one neuron.
How many divisions does the nervous system have? • Two divisions: • Central nervous system • Peripheral nervous system • Central nervous system is the control center of the body. It contains the SPINAL CORD AND BRAIN • Peripheral nervous system is a NETWORK OF NERVES that branch out from the central nervous system to the organs of your body
Topic: The nervous system Aim: What are the three parts of the brain? Do Now: Starting from the stimulus and ending with a response, describe the reflex arc in yesterday’s lab.
cerebrum medulla cerebellum The central nervous systemDescribe the brain. • The brain consists of three areas: • Cerebrum • Cerebellum • Medulla
Describe the cerebrum. • Cerebrum is the largest part of the brain. It has wrinkled grooves and looks like a walnut. • Divided into two halves (right and left)
Topic: The nervous system AIM: What is the peripheral nervous system? Do Now: What are the three parts of the brain?
Memory Thinking Speech The 5 senses Emotional thought All voluntary actions Ex: Walking, running, jumping What does the cerebrum control?
Describe the cerebellum. What does it control? • Located under the cerebrum • Second largest part of brain • Controls: • Balance • Movement (coordination)
medulla Describe the medulla. What does it control? • Located below the cerebellum • Connects the brain to the spinal cord • Controls involuntary actions • Breathing • heartbeat
Describe the spinal cord. What does it control? • Protected by vertebrae in the spinal column • Connects the brain to the rest of the nervous system • Carries impulses to and from the brain • Controls quick, automatic, and simple responses called REFLEXES
What is the Peripheral Nervous System? • Link between the central nervous system and the rest of the body • Consists of branching nerves throughout the body • Divided into two divisions • Autonomic • Somatic
How do the autonomic and somatic divisions of the peripheral nervous system differ? • Autonomic controls involuntary functions • Somatic controls voluntary functions