TOPIC: Regulation AIM: How does the nervous system carry out regulation?

TOPIC: Regulation AIM: How does the nervous system regulate the body TOPIC: Regulation AIM: How does the nervous system regulate the body? DO NOW: What is the function of your brain?

Control & Coordination (sends messages) Helps maintain HOMEOSTASIS FUNCTION REGULATION Control & Coordination (sends messages) Helps maintain HOMEOSTASIS

Impulse Electric & chemical message

Stimulus Change in the environment  starts impulse causes response

Receptor Picks up stimuli Sense organs Eyes, ears, nose, skin, tongue

Reaction to a stimulus Response

Effector Produces a response Muscle or gland

Neuron Nerve cell

The Nerve A nerve is an organ containing a bundle of nerve cells called neurons. Neurons carry electrical messages called impulses throughout the body. Picture shows hundreds of severed neuron axons

1. Dendrites: receive impulse Parts Of a Neuron

2. Cell body/cyton: contains nucleus 3. Axon: carries impulse away from cell body

4. Terminal branches: send impulse to next neuron

Schwann Cells Surround axon Produce myelin: helps impulse move faster

Impulse in a Neuron TYPICAL MOTOR NEURON dendrite muscle tissue Axon synapse cell body cell body

Synapse Space between neurons

How do impulses travel across synapses? 1. Impulse reaches terminal branches

2. Neurotransmitters (chemicals) released into synapse

3. NT carry impulse across synapse

4. Impulse starts & travels over next neuron

Neurotransmitters Synapse (gap) Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons. Neurotransmitters (pink spheres) Synapse (gap)

Review: Identify the term being described. The reaction to a stimulus. Muscle or gland that causes the response. Something in the environment that initiates an impulse. An electric and chemical message. Sense organs that detect the stimulus.

AIM: How does the nervous system regulate the body? TOPIC: Regulation AIM: How does the nervous system regulate the body? DO NOW: You are baking cookies at home. Your oven timer goes off and you take the cookies out of the oven. Identify the: a. Stimulus c. Response b. Receptor d.Effector

DID YOU KNOW? There are about 3 million miles of axons in the human brain. The human brain has 100 trillion synaptic connections.

3 Types of Neurons

Sensory Neurons Carry impulses from receptors to brain & spinal cord

Make up brain & spinal cord 2. Interneurons Make up brain & spinal cord

3. Motor Neurons Carry impulses from interneurons to effectors to carry out a response

Sensory Neuron S I M Interneuron Motor Neuron

Types of Neurons Synapse Synapse Motor Neuron Synapse Muscle Contracts Interneuron Synapse Synapse Motor Neuron Synapse Muscle Contracts Sensory Neuron

3 types of neurons Interneuron Sensory neuron Motor Neuron

Reflex Arc Path of an impulse Simple response to a stimulus

Receptor R S I M E Sensory neuron Interneuron Motor neuron Effector

Interneuron (brain & SC) Sensory neuron Motor neuron Effector F Receptor RESPONSE STIMULUS

Review: Identify the type of neurons described. 1. Carry impulse from receptors to the CNS system. 2. Carry impulses to the effectors. 3. Only found in the brain and spinal cord. 4. Carry impulses away from sense organs. 5. Connects sensory and motor neurons.

What type of neurons make up the brain and spinal cord? TOPIC: Regulation AIM: How does the nervous system regulate the body? DO NOW: What type of neurons make up the brain and spinal cord?

TOPIC: Regulation AIM: How does the nervous system regulate the body? DO NOW: Identify all parts of the reflex arc. The fire alarm rings and we all leave the building. Identify the: Stimulus, receptor, response, effector

What is a reflex? Involuntary, automatic response to a stimulus Body responds without having to think about it Controlled in spinal cord, not the brain

People typically blink about 15 times per minute People typically blink about 15 times per minute. If you are awake for 16 hours each day, then you blink approximately 14,400 each day!

Nervous System 1. Central Nervous System 2. Peripheral Nervous System

Central Nervous System (CNS) Brain & Spinal Cord

Parts of the Brain (Medulla)

1. Cerebrum Largest part

Controls: a. voluntary activities

b. the senses

c. memory, thinking, & reasoning

Coordination & BALANCE 2. Cerebellum Back of the brain Coordination & BALANCE

3. Medulla Oblongata Brain stem Controls involuntary activities (Breathing, heartbeat, digestion)

Cranium Protects brain

Spinal Cord Pathway bw brain & rest of the body Controls reflexes

Protected by spinal column (vertebrae & cartilage)

Peripheral Nervous System (PNS) Nerves that branch off brain & spinal cord

Lead to VOLUNTARY organs Divisions of the PNS 1. Somatic NS Lead to VOLUNTARY organs (Skeletal muscles)

2. Autonomic NS Lead to INVOLUNTARY organs (heart, stomach, lungs…)

DIVIDED INTO: Sympathetic NS Controls organs in times of stress (fight or flight)

b. Parasympathetic NS Controls organs in times of rest (rest & digest)

Divisions of the NS

Explain the difference between the CNS and the PNS. Review: Explain the difference between the CNS and the PNS. Explain the two divisions of the PNS. Identify the part of the brain being described: Controls heart rate Regulates balance Controls memory Regulates breathing rate Controls thinking

What does this diagram represent? Identify all labeled structures. What chemical is secreted by structure F? What is the space between neurons called?

Review: Identify the part of the neuron being described. Long part of neuron that carries the impulse to the terminal branches. First part of the neuron that receives the impulse. Release neurotransmitters. Contains the nucleus. Helps the impulse travel faster. The space in between two neurons.

DID YOU KNOW? There are approximately 100 billion neurons in the human brain. The average brain weighs about 3 pounds.