THE CONTROL SYSTEMS NERVOUS AND ENDOCRINE

THE CONTROL SYSTEMS NERVOUS AND ENDOCRINE

Introduction to nervous system

There are 3 main parts to your Nervous System 1. Your Nerves 2. Your Brain 3. Your Spinal Cord

Your Nerves Your nerves are made of nerve cells called neurons that transmit messages. They carry messages from all parts of your body to your spinal cord and brain. They carry messages away from your spinal cord and brain to all parts of your body.

Those nerve cells are called neurons. Size-wise, these cells are among the smallest cells in your body, but can be the longest cells as well. How can this be? Cell bodies are small, but axons can be really long.

neuron Cell Body Dendrites Synapse Axon

Class Activity- Neuron Model Here's the most simple model of a neuron I can think of...and you don't need any supplies. It's your hand! Hold out your arm and spread your fingers. Your hand represents the "cell body" your fingers represent "dendrites" bringing information to the cell body; your arm represents the "axon" taking information away from the cell body.

The message that is transmitted through neurons is called an impulse. It enters the neuron through the dendrite and is carried away from the cell body through the axon. Why are there so many dendrites entering a neuron? To receive messages from all sides/other neurons

Neurons don t actually touch each other to transmit an impulse. The impulse must move across a small space called a synapse in order to move from one neuron to another. A chemical must be present in this space in order for the signal to be transmitted The signal will always move in the same direction: from the axon of one neuron to the dendrite of the next.

There are 3 types of neurons: Type of Neuron Location Receives from: Sends To: Sensory Neuron Sense organs Stimuli from environme nt/ Body Brain or spinal cord (it s a receiver) Interneuron Spinal cord Sensory neuron Motor neuron (relays) Motor neuron Muscle or gland interneurons Muscle or gland (makes something happen)

An automatic response to a stimulus is known as a reflex. Most reflexes cannot be controlled consciously Why is this a good thing? So that you don t have to take time to think about it!

The path of an impulse when an object moves toward your face and you blink in response to the stimulus Let s say someone throws a ball at you and it s coming toward your face: The stimulus is the moving object, which triggers a sensory neuron in the eye to send a signal to the interneuron in the spinal cord which then sends the impulse to the motor neuron which is attached to a muscle that makes the eye blink.

The Reflex: interneuron Spinal cord Sensory neuron Motor neuron Muscle contracts

Central Nervous System: made up of the brain and spinal cord Peripheral Nervous System: made up of all nerves, including cranial and spinal nerves

The Brain by Brainpop

Brain Clip CEREBRUM CEREBELLUM BRAIN STEM

YOUR BRAIN HAS THREE PARTS: Part CEREBRUM Function Divided into 2 hemispheres Interprets impulses from senses Stores memories Controls voluntary muscles The Brain & memory

YOUR BRAIN HAS THREE PARTS: Part CEREBELLUM Function Coordinates voluntary muscle movements. Maintains balance and muscle tone

YOUR BRAIN HAS THREE PARTS: Part BRAIN STEM Function Connects brain to spinal cord Controls heartbeat, breathing, blood pressure, coordinates muscle movements.

Nerves by Brainpop

SPINAL CORD There are 31 pairs of spinal nerves Some are called somatic and control skeletal muscles Some are called autonomic and control heartbeat, breathing, digestion, salivary glands. Spinal Cord by Brainpop

SPINAL CORD Is an extension of brain stem and is considered part of the central nervous system. Is made up of bundles of neurons. Is about as big around as an adult thumb. Is approximately 43 cm in length. Contains cerebrospinal fluid. Why? To cushion neurons in the spinal cord

The Endocrine System Glands of the endocrine system receive electrical messages from the brain and release hormones into the blood stream. Hormones carry a chemical signal to target tissues. These chemical signals may be released slowly over long periods of time or may affect a tissue immediately and then slowly dissipate.

The Endocrine System Regulates activities using chemical signals. Hormones the chemical signals that affect mood growth blood sugar regulation metabolism digestion fight or flight response.