A system that controls all of the activities of the body. The nervous system is made of: The brainThe spinal cord The nervesThe senses

Neurons The functional and structural unit of the nervous system Specialized to conduct information from one part of the body to another There are many, many different types of neurons but most have certain structural and functional characteristics in common: -Cell body (soma) -One or more specialized, slender processes (axons/dendrites) -An input region (dendrites/soma) -A conducting component (axon) -A secretory (output) region (axon terminal)

3 Types of Neurons There are three types of neurons: 1)Sensory neurons: detect stimuli and transmit signals to the brain and spinal cord. 2)Interneurons: receive signals from sensory neurons and relay them to the brain and spinal cord. 3)Motor neurons: pass messages from the nervous system to other tissues, such as muscle.

Neurons transmit information in the form of electrical and chemical impulses. When a neuron is stimulated it produces an electrical impulse that travels down the neuron. Before the signal can move to the next neuron, it is changed to a chemical signal.

Messages carried throughout the body by nerves.

Basic Organization Sensory Input triggered by stimuli –conduction of signals to processing center Integration –interpretation of sensory signals within processing centers Motor output –conduction of signals to effector cells (i.e. muscles, gland cells) sensory receptor (sensory input)  integration  (motor output)  effector

Neuron Dendrite - conducts “signal” toward the cell body -- [input zone] –often short, numerous & highly branched –signal comes from sensory cell or neighboring neuron Axon - usually a single fiber -- [conducting zone] –conducts signal away from cell body to another neuron or effector cell Axon Ending –a cluster of branches (100’s to 1000’s) –each with a bulblike synaptic knob –relays signal to next neuron / effector cell

Transmission of signals

Synapse – The space between axon terminals of one neuron and the dendrites of the next neuron in which neurotransmitters flow parkinsons parkinson

The nervous system also allows you to react to a stimulus. A stimulus is a change in the environment. Example: A hot stove Or… tripping over a rock

Your reactions are automatic. Automatic means that you do not have to think about your reactions. Example: If a bug flies by your eye, you will blink.

An organ that controls your emotions, your thoughts, and every movement you make.

The Central Nervous System is made of the brain and the spinal cord. The Central Nervous System controls all the workings of your body and process information.

The peripheral Nervous System is made of the nerves and the sense organs. Nerves Sense organs

You have a nerve along your whole arm. The “funny bone” is the only place on the arm where the nerve is not protected. The “funny bone” is on the elbow.

* The Central Nervous System controls all of the body’s activities. * The Central Nervous System is made of two main organs. 1. The brain 2. The spinal cord

* The spinal cord sends messages to the brain. * The spinal cord is the part of the nervous system that connects the brain to the rest of the nervous system.

* The brain controls everything in the body. * The brain is made of more than 10 billion nerves! * The brain is divided into three parts and is protected by the skull.

* The Brain has three main parts… 1. The Cerebrum 2. The Cerebellum 3. The Brain Stem

* The Cerebrum is the largest part of the brain. 1. The cerebrum controls your thinking. 2. The cerebrum controls your memory. 3. The cerebrum controls your speaking. 4. The cerebrum controls your movement and identifies the information gathered by your sense organs.

* The cerebellum is below and to the back of the cerebrum. 1. The cerebellum controls you balance. 2. The cerebellum controls your posture.

* The Brain Stem connects the brain to the spinal cord. * The nerves in the brain stem control your heartbeat, breathing, and blood pressure.

* The vertebrae are the many bones that protect the nerves in the spinal cord.

* The peripheral nervous system is made of the nerves and the sense organs. Ear Eye Skin Nerves Tongue

* The peripheral Nervous System’s job is to connect the Central Nervous System to the rest of the body. * The peripheral nervous system carries messages between the central nervous system and the rest of the body.

* An automatic reaction that happens without thinking about it. * A reflex happens quickly in less than a second.

* The peripheral nervous system controls the body’s activities that you don’t think about. * The peripheral nervous system controls activities in your small intestine, your breathing, and your heartbeat. controls

In Summary - Nervous System There are two parts to the nervous system: –The central nervous system (CNS) Includes the brain and spinal cord –The peripheral nervous system (PNS) Includes all the nerves which transfer messages from the CNS to organs and vice versa

Peripheral Nervous System PNS is divided into two the somatic nervous system and the autonomic nervous system. –The somatic nervous system regulates all of the voluntary movements. –The autonomic nervous system regulates the involuntary functions

The autonomic nervous system is again divided into: –Sympathetic nervous system: “flight or fright” response. It prepares the body for stress. –Parasympathetic nervous system: acts to calm the body and helps conserve energy.