The Nervous System Central Nervous System Peripheral Nervous System

Procedure 1.A starting person will be chosen and will be given an object. 2.Once the teacher gives the signal, the start person will pass the object to their right. 3.Each student will take the object and pass it to their right until it makes it back to the starting person.

Procedure 4.DO NOT THROW THE OBJECT! 5.A time will be recorded for each trial 6.Repeat the process 2 more times and record the times in your spiral.

Questions In your spiral, answer the following questions about the demonstration.

Functions of the Nervous System Your nervous system controls the actions and reactions of the body in response to stimuli. –receives information –responds to stimuli –maintains homeostasis

Maintaining Homeostasis The nervous system maintains homeostasis by directing the body to respond correctly to the information it receives. –When you are hungry, your brain tells you to eat

Central Nervous System central nervous system – composed of the brain and spinal cord. –brain – receives and processes information from inside and outside your body. –spinal cord – thick column of nerve tissue that links the brain to nerves in the rest of your body. Vocabulary Word!

Peripheral Nervous System peripheral nervous system - network of nerves that connects your rain to the rest of your body. Made up of 43 pairs of nerves –12 begin in the brain –31 begin in the spinal cord One nerve in each pair goes to the right side and one to the left Vocabulary Word!

Organs of the Nervous System The nervous system consists of: –brain –spinal cord –nerves –neurons –sense organs

brain brain – receives and processes information from inside and outside your body. The skull, layers of connective tissue, and fluid protect the brain from injury Vocabulary Word!

cerebrum cerebrum – largest part of the brain that controls thinking, problem solving, the senses and memories. –reads input from the senses –controls skeletal muscles –In charge of learning, remembering and making judgments Vocabulary Word!

Cerebrum Right side –controls left side of body –controls creativity and artistic ability Left side –controls right side of body –Controls math, speech, writing, and logic

cerebellum cerebellum - second largest part of your brain that coordinates your muscles and controls your balance. Vocabulary Word!

brain stem brain stem – connects your brain to your spinal cord and controls involuntary actions like breathing, digesting and heartbeat. Vocabulary Word!

spinal cord spinal cord – a bundle of nerves that links your brain and peripheral nervous system. Protected by bone, connective tissue and fluid Vocabulary Word!

Receiving Information Because of your nervous system, you are aware of what is happening in the environment around you. Your brain is also aware of your internal conditions like temperature and glucose level.

Responding to Stimuli After receiving information, your nervous system analyzes the data and causes a response. –Putting your hand in front of your face if a ball is coming at you. –Increasing your heart rate when exercising.

Responding to Stimuli Your nervous system works by receiving information from inside or outside the body and turning that info into an electrical signal. The messages are sent out along special cells called neurons.

neuron - a cell that moves messages in the form of fast-moving electrical energy called impulses. Vocabulary Word!

The Neuron Neurons are cells that carry information around your body. Nerve impulse - The message a neuron carries

The Neuron The cell body of the neuron has two extensions –dendrite – carries impulses to the cell body. A neuron can have lots of dendrites. –axon – carries impulses away from the cell body. A neuron only has one axon. The nerve impulse begins in the dendrite, moves to the cell body then moves down the axon.

The Neuron signal goes from axon to dendrite

Kinds of Neurons Different kinds of neurons perform different functions –sensory neurons –motor neurons

Sensory Neuron sensory neuron – gathers information from the internal or external environment and converts each stimulus into a nerve impulse. The impulse travels along the sensory neuron until it reaches an interneuron in the brain or spinal cord sensory impulse travels at 76.2 m/s

Motor Neuron motor neuron – moves nerve impulses from the brain and spinal cord to the rest of the body. Motor impulse travels at 119 m/s

How a Nerve Impulse Travels Millions of nerve impulses travel your body each day. The nerve impulse travels along the neuron in the form of electrical and chemical signals.

synapse - tiny space between a the axon of one neuron and the dendrites of the next. A nerve impulse must jump this gap. Axon tips release a neurotransmitter that allows the impulse to travel the gap. How a Nerve Impulse Travels

Drugs and alcohol can affect the neurotransmitters depressants, like alcohol and marijuana slow reaction time stimulants, like meth, speed up reaction time

The Path of a Nerve Impulse /watch?v=dSkxlpNs3tU

Reflex reflex - is an automatic response that occurs very rapidly and without conscious control. Reflexes protect us from pain and injury.

Reflexes

the senses The senses gather information for the nervous system. –sight –touch –hearing –taste –smell

Body systems that work with the nervous system; The nervous system works with every system in the body.

Comparing Cells to the Body The cell part that controls the cell is the nucleus