1. The Nervous System
EQ: How do organ systems work together to enable an organism to maintain homeostasis?

2. Which of the following do not involve your nervous system?
Eating? Playing a musical instrument? Reading a book? Running? Sleeping? It’s a trick question, because ALL of these activities involve your nervous system. In fact, your nervous system controls almost everything you do

3. Your nervous system
The nervous system is all about actions and senses. Animals are able to sense what is going on in their surroundings and do something about that input. For example, if you see a bike that might hit you, you jump out of the way. Your nervous system was involved in many ways: your eyes saw the bike, your brain figured out the bike might hit you, and your brain told your muscles to make your legs jump out of the way. You sensed, then acted!

4. Peripheral Nervous system: Organs and Functions
Your nervous system is divided into two parts: Your central nervous system (CNS), which includes your brain and spinal cord Your peripheral nervous system (PNS), is all parts of the nervous system EXCEPT for the brain and spinal cord The PNS connects all parts of the body to the CNS (central nervous system). The PNS uses specialized structures called nerves to carry information between your body and the CNS. The neurons of both systems work together to help you think, survive, and change the world around you.

5. Peripheral Nervous system: Neurons
Messages about your environment travel through the nervous system along neurons. Neurons are nerve cells that are specialized to transfer messages in the form of fast-moving electrical energy. Messages can travel at speeds of up to 150 meters per second!

6. Peripheral Nervous system: Neurons
In many ways, neurons are like other cells. They have a large region in the center called the cell body that contains a nucleus and other organelles. But neurons also have special structures called dendrites and axons. Dendrites are short, branchy extensions of the cell body. Neurons receive their information via dendrites. Axons are elongated extensions of a neuron. They carry away impulses from the cell body.

7. Types of Neurons
Sensory Neurons
Motor Neurons
*Brings info TO your brain *Gather information on what is happening in and around your body. (Your 5 senses) *They have specialized nerve endings called receptors. *Receptors detect changes inside and outside the body. *For example, receptors in your eyes detect light. Sensory neurons then send this info to the CNS for processing.
*Delivers instructions FROM the brain *Send impulses from the brain and spinal cord to tissues and glands. *When muscles get messages from motor neurons, they respond by contracting. *For example, motor neurons cause muscles around your eyes to contract when you are in bright light.

8. The Central Nervous System: Organs and Functions
The Central Nervous System (CNS), receives information from the sensory neurons. It responds by sending messages through motor neurons It is made up by the: Brain Spinal Cord

9. The Brain
The largest organ of the nervous system. It is the main control center. It controls both involuntary and voluntary actions It has three main parts: Cerebrum Cerebellum Medulla

10. Cerebrum
The largest part of your brain is called the cerebrum. It is where you think and most of your memories are stored here. It controls voluntary movements and your sensory system It has two halves called hemispheres. The right hemisphere directs the left side of your body The left hemisphere directs the right side of your body.

11. Cerebellum
The second largest part of the brain. Processes sensory information from your body, such as from your skeletal muscles or joints. It helps you keep your balance

12. Medulla
The part of the brain that connects to the spinal cord. It is about 3 cm long, but you cannot live without it. It controls all involuntary processes such as blood pressure, body temperature, heart rate, and breathing.

13. The Spinal Cord
It is about as big around as your thumb It is made of neurons and bundles of axons that pass impulses to and from the brain. The spinal cord is protected by your vertebrae. It communicates with your peripheral nervous system (PNS)

14. Nerves
The central nervous system is connected to the rest of your body by nerves. A nerve is a collection of axons bundled with blood vessels and connective tissues. Nerves are everywhere in your body. Most nerves have the axons of both sensory and motor neurons

15. Types of Nervous systems
Somatic Nervous System
Autonomic Nervous System
Parts of your nervous system that are under your conscious control. Neurons that control your skeletal muscles Writing Talking Smiling Jumping
Nerves that do not need your conscious control. Control body functions that you do not think about Digestion Heart rate Balance