Topic 1: It’s My Body Part 2: Nervous System

Human Organ Systems SkeletalMuscular CirculatoryImmune RespiratoryDigestive ExcretoryReproductive NervousEndocrine Integumentary

The nervous systems uses electrical signal to response to changes The hormonal system also coordinate some of the body’s responses, using hormones. How the body response to the changes? The two organ systems helps body to adjust to these changes are:

Brain WHAT PARTS DO YOU KNOW THAT ARE IN THE NERVOUS SYSTEM? Spinal Cord Peripheral Nerves

Human Nervous System Controls and coordinates functions throughout the body Neurons are specialized cells that transmit impulses throughout the body. Nervous System ◦ Central Nervous System ◦ Peripheral Nervous System  Somatic  Autonomic

What makes up the brain, the spinal cord or your peripheral nerves? Neurons are “the cell” Cell body Nucleus Axon Dendrite What do you think surrounds the cell? What other organelles would be needed?

Structure of Neurons Dendrite Axon terminals Cell body Axon Myelin sheath Node of Ranvier

3 Types of neurons There are three main types of neurons. These types are: sensory neurons, interneurons, and motor neurons.

Neurons

AXON The synapse - where the action happens The next cell’s plasma membrane What is this in the membrane? Transport protein Close up look at your synapse (extra notes)

How does the Synapse carry the signal? (extra notes) 1.Electrical current travels down the axon 2.Vesicles with chemicals move toward the membrane - what is that called? 3.Chemicals are released and diffuse toward the next cell’s plasma membrane 4.The chemicals open up the transport proteins and allow the signal to pass to the next cell - what type of diffusion is this?

Sensory neurons begin with sensory receptors (many different types of sensory receptors designed to respond to pressure, hot, cold, light, mechanical vibration, etc. )The impulse is then carried towards the CNS (Central Nervous System) by a long dendrite to the cell body. The cell body is found outside of the CNS and the short axon transmits the impulse to interneurons in the CNS. Interneurons are located in the CNS Interneurons have many dendrites and can receive messages from numerous other neurons. Interneurons organize the numerous signals and relay the appropriate message to the motor neuron along an axon. Motor neurons receive signals from an interneuron at a dendrite. The impulse then travels to the long axon of the motor neuron and on to an effector. The effector, a muscle or gland, responds to the stimulus by contracting (muscle) or releasing a hormone or enzyme (gland). How the three neurons work together?

Synapse Neurons are not continuous Synapse is “The junction across which a nerve impulse passes from an axon terminal to a neuron, muscle cell or gland” Two types of Synapses: ◦ Excitatory ◦ Inhibitory

Are all neurons equal in size? Brain vs spinal cord vs peripheral nerves? About how many neurons are in the human brain?100 billion 1 billion around 15 feet About how many neurons are in the spinal cord? How long do you think the longest axon in the world is?

How many synapses are in one neuron? 1,000 to 10,000!!

This science is called Neurobiology Looking at the actual cells - how do they work? Looking at the connections - how and when do they work? Looking at what can change normal cells and connections Looking at diseases that occur in the brain One of the largest areas still unknown The you that is you is because of your neurons connecting!

What do you think can change neurons and their connections? Accidents Drugs Alcohol Disease

Accidents Physical injury of your neurons

Diagram of Human Brain

Drugs and alcohol bind important receptors on neurons

Repeated binding causes the neuron to die

Drugs = neuron death

Alcohol damages dendrites - can repair after abstinence Alcohol blocks receptors and slows down transmission

Parkinson's Disease ALS - Lou Gehrig’s Disease Huntington’s Disease Multiple Sclerosis Alzheimer's Cerebral Palsy Epilepsy ? SIDS

100 Billion or so neurons - what’s the problem with some of them dying? Cells multiply all the time - will your neurons? Does everyone react the same way to accidents, or drugs and alcohol? Do all organisms react the same to all stimulus? Which of your activities use your neurons?

What if neurons die here? or here

Neurobiology Activities and Labs What Does Your "Homunculus" Look Like? ( Effect of Environment on Memory ( html) html Taste Activity ( nts/experiment_truly_tasteless.html) nts/experiment_truly_tasteless.html A healthy brain? - Caffeine activity ( Pillbug behavior Lab - (

REFERENCES 0/deluxe.html 0/deluxe.html JOSHSANESPPT.PPT scent%20Substance%20Abuse%20II.ppt scent%20Substance%20Abuse%20II.ppt

REFLEX ACTION

What is a Reflex action?? “An action that is performed without conscious thought as a response to a stimulus” The signals from the receptors do not travel to the brain, instead they travel through what we call a Reflex Arc. Spinal reflexes or Brain Reflexes Stimulus – receptor – sensory neuron – association neuron – motor neuron – Effector - Response

Reflex actions

Try These?? Draw one reflex arc for your body’s response to touching a hot object. Draw one reflex arc for your body’s response to standing on something sharp. Draw one reflex arc showing your body’s response to a loud noise.

Try These?? Hypothalamus (links our nervous and endocrine systems): ◦ Control Metabolic Activities ◦ Water Balance ◦ Sugar Metabolism ◦ Body Temperature ◦ Hormone Secretion Draw a stimulus response model for how the body would handle a change in temperature? Draw a stimulus response model for how the body may respond to a drop in water concentration? Draw a stimulus response model for how the body may respond to a drop in sugar levels?

NERVOUS SYSTEM REVIEW

1. Name the Two parts of the nervous system, and provide there acronyms? 2. Draw and Label the Key Structures of a Motor Neuron? 3. What are the two components of the CNS? 4. What are the two types of matter that make up our CNS? 5. How many Neurons does our brain contain?

6. Name three parts of the Brain? 7. How much space does the Cerebrum take in our brain? 8. What does PNS stand for and what are the two components? 9. What are two examples of Receptors? 10. What function does our Somatic Nervous System play? 11. What are the two types of Photoreceptors found in the eye?

12. Apart from sound, what other function does our ear play in our body coordination? 13. What are 3 examples of stimuli our skin can detect?