The Scientific Method What parts of the reflex experiment

make up the scientific method?

Scientific Method Ask a Question Make a Hypothesis Test the Hypothesis--Experiment Analyze Results Make a Conclusion

Variables Dependent Variable

What is effected by the independent variable.

Independent Variable What you control in the experiment

Variables What were our independent and

dependant variables in the Reflex Lab?

Variables Control

The experimental condition that receives no treatment.

Ex. Drug testingWas there a control in the Reflex Lab?

Variables Constants

An experimental condition that does not change.

Were there any constants in our reflex experiment?

Variables Repeated Trials

Why do we do this?

Experimental ErrorWere there any errors in the Reflex Lab?

THE NERVOUS SYSTEM--REFLEXES

The Central Nervous System The Parts

Brain○ Collection of over 100 billion neurons

collectively known as “grey matter”Spinal Cord

○ Contains 31 pairs of spinal nerves that connect the brain to the different parts of the body.Head, neck, shoulders, arms, hands, chest,

abdomen etc.

Peripheral Nervous System All the nerve cells outside the brain and

spinal cord. Two parts of Peripheral Nervous System

Somatic NS = Voluntary Movement (Biking)Autonomic NS= Automatic Responses (blink

etc.)

Question Which part of the Peripheral Nervous

System did we experiment on? How do you know?

What are Neurons?Neurons are special cells that help the

different parts of the body communicate with the Central Nervous System, and Peripheral Nervous System.

Types of Neurons Sensory Neuron (Input)

A neuron that transmits towards the spinal cord and brain (messenger).

Motor Neuron (Output)A neuron that transmits away from the spinal

cord and brain to the body (e.g. muscle control).

The Neuron

Neuron Function Nerves from the Peripheral NS work

together to let different parts of the body communicate messages to the brain and spinal cord.

The brain or spinal cord then sends a message back which results in a response known as…

REFLEXES! A quick automatic response to a stimulus

Voluntary and Involuntary! Voluntary Reflex = the reflex game and lab

These are more commonly known as RESPONSES

Involuntary ReflexBlinkingSneezing/CoughingFrightened jump (fight/flight response)

The Reflex Arc The nerve pathway (loop) that activates

a reflex.Part I: A stimulus activates a nerve that

sends a signal to the spinal cordPart II: The spinal cord replies with a new

message that results in a physical reaction (reflex!).

A Short Video http://www.sumanasinc.com/webcontent

/animations/content/reflexarcs.html

The Response Arc (Voluntary)

The Reflex Arc (Involuntary)

What now? Using your notes on experimental

design, create an experiment that tests your INVOLUNTARY reflexes.