Download reflexes_lesson

Unit Name: Science in Sports
Lesson Name: The Nervous System (Voluntary and
Involuntary Reaction)
Objectives:
To introduce the idea that nerves carry messages throughout the body and there are two
main kinds of reactions that are changed/used in sports.
Target Age Group: 2-5 Graders
Materials:
One 12 inch ruler and one stop watch per group
Introductory Lecture:
Start by asking them about what their favorite sports? Talk about one sport in
particular.. like soccer. Ask them what muscles are involved in playing the sports…
hopefully they will say calves, etc etc and also the heart and muscles that control the
diaphragm for breathing, etc.
Ask them how do these muscle know to move; what tells them? Hopefully they
will say spinal cord and brain
How does the brain and spinal chord tell these muscles what to do? Nerve cells!!!
(like playing telephone)
Today we are going to talk about the nervous system and how it relates to sports.
What are the parts of the nervous system? (show pics)
Nerves
Spinal Cord
Brain
(Central nervous system is brain and spine)
Neuron:
Cell body: contain the organelles that keep the cell alive
Dendrites: receive information from another cell
Axon: conduct messages away from cell body
Three types of neurons:
Sensory neuron: connect sensory organs to central nervous system
(what are sensory organs? Give examples… like eyes, ears, tongue?)
Motor neuron: connect central nervous system to muscles
What muscles?
Interneurons: connect neurons with neurons
Voluntary versus involuntary reaction
In voluntary reaction, you require a conscious processing of information. (signal
goes all the way to brain and we actually think about what to do and then control the
muscles with thinking)
What are some examples of voluntary reaction??
In involuntary reaction, you react without thinking.
At this point, split into two groups to talk about each system and do each activity
separately. Then the two groups switch.
Voluntary Reaction:
We talked before about muscles and using your muscles in sports to say hit a ball (in
baseball). How do we know when to hit the ball?
We see the ball, we think about how to hit it and then we move out muscles
How does what the eye see get through to the muscle? Where does this message travel
through the body?
Message goes to the central nervous system… brain and spine
Brain or spine process what to do
Nerve cell carries message to the muscles
Muscles contract and you swing at the ball.
What affects reaction time?
Age: shortens from infancy into late 20s and then gets longer to the 50s and 60s
How awake you are/ other impairments
How much you practice.
Does this explain why most athletes are pretty young? 20s-30s
Mean age of gymnasts is 14-15
Why? Due to slower nervous speed; also old people tend to be careful
Does practicing make you faster at reacting? (Yes.. theoretically up to a certain point)
What are other examples of impairments? (fatigue, dizziness, etc)
Now do activity
Instructions: One student hold a ruler in the air with 0 inch marking closer to the ground.
A second student holds thumb and forefinger around the ruler at the 0 inch mark. The
first student drops the ruler without warning and the second student tries to catch it as fast
as possible. Repeat 10 times and record the measurement where the ruler is caught.
At the end, come back and look at results…. Who got better? Tutor versus kid reaction
time
Voluntary Reaction Worksheet
A batter has less than 0.25 seconds to react to a fast ball. How fat can you react?
Draw the path through your body that the signals travel that allow you to catch the ruler.
Convert the distance dropped to a reaction time using the table:
distance dropped
Reaction time
2 inches
0.10 seconds
4 inches
0.14 seconds
6 inches
0.18 seconds
8 inches
0.20 seconds
10 inches
0.23 seconds
12 inches
0.25 seconds
14 inches
0.27 seconds
16 inches
0.29 seconds
18 inches
0.31 seconds
My Reaction Time Data:
Trial Number
Distance caught (Inches)
Reaction Time (seconds)
1
2
3
4
5
6
7
8
9
10
My Tutor’s Reaction Time Data:
Trial Number
Distance caught (Inches)
Reaction Time (seconds)
1
2
3
4
5
6
7
8
9
10
Would you be able to see the baseball and swing the bat in time? With more practice
could you do it?
Involuntary Reaction:
1. What happens to your body when you run?
a. breath faster
b. heart beat faster
c. sweat
d. thrity
2. What else controlled by involuntary nervous system? (show the diagraph
below)
a. heart
b. lungs
c. viscera
d. glands
3. Can you control these systems?
a. No, but your general health condition can make a difference in some of
them. Use heart rate as an example.
Facts about heart rate
bpm (beats per minute) – unit for measuring heart rate
Average Resting Heart Rate for Various Ages
Age
range (bpm)
Average (bpm)
0-1 month
100-180
2-3 months
4-12 months
1-3 years
4-5 years
6-8 years
9-11 years
12-16 years
>16 years
Athelet
Polar bear
110-180
80-180
80-160
80-120
70-115
60-110
60-110
50-90
40-60
(130)
(100)
(100)
(88)
(80)
(70)
(50)
46
Note: A trained athlete's heart can pump more blood with each beat so his or her heart
rate is slower. Lance Armstrong (famous biker) has resting heart rate of 32-34bpm!
Heart rate increases during exercise
During exercise, the heart rate increases in order to pump more blood (which carries
oxygen) to the working muscles. The brain sends nerve signals to the heart to control the
rate.
What else can change heart beat?
When we are excited, scared, or anxious our heart gets a signal to beat faster. During a
fever, the heart beats faster to bring more blood to the surface of the body to release heat
and cool the body. The heart rate increases during and after a meal to send more blood to
the digestive system.
Activity
Students will discover how their heart rate changes with exercise
Involuntary Reaction Worksheet
Resting heart rate
(bpm)
Student 1
Student 2
Student 3
Tutor
Heart rate after 30
jumping jack (bpm)
Heart rate after running
around the building for 1
min (bpm)