How does the human body respond to stimuli? Watch this video to learn about regulation and communication in the human body.
Lesson B13: Human Systems: Regulation and Communication
Figure B.3.13.1 – The thyroid gland contains hormones that control metabolism.
Figure B.3.13.2 – The adrenal glands produce hormones that regulate stress.
Figure B.3.13.3 – The pituitary gland produces growth hormone.
Reading and Materials for This Lesson
Science in Action 8
Reading: Pages 146–152
Materials:
2 metal paper clips, ruler with millimetre measurements.
Hormones Regulate Many Body Systems
Have you ever heard someone say that teenagers have “raging hormones?” Teenagers do have hormones, but so do all other people of all ages! Hormones don’t just affect mood and emotions. They work to control many other functions in the body.
Hormones are produced by organs called glands in the body’s endocrine system. Hormones are chemicals that send messages around the body. These chemical messages tell body cells what to do. For example, insulin is a hormone that tells body cells to
take sugar out of the blood. The thyroid gland in the neck (Figure B.3.13.1) makes hormones that regulate metabolism, which is how fast the body uses food. The pituitary gland at the bottom of the brain (Figure B.3.13.3) makes many hormones. One of
these hormones is growth hormone, which tells a child’s body tissues to grow. The adrenal glands near the kidneys (Figure B.3.13.2) make adrenaline, which is a hormone that makes the heart beat faster in stressful situations.
The reproductive hormones estrogen and testosterone are the ones people call “raging hormones” because they affect emotions and mood. Teenagers produce large amounts of these reproductive hormones during puberty. Both estrogen and testosterone are
present in female and male bodies, but females have a greater proportion of estrogen, and males have a greater proportion of testosterone.
Watch More
Hormones and the Endocrine System
Watch this animated cartoon to learn more about hormones and the endocrine system.
When the body is under stress, it produces certain hormones. Watch this video to learn more.
The thyroid gland contains hormones that regulate metabolism. Watch this video to learn more about the thyroid gland.
Figure B.3.13.4 – Touch receptors in the skin detect pressure.
Figure B.3.13.5 – The sense of touch provides the brain with information about the environment.
Figure B.3.13.6 – Sensory receptors in the skin detect temperature.
You're So Touchy!
Your sense of touch gives your nervous system important information about your surroundings. Neurons in your skin contain sensory receptors, which are special nerve endings that detect information and send a message to the brain or spinal cord.
Your skin has sensory receptors that detect the temperature, pressure, and texture of a surface.
Touch receptors are not spread out evenly around the body. Some body parts are very sensitive to touch, because they contain many sensory receptors. Other body parts are not very sensitive to touch, because they do not contain many sensory receptors.
Watch More
The Sense of Touch
A light touch on some parts of the body feels ticklish. Why do we feel ticklish and why can’t you tickle yourself? Watch this video to learn more.
This video will show you how to stop feeling ticklish.
Hansen’s disease, or leprosy, is a bacterial disease that damages sensory nerve cells. Watch this video to learn more about leprosy and how health workers in developing countries are treating and eradicating this disease.
Try It!
Two-Point Touch
Try this experiment on a family member or friend to test the touch sensitivity of different body parts.
Materials:
2 metal paper clips
Ruler with millimetre measurements
Download:
DOWNLOAD this document. It provides an observation table for you to record the results of your touch experiment. It
also provides space for you to answer the questions at the end of this activity.
Instructions:
Bend the 2 paper clips so that they are straight.
Have your partner sit down with their eyes closed. Your partner’s eyes need to remain closed for the entire experiment.
Use the ruler to hold the paper clips 1 mm apart along the back of your partner’s hand.
Gently touch the person’s hand with the two paper clips at the same time, and ask your partner to tell you whether they feel one point or two.
If your partner feels two points, record the distance of 1 mm on the observations table. If your partner feels one point, increase the distance between the paper clips to 2 mm and repeat step 4. Continue until you reach a distance where your partner
feels two points, and record this distance on the following observation table.
Repeat steps 2-5 for your partner’s fingertip, palm, forearm, upper arm, and upper back.
Watch this video to see this experiment and its results:
Questions:
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
The fingertip and palm of the hand were the most sensitive to touch. These parts had the smallest distance to feel two points, which means they had sensory receptors closer together.
The upper back and upper arm were the least sensitive to touch. These parts had the largest distance to feel two points, which means they had sensory receptors further apart.
The more sensitive body parts are ones that we frequently use for touch. Hands are sensitive to touch, because we use our hands to pick up and handle many things everyday. The hands have a greater number touch receptors. This allows our central
nervous system to quickly get information about what we’re touching, so we don’t damage our hands.
Figure B.3.13.7 – The spinal cord is located inside the spine.
Figure B.3.13.8 – Spinal injuries require great care during rescue and treatment.
The Spine and Spinal Cord
Figure B.3.13.9 – The spine is divided into sections called vertebrae.
The spinal cord is a long tube of nerve cells that runs from the brain down the back. It connects the brain to the rest of the body. The spinal cord is surrounded and protected by the bones of the spine. The spine is made of sections called vertebrae
that are separated by cartilage discs.
A spinal cord injury occurs when broken bones in the spine move, break, and crush neurons in the spinal cord. Most spinal cord injuries do not completely break the spinal cord. Injured people are often paralyzed below the injured section of the
spine. A paraplegic spinal cord injury happens in the lower part of the spine and causes paralysis in the lower body and legs. A quadriplegic spinal cord injury happens in the neck or upper part of the spine and causes paralysis in both the arms
and the legs.
Teenagers and young adults, particularly young males, have the highest risk of getting a spinal cord injury due to involvement in risky behaviour. Physical violence, traffic collisions, and diving without checking water depth are common ways that
people get spinal cord injuries.
Figure B.3.13.10 – Spinal cord injuries cause limbs to be paralyzed.
Figure B.3.13.11 – The vertebrae interlock to help protect the delicate spinal cord inside the backbone.
Watch More
Spinal Cord Injuries
In this video, young spinal cord injury survivors tell their stories of how their spinal cord injury has affected their lives.
The Brain
The brain controls all the different functions in the body. It is like a powerful computer that receives and sends messages in your body. The brain is divided into different sections that have different tasks. To protect the sensitive brain from injury,
it is covered with a hard skull bone and a layer of fluid called the meninges.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.
Unit B Lesson 13 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum,
or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Be a Self-Check
Superhero!
Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
The brain is further away from most of the body than the spinal cord. It takes longer for messages to go to the brain and back, and damage could occur to the body in that time. If messages travel a shorter distance to the spinal cord and back,
the body is protected from harm faster.
The somatic nervous system controls movements that you choose to make, such as walking and turning your head. The autonomic nervous system controls movements that your body makes without you thinking about it, such as breathing and your
heart beating.
The man would likely have paraplegia. His body would likely be paralyzed below the broken vertebrae in his spine. The broken spine would damage the spinal cord, so messages aren’t able to travel from the lower part of the man’s body to
his brain.
The brain and spinal cord contain many neurons, which means that both these organs control many functions in the body. The bone surrounding the brain and spinal cord is hard and protects neurons from damage.
Reading and Materials for This Lesson
