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Growth SystemsHuman Body

Infancy

Childhood

Adolescence

Adulthood

Old age

Carbohydrates

Food and nutrients

Proteins Fats Vitamins Minerals

Balanced diet

Digestive system

Respiratory system

Circulatory system

Growth and development

The growth in humans can be measured by their height or weight. The growth of humans can be divided into 5 stages – infancy, childhood, adolescence, adulthood and old age.

Height (cm)

Infancy Adulthood Old age

20 13 18 65

Height stopsincreasing

steadily

Childhood

Growth slowsdown

considerably

Rapidgrowth

Rapidgrowth

Heightgraduallydecreases

Age (years)

Adolescence

1 T h e H u m a n B o d y SCIENCE LESSON 1GROWTH:

1.) Introduction

2.) Concept

3.) Growth Curve

CONCEPT MAP

Science Pratomsuksa 6 Chapter 1 Notes

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Humans grow at different rates at different stages.

Infancy (0 – 2 years old)

➙ A rapid growth takes place. The baby is fed with mother’s milk because it is the best food for the baby.

Childhood (3 – 11 years old)

➙ The growth is slower as compared to the infancy stage.

Adolescence (12 – 18 years old)

➙ At this stage, the children experience puberty. Between 12 and 14 years old, the girls are generally taller than the boys of the same age. This is because the girls reach puberty at the age of 12 years old, about one or two years earlier than the boys.

Adulthood (19 – 65 years old)➙ At this stage, humans are mature biologically, physically

and mentally. The growth has slowed down.

Old age (66 years and above)➙ The height decreases gradually. Humans experience

negative growth.

Systems

When a group of organs work together to carry out a task, it is called a system. There are many systems in our body. These include the digestive system, respiratory system, circulatory system and excretory system.

SCIENCE LESSON 2

Humans Grow at Different Stages:

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1. The diagram below shows the human growth curve.

Height (cm)

P Q R S T

20 13 18 65Age (years)

(a) P, Q, R, S and T represent stages of growth. Name the stages.

(i) P : Infancy

(ii) Q : Childhood

(iii) R : Adolescence

(iv) S : Adulthood

(v) T : Old age

(b) Which two stages have the most rapid growth?

Infancy and adolescence

(c) Describe briefly the growth in stage T.

Experiencing negative growth or Height of human decreases gradually

2. Tick (✓) the correct statements and cross (✗) the incorrect statements.

(a) We can measure our growth by measuring our height or weight at suitable intervals over a period of time. ( ✓ )

(b) The fusion of a sperm and an ovum is called ovulation. ( ✗ )

(c) The most rapid growth of humans occurs during old age. ( ✗ )

SCIENCE LESSON 2

GROWTH:

EXERCISE

Science Pratomsuksa 6 Chapter 1 Mastery Practice

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1. The diagram below shows the human growth curve. P, Q, R, S and T are the five stages of growth.

Height (cm)

P Q R S T

20 13 18 65Age (years)

(a) Which stage has the most rapid growth?

Stage P

(b) Which stage experience negative growth?

Stage T

(c) State two changes in boys during stage R.

The testes start to produce sperm. Or Hair starts to grow at pubic region

and armpits. Or Their bodies become more muscular and broader.

(d) State two changes in girls during stage R.

The ovaries start to produce ova. Or Begin to menstruate. Or Hair starts to

grow at pubic area and armpits.

SCIENCE LESSON 3

GROWTH:

EXERCISE

Science Pratomsuksa 6 Chapter 1 Notes

3

Heart

Blood supply to the arm

Blood supplyto the brain Blood

supplyto the lungs

Bloodsupply to the legs

Esophagus

Largeintestine

Anus

Mouth

Stomach

Smallintestine

Rectum

Nose

Trachea

RibLungLung

Digestive system

The food is chewed in the mouth and swallowed down through the esophagus to the stomach. Digestive juices are produced in the stomach to digest the food. The food is later further digested in the small intestine.

The digested food is absorbed through the wall of the small intestine. The undigested food is pushed to the large intestine where excess water is absorbed. Lastly, the undigested food is passed out through the anus as feces.

Digestive system is important because it helps to absorb the nutrients needed by our body.

Respiratory system

Through this system, oxygen is taken in and carbon dioxide is released from our body. The inhaled air contains more oxygen. In the lungs, the oxygen moves into the blood and the carbon dioxide in the blood moves into the lungs. Hence the exhaled air contains more carbon dioxide.

Circulatory system

This system is made up mainly of the heart and the blood vessels. Food, oxygen and water are carried by blood to all parts of the body. The blood also carries waste products from the organs. The function of the heart is to pump blood to the whole body.

SCIENCE LESSON 4

SYSTEMS

Science Pratomsuksa 6 Chapter 1 Notes

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Importance of the systems in our body

All the systems in our body are important. The systems work together to ensure the proper functioning of our body.

System Ways to keep it healthy

Digestive system

Eat easily digested foodDrink a lot of waterEat food rich in fiberEat at regular hours

Circulatory systemExercise regularly to keep the heart healthyEat healthy food and avoid food rich in fatsDo not smoke

Respiratory systemDo not smokeBreathe in more fresh air

Food and nutrients

There are five types of nutrients – carbohydrates, proteins, fats, vitamins and minerals.

Carbohydrates• Give energy for the various body processes. • Found in rice, bread, noodles, yam, maize, sweets.

Rice Bread Noodles

• Excess carbohydrates taken in can be stored as fats.

SCIENCE LESSON 4

Cont......