Chapter 8: Our Body Systems and their Functions I

Our Body Systems and their Functions I Introduction

After reading this chapter, you will appreciate that the digestive, respiratory and circulatory system perform exclusively different functions. You will also realise that some reactions in some systems are driven by enzymes. These speed up the rate of reactions in the body. There are conditions that enzymes need to function well.
You will know how the teeth are important in human beings and how they are cared for to ensure their longevity.
8.1: Enzymes
Enzymes are usually small substances that increase the rate of biological reactions.
Have you ever asked yourself why the digestion of food within your body occurs very fast without you noticing it? You should be aware that biological catalysts known as enzymes are always at work and therefore, they are present in all living tissues where biological reactions occur. In Activity 8.1 , you will discuss the meaning of enzymes and their properties.

Activity 8.1: Discussing the meaning ot enzymes and thetr properties
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do;
In groups, discuss and;
I. Define the term enzyme.

2. Discuss the general properties of enzymes.
3. The enzymes are found in different body parts of a plants and animals.
   Discuss the different types of enzymes.
4. Give the importance of having enzymes in our bodies.
5. Present your work to the rest of the class
   Enzymes act upon specific food substances as shown in the table below.

Effect of Temperature and pH on Enzyme Activity
When its very cold, you start shivering and you can’t go for games. Also when it is very hot, you cannot go for sports. Enzymes in our bodies are also affected by changes in temperature.
They are quite specific in their action and therefore enzymes have specific values of pH and temperature ranges where they are able to carry out catalysis of any given reaction. However, altering the temperature and pH affects all enzymes in the same way since it leads to denaturation/inactivation of that enzyme. This renders it unable to increase the rate of reaction. In Activity 8.2, you will investigate the
effect of temperature and pH on enzyme activity.
Activity 8.2: Understanding the effect of temperature and pH on enzyme activity
What you need: notebooks, braille paper, stylus, slate, perkins brailler

What to do:
1.Study the graphs in Figure 8.1 and answer the questions that follow
2.How many enzymes are shown in the graph?
3.The optimum temperature for enzyme A is 37 oc and works best in pH of 7.0. Identify the optimum temperature and pH value of enzyme B.
4.What would happen to enzyme A if it was put in a solution of pH greater than 7 or less than 7.
5.Identify the factors affecting the rate of enzyme activity.
6.Compile and share your work with the rest of the class.

8.2: Human Teeth

Human beings have a number of teeth whose structure and arrangement differs. These perform different functions which is called specialisation. The figure. 8.2 show different types of teeth present in the mouth. Some of the teeth are sharp while others have ridges. If you are to eat meat, which side of the mouth do you use?

Activity 8.3: Exploring the structure, types, arrangement and functions of Human teeth
What you need: Teeth of different types from a mammal like a goat, notebooks, braille paper, stylus, slate, perkins brailler
What to do
In groups;

1. Care fully observe the different types of teeth in figure 8.2 or the teeth provided.
2. Identify the types of teeth by name and discover their location in the mouth.
3. Feel the different types of teeth in the mouth and discover the distinguishing features of the different types of teeth.
4. Use the information obtained to fill up the table below.

5. Present your work to class.
6. Discuss with your classmates about your presentations.

How to Care for the Teeth
One of the most life sustaining process is nutrition which involves feeding. Feeding starts with the breakdown of food by the teeth. The teeth break down food into small particles. The food particles tend to get stuck on the teeth or on the teeth-gum interface. This facilitates growth of micro-organisms in the mouth. This leads to teeth decay, production of a bad odour from the mouth and also loss of the initial
white colour of teeth.

In Activity 8.4: you will discuss how to care for the teeth
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.

What to do
Observe the photos in Figure 8.3 and answer the questions that follow.
In groups:

1. Identify the activities taking place in each photo in figure 8.3.
2.Discuss the importance of the activities taking place in the photos in Figure 8.3.
3.Discuss the other ways you can use to care for the teeth.
4.The dentists always tell us to brush the teeth every after a meal. How is this important to the health of our teeth?
5.Present your work in class

8.3: Human Digestive System
Think about the parts in your body where food passes from mouth to the point of removal. The parts where food passes and is worked upon to give us nutrients are collectively known as an alimentary canal.
This is a system in our bodies that is responsible for breaking down food taken into the body. This system starts from the mouth and it bears different parts which play different roles in food digestion. In Activity 8.5, you will discuss the structure and functions of the human digestive system.

Activity 8.5: Discussing the human digestive system
What to do
your teacher is going to show you an animation or touch a model. Watch or listen to it and answer the following questions.
Task:
In groups:
I, Draw and label the digestive system.

2. Identify the importance of each part you have named in (1).
3. How is the digestive system important to you?
4. Compile a report and present to the rest of the class.
   The Process of Digestion and its Products
   The different parts of the digestive system handle food in different ways. Some parts of the digestive system have enzymes that are responsible for breaking down different forms of food before they are absorbed and assimilated into the body. In activity 8.6, you will discuss the process of digestion and its products.

Activity 8.6: – Discussing the prosess of digestion and its Products
What you need: A video or simulation on the process of digestion/ other reference like other textbooks, notebooks, braille paper, stylus, slate, Perkins brailler.
What to do
In groups:

1. Watch a video or read from other sources on the process of digestion in man.
2. Discuss how the process of digestion occurs in man.
3. Identify the products of digestion
4. Indicate the different points along the digestive system here:
   (a) proteins are chemically digested.
   (b) star&l is chemically digested.
   (c) Fats are chemically digested.
5. Present your work to the rest of the class.
   Absorption and assimilation of end products of digestion
   When the food is finally broken down into simpler substances that can be used by the body, it is taken up into the body cells. The body uses absorbed food in a number of functions from energy production to growth. The digestive system has specific parts where absorption occurs for different end products of digestion, When absorbed, the food is finally assimilated into the body.
6. In activity 8.7,Discussing the absorption and assimilation of end products of digestion.

What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do:
In this Activity, you are required to identify the parts of the digestive system where assimilation and absorption of end products of digestion occur basing on Activities 8.5 and 8.6
In groups,

1. Study Figure 8.6 below and answer the questions that follow.

1.List the parts of the digestive system responsible for food absorption.
2.Describe how the parts you have identified are adapted for the absorption of food nutrients.
3.Define the term assimilation as applied to digestion.
4.Present your work in class.
When digested food is absorbed into the body, it is used as follows;

1. Amino acids for body building .
2. Fats and oils for insulation and energy production.
3. Vitamins and mineral salts for defense purposes like manufacture of anti bodies.
4. Starch for energy production.
   8.4: The Human Circulatory System

In the human body, there are structures which are responsible for propelling blood and other body fluids. These structures are in form of vessels and their work is governed by a major pumping organ which is the heart. These structures have different parts and this is due to the different roles they play involved in blood conduction.
Blood contains various substances that are essential in body protection and oxygen carriage.
The diagrams below show some of the constituents of the circulatory system which can guide you through the sub-topic.
.Activity 8.8: Exploring the Human Circulatory System
What you need: A video or simulation on the human circulatory system, notebooks, braille paper, stylus, slate, Perkins brailler.

What to do:
In groups:

1. Watch a simulation or a video or study Figure 8.7 about the human circulatory
   system;
   (a)Describe the structure of the heart and how it functions.
   (b)Explaining the structural differences with illustrations among the veins, arteries and capillaries.
   (c)Suggest the reasons for the difference in the thickness of the blood vessels.
   (d)Finding out about blood, its components and their functions

2. Compile your work into a report.
3. Present your findings to the rest of the class
   8.5: The mammalian heart
   The heart has four muscular chambers, for receiving and pumping blood to all parts of the body.
   The aorta carries oxygenated blood that is transported by arteries to all parts of the body. The vena cava receives deoxygenated blood from all parts of the body to the heart. The pulmonary artery transports the de-oxygenated blood to the lungs. The oxygenated blood from the lungs is transported back to the heart by the pulmonary vein.
   The heart is surrounded by fats for protection and insulation. It is supplied by a coronary system which is special to only supply the heart.
   The heart produces its own beat; therefore its called a myogenic organ. Let us find out the structure of the mammalian heart.

Activity 8.9: Modeling the structure of the mammalian heart
What you need; The diagram showing the structure of a mammalian heart, locally available materials like used boxes, marker, dyes among others, notebooks braille paper, stylus, slate, Perkins brailler.
What to do;

1. Sketch the structure of a mammalian heart.
2. Model the structure you have drawn.
3. Organise it for a presentation on the functioning of the heart.
4. Present your work to the entire class.
   8.6: The blood
   In primary, you studied about blood; this contains components like white blood cells, red blood cells and others. These •-ar bc lurther studied as in Activity 8.10

Activity 8.10: Exploring blood components and their functions
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do;

1. Copy and fill the table below

Blood Group

Have you ever heard about someone going for blood transfusion or the heart and kidney transplant? Of course they will tell you they need a donor of the same type of blood. Doctors always want to transfuse blood of the same blood group. What do you understand by the term ‘blood group’?
In activity 8.11, you will be able to know the blood groups and how they are important in medicine.
Activity 8.11: Understanding the blood group of human beings
What you need: notebooks, braille paper, stylus, slate, Perkins brailler
What to do:
In a group:

1. Study the table below and answer the questions that follow:

1.Identify the four blood groups shown in the table
2.If a person has blood group O, it means he or she can donate blood to?
3. If a person has a blood group of AB, he or she can receive blood from?
4. What is the importance of knowing blood groups?
5.
8.7: Gaseous Exchange In Humans
In the body of a human being, there are structures which are responsible forgaseous exchange, the structures are collectively called the respiratory system.
In this section, you will learn about the need for gas exchange in humans, the mechanism of gas exchange in humans, adaptations of lungs as an organ of gas exchange and the alveoli as surfaces for gas exchange and analyse the variation in the percentage composition of gases in inhaled and exhaled air.
The Respiratory System
Activity 8.12: Discussing the structure of the human respiratory system
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.

In groups;
Study Figure 8.7 and answer
the questions that follow.

1. Discuss the functions of each part shown in Figure 8.7.
2. What would happen if the trachea develops holes?
3. Organise your work on a chart.
4. Present and discuss it with the class.
5. Individually write the class conclusions and the diagram in your notebook

From Activity 8.12, you have discovered that the human respiratory system is made up of many structures.
How do these structures work together to enable human beings breathe? If you breathe in and out, what changes occur in every structure.
Therefore in the next activity, you will learn the breathing in and out.

Activity 8.13: Exploring the process of gaseous exchange in Humans
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.

Having looked at the structure of the respiratory system in the Figure 8.8, you can now go ahead to measure changes in volume of chest cavity during inhalation and exhalation (Activity 8.14) and make a model to illustrate the mechanism that brings air in and out of the lungs.
Activity 8.14: Measuring changes in chest volume during inhalation and exhalation
You need to appreciate that different body parts respond to the process Of gaseous exchange in different ways and you can be able to detect these changes when the series of inhalation and exhalation are put into practice.
What you need: tape measure, pen, notebooks, braille paper, stylus, slate, Perkins brailler.
What to do:
In pairs:

1. Using a tape measure, take the chest circumference of each other as you breath in and out deeply.
2. Record the measurements in a table and get the average measurement for both of you during inspiration and expiration.
3. Explain the difference in the average chest circumferences during inhalation and exhalation circumference
4. Design an experiment to demonstrate how air comes into lungs and leaves them
5. Present your work to the rest of the class.

Variations in the Percentage Composition of Gases in inhaled and Exhaled Air
The air we breathe in or take into our respiratory system is always a mixture of gases from the atmosphere. They are of different percentages. The body uses at most only oxygen and to a less extent carbon dioxide. Other gases are of no importance in our bodies. They get out of the body in the real amounts they entered in. Others increase amounts as they get out of the body since they are quite toxic.
In activity 8.15, you will explain the variations in the percentage composition of gases in inhaled and exhaled air.
Activity 8.15: Explaining variations in the percentage composition of gases in inhaled and exhaled air
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do:
In groups: Look at the table 8.1 below showing variation of gases in inhaled air and exhaled air.
Table 8.1: Comparing composition of inhaled and exhaled air

1.List down the gases in inspired and expired air.
2.Explain the differences in the proportion of gases in inspired air and expired air.
4.Why does nitrogen percentage remain the same in inhaled air and exhaled air.
5.Use the Venn diagram and show or compare inhalation and exhalation.
6. Share your findings with the rest of the class

8.8: Respiration
By the end of this sub topic, you should be able to:

1. Know the meaning of respiration and explain the types of tissue respiration.
2. Know the importance of aerobic respiration.
3. Understand the process of aerobic respiration.
4. Understand the relationship between plants and animals in relation torespiration and photosynthesis.
5. Know the word equation for anaerobic respiration in plants and animals.
6. know the products of aerobic respiration in plants and animals.
7. Identify the various applications of aerobic respiration in everyday life.
8. IJnderstand the differences between aerobic and anaerobic respiration .
9. Energy is a fuel source for all processes running within the living organisms. The energy needed by the body is generated through a process called respiration. This process can either occur in presence or absence of oxygen to give varied products in plants and animals. In plants, this process works together with photosynthesis. They exchange products that are essential in starting the process. In activity 8.13, you will discuss tissue respiration in man, its types and functions in daily life. You will discuss the process of digestion and its products.

What you need: A video or simulation on respiration and gaseous exchange in man, text books or Internet, notebooks, braille paper, stylus, slate, Perkins brailler.
What to do;
In groups:

1. Using text books or Internet, explain the following terms;
   (a) Respiration
   (b) Gaseous exchange
2. Name two types of respiration.
3. Describe the process of aerobic respiration and its functions.
4. Explain the relationship between plants and animals in relation to respiratio
   and photosynthesis.
5. Discuss the various applications of anaerobic respiration in daily life.
   Fermentation in yeast

Have you ever seen bubbles coming out of beverages like juice which has been kept for some days?
The bubbles are a result of fermentation. This is where cells like yeast breakdown compound; for example, glucose to produce ethanol and carbon.
Other organisms like bacteria and other micro organisms also carryout fermentation. These organisms produce enzymes that work on the substrate in the surrounding environments.

Activity 8.17: Understanding fermentation of starch by yeast
What you need: Notebooks, braille paper, stylus, slate, Perkins brailler, delivery tube, measuring cylinder, conical flask, boiling tube, rubber cork, two test tubes, rubber bands, glass tube, glucose solution, lime water, liquid paraffin, and yeast.
Reagents: saturated glucose solution and yeast

What to do

1. Using a measuring cylinder measure 100 cm3 of glucose solution into a
   round bottomed flask.
2. Arrange your apparatus asshown in Figure 8.9.
3. Incubate the set up in a warm place for 3 days.
4. Record the observation after 3 days.
   Questions:
5. Write orbraille the word equation for anaerobic respiration in plants and animals.
6. What are the products of anaerobic respiration in plants and animals?
   Activity 8.18: Debating about respiration
   What you need: notebooks, braille paper, stylus, slate, Perkins brailler
   What to do

1. Do extra reading or talk to a resource person on:
   (a) Relationship between plants and animals in relation to respiration
   and photosynthesis,
   (b) Process of aerobic respiration.
   (c) Importance of aerobic respiration.
2. As a class form 2 groups. Elect a chairperson and a timekeeper for the debate.

3. Have a class hold a debate on the MOTION “Plants and animals can live
   and survive entirely independent of each other”.
4. Record the issues you have raised in the debated in your notebook or write
   them by braille.’
   8.9: Comparing Anaerobic and Aerobic Respiration
   Anaerobic and aerobic respirations have some similarities and differences.
   In Activity 8.19, you will determine the similarities and differences between aerobic and anaerobic respiration
   Activity 8.19: Comparing anaerobic and aerobic respiration
   What you need: A video or a simulation on aerobic and anaerobic respiration, notebooks, braille paper, stylus, slate, Perkins brailler.
   What to
5. Watch the video on aerobic and anaerobic respiration and in groups complete the tasks below.
6. Discuss the similarities between aerobic and anaerobic respiration.
7. Write your differences in a tabular form.
8. Present your work to the rest of the class.
   Consumption of Food Rich in Excess Energy
   There are Ike white bread, highly processed maize meal (posho) have a lot of energy and when mnsumed in excess, the excess energy is always dangerous to the body.
   In Activity 8.20, you will discuss the effect of consumption of food rich in excess energy

What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do

1. Identify food stuffs that supply energy to us.
2. Discuss what happens when one consumes food rich in excess.
   energy than what is required.
3. What remedies do you recommend to such a person.
   Sample Activity of Integration
   In our societies, some people have difficulties with their teeth, digestive system,
   respiratory system and circulatory system. Such difficulties include; constipation,
   dirty teeth, diseases among others.