SECOND TERM E-LEARNING NOTES JS 2 SUBJECT: BASIC SCIENCE SCHEME OF WORK FOR SECOND TERM

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SECOND TERM E-LEARNING NOTES

JS 2

SUBJECT: BASIC SCIENCE

SCHEME OF WORK FOR SECOND TERM

WEEK TOPIC

1. Revision of first term^,s work
2. Changes in living things
3. Changes in non living things
4. The human body (skeletal system and movement)
5. Respiratory system
6. Circulatory system
7. Digestive system
8. Reproductive system
9. Excretory system
10. Revision
11. Examination

WEEK 1 Revision of first term work

WEEK 2

TOPIC: Changes in living things (Growth and Development)

CONTENT: 1. Definition of growth and development [mediator_tech][mediator_tech]

1. Growth and developmental changes (Childhood and infancy, adolescence,

adulthood

1. Characteristic features of stages of development
2. Classifying growth and developmental changes(Temporary and permanent

chages).

SUB-TOPIC 1: Definition of growth and development

Growth is the permanent increase in size of an organism due to increase in number of cells. Growth is brought about by cell division and depends on the type of food taken.

Development is a series of orderly changes by which a living thing comes into maturity .It is a series of changes that occur during growth .It is a gradual process leading to maturation of organs and behaviours of individual like social, emotional as well as skill acquisition.

Growth and developmental changes

The noticeable change in the body size over time is termed growth change. Growth change can be determined by measure of height and weight at time intervals while developmental changes can be observed by appearance of certain characteristics features and capabilities. Development leads to transition from one stage of life to another e.g a baby develops from infancy to childhood, then to adolescence and to adulthood. Developmental changes are progressive and move from simple to complex.

Sub-topic 2

Characteristic features of developmental stages

The developmental changes are characterized by certain features which include the following:

1. Infancy and childhood

Infancy is period of dramatic growth which last from birth to around two years. It is also a time when children form emotional attachments to their care givers e g mother. Childhood is the stage from birth to puberty. After infancy, children can walk, run and speak in simple sentences. Childhood is characterized by light body weight, small size, very rapid growth particularly in the first two years of life very active body and restlessness.

2 Puberty/Juvenile: This is the transition stage from childhood to adolescence. As children approach the ages of 9 and 10 years, they become more independent and might start noticing the physical changes of puberty. A major growth spurt can occur at this time as the body begins sexual development. This also can be a time of stress for children as peer pressure takes its toll. Body image along with emotional changes often causes children to feel less confident. Juveniles also start preparing for middle school by taking on more academic responsibilities and focusing on goal-setting and accomplishment

Sub-topic 3

3 Adolescence: This is the stage between adulthood. From ages 12 to 18 years, children experience distinct mental and physical changes. According to the National Institutes of Health (NIH), the beginning of a girl’s menstrual cycle typically occurs 2 years after the onset of puberty. The NIH reports that boys do not begin puberty with a distinct marker and tend to mature with adult genitalia about age 16 or 17 years. During this time of physical change, adolescents may become more self-centered. In middle to late adolescence, teen-agers are often characterized as becoming more comfortable with their body sexually and ready to have romantic friendships. Adolescent behavior often includes the teen-agers’ need to pull away from parents and authority figures to establish their own self-identity and make decisions on their own.

4 Adulthood: This is the stage of full maturity. It is often noted when a person is considered chronologically, legally and behaviorally ready to hold responsibilities such as operating a motor vehicle, voting, taking the vows of marriage, entering into a contract and serving in the armed forces. The process of becoming mature does not end with adolescence but continues throughout adulthood as psychological, safety and self-actualization needs are met. Adulthood is often divided into three categories: young adulthood, middle age and old age.[mediator_tech]

Classifying growth and developmental changes (Temporary and permanent changes)

Temporary changes:

These include growth of pimples in male and female at adolescence, malnutrition or kwashiorkor, fatness, enlargement of stomach after a meal or intake of water. These changes are usually due to food in-take. Other temporary changes are bedwetting, sweating and rise in body temperature .Temporary changes may naturally disappear after some time .They can also be corrected medically or by change in behavior

Permanent changes: These are changes that remain for life and are not reversible. Features that associated with each of the human developmental stages of childhood, adolescence and adulthood are permanent changes and remain with the individual throughout life.

Factors affecting growth and development

i. Food

ii. Heredity

iii. Exercise and rest

iv. Gland

v. Love and care

vi. Diseases.

EVALUATION:

Define growth and development.

List the human developmental stages.

List the factors affecting growth and development.

WEEKEND ASSIGNMENT: In STAN JSS 2 text book, write short notes on the factors affecting growth and development.

WEEK 3

TOPIC: Changes in non-living things

CONTENTS: Types of changes in non-living things (Physical and chemical changes

Characteristics of physical and chemical changes.

Sub-Topic 1: Types of changes in non living things

Non-living matter undergo changes i.e they can be made to change from one state to another. They can be made to form new substances.

1. Physical changes
2. Chemical changes

Physical changes: These are changes in which no new substances are formed. A physical change is a temporary change. It is reversible .The composition of the new substance does not change when undergoing a physical change. Examples are:

1. Melting of candle wax.
2. Dissolution of salt in water to form a salt solution.

Salt + water ____________ salt solution

3 All changes of state of matter are physical changes.

i vapourization of liquid to gases

Ii.Melting of solids to liquids e.g ice to water

iii. Liquefaction of gases to liquids e.g cooking gas is liquefied under pressure.

Iv . Sublimation of solids to vapours

V All processes of separation of mixture are physical changes e.g distillation

Vi. Magnetization and demagnetization of iron.

Sub-Topic 2: Chemical changes:

These are changes in which new substances are formed. t is a permanent change and not easily reversible. The composition of a substance changes during the process of chemical change. Examples of chemical changes are:

1. Burning of substance in air e.g burning of paper or wood.
2. The rusting of iron.
3. Dissolution of metals in or limestone in acids.

E.g. Zn + H₂SO₄———— ZnSO₄ +H₂

1. All processes of fermentation and decaying of substances are chemical changes
2. The addition of water to calcium oxide

Sub-Topic 3: Characteristics of physical and chemical changes

EVALUATION:

1. Explain the following: i. physical change ii. Chemical change.
2. Differentiate between physical change and chemical change.

WEEKEND ASSIGNMENT:

Read STA N Basic Science J S S 2, Chapter 7 ,pages 37-41.

WEEK 4

TOPIC: The human body (Skeletal system and Movement)

CONTENT:1. Human skeleton

1. Functions of the skeleton[mediator_tech]
2. Parts of the body responsible for movement e.g
3. Bones, muscles and joints.
4. Importance of movement to human beings:

Sub-Topic 1: Human skeleton

Bones are of hard chemical materials called Calcium (II)Tetraoxophosphate (IV), Calcium (II) Trioxocarbonate(IV).These are living cells that can grow.

The parts of the body responsible for movement are bones, joints and muscles. Human body is built on supporting framework of bones called Skeleton. Skeletons are bony structures, which give animals rigidity, support and also protect delicate organs of the body.

Human skeletal system

Skeleton could be divided into two main groups:

1 Axial skeleton

2 Appendicular skeleton

1 Axial skeleton

This consists of the skull, the vertebral column or back bones and the rib cage.There are up to 80 bones

of axial skeleton.

. [mediator_tech]

2 Appendicular skeleton. This consists of the bones of the limbs and limb girdles. The limbs are the fore limbs (arms) and the hind limbs (legs and feet).The girdles are the pectoral (shoulder) and the pelvic girdles (hip).The appendicular skeleton has up to 126 bones.

Functions of the skeleton

1It provides support for the body.

2 it protects vital organs.

3 It gives shape to the body.

4 It provides surface for attachment of muscles for movement

5 Red blood cells are formed in the bone marrow.

6 Bones store salt (calcium and phosphorus).

Sub-Topic 2: Muscles and Joints

Muscles are bundles of elastic substance in an animal body. Muscles are attached to bones by means of tendons. Muscles are made up of many tiny cells, which are held together by thin strands of connective tissues .A tight cord which holds bones together is called ligament. A flexible connective tissue which is found between one vertebra and the other is called Cartilage. It serves as shock absorber which prevents the bones from wearing out.

Types of muscles

1 Skeletal muscle: These attached to the bones of the skeleton which help to move.

2 Smooth muscles: These lined many structures in our body such as intestine and blood vessels.

3 Cardiac muscles: Are special striped muscles with the ability to work continuously.

Joints

The point where two bones meet is called a joint. The bones are actually held together by rope-like materials called ligament.

Types of joints

1 Ball and socket joints: These allow free rotation of the bones e.g the hip bones.

2 Pivot joint: This is found only in the neck bone. It allows the rotation of the head on the neck. It also permits nodding and limited bending movements.

3 Hinge joint: This allows movement in one direction only e.g elbow joint.

4 Gliding /sliding joint: This allows the sliding, twisting or turning of one bone over another e.g joints at the wrist, ankle joint.

5 Suture joint: This is found in the skull.

Sub-Topic 3: Importance of movement to human beings

Human beings move in order to

1 Look for food

2 For reproduction/sexual partner

3 To run away from danger.

4 To look for shelter and safety.

5 To respond to environment.

6 To celebrate with each other /attend social functions.

7 To practice profession of their choice to earn a living.

8 To keep themselves and their surroundings neat and tidy.

9 To enjoy themselves.

EVALUATION: 1 Mention the importance of movement to human beings.

2 List types of joints and muscles.

3 Explain the following: a Tendon b Cartilage c Ligament.[mediator_tech]

WEEKEND ASSIGNMENT: Read STAN Basic Science chapter 10, pages 56 -59.

REF. TEXTS:1 STAN Basic Science Project ,book two

2 Basic Science Made Easy, Book Two

3 Longman Basic Science, Book Two

Week 5

TOPIC: Human Respiratory System

CONTENT: 1 Meaning of respiration

2 Parts of human respiratory system

3 Functions of the respiratory system

4 Problems associated with breathing

Sub-Topic 1: Meaning of respiration

Respiration is the process by which food substances are broken down in our body to release energy. In big animals like human beings, air enters the body through special organs. These organs are called respiratory organs. Respiratory organs include ; Nostrils ,larynx ,pharynx ,trachea(wind pipe) ,bronchi ,lungs ,bronchioles ,alveoli ,and sometimes mouths.

Parts of respiratory system

EVALUATION: i Define respiration

ii List five respiratory organs

Sub-Topic 2: Types of respiration

1 Aerobic respiration: This involves the use of oxygen to librate energy

C₆ H₁₂ O₆ + 6O₂ _________ 6CO₂ + 6H₂O + energy

Glucose Oxygen Carbon dioxide water

2 Anaerobic respirations: This involves a chemical process through which energy is released in the absence of oxygen.

C₆H₁₂O_{6_________________} 2C₂H₅OH + 2CO₂ + energy

Glucose Ethanol Carbon dioxide

Functions of the respiratory system

The main functions of the respiratory system are:

1 Breathing [External respiration]

2 Cellular respiration [Internal respiration]

Breathing is the exchange of gases in which oxygen is breathed in and carbon-dioxide is breathed out. Breathing is one of the stages in respiration. Breathing supplies oxygen for respiration and takes away carbon dioxide which is a poisonous end product of respiration, while respiration is the process by which oxygen breathed in from the atmosphere is used in breaking down food substance in our body cells to release needed energy with carbon dioxide and water as the waste product

EVALUATION: Differentiate between breathing and respiration

SUB-TOPIC 3

Problems associated with breathing

1 Asthma

2 Tuberculosis

3 Pneumonia

4 Bronchitis

5 Severe acute respiratory syndromes [SARS]

6 Hay fever

7 Silicosis

EVALUATION: Mention the problems associated with breathing

WEEKEND ASSIGNMENT: Explain the following [I] Inspiration [ii] Expiration

Read STAN Basic Science Book Two, Chapter 9; Pages 50-55

REF. TEXTS:1 STAN Basic Science Project ,book two

2 Basic Science Made Easy, Book Two

3 Longman Basic Science, Book Two

WEEK 6

TOPIC: Circulatory system

CONTENT: Meaning of circulatory system

Parts of the respiratory system
Simple structure and function of the heart and blood vessels

Importance of the circulatory system

Blood defects and diseases

Importance of blood test and groupings e.g HIV/AIDS, sickle cell anaemia, leukemia

Sub-Topic 1: Meaning of circulatory system

The parts of the body which work together to ensure the circulation of oxygen ,digested food substance as well as transportation of waste products from one part of the body to another is referred to as the circulatory system.

Circulatory systemParts of the human circulatory system

The circulatory system is made up of

• The blood,
• The heart ,and
• The blood vessels.
• Components of blood
• Blood consists of the following:
• Red blood cells [Erythrocytes]
• White blood cells [Leucocytes]
• Platelets
• Plasma

Platelets White blood cells Red blood cells [mediator_tech]

Blood constituents

Functions of the blood

1 It carries the digested food materials to all parts of the body

2 It protects body against diseases.

3 It transports oxygen to all parts of the body for oxidation of food.

4 It regulates body temperature

5 It transports waste materials to excretory organs for excretion

EVALUATION: 1 Mention functions of blood

2 List the components of the blood

Sub-Topic 2: Structure of the Heart

The Heart

Heart is a muscular organ which has four chambers. The four chambers consist of two upper chambers which are the right auricle and the left auricle. The two lower chambers which are the right ventricle and the left ventricle. Between the auricles and ventricles are two small openings [valves].The openings between the left auricle and the left ventricle is called the bicuspid valve while the opening between the right auricle and the right ventricle is called the tricuspid valve. The heart is located in the chest cavity of the body and is connected to all parts of the body by means of blood vessels.

Functions of the heart

1 It is the organ for pumping blood to all parts of the body.

2 It keeps blood in continuous circulation.

3 Pumping action of the heart is known as heart beat, man has an average of 72 heat beat per minute.

Blood Vessels: Blood moves around our body through tubes called blood vessels. There are three main types of blood vessels on the human circulatory system .These are arteries, veins and capillaries. Arteries

Arteries carry blood away from the heart to all parts of the body.

Veins carry blood to the heart from all parts of the body.

Capillaries connect arteries to veins.

EVALUATION: 1 Mention the functions of the heart.

2 List blood vessels and their uses.

Sub-Topic 3: Importance of the human circulatory system

1 It serves as the transport system of our body, for carrying many substances from one part of the body to another.

2 It serves as body defense against diseases and harmful organisms.

3 It serves as the cleaning agent for the body by carrying poisonous waste products from where they are produced to the parts of the body to remove them.

Blood detects and diseases

1. Sickle cell
2. Anaemia
3. Leukemia
4. High blood pressure
5. Coronary thrombosis
6. Stroke
7. Hemophilia
8. HIV/AIDS[mediator_tech]

Sub-Topic 3: Importance of blood test

1 To determine the health status of an individual.

2 To detect some blood diseases e. g HIV/AIDS.

3 To determine the blood group of an individual.

4 To screen blood before transfusion.

5 To confirm pregnancy.

6 To monitor known health condition e. g blood sugar level.

7 To choose marriage partners.

8 To determine the genotype of an individual e .g AA, AS, SS

Blood groups

Human blood is classified into four groups. The groups are:

Group A, B, AB, O

Group A can receive blood from group A and O

Group B can receive blood from group B and O

Group AB can receive blood from group A, B, and O

Group O can receive blood from group O only.

Blood group O is a universal donor and blood group AB is a universal recipient.

EVALUATION: 1 Mention the blood groups.

2 List five importance of blood test.

WEEKEND ASSIGNMENT: Read STAN Basic Science for JSS 2 Pages 42-49

Mention the digestive organs.

REF. TEXTS: 1. STAN Basic Science Project, book two

2. Basic Science Made Easy, Book Two

3. Longman Basic Science, Book Two

WEEK 7

TOPIC: Digestive system

CONTENT: Definition of terms e. g digestion and digestive system etc.

Parts of digestive system from mouth to anus.

Digestion process at various stages.

Absorption of food.

Simple food test.

Sub-Topic 1: Definition of terms e. g digestion and digestive system etc.

Digestion is the process by which food substances are broken down into simple and soluble form that can be readily absorbed into the body.

Digestive system

All the parts of the body which work together to ensure digestion of food are called the digestive system.

Ingestion: This is the taking in of food into the mouth.

Absorption: This process by which food from digestion is taken into the animal body fluid.

Egestion: This is the process whereby undigested food is removed as faeces through the anus from the body.

Parts of the digestive system

The digestive system consists of a long tube from the mouth to the anus with various organs connected with it. The long tube is the alimentary canal and is made up of the organs below:

Digestive organs	Human alimentary canal
The mouth The gullet oesophagus [] The stomach The small intestine The large intestine The anus

Sub-Topic 2: Digestion process at various stages

1 The mouth: Food is mixed with saliva from the salivary glands.Saliva contains the enzyme ptyalin which starts the digestion of starch, and converts it to maltose.The softened food is swallowed into the oesophagus (gullet) as a small ball or bolus.[mediator_tech]

2 The oesophagus (gullet): It is a narrow tube which connects the mouth to the stomach. Food that has been chewed and partially digested in the mouth is pushed down the gullet into the stomach by the process of peristalsis. Peristalsis is the motion by which food is pushed along the gullet.

3 The stomach: The stomach is a sac-like organ. It is made up of connective tissue which holds the organ together. The stomach secretes which contains hydrochloric acid which stops starch digestion; enzyme pepsin acts on proteins and converts it to peptone and enzyme rennin coagulates milk. The semi-liquid and partly digested food in the stomach is called chyme and passes into the first section of the small intestine-duodenum.

4 Small Intestine: Pancreas in the small intestine secretes pancreatic juice which contains enzymes lipase, tripsin and amylase that help to digest fats and oil, protein and carbohydrates in the duodenum which is the first section of the small intestine. Bile from the liver is stored in the gall bladder, and enters the duodenum through bile duct. Bile emulsifies fats .Digestion of food is completed in the small intestine.

5 Large Intestine: The part of the food reaching the large intestine is waste materials, and is useless to the body. The large intestine absorbs any water in the waste materials. The hard waste (faeces) is passed out through the anus.

Sub-Topic 3: Absorption of food

At the end of the digestion all end products, vitamins, salts and water are absorbed in the small intestine through special structures which appear like small fingers on the wall of the intestine. They are called villi. They help to increase the surface area of the small intestine for absorption of food substance into the blood stream.

Simple food test

All food we eat can be classified into six types. They are carbohydrates, vitamins, fats and oils, mineral salts, proteins and water. All these food are chemical in nature. They can react with other chemicals to produce new substances .The scientists use simple food tests to identify food types or the contents of food materials.

WEEK: 8

TOPIC: REPRODUCTIVE SYSTEM

CONTENTS: 1.Parts of Reproductive system (male and female) and their functions.

1. Puberty
2. Secondary sexual characteristics
3. Importance of Reproduction

Sub-topic 1: Parts of Reproduction (male and female) and their functions

Reproduction is the ability of living organisms to produce young ones of their kinds. Reproduction is one of the characteristics of living things that ensure continuity of life.

TYPES OF REPRODUCUTION

There are two types of reproduction. These are (i) Asexual Reproduction: This involves one individual forming new off-springs. Examples are (a) Vegetative propagation in plants (b) Binary fission in amoeba (c) Budding in Hydra and (d) Spore production in Mucor and Mushroom. (ii) Sexual Reproduction: This involves mating of male and female in order to give rise to new off-springs. All new life comes from cells i.e sex cells. The male sex produces the male gametes (sperms or spermatozoa) from testes, the reproductive organs. The female sex produces the female gametes (ovum or egg cell) from the ovary, the female reproductive organs.

Male Reproductive Organs

Female Reproductive Organs

EVALUATION

1. What is reproduction?
2. Mention the two types of reproduction we have[mediator_tech]
3. State the female reproductive organs we have

Sub-Topic 2:

PUBERTY: This is the same as Adolescence. It is the age at which a boy or a girl reaches maturity (grow into adult).There are series of signs when a boy or a girl grow into maturity. These are:

Male Reproductive System Female Reproductive System.

Sub-Topic 3: Secondary Sexual Characteristics

Secondary sexual characteristics are features that distinguish the two sexes of a species, but that are not directly part of the reproductive system. In humans, secondary sexual characteristics include:

• Male
  • Growth of body hair, including underarm, abdominal, chest, and pubic hair. Loss of scalp hair androgenic alopecia can also occur
  • Greater mass of thigh muscles in front of the femur, rather than behind it as is typical in mature females
  • Growth of facial hair
  • Enlargement of larynx (Adam’s apple) and deepening of voice Increased stature; adult males are taller than adult females, on average
  • Heavier skull and bone structure
  • Increased muscle mass and strength
  • Larger hands and feet than women, prepubescent boys and girls
  • Square face
  • Small waist, but wider than females
  • Broadening of shoulders and chest; shoulders wider than hips Increased secretions of oil and sweat glands, often causing acne and body odor Coarsening or rigidity of skin texture, due to less subcutaneous fat
  • Higher waist-to-hip ratio than prepubescent or adult females or prepubescent males, on average
  • Enlargement growth of the penis
• Female
  • Enlargement of breasts and erection of nipples. Growth of body hair, most prominently underarm and pubic hair
  • Greater development of thigh muscles behind the femur, rather than in front of it
  • Widening of hips; lower waist to hip ratio than adult males, on average
  • Smaller hands and feet than men
  • Rounder face
  • Smaller waist than men
  • Increased secretions of oil and sweat glands, often causing acne and body odor
  • Upper arms approximately 2 cm longer, on average, for a given height Changed distribution in weight and fat; more subcutaneous fat and fat deposits mainly around the buttocks, thighs and hips.

IMPORTANCE OF REPRODUCTION.

1. It creates next generation.
2. It maintains the unique identity of a species.
3. It creates variations in species.
4. New species facilitate evolution of organisms which is necessary for survival as
   environmental conditions keep on changing from time to time.

EVALUATION

1. What is Reproduction?
2. State the two types of Reproduction.[mediator_tech]
3. State four signs of puberty in girls.
4. Mention five signs of sexual characteristics in male.
5. Enumerate three importance of Reproduction.

WEEKEND READING ASSIGNMENT

Students are to read about ‘The Excretory System’ from (i) ‘Nigerian Basic Science Project’ pages 60-62 and (ii) Basic Science (made easy) Book Two pages 27-30.

WEEK: 9

JSS 2

TOPIC: EXCRETOTY SYSTEM

SUB-TOPIC

I. Meaning of Excretion

II. Excretory organs and their functions

III. Excretion and the need for it

IV. Excretory Products/Wastes

Sub-Topic I: Meaning of Excretion

Excretion is the process by which an organism gets rid of metabolic waste products from the body. These waste products, if they are not removed, may be toxic and harmful to the body. Excretion can also be defined as removal or elimination of substances absorbed by the intestine that are not used for growth, repair or respiration. Removal of undigested food (faeces) is not excretion, it is egestion. Excretion is the removal of Carbondioxide and water produced during respiration.

EVALUATION

1. What is excretion?
2. Is excretion and egestion the same?

Sub-Topic 2: Excretory Organs and their Functions

The Excretory organs include: Kidneys, Skin, Lungs and Liver.

The Kidney: The kidney is the urinary system. Kidneys are two bean-shaped organs located in the abdominal region of the body. They help in removing urine from the body. Urine contains 96% water, 2% salt and 2% urea.

Functions of Kidney

1. It helps to remove the poisonous liquid wastes [urine] from the body
2. It purifies the body by removing toxic and harmful materials from the blood
3. It helps to regulate the amount of water and salt in the body.

The Skin: The skin is the external part of the body and protects the inner structures. The human skin is made up of two layers, namely (i) The Epidermis: the very outer layer and (ii) The Dermis: The inner layer otherwise called true skin.

FUNCTIONS OF THE SKIN

1. Skin protects the body from mechanical injury and bacterial infections
2. It helps in temperature regulation, that is, layer of fat under the skin act as insulator while evaporation of sweat cools the body.
3. Skin act as a sense organ, that is, it contains sensory cells that makes one respond to the stimuli of touch, pains, pressure, coldness or hotness.

The Lungs: Oxygen from the air breathed in is used during respiration by our body cells. The waste gases such as carbon (iv) oxide and water vapour are sent out into atmosphere through the lungs. The lungs excrete carbon (iv) oxide and water vapour which are by-products of respiration. The lungs function both as respiratory and as excretory organ

The Liver: Liver, largest internal organ of the human body that performs more than 500 different functions, all of which are essential to life. It’s essential functions include helping the body to digest fats, storing reserves of nutrients, filtering poisons and wastes from the blood, synthesizing a variety of proteins, and regulating the levels of many chemicals found in the bloodstream.

Functions of Liver

1. Liver helps in storing energy in form of glycogen
2. It produces bile for the digestion of lipids or fats
3. It helps in clearing toxic substances such as drugs and alcohol from the blood stream
4. Vitamins are stored in the liver
5. Liver is the body’s chemical factory, that is, it produces several important proteins found in the blood, globin and several other chemicals that help in healing wound.

EVALUATION

1. Mention the four excretory organs we have
2. State the components of urine
3. Which of the organs is important? Support your answer with four reasons.

Sub-Topic 3: The Need for Excretion

Excretion is the removal of harmful waste products of metabolic activities from the human body. If this process of excretion does not take place, wastes accumulate in the body and may poison or destroy the body. The need for excretion includes the following:

i. It is necessary to remove toxic and harmful waste products from the body

ii. To maintain salt content of the body

iii. To remove excess water from the body

Sub-Topic 4: Excretory Products/Wastes

The waste products removed by different excretory organs in man include:

EVALUATION

1. State three reasons why excretion is needful.[mediator_tech]
2. List the organs of the body and their waste products.

READING ASSIGNMENT

Students are to read all the term’s E-Note in preparation for exams.