Growth

GROWTH

HUMAN GROWTH

1. Growth is a process that take place in all living things.

2. The process of growth involves

         i. increase in size of organism.

        ii. change in appearance of organism.

       iii. increase in number of cells.

       iv. development of organs function of organism.

The Characteristics of Human Growth.

1. The human growth pattern is a curve.

2. It is divided into five stages of growth:

        a. Infancy

        b. Childhood

        c. Adolescence

        d. Adulthood

        e. Old age

Comparing the Growth Rates of Boys and Girls

The rate of growth in humans differ according to gender.

Both sexes are of a comparable shape and size during

infancy and childhood.

There are four characteristic stages of growth from birth to adult:

● Rapid growth in infancy and early childhood

● Slow, steady growth in middle childhood

● Rapid growth during puberty

● Gradual slowing down of growth in adolescence until adult height is reached

Patterns of Growth - Changes in Proportions

The physical proportions of the body at birth are very

different from those of the adult.

Some body parts grow more than others during development to reach the final adult proportions.

Changes in the size and shape of the body are caused by different segments growing at different times.

Nutrition 

A growing child who does not have

sufficient protein may develop a

dieses called kwashiorkor.

Those suffering from kwashiorkor

would be physically weak and show growth retardation.

"The importance of reproduction is to ensures that a particular species does

not extinct''

SEXUAL AND ASEXUAL REPRODUCTION

Reproduction =
involves the production of new generation of                        
individuals of same species.
                       
Sexual reproduction
involve male and female organisms.

Asexual reproduction
involves only one parent.








Asexual reproduction
- Binary fission (unicellular organism divides into two equal parts
(daughter cells)
- Budding (the parent produces an outgrowth or bud which detaches
to become a new individual)
- Spore formation
- Vegetative reproduction
- Regeneration (Regrowth of lost or destroyed parts or organs)

 Binary fission 

Vegetative reproduction

          This type of asexual reproduction is seen in many

            flowering plants.

Part of a plant detaches and grow into a new plant.

Example:

i. Runner

ii. Bulb

iii. Rhizome

iv. Corm

v. Stem tuber

i. Runner

A slender, creeping stem that puts forth roots from  

nodes spaced at intervals along its length.

The runner bears roots and becomes independent

before the parent plant die.

Example : grass, strawberry

ii. Bulb

A short, modified, underground stem surrounded by

usually fleshy modified leaves that contain stored food

for the shoot within.

Example : Onion, lilies 

iii. Rhizome

A horizontal, usually underground stem that often

sends out roots and shoots from its nodes.

Example: ginger, Canna

iv. Corm

A short, thick, solid, food-storing underground stem,

sometimes bearing papery scale leaves.

Examples: cocoyam , water chestnut

iv. Stem tuber

The swollen ends of underground stems

New shoot sprout out from axillary buds or ‘eyes’.

Example: potato, beet

The male reproductive system

- Secondary sexual characteristics (male)
Growth of hair on face, chest, in pubic region and
armpits.

The voice becomes deeper.

Body becomes more muscular.

Chest becomes broader.

Certain mental and emotional changes.

 - Male gamete (sperm)
The role of the sperm is to swim towards
the ovumand fuses with it to form zygote.

Zygote will develop into an adult individual.












The female reproductive system

- Female gamete (ovum)
The ovum stores some food in its cytoplasm.
The food is used to nourish the embryo which develops
from the zygote.














- Secondary sexual characteristics (female)
Growth of hair in pubic region and armpits.
Commencement of menstruation.
Production of ova by the ovaries.
Pelvis becomes broader.
Fat deposits on hip and thighs.
Growth and development of breasts.
Certain mental and emotional changes.

Excretion

Transport notes

UNIT 2

Transport in plants 

Plants don’t have a circulatory system like animals, but they do have a sophisticated transport system for carrying water and dissolved solutes to different parts of the plant, often over large distance.














TRANSPIRATION MORE LIKE WATER CYCLE











 XYLEM

Xylem is woody tissue that carries water and minerals from the roots hroughout the plant and provides the plant with mechanical support.In transpiration process the loss of water from the leavesdrives themovement of water and minerals in the xylem.

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 STOMATA

The rate of transpiration is directly proportional to the opening and number of stomata.

In the daytime, the stomata is open to release water in atmosphere, which is then broken down
 into oxygen and hydrogen. In return, the atmospheregives carbon-dioxide to the plant to complete
 its process of photosynthesis.

Blood circulation and transport notes

UNIT 2
BLOOD CIRCULATION AND TRANSPORT

Introduction to function of HearT

The role of the heart is to pump oxygen-rich blood to every living cell in the body. In order to achieve its goal, it must continuously beat for a person’s entire lifespan. Because of its vital role, a non-beating heart always results in death. The human heart beats approximately 80,000 to 100,000 a day and pumps almost 2,000 gallons of blood. This means that in a person’s life lasting 70 to 90 years, the heart beats approximately two to three billion times and pumps 50 to 65 million gallons of blood. Because the heart is so essential for human sustenance, it is made up of a muscle different from skeletal muscle that allows it to constantly beat.

In order for the heart to deliver oxygenated blood to all cells, blood is pumped through arteries. Veins bring deoxygenated blood cells to the lungs, which then are oxygenated, and then sent back to heart. In this way, a continuous cycle is formed of the heart pumping oxygenated blood and deoxygenated blood out to their designated destinations, and therefore the heart maintains the circulatory system.

Systole: Stage when the ventricles of heart are contracting resulting in blood being pumped out to the lungs and the rest of the body.
- Thick, muscular walls of both ventricles contract.
- Pressure rises in both ventricles, causing the bicuspid and tricuspid valves to close. Therefore, blood is forced up the aorta and the pulmonary artery.
- The atria relax during this time. The left atrium receives blood from the pulmonary vein, and the right atrium from the vena cava.

Diastole: Stage when the ventricles of the heart are relaxed and not contracting. During this stage, the atria are filled with blood and pump blood into the ventricles.
- Thick, muscular walls of both ventricles relax.
- Pressure in both ventricles falls low enough for bicuspid valves to open.
- The atria contract, and blood is forced into the ventricles, expanding them. The blood pressure in the aorta is decreased, therefore the semi-lunar valves close.

Respiration notes

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SCIENCE FORM 3

Unit 1
Respiration

Human Breathing Mechanism

                             





    Human Respiratory System
1. Living organisms must be able to take oxygen from the air and get rid of carbon dioxide to the air.
2. Gas exchange takes place through a gas exchange surface, also known as a respiratory surface.
3. Breathing is also known as external respiration.
4. Breathing consists of two stages:
                   a. Inhalation - during which air is taken into the lungs.
                   b. Exhalation - during which air passes out of the lungs.
5. The breathing system or the human respiratory system consists of the following structures or organs:
                   a. The nasal cavity                                     
                   b. Trachea
                   c. Bronchus (plural: bronchi)
                   d. Bronchiole
                   e. Lungs
                   f. Alveolus (plural: alveoli)
                   g. Rib cage
                   h. Diaphragm
                   i. The intercostal muscles
                   j. Internal intercostal muscles,
                   k. External intercostal muscles.







6. Flow of air into the lungs
                       a. Air is breathed in through the nose and enters the nostrils.
                       b. The nostril leads to the nasal cavity where the air is warmed up and moistened.
                            i. Hairs and sticky mucus trap particles inside the nasal cavity.     
                       c. The air then enters the trachea.


 

Respiration