body systems

What is health?

Health is a state of complete physical, mental, and social well-being, not just the absence of disease or infirmity.

Why is our health important?

It reduces the risk of chronic diseases, improves quality of life, and helps us live longer.

What are living things made of?

All living things are made up of at least one cell.

What are cells?

Cells are the building blocks of life, existing in many shapes and sizes.

What is a unicellular organism?

An organism made of only one cell that performs all life processes.

What is a multicellular organism?

An organism made up of many cells specialised for different functions.

What are the seven life processes?

Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

How are cells organised in multicellular organisms?

Cells → Tissues → Organs → Organ systems → Organism.

Why do multicellular organisms need organ systems?

To communicate between cells, supply nutrients, and control exchanges with the environment.

Name six major body systems.

Digestive, Circulatory, Excretory/Urinary, Musculoskeletal, Respiratory, Reproductive.

What is the main function of the digestive system?

To break food into small particles that can pass into the bloodstream for energy, growth, and repair.

Why do animals need food?

For energy, growth, and repair of the body, and to carry out life processes.

What is a balanced diet?

A diet containing a variety of foods from different groups that provide all necessary nutrients.

What are the main nutrients the body needs?

Carbohydrates, Proteins, Lipids, Vitamins, Minerals

What are carbohydrates made of?

Carbon, hydrogen, and oxygen.

What is the main function of carbohydrates?

They are the body's main source of energy.

What are examples of carbohydrate sources?

Fructose, Lactose, Sucrose, Starch

What happens to excess glucose?

It is converted to fat and stored.

What are proteins made of?

Amino acids.

What are the functions of protein?

Growth and repair of cells, and energy (about 10% of body energy).

What are sources of protein?

Meat, chicken, fish, and eggs.

What are lipids?

High in energy, includes fats and oils.

What are the functions of fats?

Energy storage, insulation, building cell membranes and nerve cells, and containing vitamins.

What are common sources of lipids?

Oils, corn, peanuts.

What do vitamins do?

Needed in small amounts to speed up chemical reactions and maintain health, though they don't provide energy.

What happens if we lack vitamins?

Deficiency diseases or health problems.

Give examples of important vitamins and sources.

Vitamin A: cheese, eggs, milk; Vitamin C: fruits & vegetables; Vitamin D: fish, red meat, egg yolks.

What are minerals?

Chemically simple substances needed for growth and preventing deficiency disease.

What are the two types of minerals?

Major elements (calcium, sodium, chlorine) and trace elements (iron, zinc, fluorine).

What can happen with too much or too little of a mineral?

It can cause health problems or deficiency diseases.

What is digestion?

the process where food matter is broken down into smaller simple substances, such as glucose, that are absorbed into the bloodstream and transported to cells that need these nutrients

What are the two types of digestion?

Physical (mechanical) and chemical digestion.

What is physical digestion?

The mechanical breakdown of food into smaller pieces to increase surface area.

Where does physical digestion start?

In the mouth using the teeth and tongue.

What are incisors for?

Spade-shaped, cutting and biting food (8 total).

What are canines for?

to shear and tear through tough food like meat (4 total).

What are premolars for?

2 pointed cusps, rolling and crushing food (8 total).

What are molars for?

3-5 rough cusps, used for grinding food (8-12 total, last 4 are wisdom teeth).

What is chemical digestion?

Breakdown of large molecules of food using enzymes and acids so that they are small enough to be absorbed into the bloodstream.

Where does chemical digestion start?

In the mouth with amylase, which breaks starch into glucose.

What happens in the stomach?

Physical digestion (relaxation and contraction of stomach walls) and chemical digestion (food mixed with acids and enzymes).

What enzyme and acid are in the stomach?

Pepsin (breaks proteins/fats) and hydrochloric acid (kills bacteria and aids digestion).

What is chyme?

The semi-liquid mixture of food and gastric juices.

What happens in the small intestine?

The chyme enters from the stomach into the small intestine, and pancreatic juices containing enzymes are released, neutralising the acidic chyme. The small intestine is long and thin, with its main role of absorbing nutrients.

What is the main function of the small intestine?

Absorbing nutrients into the bloodstream.

What enzymes act in the small intestine?

Carbohydrase, Protease, Lipase.

What happens in the large intestine?

Unnecessary Nutrients that weren’t digested in the small intestine reach the large intestine, and the water and minerals are absorbed into the bloodstream. The remaining waste product remain and become faeces, and are stored in the rectum and expelled from the anus.

What is the function of the rectum and anus?

Rectum stores faeces; anus expels them.

What is bolus?

The lump of food and saliva formed before swallowing.

How does bolus move to the stomach?

Down the oesophagus By muscular contractions called peristalsis.