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SCIENCE 6. UNIT 1. NUTRITION I

DIGESTIVE & CIRCULATORY SYSTEMS

C.E.I.P. SANTA ANA (Madridejos)

NUTRITION is the process in which living

beings get oxygen and nutrients, that they use to

get energy and grow. Later they expel waste pro-

ducts.

USEFUL WORDS: .– nutrition .– circulatory system .– Digestive system

.– respiratory system .– excretory system. .– nutrients .– carbohydrates

.– fats .– proteins .– vitamins .– minerals.

CONTENTS:

1.– Nutrition: digestive, circulatory, respiratory & excretory.

2.– Types of nutrients:

3.– Digestive system:

3.1.– Digestive tract, digestive glands. Digestive process.

3.2.– Protect your health: food pyramid & diet.

4.– Circulatory system:

4.1.– Blood components.

4.2.– Blood vessels.

4.3.– Heart.

4.4.– Blood circulation.

4.5.– Protect your health.

CIRCULATORY SYSTEM:

Carries nutrients and oxygen to every cell, and removes

CO2 and waste products from cells to the exterior.

DIGESTIVE SYSTEM:

Transforms food into nutrients, that go

to the blood, and expels waste products to

the exterior.

EXCRETORY SYSTEM:

Produces urine and sweat and

expels waste products from cells

to the exterior .

RESPIRATORY SYSTEM:

Gets oxygen from the air, passes to the

blood and removes CO2 from blood, and

expels to the exterior.

Some systems work together in

NUTRITION:

.– CIRCULATORY SYSTEM.

.– DIGESTIVE SYSTEM.

.– RESPIRATORY SYSTEM.

.– EXCRETORY SYSTEM.

2.– TYPES OF NUTRIENTS:

There are different types of nutrients, like carbohydrates, fats, proteins, vita-

mins, and there are inorganic nutrients like, minerals, water and oxygen.

A.– Carbohydrates are needed to give the body energy. We can find

them in cereals, potatoes, pasta, flour, and in sugars (in fruits, honey…)

B.– Fats are concentrated sources of energy, and help to insulate in cold

weather. There are animal and vegetable fats. (meat, butter, olive oil…)

C.– Proteins help to grow and form tissues in the body. We can find

them in meat, fish, milk, cheese, dairy products, eggs…

D.– Vitamins are needed in small amounts for growth and and be

healthy. There are different kinds of vitamins with different properties.

E.– Minerals are needed in small amounts to help the body on vital

functions, and to be healthy and strong (Examples: calcium, Iron, sodium,

potassium…) We can find them in fruit, vegetables, water...

f.– Water is needed for life. Living beings are composed by water in a

high proportion. If they don’t have enough water, they will be dehydrated and die.

Nutrients are components (mostly

in foods) that an organism uses to

survive, get energy and grow.

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USEFUL WORDS:

.– digestive tract .- pharynx .– oesophagus

.– stomach .- small intestine .– large intestine

.– rectum .– anus .– salivary glands

.– gastric juice .– chyme .– bile

.– gall bladder .– páncreas .– chyme .- chyle

Digestion is the process of breaking down food molecules

into smaller substances called nutrients. Nutrients pass to

the blood, and waste productucts are expelled.

3.– DIGESTIVE SYSTEM:

The digestive system is formed by the digestive tract

and some glands that cooperate to the digestion process.

3.1.– A) DIGESTIVE TRACT: is a muscular tube formed by mouth, the pharynx, the oesophagus, stomach,

small intestine, large intestine, the rectum and the anus.

This tube is formed by muscle tissue that moves the food down with their contractions.

B) DIGESTIVE GLANDS: are glands that produce different liquids which help to dissolve food into nutrients.

.– Salivary glands produce saliva to moist food and form the bolus.

.– Microscopic glands in the stomach produce gastric juice, to form the chyme.

.– Liver produce bile, that is a liquid to help to divide fats. The gallbladder stores bile from the liver.

.– Pancreas produce pancreatic juice to help in digestion.

.– Microscopic glands in the small intestine produce intestinal juice to form the chyle.

MOUTH: with teeth and tongue. It breaks down food into parts.

LIVER: produces bile for fats digestion. It makes other vital functions.

GALL BLADDER: stores bile from liver.

RECTUM: stores the waste products (faeces)to expell them.

SALIVARY GLANDS: produce saliva to moist food and break down carbohydrates

PHARYNX: controls that food goes down to the esophagus.

OESOPHAGUS: transports food from mouth to stomach.

STOMACH: produces mechanical contractions and gastric juice to break down food.

PANCREAS: produces pancreatic juice into small intestine.

SMALL INTESTINE: produces juices and there, nutrients, vitaminns, mine-rals, water… pass to the blood.

ANUS

LARGE INTESTINE: water is absor-bed, and waste products are transfor-med into faeces.

C) DIGESTIVE PROCESS, or DIGESTION.

Digestion is the process of breaking down food molecules into smaller

substances called nutrients. Nutrients pass to the blood, and waste produc-

tucts are expelled.

1.- Digestion in the mouth: Teeth break down food into pieces, salivary

glands produce saliva and the tongue mixts it with the small pieces of food

to form the bolus.

Saliva also starts to dissolve carbohidrates in the mouth.

teeth

tongue

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USEFUL WORDS:

.– gastric juices .– chyme .– bile

.- pancreatic juice .- chyle .– intestinal villi

.– peristalsis .- rectum .– anus

2.– Digestion from the mouth to the stomach:

The tongue pushes the bolus to the pharynx, then we swallow and the bolus goes

to the oesophagus.

The oesophagus is a muscular tube that help the bolus to get to the stomach. Mo-

vements that digestive tract do are called peristalsis.

The stomach is a muscular bag with

microscopic glands that produce

some juice called gastric juice.

This substance is very acid, and it

continues dissolving the food.

The stomach contracts and moves,

and it mixes the food with the gas-

tric juice forming a paste called

chyme.

3.– Digestion in the small intestine:

The chyme goes to the small intestine, where it mixes

with the bile from the liver, the pancreatic juice and the

intestinal juice from glands in the small intestine to form

the chyle.

The small intestine is a muscular tube about seven metres

long with millions of intestinal villi. These small hairs

have got capillaries that absorb nutrients to the

bloodstream.

pharynx

oesophagus

stomach

small intestine intestinal villi

capillaries: artery & vein

4.– Digestion in the large intestine:

Large intestine is a muscular tuve, shorter and wider than the

small intestine.

The substances that weren’t absorbed go to the large intestine.

There, juices, water and some minerals are absorbed.

The rest of materials form the faeces. They are stored in the rec-

tum, and are expelled through the anus.

Large intestine

apendix

rectum

anus

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USEFUL WORDS:

.– dairy products .– poultry .– sugary drinks

.– whole grains .– whole wheat . – weight control

3.2.– PROTECT YOUR HEALTH :

There are some rules related with the digestive system to avoid pro-

blems with our health. Some are related with hygine, and others

with diet:

.- Wash your hands before cooking or before having every meal.

Some microorganisms can produce infections in our digestive tract.

.– Wash fruit and vegetables before eating them.

.– Clean your teeth two or three times a day.

.– Keep a balanced and healthy diet.

Food pyramid and healthy diet.

If you eat a balanced diet, your organs and systems will work better.

Eating a great variety of foods is needed to be healthy.

So you must...

1.– Eat a lot of vegetables, cereals, pasta, fruits… These foods contain different nutrients (minerals, vita-

mins, fibre…)and lots of energy from carbohydrates. And don’t forget to drink a lot of water or liquids.

2.– Eat moderately fish, meat, eggs, dairy food (milk, yogourt…) will provide proteins, minerals and

vitamins to grow and stay healthy.

3.– Eat in small amounts: sugars, sweets, oil and animal fats. They can provoque healthy problems.

Don’t forget to drink two

litres of liquids a day.

Some microorganisms feed from remains of

food, producing some substances that attack

our teeth and create caries.

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The Circulatory system carries nutrients and

oxygen to every cell, and removes CO2 and waste

products from cells to the exterior.

C.E.I.P. SANTA ANA (Madridejos)

.– blood vessel .– plasma .– red blood cell

.– blood clot .– platelet .– white blood cell

.– arteries .– veins .– capillaries

4.– CIRCULATORY SYSTEM.

The circulatory system is formed by blood vessels (arteries,

veins and capillaries), heart and the blood.

This system transports different substances in the body floa-

ting in the blood:

4.1.– BLOOD COMPONENTS:

Blood is a thick red liquid formed by different components:

plasma and blood cells.

a.– Plasma is a yellow translucent liquid formed mostly by

water, where blood cells, nutrients and waste products are

floating.

b.– Red blood cells (erythrocytes) are red disk-shaped that

transport oxygen from the lungs to cells, and CO2 from cells

to lungs.

c.– White blood cells (leukocytes) protect our body from

microorganisms and viruses. Our body produce more

leukocytes when we are sick.

d.– Platelets heal wounds and form a blood clot to avoid

bleeding.

.– Oxygen that lungs get from the air, and is carried to cells.

.– Nutrients: proteins, glucose, minerals… (from the small intestine).

.– Carbon dioxide and waste products formed by the transformation

of nutrients and oxygen in cells.

Platelets

forming a

Blood clot

white blood cell red blood cells platelets

plasma

B.– Veins carry blood from the organs

to the heart. Veins have valves to help

that the blood only circulates in one

direction (forward).

4.2.– BLOOD VESSELS:

They are tubes that contains blood, and

transport it to every cell in our body.

There are three types:

A.– Arteries carry blood away from

the heart to the organs.

C.– Capillaries are very narrow tubes that connect arteries and veins. They

permit the exchange of gases and substances between blood and every cell.

In the capillaries of the arteries, oxygen and nutrients go out to cells.

In the capillaries of veins, CO2 and waste products pass to the blood.

Blood vessels:

.– Arteries

.– Veins

.– Capillaries

Blood components: plasma, platelets,

red blood cells, and white blood cells.

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Right part of heart: CO2 / Left part of heart: O2

Blood enters to the atrium, and goes out through

the ventricle

C.E.I.P. SANTA ANA (Madridejos)

.– right atrium .– left atrium .– right ventricle .– left ventricle

.– beat .– systole .– diastole .– aorta artery

.– vena cava .– pulmonary circulation .– systemic circulation

4.3.– THE HEART.

The heart is a muscular organ that pumps blood through the

blood vessels around the body. It beats about 72 beats/minute.

It’s divided in two halves:

The right side with blood rich in CO2, and the left side with

blood rich in O2.

The heart has got four chambers: right atrium, left atrium,

right ventricle and left ventricle.

Right part Left part

4.4.– BLOOD CIRCULATION:

Blood circulation is the route your blood takes around the body. It has 2 circuits:

.– Pulmonary circulation: when the blood goes from the heart to the lungs to

release CO2 . to get oxygen and returns.

.– General circulation (or systemic): is the circulation of the blood to all parts

of the body except the lungs (releases O2 in cells and gets CO2 ).

Blood enters in the atrium (upper part) through veins, pass through a

valve to the ventricle (lower part) and goes out to the body through

arteries.

The heart contracts and expands to pump blood, this movement is ca-

lled beat.

Every beat has got two steps:

1.– The heart expands (diastole) and blood enters from the veins.

2.- The heart contracts (systole) and pumps blood through arteries.

2.- In the lungs arteries become capillaries, where blood releases CO2 and gets oxigen.

3.- Blood returns through the pulmonary veins to the heart. Blood comes into the left atrium.

PULMONARY CIRCULATON: 1.- Blood leaves the right ventricule and goes through the pulmonary arteries to the lungs.

SYSTEMIC CIRCULATION: 1.– Blood passes from the left atrium to the left ventricle, and goes out through the aor-ta artery to the rest of the body.

2.– Aorta (the largest ar-tery) is divided into other arteries and finally into ca-pillaries, where blood re-leases O2 and gets CO2 from cells.

3.- Blood rich in CO2 comes from capillaries to veins. Finally the largest vein (vena cava) carries blood to the right atrium.

4.– Blood passes from the right atrium to the right ventricle and to the lungs, and pulmo-nary circulation starts again.

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USEFUL WORDS:

.– hypertension / high blood pressure .– cholesterol

.– arteriosclerosis .– heart attack

3.2.– PROTECT YOUR HEALTH :

First we are going to learn about the most common problems with the circulatory system, and later we’ll see some

rules to avoid them. These kind of deseases are typical for adult people, but we must always keep healthy habits.

4.– Heart attack is usually caused by a blood clot (in coronary arteries), which stops

the blood flowing to a part of the heart muscle, so cells from the heart will die.

B.– WHAT WE MUST DO TO PREVENT THESE

PROBLEMS:

1.- Adults must control their blood pressure and their level

of cholesterol. So adults must check them regularly.

To keep them under control we must do:

2.– Keep a healthy diet is a good way of regulate the levels of

colesterol and blood pressure:

.– Eat lots of vegetables and fruit.

.– Eat more fish like salmon, blue fish…

.– Eat legumes (lentils, chickpea…) and nuts.

.– Low salt intake.

3.– Don’t smoke, and use alcohol drinks moderately. These

substances are very dangerous for blood vessels, and they can

provoque important problems on them.

4.– Practice sports and do exercise regularly. They are the

best way to feel good and stay healthy.

Adults must control their level of blood pressure.

Cholesterol and arteriosclerosis can provoque

arteries become narrower and narrower.

1.– Hypertension or high blood pressure is a problem. When the

blood pressure in arteries is too high over the years, it can do some

damages to arteries, to the heart (heart attack), to the brain (stroke)..

2.– Cholesterol is a kind of fat. We get it from animal fats from food.

When the level of cholesterol is high, it can cause blockage of blood

flow in arteries (atheroma).

3.– Arteriosclerosis is the thickening, hardening and the loss of elasti-

city of the walls of arteries. This process provoque that cells in organs

or tissues get less blood than in normal conditions.

A.– PROBLEMS ON THE CIRCULATORY SYSTEM.

Practice sports and do exercise regularly.

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