Learn about your Digestive System

The Digestive System

• Feeding is the process of introducing foodstuffs into your body.

• Nutrition is the transformation of food so it can be used by the body. The energy obtained from food is necessary for development, growth and activity.

• Nutrition is possible because of the joint action of the digestive, respiratory, circulatory and excretory systems.

How Digestion Begins

• As food passes through the digestive system, it is broken down into simple substances that our bodies are able to use.

• The digestive process starts in the mouth and is set in motion by the teeth, the tongue, and saliva.

• The sharp-edged teeth chop and tear the food, while the premolars and molars, which have flatter surfaces, grind it up. This is the process of mastication, or chewing.

Incisor Canine Premolar Molar

• The tongue is the most muscular organ in the body. It can carry out any kind of movement. It pushes the food and places it between our teeth.

• The 1 to 2 litres of saliva secreted daily by the salivary glands helps to dissolve the food and make it easier to swallow. While the saliva lubricates the food, some of the special proteins it contains start to act on the starch.

The Tongue

Swallowing • In the digestive process, there are

two phases: the mechanical phase and the chemical phase. The mechanical phase is carried out in the mouth by the teeth and in digestive tract by the muscles that move the bolus of the food along.

• The chemical phase is the transformation carried out by the different digestive juices. The first of these to have affect is the saliva. Swallowing is a total mechanical process that consist of a series of movements which propel the bolus toward the stomach.

The Stomach

• The stomach has two muscles that control the food that enters it and that leaves it. The stomach is made up of three layers.

• The most important layer is the internal layer arranged in numerous folds which contains the glands that secrets gastric juices. The middle muscular layer of the stomach helps to breaks the food to a small mass.

The Small Intestine • The small intestine is more than 20

feet (7 meters) long. It is divided into three parts. These are called the duodenum, the jejunum and the ileum.

• In the first part the duodenum secretions are produced by the liver and by the pancreas. Digestion occurs here.

• Next the food reaches the jejunum and the ileum, where the process of digestion ends. The food has now been broken down into small particles that are ready to pass into the bloodstream through small finger-like projections (called villi) which line the ileum.

The Large Intestine • The waste products that have

neither been digested nor absorbed make up the faeces.

• The function of the large intestine is basically to absorb water to maintain the consistency of the faeces.

• For the faeces to pass easily through the large intestine and out of the anus it is important to eat a lot of fibre. This helps the food move along the gut and adds bulk to the faeces. It prevents constipation and keep the colon (part of the large intestine) healthy.

The End

This was done by

Bernice Gauci

and Vanessa

Zerafa

Monocots & dicotsMonocots & dicots

Rebecca Bonnici & Donna Rebecca Bonnici & Donna MicallefMicallef

Differences Between Differences Between Monocots & Dicots Monocots & Dicots Embryo: Monocots have one Embryo: Monocots have one

cotyledon while Dicots have cotyledon while Dicots have two cotyledonstwo cotyledons

Leaf venation: Monocots have Leaf venation: Monocots have parallel veins while dicots parallel veins while dicots have web-like veinshave web-like veins

Roots: Monocots have a fibrous Roots: Monocots have a fibrous root system while Dicots root system while Dicots have taprootshave taproots

Stems: Monocots have vascular Stems: Monocots have vascular bundles scattered while bundles scattered while dicots have vascular bundles dicots have vascular bundles in a ringin a ring

Flowers: Monocots have floral Flowers: Monocots have floral parts usually in groups of parts usually in groups of three and dicots have floral three and dicots have floral parts usually in groups of fourparts usually in groups of four

Monocot Seedling LeafMonocot Seedling Leaf

Monocots: have Monocots: have only one seedling only one seedling leaf (cotyledon) leaf (cotyledon) and usually have and usually have scattered vascular scattered vascular bundles, parallel bundles, parallel veined leaves and veined leaves and flower parts in flower parts in multiple of three. multiple of three.

Dicot Seedling LeafDicot Seedling Leaf

The seed of a dicot The seed of a dicot has two halves. It has two halves. It has two cotyledons has two cotyledons that are fleshy and that are fleshy and has network of has network of veins in leaves.veins in leaves.

Dicot flowerDicot flower

Dicots: have flowers Dicots: have flowers in which the floral in which the floral parts are in parts are in multiples of 4 or 5. multiples of 4 or 5. The picture on the The picture on the right shows a right shows a typical dicot floral typical dicot floral structure with 5 structure with 5 petals and 4 petals and 4 anthersanthers

Monocot flowerMonocot flower

If you count the If you count the number of petals, number of petals, stamens or the stamens or the other floral parts, other floral parts, you will find that you will find that monocot flowers monocot flowers have a number of have a number of parts that is parts that is divisible by three, divisible by three, usually three or six.usually three or six.

Monocot - rootMonocot - root

In the fibrous root In the fibrous root system of monocots, system of monocots, the main root is the main root is almost non-existent. almost non-existent. Many roots come out Many roots come out from the same point. from the same point. These secondary roots These secondary roots are important in are important in absorption but are not absorption but are not as deep as the primary as deep as the primary root of most dicots.root of most dicots.

Dicot - rootDicot - root

The tap root The tap root system is deep system is deep with a long with a long primary root. primary root. Less important Less important secondary secondary roots branch roots branch off.off.

Leaves of monocotsLeaves of monocots This is a typical monocot leaf and it This is a typical monocot leaf and it

has parallel veins and the leaves are has parallel veins and the leaves are always straight, narrow and long. always straight, narrow and long. Examples of plants which are Examples of plants which are monocots include the Dwarf Fan monocots include the Dwarf Fan Palm, Narcis, Daffodil and Ilsien in-Palm, Narcis, Daffodil and Ilsien in-nisa.nisa.

Leaves of dicotsLeaves of dicots

The leaves of dicots have network The leaves of dicots have network veins this means that they are spread veins this means that they are spread out and the leaves are wide and broad. out and the leaves are wide and broad. Examples of dicot plants are the Rose, Examples of dicot plants are the Rose, Vine, Fig, Oak.Vine, Fig, Oak.

End End

The Heart The Heart

An important organ An important organ in your bodyin your body

The HeartThe HeartYour heart never rests. It started to beat before Your heart never rests. It started to beat before you were born and it will go on beating steadily you were born and it will go on beating steadily throughout your life. Your heart is made of a throughout your life. Your heart is made of a special type of muscle called cardiac muscle special type of muscle called cardiac muscle and it gets bigger as you grow. It’s about the and it gets bigger as you grow. It’s about the same size as your clenched fist, and weights same size as your clenched fist, and weights about 250 grams.about 250 grams.

If you place your fist against the centre of your If you place your fist against the centre of your chest with your knuckles pointing to your left chest with your knuckles pointing to your left side, you will feel your heart beating about side, you will feel your heart beating about once every second. Surrounded by your lungs once every second. Surrounded by your lungs and protected by your rib cage, your heart and protected by your rib cage, your heart works like a powerful pump, sending blood to works like a powerful pump, sending blood to every part of your body. Sometimes your heart every part of your body. Sometimes your heart changes its speed , by beating faster or slower changes its speed , by beating faster or slower depending on how much oxygen your body depending on how much oxygen your body needs.needs.

Inside your heart Inside your heart Your heart is divided into two halves which lie to Your heart is divided into two halves which lie to

the right and left of each other ,separated by a wall the right and left of each other ,separated by a wall called the septum . Each half is made up of 2 parts: called the septum . Each half is made up of 2 parts: an upper chamber called the atrium and a lower an upper chamber called the atrium and a lower chamber called the ventricle . chamber called the ventricle .

The upper chambers fill with blood at the same The upper chambers fill with blood at the same time. Their thin muscular walls contract and time. Their thin muscular walls contract and squeeze blood into the lower chambers through squeeze blood into the lower chambers through valves which act like one-way doors, closing firmly valves which act like one-way doors, closing firmly once the blood has passed through them. When the once the blood has passed through them. When the ventricles are full of blood , they give a powerful ventricles are full of blood , they give a powerful squeeze and push blood into the arteries ,the squeeze and push blood into the arteries ,the strong tubes that carry blood away from the heart.strong tubes that carry blood away from the heart.

Have a look at your heartHave a look at your heart

HOW DOES YOUR HEART HOW DOES YOUR HEART WORK?WORK?

Your heart is the centre of your body’s Your heart is the centre of your body’s transport system , pumping blood to every transport system , pumping blood to every part of your body , this is called circulation.part of your body , this is called circulation.

There are 3 main parts to your circulation. There are 3 main parts to your circulation. 1) One circuit connects your heart to your 1) One circuit connects your heart to your

lungs.lungs. 2) A second circuit collects blood from the 2) A second circuit collects blood from the

abdomen area and carries it to the liver. abdomen area and carries it to the liver. 3) The third sends blood around the rest of 3) The third sends blood around the rest of

your body again. The journey from the heart your body again. The journey from the heart to the lungs and back again is called to the lungs and back again is called pulmonary circulation .pulmonary circulation .

The Cardiac CycleThe Cardiac Cycle

First of all , blood carrying carbon dioxide First of all , blood carrying carbon dioxide comes into the heart through the comes into the heart through the Vena CavaVena Cava and collects in the right atrium. As the right and collects in the right atrium. As the right atrium fills up with blood valves separating it atrium fills up with blood valves separating it from the right ventricle are closed. Then blood from the right ventricle are closed. Then blood is squeezed into the right ventricle . is squeezed into the right ventricle .

The blood is then pumped to the lungs out of The blood is then pumped to the lungs out of the the Pulmonary ArteryPulmonary Artery where through where through thousand of tiny air sacs, carbon dioxide is thousand of tiny air sacs, carbon dioxide is exchanged for a fresh supply of oxygen.exchanged for a fresh supply of oxygen.

The oxygenated blood then flows back The oxygenated blood then flows back through the through the Pulmonary VeinPulmonary Vein to the left to the left atrium of the heart. As the atrium fills up, atrium of the heart. As the atrium fills up, valves are kept close. These then open when valves are kept close. These then open when the blood is pushed into the left ventricle. the blood is pushed into the left ventricle.

Blood leaves the left side of the heart Blood leaves the left side of the heart through the through the AortaAorta which pumps blood all which pumps blood all over your body, delivering oxygen wherever it over your body, delivering oxygen wherever it is needed . It picks up waste carbon dioxide is needed . It picks up waste carbon dioxide and returns through veins to the right side of and returns through veins to the right side of your heart to begin its journey all over again .your heart to begin its journey all over again .

This is a photo showing the valves This is a photo showing the valves that stop blood from flowing that stop blood from flowing

backwards into the heartbackwards into the heart

This diagram shows how valves This diagram shows how valves

close when blood leaves the heart.close when blood leaves the heart. These valves are called semi-lunar These valves are called semi-lunar

valves.valves.

The right side of your heart sends The right side of your heart sends deoxygenated blood (blood with deoxygenated blood (blood with carbon dioxide) back to your lungs, carbon dioxide) back to your lungs, for a fresh supply of oxygen . This for a fresh supply of oxygen . This journey from the heart to the lungs is journey from the heart to the lungs is short so blood is pumped not under short so blood is pumped not under very high pressure. This gives time for very high pressure. This gives time for gas exchange and also protects the gas exchange and also protects the delicate air sacs in the lungs.delicate air sacs in the lungs.

The left ventricle has to pump blood The left ventricle has to pump blood all round your body . To give it extra all round your body . To give it extra strength, its muscular walls are strength, its muscular walls are thicker than those of the right thicker than those of the right ventricle .ventricle .

Heart diseaseHeart disease Heart disease kills more people than any other type of Heart disease kills more people than any other type of

illness. illness. It’s worth looking for the reasons why because you can It’s worth looking for the reasons why because you can

reduce the risk of heart disease . reduce the risk of heart disease . As you grow older, the elastic fibres in the arteries begin to As you grow older, the elastic fibres in the arteries begin to

lose their ability to expand and contract . Sometimes they lose their ability to expand and contract . Sometimes they become “clogged up” so that blood cannot flow as easily as become “clogged up” so that blood cannot flow as easily as it should. This blockages can lead to serious results . it should. This blockages can lead to serious results .

It’s certainly worth doing something positive to make sure It’s certainly worth doing something positive to make sure that you avoid having problems with you heart . Life can be that you avoid having problems with you heart . Life can be very hectic . People rush about getting tired and angry as very hectic . People rush about getting tired and angry as they cope with over-crowded places or traffic jams . This they cope with over-crowded places or traffic jams . This leads to stress which, together with smoking and drinking , leads to stress which, together with smoking and drinking , increase the risk of damage to your heart. Eating a lot of increase the risk of damage to your heart. Eating a lot of fatty food with cholesterol can also block your arteries and fatty food with cholesterol can also block your arteries and lead to heart disease.lead to heart disease.

If you begin a healthy lifestyle when you’re young , you If you begin a healthy lifestyle when you’re young , you greatly improve your chances of having a fit and healthy greatly improve your chances of having a fit and healthy heart .heart .

THETHE ENDEND

Leanne Mifsud Leanne Mifsud

The Animal The Animal KingdomKingdomVertebratesVertebrates

(animals with a backbone)(animals with a backbone)

VertebratesVertebrates

There are 5 classes of vertebrates:There are 5 classes of vertebrates:

MammalsMammals ReptilesReptiles AmphibiansAmphibians FishFish BirdsBirds

FishFish Fish are cold blooded vertebrates, meaning they cannot Fish are cold blooded vertebrates, meaning they cannot

control their body temperature internally but depend alot control their body temperature internally but depend alot on the environment to get warmer or cooler.on the environment to get warmer or cooler.

Their body is streamlined to swim faster. It is covered Their body is streamlined to swim faster. It is covered with scales. Their scales are continuously being with scales. Their scales are continuously being replaced. replaced.

Their fins help them move and they are made up of skin Their fins help them move and they are made up of skin held by bony spines.held by bony spines.

They breathe through gills that are supplied with blood They breathe through gills that are supplied with blood where oxygen comes in and carbon dioxide goes out. where oxygen comes in and carbon dioxide goes out.

Nostrils are used for smelling.Nostrils are used for smelling.

Fish are divided into 2 groupsFish are divided into 2 groups

Bony FishBony Fish These fish have a skeleton made of bone These fish have a skeleton made of bone

and they breath through an operculum. They and they breath through an operculum. They have a swimming bladder which helps them have a swimming bladder which helps them float even when they are not swimming. float even when they are not swimming. Their reproduction is external. Their reproduction is external.

Cartillagenous FishCartillagenous Fish

These fish have a skeleton made of These fish have a skeleton made of cartilage. They breathe through 5 gills cartilage. They breathe through 5 gills slits. These fish do not have a swimming slits. These fish do not have a swimming bladder so they sink to the bottom if they bladder so they sink to the bottom if they stop swimming. Their reproduction is stop swimming. Their reproduction is internal. internal.

MammalsMammals

Mammals are warm blooded with four limbs and five Mammals are warm blooded with four limbs and five digits. digits.

The brain is better developed in mammals.The brain is better developed in mammals. They have sweat glands and a four chambered heart in They have sweat glands and a four chambered heart in

between the lungs.between the lungs. They have lungs which are important for breathing.They have lungs which are important for breathing. Mammals have a thick layer of fat to keep them warm and Mammals have a thick layer of fat to keep them warm and

their bodies are covered with hair or fur. their bodies are covered with hair or fur. The tail is used for balance.The tail is used for balance. Fertilization is internal and the young developed in the Fertilization is internal and the young developed in the

female’ s womb. The parents take great care of their female’ s womb. The parents take great care of their young. They suckle their young on the milk from the young. They suckle their young on the milk from the mammary glands.mammary glands.

ReptilesReptiles

These are cold blooded vertebrates but can control These are cold blooded vertebrates but can control their temperature a bit by staying in the sun to get their temperature a bit by staying in the sun to get warm. warm.

They have tough skin and their body is covered in They have tough skin and their body is covered in scales to resist water loss. scales to resist water loss.

They have well developed lungs and do not breathe They have well developed lungs and do not breathe through the skin. through the skin.

Fertilization occurs internal. Some reptiles keep the Fertilization occurs internal. Some reptiles keep the eggs inside them. Others lay legs and keep them well eggs inside them. Others lay legs and keep them well hidden. The eggs have a very tough shell that hidden. The eggs have a very tough shell that prevents water loss.prevents water loss.

AmphibiansAmphibians

These are cold blooded vertebrates and live in damp These are cold blooded vertebrates and live in damp environments. environments.

Their skin is damp because gas exchange takes Their skin is damp because gas exchange takes place through it. The adults also have lungs. They place through it. The adults also have lungs. They use their lungs for breathing. use their lungs for breathing.

They have four limbs and their hind limbs are They have four limbs and their hind limbs are webbed and help in swimming. webbed and help in swimming.

Their eyes bulge out to give them an all round vision. Their eyes bulge out to give them an all round vision. They lay soft eggs in water. Reproduction is external.They lay soft eggs in water. Reproduction is external. They are carnivores.They are carnivores.

BirdsBirds

Birds are warm blooded vertebrates. Birds are warm blooded vertebrates. They have nostrils for breathing.They have nostrils for breathing. They are covered with feathers which are used for They are covered with feathers which are used for

flight and to keep warm. flight and to keep warm. Birds have four limbs: the front limbs are the wings Birds have four limbs: the front limbs are the wings

and the hind limbs are the legs and are covered in and the hind limbs are the legs and are covered in scales.scales.

The upper and lower jaw are developed into a beak. The upper and lower jaw are developed into a beak. They have an ear drum but no external ear.They have an ear drum but no external ear. Fertilization is internal and they lay eggs with hard Fertilization is internal and they lay eggs with hard

shell. shell.

Made byMade by

Audrienne ChetcutiAudrienne Chetcuti