It is not Rocket Science: NATURAL SCIENCE 6

Welcome!!
On this page you are going to find many resources of Natural Science.

Let´s start with the nervous system.

UNIT 1. INTERACTION

What is the nervous system?

It sends messages from the brain to different parts of the body, which allows us to respond to the stimuli from our senses. It also controls our internal system such as the digestive or respiratory systems.

The nervous system.

Which are the parts of the nervous system?

The nervous system is divided into the central nervous system (brain and spinal cord) and the peripheral nervous system (sensory neurons, brain and motor neurons).

VIDEOS:

The nervous system

How your brain and nervous system work

EXERCISES: Try the following quiz about the nervous system:

Brain quiz

What is the function of our senses?

Our senses help us interact with the world around us. They detect information which is then transmitted to the brain, where it is deciphered. The brain then reacts to the stimulus.

VIDEOS: Eye anatomy and how we see
Ear anatomy and how we hear
Our tongue and how we taste
How your nose works
Our skin and the sense of touch
Optical illusions: Can you believe what your eyes are telling you?

How many senses do we have?

We always learn there are five senses (sight, smell, touch, taste and hearing) but the last investigations show that we have more than 10!

Humans have a lot more than five senses
How many senses do we have?

Human sense organs

How do we move?

We move thanks to our skeleton, joints and muscles.

GAMES:

- Learn the skeletal system with the following game. Have fun!

LEARN THE SKELETAL SYSTEM

- See how your body moves with this game.

How does your body move?

- Try this joints game and see what happens!

The joints explorer

- Enjoy this muscles game!

The muscles game

VIDEOS:

   - See how your muscles work:

  How your muscles work

- Test how quickly your nerves and brain send messages.

Fast messages

UNIT 2. NUTRITION

Let´s learn how the human body works.

A. THE CIRCULATORY SYSTEM

The circulatory system transports the energy to different parts of the body, and delivers blood to the body´s tissues through blood vessels.

Blood is made up of:

1. Plasma: yellowish liquid (which is 90% water) that carries nutrients and waste products.

2. Red blood cells: give blood its colour, and carry oxygen and carbon dioxide.

3. White blood cells: fight infection, and surround and absorb germs which enter the body.

4. Platelets: cells fragments that join together and help stop bleeding.

Blood is transported through three types of blood vessels:

Arteries: they carry blood from the heart to the rest of the body which contains oxygen.

2. Veins: they carry blood back to the heart which contains carbon dioxide.

3. Capillaries: they are tiny blood vessels which connect the arteries and the veins. They have very thin walls for gases and nutrients to pass easily through them to the cells.

The heart is a hollow muscle which pumps blood through the body. It usually beats between 60 and 100 times per minute. It is made up of four chambers inside a thick muscular wall. The top and bottom chambers are separated by valves (to prevent blood from flowing backwards).

- Top two chambers: RIGHT and LEFT ATRIA (they receive blood coming into the heart).

- Bottom two chambers: RIGHT and LEFT VENTRICLES.

In circulation blood floods around the body, and it does it in a double circuit.

a) During pulmonary circulation, blood flows from the heart to the lungs and back to the heart again.

b) During systematic circulation, the blood flows from the heart to the rest of the body.

In circulation:

The deoxygenated blood passes from the right atrium of the heart to the right ventricle. Then it leaves the heart via the pulmonary artery and travels to the lungs.
In the lungs, blood releases carbon dioxide and collects oxygen. Blood returns to the heart through the pulmonary veins.
The oxygenated blood flows into the left atrium and then into the left ventricle. From there the blood is pumped through the aorta (the biggest artery in the body) to the rest of the body.
The aorta carries the blood into small arteries and then to the capillaries. There, the blood releases oxygen and nutrients into the cells and collects carbon dioxide and other waste substances.
The deoxygenated blood passes from the capillaries to the small veins and then to the superior vena cava and the inferior vena cava (the largest veins in the body). These veins carry the blood to the heart and the process begins again.

VIDEOS:

Human circulatory system.

Blood circulation.

How your heart works.

How the heart actually pumps blood.

How the heart works 3D.

The heart and circulatory system. How they work.

GAMES:

B. THE DIGESTIVE SYSTEM

The digestive system is a group of organs that process the energy (nutrients) we receive from food and drink.

These are the five steps of digestion:

THE NOSE AND MOUTH: our sense of smell triggers the production of saliva in our mouth. This helps the teeth to crush food as we chew it.
THE OESOPHAGUS: the tongue shapes the food into a ball (bolus). When we shallow, the bolus passes into the oesophagus (stretchy tube that links the back of the throat with the stomach). The epiglottis (a special flat part at the back of the tongue) prevents food from going down the windpipe and into the lungs. The muscles in the wall of the oesophagus squeeze the food down the stomach.
THE STOMACH: it breaks down food by using its strong muscular walls and excreting gastric juices which mix with the bolus and kill dangerous bacteria.
THE SMALL INTESTINE: when the food is dissolved into a liquid, it passes into the small intestine. Here it mixes with bile (produced by the liver) and pancreatic juices (produced by the pancreas). The food mixture is broken down into proteins, carbohydrates, vitamins, minerals and fats. These nutrients pass through the walls of the small intestine and are absorbed into the blood.
THE LARGE INTESTINE: the waste that our body does not need passes to the large intestine, where water from this waste is absorved into the blood. The solid waste leaves our body through the anus.

VIDEOS:

How the digestive system works.

Digestive system.

Digestive system. The Dr. Binocs show.

GAMES:

C. THE EXCRETORY SYSTEM

The excretory system eliminates waste products from our body.

It is divided into the urinary system and sweating.

1. The urinary system:

It is the principle way in which the body gets rid of waste from blood. It produces about 1.4 litres of urine a day.

The renal arteries carry blood to the kidneys.
The kidneys eliminate water and waste products from the blood, which forms the urine.
Urine leaves the kidneys and passes down through the ureters to the bladder.
When the bladder is about half-full, it sends signals to the brain that it needs to be emptied.
The bladder is emptied by the urethra.

2. Sweating:

Our body also eliminates waste products through the skin. When we get hot, sweat glands in our skin excrete sweat (mixture of water and minerals) that leaves our body through pores. They are activated to cool down the body.

VIDEOS:

How the urinary system works.

Excretory system parts and functions.

Urine formation.

GAMES:

D. THE RESPIRATORY SYSTEM

The respiratory system extracts oxygen from the atmosphere and uses it to convert the nutrients into energy.
The cells produce carbon dioxide (CO2) that has to be expelled from the body. To obtain oxygen and get rid of carbon dioxide we use the respiratory system.

During respiration:

When we breathe, air enters through the nose and mouth, it passes down the pharynx and then to the trachea (or windpipe). The trachea divides into two tubes called bronchi.
Each bronchi subdivides into smaller and smaller bronchi. The smallest are bronchioles. At the end of each bronchiole is a cluster of tiny air sacks called alveoli (which are covered with a network of capillaries) where the gas exchange takes place. Oxygen passes from the alveoli to the capillaries and into the blood.
At the same time, carbon dioxide leaves the blood and enters the alveoli. The air carrying carbon dioxide goes through the bronchioles to the bronchi and the trachea and finally out through the mouth and nose.

INHALATION: When we breathe, our diaphragm contracts and flattens to allow the lungs to inflate. The ribs expand and move up to make more room.

EXHALATION: When we breathe out, the ribs relax and move back in. The diaphragm relaxes and moves up, pushing the carbon dioxide out of the lungs and back to the trachea, out of the nose and mouth.

VIDEOS: