SENSORY ORGANS

We have five sensory organs in our body. Their are;

1. Eyes
2. Nose
3. Ears
4. Tongue
5. Skin

The changes detected in the surrounding are called stimuli. For example, eyes detect light from lamp. Therefore, light is referred to as stimuli. Each sensory organ has special structures that are very sensitive to stimuli. These structures are called receptors.

PATHWAY OF AN IMPULSES FROM THE SENSORY ORGAN TO THE BRAIN

Sensory organs > Receptors> Nerves > Brain > Nerves > Muscle > Response

HUMAN CIRCULATORY SYSTEM

Heart is muscular blood pumping organ. It is located at the centre near the chest. It is the size of our clenched fist. Human’s heart is enclosed in a sack called pericardium. The pericardium is made up of thin layer protecting the heart.

The heart is made up of four chambers. The chambers at the upper part (right and left side) of the heart are called auricles. Meanwhile the two chambers at the lower part are called ventricles.

The right and left side of the heart are separated by septum. The function of the septum is to prevent the mixing of oxgenated blood (rich in oxygen) and deoxygenated blood ( poor in oxygen).

PATHWAY OF BLOOD

1. Deoxygenated blood enters right atrium through superior and interior vena cava.


2. Blood from the right atrium then through right ventricle.


3. The deoxygenated blood flows into pulmonary artery and then brought to the lungs.


4. From the lungs, oxygenated blood flows into pulmonary vein and into left atrium.


5. From the left atrium the oxygenated blood then moves into left ventricle.


6. Then passes into the aorta to go to the rest of the body.

REMEDY FOR a CLEAR SKIN

Tired of acne!
Trying all sort of ways for a beautiful skin but it never seem to happen!
Expensive skin care products?
Then try this..

Grandma's recipe

Ingredients
1. Powdered green beans
2. Egg white
3. Lime (optional) *

Methods
1. Take 2-3 tablespoon of powdered green beans and put it in a bowl.
2. Mix one egg white with the powdered green beans.
3. Mix it well. *(2 - 5 drops of lime juice)
4. Wash your face with a cleanser and dry your face with a towel.
5. You can start applying the green bean mixture to your face as a mask
6. Wash your face with cold water after 15 minutes.
7. You will be able to notice the changes.
8. Try this remedy twice a week.

IMPORTANCE OF A HEALTHY RESPIRATORY SYSTEM

We breathe air that contain substances that are dangerous to our respiratory system. There are so many times of substances which are harmful to our system such as:

• Exhaust gases
• Oxides of nitrogen
• Haze
• Cigarette smoke
• Carbon monoxide
• Sulphur dioxide

Several diseases related to the respiratory system are;

• Lung cancer
• Emphysema
• Bronchitis
• Asthma
• Heart and vascular diseases

Do you know that smoking is one of the major causes of respiratory diseases ?

Cigarette smoke cause heart diseases, lung cancer, bronchitis and also worsen respiratory problems such as asthma and pneumonia. Cigarette smoke contains more than 4000 chemical substances. It also contain poisonous chemicals such as:

• Tar
• Nicotine
• Carbon monoxide

Tar

A carcinogen substance that causes cancer. This chemical substance covers the cillia and affects lung, difficulties in breathing and coughing.

Nicotine

Nicotine in tobacco causes addition to smoking and raises blood pressure. Apart from that, it increases cholesterol level in the body and also affects blood vessels and nervous system.

Carbon Monoxide

This is a poisonous gas. It combines with haemoglobin in the red blood cells alot quicker than oxygen. Therefore , transportation of deoxygenated blood in bloodstream is affected

Therefore, smokers it is time you start kicking this habit before it is to late. Get help!
Everybody should try to stop or decrease the use of products that contain harmful substances.

TRANSPORT OF OXYGEN IN THE HUMAN BODY

Oxygen is inhaled from the surrounding

The inhaled air which is rich in oxygen is found inside the alveolus

The oxygen dissolves in the moist lining of the alveolus and then diffuses into the blood cappilaries

The blood inside the cappilaries contains red blood cells which are rich in a substance called haemoglobin.

The oxygen combines with the haemoglobin to form oxyhaemoglobin.

The blood rich in oxygen is then carried away from the lungs to the heart.

When the heart pumps, oxygenated blood is distributed to all parts of the body.

When blood reaches the cells or tissues with insufficient amout of oxygen, the oxyhaemoglobin is broken down and oxygen is released.

Oxygen then diffuses into the cells and simultaneously carbon dioxide from the cell diffuses into the capillaries to be carried back into the lungs.

CHARACTERISTICS OF ALVEOLI WHICH MAKES DIFFUSION OF GASES EASIER

• Consists of million of alveoli
• Alveolus has one cell wall thick
• Moist cell wall
• Large surface area
  

BREATHING MECHANISM

Our body takes in oxygen and gives off carbon dioxide and water vapour during respiration process.

INHALATION

During inhalation

1. The ribcage moves upwards and outwards.
2. The diaphragm flatten and contracts.
3. Air from outside enters into the lungs.
4. The volume in thoracic cavity increases.
5. The air pressure in thoracic cavity decreases.

EXHALATION

During exhalation:

1. The ribcage moves downwards and inwards.
2. The diaphragm flatten and curves upwards.
3. The air pressure in te thoracic increases.
4. The volume in the thoracic cavity decreases.
5. The air is forced out of the lungs.
   
   

HUMAN RESPIRATORY SYSTEM

HUMAN RESPIRATORY SYSTEM

Human respiratory system is the system in the body which help us to breathe.
The human respiratory tract consists of:

The nasal cavity

Hollow space where air passes through

Bronchus

Main branches of the trachea

Bronchiole

Extension tubes of bronchus

Diaphragm

Sheets of muscles

Trachea

Tube supported by ring and cartilage

Ribs

Bones that form rib cage to protect lungs

Intercostal muscles

Muscles fouund between the ribs

Lung

Rich with blood cappilaries and alveoli

AIR PASSAGE INTO THE LUNGS THROUGH THE FOLLOWING PARTS :

Nose > Trachea > Bronchus > Bronchiole > Alveolus