THE RESPIRATORY

SYSTEMChapter 5(Biology)

The breathing system is used by the body to get the oxygen needed for respiration. It is also use to get rid of the waste product of respiration, the gas carbon dioxide.Breathing in and breathing out are separate processes in the body:

What is breathing?

Breathing in is also known as inhalation. When you inhale you breathe in air, including oxygen, into your lungs.  Breathing out is also known as exhalation. When you exhale you breathe out the contents of our lungs and getting rid of the waste gas carbon dioxide.

To make energy, your body needs two things:

and

Your cells take in these two chemicals and do a chemical reaction.

This process is called RESPIRATION.

Aerobic respiration: word equation activity

Respiratory system function

■Respiratory systems allow animals to move oxygen (needed for cellular respiration) into body tissues and remove carbon dioxide (waste product of cellular respiration) from cells.

Location of the respiratory system- Head- Neck and- Chest

The Respiratory System

Ribs

Bronchioles

BronchiTrachea

Rib muscles

Lung

DiaphragmAlveoli (“air sacs”)

The respiratory system can be divided into 3 parts:

1) The air passages and tubes

2) The pump3) The

respiratory surface

1) The air passages and tubes

a) The nose b) The trachea

c) Bronchi and

bronchiolesFunction:- Air enters through the

nose.- Hairs in the nose trap

dust particles- Lining of the nose

produces a watery liquid called mucus (makes air moist and traps bacteria)

- Blood vessels beneath the nasal lining warms the air.

- It is about 10 cm long and 1.5 cm wide.

- Made of rings of cartilage.

- Each ring is in the shape of a ‘C’

- The inner lining is made up of mucus secreting cells and ciliated epithelial cells

Function:- Mucus traps dust and

bacteria- Cilia move the mucus

to the top of the trachea where it enters the back of the mouth and is swallowed.

c) Bronchi and bronchioles

■The trachea divides into two smaller pipes called Bronchi (singular: Bronchus)

■The 2 bronchi are also made of hoops of cartilage and have the same lining as the windpipe.

■The bronchi divide up into many smaller tubes called bronchioles (diameter of 1mm).

■The bronchioles divide many times.

■The bronchioles have walls made of muscles, but, do not have hoops of cartilage.

■The wall muscles can make the diameter of the bronchioles narrower or wider.

■Some peoples suffer from asthma.■They suffer from allergy to certain

proteins in food or proteins in dust or animal fur/feathers.

■The presence of these proteins in the air causes the bronchioles to become narrower. This makes breathing very difficult.

■A person suffering from an asthmatic attack can use an inhaler.

■The chemicals in the inhaler makes the muscles relax to widen the bronchioles.

a) The chest wall

b) The diaphragm- Is made by ribs and their

muscles.- Each rib is attached to the

backbone by a joint that allows only as small amount of movement.

- The muscles between the ribs are called the internal and external intercostal muscles.

- The action of these muscles moves the ribs.

- Large sheet of muscle attach to the 10th rib.

- It separates the chest cavity, from the body cavity, which contains the stomach, intestines, liver and kidneys

2) The air pump(The small space between the lungs and the chest wall is called the

pleural cavity)

Breathing movementsBreathing movement

Inspiration Expiration

External intercostal musclesRib action

Diaphragm muscles

Diaphragm action

Change in chest volumeAir

Breathing movementsBreathing movement

Inspiration Expiration

External intercostal muscles

Contract Relax

Rib action Move up Move down

Diaphragm muscles Contract Relax

Diaphragm action Moves down and becomes flatter

Moves up and becomes dome shaped

Change in chest volume

Increases Decreases

Air Moves in Move out

Gaseous exchange (in the respiratory surface)

Use the video to answer the following question.

Q) How does gas exchange take place in the alveoli?