Download respiratory system

Structure of the respiratory system:
Lungs, nose, and mouth
Pharynx, larynx (voice box), trachea (tube connecting our nose, mouth, pharynx to bronchi)
Alveoli each alveoli has a capillary bed surrounding it. The alveoli are able to stretch.
Negative pressure (drag or pull something) intercostal muscles. When we create space inside a
object the air rushes in and this creates negative pressure
Diaphragm muscle works on the addendum.
There must always be some air in the lungs for emergency.
Tidal volume- the amount of air that we normally breathe out.
Residual- emergency, back up
Tidal volume + residual= maximum amount of air we breathe
Do boys or girls have more lung capacity? Bigger or not
The nostrils: Nostrils are involved in air intake, i.e. they bring air into the nose,
where air is warmed and humidified. The tiny hairs called cilia filters out dust and
other particles present in the air and protects the nasal passage and other regions of
the respiratory tract.
Trachea: The trachea is also known as windpipe. The trachea filters the air we
inhale and branches into the bronchi.
Bronchi: The bronchi are the two air tubes that branch off of from the trachea and
carry atmospheric air directly into the lungs.
Lungs: The main organ of the respiratory system is lungs. Lungs are the site in body
where oxygen is taken into and carbon dioxide is expelled out. The red blood cells
present in the blood picks up the oxygen in the lungs and carry and distribute the
oxygen to all body cells that need it. The red blood cells donate the oxygen to the
cells and picks up the carbon dioxide produced by the cells.
Alveolus: Alveolus is the tiny sac like structure present in the lungs which the
gaseous exchange takes place.
Diaphragm: Breathing begins with a dome-shaped muscle located at the bottom of
the lungs which is known as diaphragm. When we breathe in the diaphragm
contracts and flatten out and pull downward. Due to this movement the space in the
lungs increases and pulls air into the lungs. When we breathe out, the diaphragm
expands and reduces the amount of space for the lungs and forces air out.
Diseases associated with respiratory system are asthma, bronchiolitis, chronic obstructive
pulmonary disease (COPD), cystic fibrosis, pneumonia, etc.
Parts of the Upper Respiratory Tract

Mouth, nose & nasal cavity: The function of this part of the system is to warm, filter and moisten the
incoming air

Pharynx: Here the throat divides into the trachea (wind pipe) and oesophagus (food pipe). There is also
a small flap of cartilage called the epiglottis which prevents food from entering the trachea

Larynx: This is also known as the voice box as it is where sound is generated. It also helps protect the
trachea by producing a strong cough reflex if any solid objects pass the epiglottis.
Parts of the Lower Respiratory Tract

Trachea: Also known as the windpipe this is the tube which carries air from the throat into the lungs. It
ranges from 20-25mm in diameter and 10-16cm in length. The inner membrane of the trachea is
covered in tiny hairs called cilia, which catch particles of dust which we can then remove through
coughing. The trachea is surrounded by 15-20 C-shaped rings of cartilage at the front and side which
help protect the trachea and keep it open. They are not complete circles due to the position of the
oesophagus immediately behind the trachea and the need for the trachea to partially collapse to allow
the expansion of the oesophagus when swallowing large pieces of food.

Bronchi: The trachea divides into two tubes called bronchi, one entering the left and one entering the
right lung. The left bronchi is narrower, longer and more horizontal than the right. Irregular rings of
cartilage surround the bronchi, whose walls also consist of smooth muscle. Once inside the lung the
bronchi split several ways, forming tertiary bronchi.

Bronchioles: Tertiary bronchi continue to divide and become bronchioles, very narrow tubes, less than
1 millimeter in diameter. There is no cartilage within the bronchioles and they lead to alveolar sacs.

Alveoli: Individual hollow cavities contained within alveolar sacs (or ducts). Alveoli have very thin walls
which permit the exchange of gases Oxygen and Carbon Dioxide. They are surrounded by a network
of capillaries, into which the inspired gases pass. There are approximately 3 million alveoli within an
average adult lung.

Diaphragm: The diaphragm is a broad band of muscle which sits underneath the lungs, attaching to the
lower ribs, sternum and lumbar spine and forming the base of the thoracic cavity.