Respiratory System

RESPIRATORY SYSTEM.

Introduction.

The respiratory system includes tubes that remove particles from incoming air

and transport air to and from lungs and the air sacs where gases are exchange.

Respiratory is the entire process of gas exchange between the atmosphere and

body cells.

Respiratory is biological system for all organisms that involve gas

exchange. Body tissues received the oxygen by respiratory system and the rate

of oxygen is increased during exercise.

Organs of the Respiratory System.

The organs of the respiratory system can be divided into two groups. The upper

respiratory tract includes the nose, nasal cavity, and pharynx and the lower

respiratory tract includes the larynx, trachea, bronchial tree and lungs.

ORGANS OF THE RESPIRATORY SYSTEM

THE UPPER RESPIRATORY THE LOWER RESPIRATORY

NOSE

NASAL CAVITY

PHARYNX

LARYNX

BRONCHIAL TREE

LUNGS

NOSE.

Bone and cartilage support nose internally. Its two nostrils are openings

through which air can enter and leave the nasal cavity. Many internal hairs guard

the nostril for preventing entry large particles carried in the air.

NASAL CAVITY

The nasal cavity is a hollow space behind the nose. The nasal septum,

composed of bone and cartilage, divides the nasal cavity into right and left

portions. Nasal conchae are bones that curl out from the lateral walls of the nasal

cavity on each side, dividing the cavity into passageways. Nasal conchae also

support the mucous membrane that line the nasal cavity and help increase its

surface.

The mucous membrane filters, warms, and moistens incoming air. Ciliary action

carries particles trapped in mucus to the pharynx, where they are swallowed.

PHARYNX.

The pharynx or throat is behind the oral cavity, the nasal cavity and the

larynx. It is a passageway for food travelling from the oral cavity to the

esophagus and for air passing between the nasal cavity and the larynx. It also

helps produce the sounds of speech.

Pharynx are consists 3 parts. Those are nasopharynx, oropharynx and

laryngopharynx.

LARYNX.

The larynx is an enlargement in the airway at the top of the trachea and

below the pharynx. It is composed of muscles and cartilages and is lined with

mucous membrane.

The larynx contains the vocal cords, which vibrate from side to side and

produce sounds when air passes between them. Inside the larynx, two pairs of

horizontal vocal folds. The upper folds are called false vocal cords and the lower

folds are called true vocal cords.

The glottis and epiglottis help prevent foods and liquids from entering the

trachea.

TRACHEA.

The trachea is a flexible cylindrical tube about 2.5 cm in diameter and

12.5cm in length. It extends downward anterior to the esophagus and into the

thoracic cavity, where it splits into right and left bronchi.

A ciliated mucous membrane with many goblet cells lines the trachea’s

inner wall. This membrane filters incoming air and moves entrapped particles

upward into the pharynx, where the mucus can be swallowed.

The cartilaginous rings prevent the trachea from collapsing and blocking

the air-way. The soft tissues that complete the rings in the back allow the nearby

esophagus to expand as food moves through it to stomach

BRONCHIAL TREE.

The bronchial tree consists of branched airways leading from the trachea

to the microscopic air sacs in the lungs. Its branches begin with the right and left

primary bronchi, which arise from trachea at the level of fifth thoracic vertebra.

Each primary bronchus divides into secondary bronchi, which in turn branch into

tertiary bronchi and then into finer and finer tubes.

Among the smaller tubes are bronchioles that continue to divide, giving rise to

terminal bronchioles, respiratory bronchioles and finally to very thin tubes called

alveolar ducts. These ducts lead to thin-walled outpouchings called alveolar

sacs. Alveolar sacs lead to smaller microscopic air sacs called alveoli.

The branches of the bronchial tree air passages whose mucous membranes

filter incoming air and distribute the air to alveoli throughout the lungs. The

alveoli provide a large surface area of thin simple squamous epithelial cells

through which gases can easily be exchanged.

LUNGS.

The lungs are soft, spongy, and cone-shaped in the thoracic cavity. The

mediastinum separates the right and left lungs medially and diaphragm and

thoracic cage enclose them.

Visceral pleura firmly attach to each lung surface and folds back to become the

parietal pleura.

A major branch of the bronchial tree supplies each lobe. A lobe also has

connections to blood and lymphatic vessels and lies within connective tissues.

Thus, a lung includes air passages, alveoli, blood vessels, connective tissues,

lymphatic vessels and nerves.