Summary about Respiratory System at English text, in Biology
(Source: Maharani.2011. Respiratory System. Ponorogo: Junior High School 1 Ponorogo.)
Respiration is sequence of events that result in gas exchange between the body’s cells and the environment. The human respiratory system includes all structures that conduct air in a continuous pathway to and from the lung. Air pathway: nose-pharinx-trachea-bronchi-lung
| Structure | Function |
| Nasal cavity | Filter, warm, and moisten |
| Pharynx (throat) | Connection to larynx |
| Glottis | Permits passage of air |
| Larynx (voice box) | Sound production |
| Trachea | Passage of air to bronchi |
| Bronchi | Passage of air to lung |
| Bronchioles | Passage of air to alveoli |
| Alveoli | Air sac for gas exchange |
I) Nose
Nose cavity= cavum nasalis. Oil gland (sebasea gland) and sweat gland (sudorifera gland). Short hair and thick hair that the function is filtering particle that enter with air. Konka that have many blood capillary is function to worm air that enter.
II) Pharynx
Pharynx as digestive and respiration tract.
III) Larynx
Voice box, connecting pharynx, made of cartilage; contains vocal cords.
IV) Epiglottis
Flap of tissue that covers trachea; ensures food travels down the esophagus.
V) Trachea
Trachea is tube that arrange by smooth muscle and cartilage that the form is C and divide by bronchi. Trachea’s wall arrange by three layer:
1) external layer arrange by brunch tissue.
2) center layer arrange by smooth muscle and cartilage of ring.
3) internal layer arrange by ciliated epithelium tissue. The function ciliated epithelium is holding and removing faces that followed with air in order to don’t enter to lung.
VI) Bronchi
Bronchi is:
Ø Branch of trachea
Ø Enter to lung
Ø Bunch tissue, smooth muscle
Ø Have a cartilage ring
Ø Layer of epithelium tissue.
VII) Bronchioles
Bronchioles is:
Ø Branch of bronchus
Ø Ring of cartilage with ciliated epithelium
Ø Ending with soft bublle
Ø That is alveolus
VIII) Lung
Wrapped by lung’s membrane that is pleura. Located inside of chest cavity, limited by rib and chest muscle, beneath is limited by diaphragm muscle that strong. Diaphragm is partition of chest cavity
IX) Alveoli (air sac)
Provide large surface area for gas exchange one lung equivalent to a tennis court of surface area using alveoli.
Breathing mechanism
A) When breathing will happened:
1) inhalation/ inspiration: entering O2 to lung.
2) Exhalation/ expiration: excretion CO2 and steam to out of body.
B) Inhalation/ inspiration (active process)
Ø Air movement from high pressure to low pressure.
Ø During inhalation, diaphragm pressed down in order to the lung expand.
Ø When the lung is expanding, volume of lung is raising, so that it will make pressure inside of lung going down=> the pressure inside of lung is lower, in order to the air enter to lung.
C) Exhalation/ expiration (passive process)
Ø Diaphragm relaxes
Ø Volume inside of lung and chest cavity small, so the pressure inside of lung raising.
Ø So the air inside of chest cavity that rich of carbon dioxide go out.
Volume udara pernadasan pada orang dewasa:
Ø Udara pernafasan (UP) : 500 ml
Ø Udara komplementer (UK) : 1500 ml
Ø Udara suplementer (US) : 1500 ml
Ø Udara residu (UR) : 1500 ml +
Volume total paru-paru : 5000 ml
*) kapasitas paru-paru: UP+UK+US