RESPIRATION

Science Form 3

Prepared by:En. Muhd Fazli b. Dollah

Science TeacherSBP Integrasi Gopeng, Perak.

Conceptual Map

RESPIRATION

Human Respiratory

System

Structure of Human

Respiratory System

Breathing mechanism

InhalationExhalation

Transportation of Oxygen

Importance of Healthy Respiratory System

Harmful substances

Effects of pollutants

Diseases of respiratory

system

Ways to improve air

quality

LEARNING OUTCOMES

To identify the structure of the human respiratory system;

To identify the structure of the lung;To describe the process of inhalation

& exhalation;To relate the changes of air pressure

in the thoracic cavity to inhalation & exhalation;

To describe the breathing mechanism.

The human respiratory system…..Provides an area for

◦Gas exchange (blood environment) Taking O2 Eliminate CO2

Breathing – external respiration◦Taking in & letting out of air.

Structure of the Human Respiratory System

Structure of the Human Respiratory System

Nasal cavity

Trachea

BronchusBronchiole

Structure of the Human Respiratory System

Nasal cavity – dust trapped by the hairs (cilia).

Trachea – C-shaped rings of cartilage give support & prevent from collapsing.

Bronchus (plural – bronchi)

Bronchioles – smaller tubes of bronchus.

Alveolus (plural – alveoli) – millions of tiny air sacs

Lungs = alveoli + bronchioles + blood capillaries

Thoracic cavity – a space where the lungs are located

Ribcage (ribs + intercostal muscles) – protect the lungs.

Diaphragm – separates the thoracic cavity from the abdomen.

Structure of the Human Respiratory System

Adaptation of the alveoli for efficient gas exchange

ALVEOLI

Large Surface Area

Moist Inner Surface

Surrounded by Numerous Blood

Capillaries

Very Thin Walls

Structure of alveolus

Mechanism of Human Breathing

Comparison between inhalation & exhalation

INHALATION EXHALATION

Diaphragm muscle contract, flatten out

Diaphragm muscle relax, arches upwards.

Intercostal muscle contract Intercostal muscle relax

Ribcage moves upwards, outwards

Ribcage moves downwards, inwards

Volume of thoracic cavity increases

Volume of thoracic cavity decreases

Air pressure surrounding the lungs decreases

Air pressure surrounding the lungs increases

Air flows into the lungs Air flows out of the lungs

Mechanism of Human Breathing

Mastery 1.1Do Formative Exercise 1.1 page 5

(textbook).