Selasa, Mac 15, 2011

Nota Ringkas: Science Form 3: Chapter 1 : Respiration (Part 2)

FOKUS SPM: MAC

RESPIRATION ( PART 2 )

·         Pathway taken by air during inhalation:       
        Nostril ---> Nasal cavity--> Trachea--->Bronchus---->Bronchiole--->Alveolus

·         Pathway taken by air during exhalation:
      

Alveolus

 ---> 
Bronchiole
--> 
Bronchus
--->
Trachea
---->
Nasal cavity
--->

Nostril


Transport of oxygen in human body
v  Exchange of gases  takes place in the alveoli by diffusion.

v  Characteristics of alveoli that help exchange of gases to take place effectively:
 


Ø  Has one-cell thick wall ( very thin)
Ø  Inside surface has thin film of moisture
Ø  Huge number of alveoli
Ø  Network of blood capillaries surround each alveoli


   TRANSPORTATION OF OXYGEN
  1. Oxygen dissolves in the moist lining of the alveolus
  2. Then, oxygen diffuses into the blood capillaries
  3. Blood inside the capillaries contains red blood cells that are rich with haemoglobin
  4. Oxygen combines with haemoglobin to form oxyhaemoglobin
  5. Oxyhaemoglobin is transported in the blood to heart and then pump to all parts of the body
  6. Oxyhaemoglobin breaks down, oxygen diffuses into the cells, at the same time carbon dioxide diffuses  into the blood 
EFFECTS OF OTHER AIR POLLUTANTS
CHEMICAL SUBSTANCE
SOURCES
DAMAGING EFFECTS
Carbon monoxide
Car exhaust
Reduces amount of oxygen in the food
Sulphur dioxide
Industry, vehicles
Damages lung tissues
Hydrocarbons
Industry, vehicles
Cause cancer
Nitrogen oxide
Industry, vehicles
Interacts with hydrocarbons to form haze
Haze
Industry, vehicles, open burning
Causes breathing difficulties

Nota Ringkas: Science Form 3: Chapter 1 : Respiration

FOKUS SPM : FEBRUARI

RESPIRATION
·         Definition : a process in breaking of glucose ( food ) with the presence of oxygen to produce energy / oxidation of food process.
·         During respiration, humans obtain oxygen which at the same time remove carbon dioxide and water vapour through the respiratory system.
·         Oxygen is obtains through breathing.


HUMAN BREATHING MECHANISM

  
STRUCTURE
FUNCTION
NASAL CAVITY
Air entering from the nostrils is led to the nasal cavity

TRACHEA
An airway through which respiratory air travels. The rings of cartilage within its walls keep the trachea open.

BRONCHUS
Passage divided from trachea
 [ singular = bronchus, plural = bronchi ]

BRONCHIOLE
A narrow tube inside the lungs that branches off the main air passages bronchi

ALVEOLUS
Place where exchange of gases take place

RIB CAGE
To protect the lungs and help in breathing mechanism

LUNG
A respiratory organ

INTERCOSTAL MUSCLES
Antagonistic muscles that help the movement of rib cage for breathing mechanism

DIAPHRAGM
A  muscular membrane that separates the thoracic cavity and the abdominal cavity


BREATHING MECHANISM

INHALATION

= a process when air is force into the lungs
EXHALATION

= a process when air is force out of the lungs

External intercostal muscle contract, while internal intercostal muscle relax
Intercostal muscle
External intercostal muscle relax, while internal intercostal muscle contract
Moves upwards and outwards
Rib cage

Move downwards and inwards
Contract and become flat
Diaphragm

Relax and become “dome” shape
Volume increase
Thoracic cavity

Volume decrease
Decrease
Air pressure in the lung

Increase
Air from outside enters the lungs
Air movement

Air is force out of the lungs
**** You just need to memorize 1 process because the other part is just the OPPOSITE

Nota Ringkas: Science Form 3


Mulai Februari 2011, saya mendapat peluang untuk membantu calon-calon PMR dengan menulis ruangan Science PMR dalam majalah Fokus SPM. Dalam ruangan ini saya sertakan nota-nota ringkas serta contoh-contoh soalan PMR bagi topik-topik Sains Tingkatan 3. Saya akan upload nota-nota ringkas tersebut di dalam blog ini, tetapi kalau inginkan yang terkini dan lebih lengkap berserta soalan perlulah dapatkan majalah Fokus SPM setiap bulan yer... =)