Explain exchange of gases on humans.
Gaseous exchange in humans occurs through diffusion. In the lungs, oxygen from alveolar air diffuses into blood vessels surrounding the capillaries, and blood is given out into the lungs. This oxygen is carried to the tissues and it diffuses from the blood vessels into the tissues. The carbon dioxide produced in the tissues diffuses into the blood vessels supplying the tissues, from where it is carried to the lungs.
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The diagram attached is very helpful.
RESPIRATION
The food material taken in during the process of nutrition is used in cells to generate energy for various life processes.
Respiration is the process of breaking down of organic compounds (particularly glucose) to obtain energy.
Aerobic respiration, During this process breakdown of glucose occurs in the presence of oxygen.
Anaerobic respiration, During this process breakdown of glucose occurs in the absence of oxygen.
Breaking down of glucose can occur by different pathways;
In presence of oxygen: -
Breaking down of glucose into pyruvate (in cytoplasm) takes place in Mitochondria of a cell and End products are CO₂ , H₂O and energy.
Glycolysis is the breakdown of glucose in first step. Which common to both types of respiration. It occurs in cytoplasm. In glycolysis process, one molecule of glucose (6-carbon molecule) is broken down into two molecules of pyruvic acid or pyruvate (3-carbon molecule) with four molecules of ATP.
In insufficient presence of oxygen: -
In muscle cells, the cells undergoes anaerobic respiration due to insufficient presence of oxygen & forming Lactic acid and lot amount of energy.
In absence of Oxygen: -
In absence of Oxygen, glucose breakdown into pyruvate in cytoplasm only & final product are Ethanol, and small amount of energy
The energy obtained during cellular respiration is immediately used to synthesise a molecule called ATP which is used to fuel all other activities in the cell.
The respiratory system
The respiratory system, also known as pulmonary system, consists of several organs that function as a whole to oxygenate the body through the process of respiration (breathing).
Functions of The respiratory system :
- Breathing – movement of air.
- Sound Production.
- Gas Exchange – oxygen and carbon dioxide.
- Olfactory Assistance – sense of smell.
- Protection – from dust and microbes entering body through cilia, mucus production, and coughing.
Human respiratory system parts:
- Nose
- Mouth
- Throat (pharynx)
- Voice box (larynx)
- Windpipe (trachea)
- Large airways (bronchi)
- Small airways (bronchioles)
- Lungs.
Pharynx
The nasal cavity and the mouth meet at the throat or pharynx . Which is at the back of the mouth & nose. It is the common part of the digestive system as well as the respiratory system because it carries both food and air.
At the bottom of the pharynx, this pathway divides in two pathways, one for food called the oesophagus which leads to the stomach and the other for air.
Voice box (larynx)
The larynx, is the top part of the air-only pipe.It is also called voice box. It is short tube contains a pair of vocal cords, which vibrate to make sounds.
The epiglottis a small flap like tissue, covers the air-only passage when we swallow,preventing food and liquid from going into the lungs.
The trachea, also called windpipe, is the continuation of the airway below the larynx. Rings of cartilage are present in the throat. These ensure that the air-passage does not collapse. The trachea is also lined with cilia, which sweep fluids and foreign particles out of the airway so that they stay out of the lungs.
At the bottom end, the trachea divides into left and right air tubes known as bronchi, which connect to the lungs. Inside the lungs, Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon-like structures which are called alveoli.
where the exchange of oxygen and carbon dioxide actually takes place. Each person has hundreds of millions of alveoli in their lungs.
The lungs is made up of elastic tissues that allow them to inflate and deflate without losing shape.
The chest cavity, or thorax is the airtight box that houses the bronchial tree, lungs, heart, and other structures. The top and sides of the thorax are formed by the ribs and attached muscles, and the bottom is formed by a large muscle called the diaphragm. The chest walls form a protective cage around the lungs and other contents of the chest cavity.