Life process chapter 6 class 10

 

Respiration in plants

The plants get energy by the process of Respiration. During Respiration the plants exchange oxygen and carbon dioxide. so, oxygen and carbon dioxide are called respiratory gases.

Respiration differs from that of animals.

• All plant parts perform Respiration individually

While animals respire as a unit. 

• The transport of gases in plants from one part to another is very little as compared to animals.

• The rate of Respiration in plants is much slower as compared to animals 

Exchange of gases in roots 

The roots of a plant take the oxygen needed for Respiration from the air present in between the soil particles by the process of diffusion. The root hairs are the extensions of the epidermal cells. Oxygen diffuses into root hairs and passes into other cells of the root cells move out into the soil by the process of diffusion.

Exchange of gases in stems 

The oxygen from air diffuses into stem of a herbaceous plant through stomata and reaches all the cells for Respiration. The carbon dioxide gas produced during Respiration diffuses out into air through the same stomata.

Exchange of gases in leaves

The exchange of gases in leaves occurs through stomata present on their surfaces. Stomata consists of a stomatal pore surrounded by kidney-shaped or dumb bell shaped guard cells l. Guard cells regulate the opening and closing of stomata depending upon the requirements of the plants. 

The process of Respiration takes place at day time as well as at night but photosynthesis takes place only during day time.

Respiration in Animals

Animals also require oxygen for Respiration and they also need to get rid of carbon dioxide produced during the process. They continuously exchange gases takes place at particular surface called respiratory surfaces.

Some characteristics of a good respiratory surface:

• It should have a large surface area to get enough oxygen. 

• It should be thin for easy diffusion of gases.

• It should be moist to counterbalance drying due to movement of gases.

• It should be permeable to respiratory gases.

• It should be richly supplied with blood capillaries so that the respiratory gases can diffuse easily and rapidly.

Excahnge of gases in Animals

•Lower animals like Amoeba, paramecium, spirogyra, Hydra etc. 

• Animals having moist skin like earthworm, leech, frog, etc

 Exchange gases through skin. 

• Aquatic animals like fish, prawn, tadpole, snail, etc. 

Respiration in humans 

Human respiratory system

Human Respiratory system begins with two external nostrils, through which air is drawn into nasal cavity. The nasal cavity is separated from mouth cavity by a hard, bony palate so that we can breathe in Air even when we are eating food. 

The trachea is covered by a flap of soft cartilage called epiglottis. Epiglottis covers the glottis while swallowing. This prevents the entry of food and water into the trachea.

The trachea is provided with incomplete cartilaginous rings. These rings prevent trachea from collapsing when no air is present in it. The upper end of trachea has a voice box called larynx. 

The trachea runs down the neck and divides into two similar tubes called bronchi at the lower end the two bronchi are connected to the two lungs.

Lungs are spongy, highly elastic bag like structures. They are roughly cone - shaped. The lungs are covered by two thin membranes called pleura. 

Each bronchus divides in the lungs to form a large number of smaller tubes called bronchioles. The air - sacs at the end of the smallest bronchioles are called alveoli. 

The walls of the alveoli contains an extensive network of blood vessels. In the alveoli, the gaseous exchange takes place. 

The oxygen is taken into the body and carbon dioxide is eliminated. 

Below the lungs, the diaphragm is present in the form of sheet.  

It helps in breathing in and breathing out in association with the chest muscles.