Skip to main content

Notes for Class 11 Biology- Digestion and Absorption – The Process of Egestion

Notes for Class 11 Biology-  Digestion and Absorption – The Process of Egestion

Mechanism of Egestion:
Peristalsis (muscular contractions and relaxations that take place in the digestive tract), gradually pushes the indigestible materials of the small intestine into the large intestine or colon. Normally 1500 ml of chyme passes into the large intestine per day. The colon absorbs most of the water. It also absorbs electrolytes, including sodium and chloride from the chyme.
The epithelial cells of the colon also excrete certain salts such as iron and calcium from the blood. Escherichia coli(bacterium) live in the colon which feeds on the undigested matter. This bacterium, in turn, produces vitamin B12 (cobalamin), vitamin K, vitamin В1 (thiamine) and vitamin B2 (riboflavin) which are absorbed by the wall of the colon. Consequently, the chime converts into semisolid faeces.
The faecal matter is stored in the rectum, the lower part of the large intestine, as the pellets of faeces enter the rectum; distension of rectal wall induces the feeling of defecation due to a “defecation reflex”. This reflex initiates peristalsis in the last part of the colon (sigmoid colon) and the rectum, forcing the faeces towards the anus. As the faeces reach anus, involuntary relaxation of the internal anal sphincter and voluntary relaxation of external anal sphincter cause defecation. Defecation is the final act of digestion, by which organisms eliminate solid, semisolid, or liquid waste material from the digestive tract via the anus.
Read more articles of Class 11 Biology notes, click our Science section
Labels:

Comments

Post a Comment

Thank you we will contact ASAP.

Popular posts from this blog

Why is Hindi Day celebrated on 14 September?

Why is Hindi Day celebrated on 14 September? After independence, the Government of India set a goal to give an ideal form to the mother tongue of the country and set a target for grammar and orthography using the Devanagari script to bring standardization in writing. Subsequently, on September 14, 1949, the Constituent Assembly decided by a vote that Hindi would be the official language of India. To propagate the importance of this decision and to spread Hindi in every region, India is celebrating Hindi Day every year from 1953 to 14 September, at the request of Rashtrabhasha Prachar Samiti, Wardha. Apart from this, 14 September is also the birthday of Rajendra Singh, who worked tirelessly to make Hindi the official language of India. Hindi Day is observed every year on 14 September to mark the importance of the Hindi language in the country. The Hindi language is one of the oldest languages, which derives most of its academic vocabulary from the Sanskrit language written in the Deva
Post a Comment
Read more

Magnetic and non-magnetic material Class 6 Science

Magnetic and non-magnetic material  Class 6 Science A magnet is a substance that is drawn to certain magnetic materials like iron, cobalt, and nickel. Magnets have the ability to draw iron to them. Natural magnets are rocks that naturally draw iron. Non-magnetic materials include things like wood, rubber, coins, feathers, leather, etc. that are not drawn to iron. Magnet characteristics It pulls magnetic materials, such as iron. The magnet's two ends are referred to as its poles. The magnet's diametrically opposed poles are drawn together. Heating, hammering, or dropping causes it to lose its characteristics. On the basis of properties types of Magnets Temporary magnets are those magnets that are magnetic for only a little duration. Typically, iron, cobalt, or nickel are used to make them. When they are close to the powerful magnet, they act like a magnet. When they are yanked away from the powerful magnet, they stop being magnetic. Permanent magnets are magnets that have magne
Post a Comment
Read more