Life Process- Nutrition Blog 5

Lesson 5

Welcome back students!

Let us check our answers of yesterday’s assignment.

Q1) Explain the process of digestion in amoeba (must write in points)and draw figure 6.5  page 98.      (for answer please check page 98, 6.2.3)

Q2) Explain how Paramecium obtains it’s food? (for answer please check page 98, 6.2.3)

Q3) Give one example each of plant parasite, animal parasite, ecto parasite and an endo parasite.

A3) plant parasite- Cuscuta                           animal parasite - ticks, lice

 ecto parasite- lice ( lives outside the host body) and     an endo parasite – tapeworm(lives inside the host body)

GREAT! WE NOW BEGIN WITH TODAY’S LESSON.

By the end of today’s class you will be able to

     1)      List various parts of human alimentary canal

     2)      Draw a neat labeled diagram of it

     3)      Study the process of digestion in every part of human alimentary canal.

PLEASE COPY EVERYTHING IN YOUR BIOLOGY NOTEBOOK EXCEPT THAT WHICH IS WRITTEN IN RED. KEEP YOUR NCERT WITH YOU FOR ANY REFERENCE.

HOLOZOIC NUTRITION IN HUMANS     Draw a neat labelled diagram of human alimentary canal (digestive system)

PROCESS OF DIGESTION

1)      MOUTH – a) digestion begins in mouth.

b) The teeth help in grinding, cutting and chewing food

c) Salivary glands – secrete (give out) an enzyme (digestive juice) – saliva

   which acts on starch and converts it into simple sugar (glucose).

(complex carbohydrate starch is broken down into simple sugar)

                 

                 d) Tongue – helps in swallowing food and mixing it with saliva.

( TEETH DIAGRAM NOT TO BE DRAWN) 

2)      OESOPHAGUS (food pipe)

      a) From the mouth food enters oesophagus.

b) The lining of the oesophagus has muscles that contact rhythmically in order to push the food forward and this movement is called PERISTALTIC movement or simply PERISTALSIS.

 (The downward movement of food is not because of gravitation) DIAGRAM NOT TO BE DRWAN.

https://youtu.be/8YNH7nCVrbQ    ( WATCH THE VIDEO)

3)      STOMACH-  a) The muscular walls of the stomach have GASTRIC GLANDS which secrete Gastric juice.

b) Gastric juice contains

     An Enzyme Pepsin- which breaks down proteins.

     HCl – creates an acidic medium for the action of enzyme pepsin ( if food is not acidic,    pepsin will not work) , it also kills germs.

      Mucus – protects the lining of stomach from the action of the acid.

c) Exit of food from stomach is controlled by sphincter muscle.

4)      SMALL INTESTINE- 

      a) The food now enters small intestine .

b) its first part is called duodenum and receives secretion from liver and pancreas.

c) LIVER – Is the largest gland and secretes BILE JUICE.

Bile juice is stored in gall bladder.

Bile juice contains bile salts and pigments which help in emulsification of fats (breaking down fat globules)

Bile juice also makes the food alkaline for the action of pancreatic enzymes.

                      d) PANCREAS – releases pancreatic juice which contains three enzymes

                                              Trypsin – breaksdown proteins

                                              Amylase – Breaksdown starch

                                              Lipase – breaks down emulsified fats  

                           ( Medium required alkaline)

    

               (NOT TO BE DRAWN)

e) The walls of intestines release Intestinal juice which complety breakdown of

 proteins into amino acids ,

 fats into fatty acids and glycerol

and starch into glucose.

f) VILLI – are finger like projections on the walls of intestines, surrounded Blood capillaries to absorb digested food.

5) LARGE INTESTINE- undigested food is absorbed by it.

Presence of villi helps in absorption of water, undigested food is expelled through anus.

(anal sphincter)

THIS IS ALL FOR TODAY ! THE ENTIRE PROCESS OF DIGESTION IS EXPLAINED IN THE VIDEO BELOW. KINDLY WATCH. DO GO THROUGH THIS CLASS AT LEAST TWICE, FOR BETTER UNDERSTANDING)

https://youtu.be/Og5xAdC8EUI

THANK YOU AND TAKE CARE! TRY TO DO FOLLOWING QUESTIONS.

ASSIGNMENT

READ PAGES 99 AND 100 of ncert.

Q1) Why do herbivorous animals have a larger small intestine?

Q2) list differences between the two protein digesting enzymes-

Trypsin and pepsin

Q3) How are villi of small intestine different from those of large intestine?