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FORMATIVE ASSESSMENT: I CLASS: _______________________ REF: 2016-17/ SCI/ FA II/ STD 7/ HO-02 NAME: _______________________ SUBJECT: SCIENCE DATE: ________________________ TOPIC: NUTRITION IN ANIMALS

MIND MAP FOR NUTRITION Sun (ultimate source of energy ) autotrophs (only green plants traps solar energy) (producers) Food consumed by heterotrophs source of (consumers) gives energy nutrients Food Components Process of nutrition

- Ingestion

Carbohydrates Proteins Fats Vitamins water - Digestion Minerals

Example-Digestive system of Man - Absorption Digestive system of Cow

Digestive system of Amoeba

- Assimilation

- Egestion

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All organisms require food for survival and growth. Requirement of nutrients, mode of

intake of food and its utilization in body are collectively known as nutrition.

DEFINITION OF NUTRITION:

The process by which living organisms obtain food and use it for growth,

metabolism, and repair.

The stages of nutrition include ingestion, digestion, absorption, transport,

assimilation, and excretion.

What are nutrients?

Components of food required by our body for its healthy growth are called nutrients.

MODES OF NUTRITION

Modes of nutrition in all living organisms can be divided into two categories

1. Autotrophic nutrition

2. Heterotrophic nutrition

Organism such as plants which make their food from simple substance such as Carbon

dioxide, Water and sunlight are called Autotrophs or producers.

Animals cannot make their own food but depend upon others for their food. This mode of

nutrition is called Heterotrophic Nutrition. Therefore all animals including human beings

are called Heterotrophs.

Modes of Feeding

Modes of taking food into the body varies in different organisms e.g. snakes swallow their prey as

a whole and bees suck the nectar of flowers.

Observe commonly found animals around you. Fill up the table given below for any ten animals.

One example is done for you. For five animals the mode of feeding is also mentioned.

S.no Name of animal Food they eat Mode of feeding

1. Butterfly Nectar Sucking

2. Scraping

3. Chewing

4. Capturing

5.

Swallowing

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6.

7.

8.

9.

10.

Human Digestive System

The food is first broken down into simpler forms, and then absorbed by the body cells

through blood. It then gets oxidized with O2 to release energy. Digestive system includes

intake of food – ingestion, digestion of food – Digestion, Absorption and Assimilation of

digested food and egestion of waste material. A number of organs such as mouth,

oesophagus, stomach, intestines, liver, pancreas, gall bladder and anus together form an

organ system (Digestive system) of human body.

The various steps involved in the process of nutrition are as follows:

a) Ingestion - taking food in to the body

b) Digestion - chemical simplification of food in to simple substances by digestive

enzymes.

c) Absorption - diffusion of digested food in to the blood through the walls of alimentary

canal.

d) Assimilation - utilization of digested food by different parts of the body

e) Egestion - removal of undigested waste materials out of the body.

Parts of Human Digestive System

DIGESTIVE SYSTEM

Digestive system is divided into Alimentary canal and Digestive glands.

Alimentary canal consists of: Digestive glands

1) Mouth 1) Salivary glands:

2) Oesophagus 2) Liver

3) Stomach 3) Pancreas

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4) Small intestine

5) Large intestine

6) Rectum

7) Anus

Human Digestive System

Mouth is the first organ of the digestive system. It includes:

Teeth

Tongue

Salivary glands

The water that occurs in the mouth is called saliva. It helps in changing the thickness of

food into a” pulp”. It also converts carbohydrates of food into simple sugars. The process

of chewing food while it gets mixed with saliva is called mastication.

TEETH: single tooth has many different parts that make it work and teeth play an

important role in our daily life.

Although babies have the beginnings of their first teeth even before they are born, teeth don't

become visible until babies are about 6 to 12 months old.

After that first tooth breaks through, more and more teeth begin to appear. Most kids have their

first set of teeth by the time they are 3 years old. These are called the primary teeth, baby teeth,

or milk teeth and there are 20 in all. When a child gets to age 5 or 6, these teeth start falling out,

one by one.

A primary tooth falls out because it is being pushed out of the way by the permanent tooth that is

behind it. Slowly, the permanent teeth grow in and take the place of the primary teeth. By about

age 12 or 13, most kids have lost all of their baby teeth and have a full set of permanent teeth.

There are 32 permanent teeth in all — 12 more than the original set of baby teeth. Most people

have four teeth (called wisdom teeth) grow in at the back of the mouth when they're between 17

and 25 years old. These complete the adult set of 32 teeth.

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PARTS OF TOOTH: The part of the tooth that can be seen, which is not covered by the gum is

called the crown. The crown of each tooth is covered with enamel which is very hard and often

shiny. Enamel is a very tough substance and it acts as a tooth's personal bodyguard. Enamel

works as a barrier, protecting the inside parts of the tooth.

If you were able to peel away the enamel, you would find dentine. Dentine makes up the largest

part of the tooth. Although it is not as tough as enamel, it is also very hard.

Dentine protects the innermost part of the tooth, called the pulp. The pulp is where each tooth's

nerve endings and blood supply are found. When you eat hot soup, bite into a super-cold scoop

of ice cream, fall and hurt a tooth, or get a cavity, it's your pulp that hurts. The nerve endings

inside the pulp send messages to the brain about what's going on . The pulp also contains the

tooth's blood vessels, which feed the tooth and keep it alive and healthy.

The pulp goes all the way down into the root of the tooth, which is under the

gum. Cementum makes up the root of the tooth, which is anchored to the jawbone.

Tooth Types

You've probably noticed that you have different types of permanent teeth in your mouth. Each

one has its own function.

Your two front teeth and the teeth on either side of them are incisors. There are four on the top

and four on bottom.

Incisors are shaped like tiny chisels, with flat ends that are somewhat sharp. These teeth are

used for cutting and chopping food. Think back to that apple you ate: You used your incisors to

crunch into the skin of the apple.

The pointy teeth beside your incisors are called canine teeth. There are four of them, two on top

and two on bottom. Because these teeth are pointy and also sharp, they help tear food.

Next to your canine teeth are your premolars which are also called bicuspid teeth. You have

eight premolars in all, four on top and four on the bottom. You'll need to open a bit wider to see

these teeth, but when you do, you'll notice that their shape is completely different from both

incisors and canines. Premolars are bigger, stronger, and have ridges, which make them perfect

for crushing and grinding food.

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If you open your mouth really wide, you'll see your molars. You have eight of these, four on the

top and four on the bottom. Sometimes these are called your 6-year molars and your 12-year

molars because that is around the time when they come in.

Molars are the toughest of the bunch. They are even wider and stronger than premolars, and

they have more ridges. Molars work closely with your tongue to help you swallow food. How? The

tongue sweeps chewed-up food to the back of your mouth, where the molars grind it until it's

mashed up and ready to be swallowed.

As we mentioned earlier, the last teeth a person gets are wisdom teeth. These are also called

third molars. They are all the way in the back of the mouth, one in each corner.

Wisdom teeth may have to be removed because they can cause problems in a person's mouth.

Some people believe that wisdom teeth may have been used by people millions of years ago

when humans had larger jaws and ate food that needed a lot of chewing. It's believed that they're

called wisdom teeth because they come in later in life, when a young person is becoming older

and wiser.

Your teeth are great for chewing, but you also need them to talk. Different teeth work with your

tongue and lips to help you form sounds. Try saying the word "tooth" slowly and notice how your

tongue first hits the inside of your incisors to produce the hard "t" sound and then goes in

between your upper and lower teeth to make the "th"

sound.

HOW TO CARE FOR YOUR TEETH

:

Brushing your teeth with fluoride toothpaste is your best

bet when it comes to keeping your teeth in tip-top shape.

Try to brush after eating or at least twice a day. It's

especially important to brush before bedtime.

The best way to brush your teeth is in little circles — go

around and around until you have covered every surface

of every tooth. Brush up and down, rather than side to

side. You'll also want to clean between your teeth with

dental floss (a special string for cleaning your teeth) at least once a day. That removes food and

plaque (sticky stuff that can cause cavities or gum disease) that get stuck in between your teeth.

You can also brush your tongue to help keep your breath fresh! Your dentist may suggest that

you use an alcohol-free mouth rinse.

It's also important to visit your favourite tooth experts — your dentist and dental hygienist. During

your appointment, they'll look out for any problems and clean and polish your teeth. Sometimes

the dentist will take X-rays to get a better picture of what is going on in your mouth.

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NOTES ABOUT TOOTH DECAY

Tooth decay happens when acids wear away the tooth's hard surface layer, called enamel.

These acids are made by a sticky film called plaque. Plaque has germs that feed on sugary

foods. The process of digesting these sugars makes acids that attack tooth surfaces.

Over time, tooth decay can cause holes in the tooth surface. These are called cavities. If left

untreated, cavities can get bigger. They can even

destroy the tooth.

If you think you have a cavity, see your dental team.

Your dentist is likely to put in a filling. Fillings may stop

the cavity from getting bigger.

Acids constantly attack your tooth surfaces, but tooth

decay doesn't happen all at once. That's because other

elements in your mouth work to strengthen your teeth

and stop the tooth decay process. One of these

elements is saliva. Saliva has minerals that help

strengthen tooth surfaces. Fluoride, a natural mineral

that is often added to water and found in toothpaste,

also helps to make teeth stronger.

The dull spot on the tooth's surface may be decay. Brushing with a fluoride toothpaste

and flossing may prevent it from becoming a cavity.

The decay is now a cavity. It has gone through the tooth's hard surface layer.

Now that the cavity has reached the softer layer of the tooth, it will get bigger faster.

If the cavity is not filled, it can cause bigger problems deeper in the tooth. This is why it's

important to see your dental team regularly.

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TONGUE:

The tongue is a fleshy, muscular organ attached at the back of the mouth, which performs the

following functions:

Tasting food

Mixing food with saliva

Swallowing food

SALIVARY GLANDS:

The salivary glands produce saliva, which keeps the mouth and other parts of

the digestive system moist. It also helps break down food and lubricates

There are three main pairs of salivary glands: the parotid, the submandibular and

the sublingual glands

The parotid gland is located near the ear (par- = next to, -otid = ear), and is the largest of the

salivary glands.

The sublingual gland lies underneath the tongue.

The submandibular gland is a U-shaped structure, and lies beneath the mandible (the angle

of the chin).

Do you realize that you

cannot talk without the

help of your tongue? Try

to do that and have fun!!

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What happens when you talk or laugh while eating? The air that enters through the

nostril goes into the wind pipe.The food pipe is located adjacent to the wind pipe. But

inside the throat, air and food share a common opening. The food is prevented from

entering wind pipe with help of a flap - like valve (EPIGLOTIS)which closes the passage

of the wind pipe and guides the food into OESOPHAGUS.

1. Food is chewed in the mouth and mixed with saliva.

a. Three pairs of salivary glands secrete saliva by way of ducts into the mouth.

b. Salivary amylase is an enzyme that begins starch digestion; maltose is common

end product.

salivary amylase starch + H2O -------------> maltose

c. Taste buds are located primarily on tongue but also on the surface of the mouth;

chemical receptors are stimulated by chemical composition of food.

d. Food is chewed and mixed with saliva to form a bolus in preparation for swallowing.

The Pharynx and the Oesophagus

1. Digestive and respiratory passages come together in pharynx, then separate.

a. During swallowing, path of air to lungs could be blocked if food entered trachea.

b. Epiglottis covers opening into trachea as muscles move bolus through pharynx into

esophagus.

2. Oesophagus is a muscular tube that moves swallowed food to stomach by

peristalsis. It is a long tube about 30 cm in length commonly called as food pipe. It

connects the mouth cavity with the stomach. It acts as a passage for food to be taken

from mouth to the stomach. The food moves in it due to the alternate contraction and

expansion of muscles, the process known as Peristalsis.

Do you know that vomiting is a process of reverse

peristalsis due to which the food is pushed in the

opposite direction.

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Stomach is a flattened J-shaped elastic bag which has a thick wall. It is the widest part

of the digestive system. It is connected to the food pipe at one end and to the small

intestine on the other end.

The gland present on the inner wall of the stomach secretes:

i) Mucous

ii) Hydrochloric acid

iii) Digestive juices

Mucous protects the lining of the stomach.

1. Stomach stores a liter of partially digested food freeing humans from continual eating.

2. Hydrochloric acid (HCl) lowers pH of the gastric contents to about 2.

a. Epithelial lining of the stomach has millions of gastric pits leading to gastric glands.

b. This acid kills most bacteria and other microorganisms.

c. Low pH also stops activity of salivary amylase and promotes activity of pepsin.

3. Pepsin is a hydrolytic enzyme that acts on proteins to produce peptides.

pepsin

protein + H2O ---------------->peptides

4. A thick layer of mucus protects wall of the stomach and first part of duodenum from HCl and

pepsin.

5. Ulcers develop when lining is exposed to digestive action;

6. Stomach contents, a thick, soupy mixture, are called chyme.

7. At base of the stomach is a narrow opening controlled by a sphincter (a circular muscle

valve).

a. When the sphincter relaxes, chyme enters duodenum; a neural reflex causes the

sphincter to contract closing off the opening.

b. Duodenum is first part of the small intestine.

c. The sphincter relaxes and allows more chyme to enter the duodenum.

d. The slow, rhythmic pace with which chyme exits the stomach allows thorough

digestion.

The Small Intestine

The next part of the digestive system is

the small intestine. It is the longest part

of the digestive system. It is approximately

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6-7 meters long and highly coiled. It plays an important role in the digestion

of all kinds of food in our body.It digests (breaks down) proteins, fats and carbohydrates.

It receives digestive juices from the liver, pancreas and its own inner walls. The small

intestine is designed to keep food in it for a long time so that all its nutrients are extracted

from it before it enters the large intestine.

1. Mucous membrane lining of small intestine are covered by villi.

a) Villi are finger-like projections whose surface cells are covered by microvilli.

b) Microvilli are minute projections, a brush border, of surface cells of intestinal

villi.

c) Villi, and microvilli greatly increase effective surface area of small intestine.

2. As chyme enters duodenum, proteins and carbohydrates are partly digested; no fat digestion

occurs.

3. Additional digestion is aided by secretions from liver and pancreas.

The liver is situated on the right side of the abdomen. It is the largest gland in our body.

a. Bile is a secretion of liver temporarily stored in gallbladder before sent to duodenum.

b. Bile emulsifies fat; bile is a green byproduct of the breakdown of hemoglobin.

c. Bile contains bile salts that help in emulsification of fat.

1. Emulsification breaks fat globules into microscopic droplets.

bile salts fat ----------------> fat droplets

2. This increases fat digestion by increasing surface area of fat globules exposed to

enzymes.

d. The Pancreas is a large leaf like, cream colored structure located just below the stomach.

Pancreatic juice secreted by pancreas and contains the following:

1. It neutralizes acidity of chyme; pH of small intestine is slightly basic;

2. pancreatic amylase that digests starch to maltose

pancreatic amylase

starch + H2O ------------> maltose:

3. trypsin and other enzymes that digest protein to peptides;

trypsin protein + H2O --- -------------> peptides :

4. lipase that digests fat droplets to glycerol and fatty acids.

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lipase fat droplets + H2O --------------> glycerol + fatty acids

e. Epithelial cells of villi produce intestinal enzymes attached to plasma membrane of microvilli.

f. Intestinal secretions complete digestion of peptides and sugars; peptides are digested by peptidases to amino acids;

peptidases peptides + H2O ----------------> amino acids .

and maltose from the first step in starch digestion is converted by maltase to glucose. maltase maltose + H2O ------------------> glucose

4. Large molecules of carbohydrates, proteins and fats are broken into small

molecules absorbed by villi.

.Absorption and Assimilation of Food

In the lower part of the small intestine, its inner walls have thousands of folds called

VILLI, which look like fingers. Because of the folds, the inner surface has a much larger

surface area than the outer walls. This provides a very large surface area for

ABSORPTION of food.

The digested food passes into the blood vessels in the

walls of the small intestine. Each villus has a network of

thin and small blood vessels close to its surface. The villi

absorb digested food and transport them via these blood

vessels to different organs of the body.

These organs utilize digested substances to build

proteins or fats as required by the body. This process is

called Assimilation. In the cells with the help of Oxygen,

glucose breaks down CO2 and water and energy is

released.

STEPS OF ASSIMILATION

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Large Intestine

The undigested and unabsorbed remains of the food pass into the large intestine. The

large intestine is so called because of its wider diameter as compared to the small

intestine. The tube is shorter and is about 1.5meters long. It absorbs water and some

salts from the undigested food and collects the rest of the waste in the rectum waste is in

the form of a semi-solid called Faeces. This faecal matter is removed through the anus

from time to time by a process called egestion. Egestion is also known as defecation.

Main Digestive Enzymes Found in the Human Digestive System

Digestive organ

Enzyme/juice Food acted upon

Substance produced

1 Mouth(salivary gland)

amylase starch Maltose(sugar)

2 Stomach Gastric juice (pepsin)

Proteins Peptides

3 Pancreas Pancreatic juice Amylase Trypsin lipase

Starch Proteins Lipids(fats)

Maltose(sugar) Peptides and peptide fragment Fatty acids and glycerol

4

Small intestine

Maltase Sucrase peptidases

Maltose Sucrose peptides

Glucose Glucose &fructose Amino acids

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Digestive system disorders:

1. Diarrhoea-condition of passing watery stool frequently than normal. It is caused due to

infection by water-borne bacteria, indigestion and food poisoning.

2. Constipation-condition in which individual has fewer bowel movement. The stool is generally

hard, dry and difficult to pass.

A proper diet eaten regularly helps in avoiding digestive disorders.

Digestion in Grass Eating Animals -

Ruminants: We cannot digest cellulose which is a major component of the food eaten

by herbivores. The plant eating animals digest their food in two steps. The stomach of cud chewing animals like cow consists of 4 parts :

1) Rumen

2) Reticulum

3) Omasum

4) Abomasum

When a cow swallows a mouthful of grass, it is partially chewed and mixed with saliva to

form a ball like structure known as bolus before being swallowed and passed down the

oesophagus into the stomach.

When these animals are grazing they tend to swallow their food quickly, with only

minimal mastication.

When the animal is resting after grazing, it regurgitates (bring back in to their mouth) this

partially chewed food, re-chews it, and then swallows it again. This process is known as

chewing the cud, or rumination and these animals are known as ruminant animals.

Depending on the amount of fibre in their food, cattle may spend between 3 – 6 hours

per day chewing their cud.

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Ruminants differ from other animals like humans in the following important ways:

a) They have no upper canine teeth, or incisors, and have long, thick and rough

tongues.

b) They ruminate, by chewing the cud, the food particle size will be reduced, and

saliva will be mixed with the food.

c) The ruminant digestive system includes a fermentation chamber, called the

rumen. The rumen contains micro-organisms which help in digestion of grass.

The human stomach has only one chamber. They cannot digest cellulose.

The plant cell wall is made up of cellulose. The microorganism present in

the rumen helps to digest this cellulose

Nutrition in Amoeba

Amoeba is a microscopic single-celled

organism found in pond water. Amoeba has

a cell membrane, a rounded, dense nucleus

and much small bubble – like vacuoles in its

cytoplasm. It constantly changes its shape

and position. It pushes out one, or more

finger – like projections, called pseudopodia

or false feet for movement and capture of food.

Amoeba feeds on some microscopic organisms. When it sense food, it pushes out

pseudopodia around the food particle and engulfs it. The food becomes trapped in a food

vacuole. Digestive juices are secreted into the food vacuole. They act on the food and

break it down into simpler substances. Gradually the digested food is absorbed. The

absorbed substances are used for growth, maintenance and multiplication. The

undigested residue of the food is expelled outside by the vacuole.