Nuitrition in Animals

It is important for animals to have a proper diet in order to maintain their health and well-being. A balanced diet is key to ensuring that an animal's body is getting the right nutrients it needs. There are a variety of factors to consider when creating a diet for an animal, including the animal's age, weight, lifestyle and health condition.

Food we eat has mainly six components carbohydrates proteins fats minerals vitamins minerals and rahoge.

Modes of taking food by animals are (Scraping, Chewing, Siphoning, Capturing and Swallowing, Sponging, Sucking etc.)

Nutrition

Nutrition is an essential part of life for all living organisms. Autotrophs and heterotrophs obtain their nutrition in different ways. Autotrophs, such as plants, obtain their nutrition by photosynthesis, while heterotrophs, such as animals, must consume other organisms to obtain their nutrients. Photosynthesis is the process in which plants use light energy from the sun to turn carbon dioxide and water into glucose and oxygen. This process provides the necessary energy for plants to grow and thrive. Heterotrophic organisms rely on other sources of nutrition such as other plants or animals to get the nutrients they need to survive. Both autotrophic and heterotrophic modes of nutrition are essential for sustaining life on Earth.

Animals that are not getting the right nutrients in their diet can become malnourished. Malnutrition can lead to a variety of health problems, including weight loss, weakness, hair loss, and even death.

Types of nutrition

Nutrition is the process of obtaining energy and essential nutrients from food. It is an important factor in the growth and development of living organisms.

Nutrition can be divided into two main types: autotrophic and heterotrophic nutrition.

Autotrophic nuitrition means plants and some animals manufacture their own food with the help of raw materials like water carbon dioxide and sunlight in the chlorophyll present in mesophyll of plant cells. These are called autotrophs.

Heterotrophic nuitrition means animals and some plants obtain their food from plants and other animals these are called heterotrophs.

Nuitrition in Human beings.   

Human beings falls in the category of heterotrophs because they can't produce their own food they are reliable on autotrophs and some other heterotrophs for their food.

They eat both animals and plants and their products hence are also called omnivores.

Nuitrition is of the holozoic type as they eat solid food materials chew them and digest them in their digestive tracts then absorb the nutrients in blood stream. 

Steps of digestion in humans.

There are broadly five steps of digestion or nuitrition in Human beings and these are as follows

Ingestion.

The taking of food directly from plants and animals by mouth or putting food inside our mouth is called ingestion of food. Or in simple words process of taking food into the human body is called ingestion and we take food by hand or fingers put in mouth or drink directly by straw by lips etc.

Digestion.

The food we eat is of a complex nature mainly consists of small components we called nutrients and these are of six types as carbohydrates proteins fats minerals vitamins and rahoge and water.

The breaking down of this complex food into its basic components like glucose amino acids fatty acids glycerol etc is called digestion. It starts from mouth and ends in small intestines. 

Absorption.

Taking of digested food by blood vessels in small intestines through villi and membrane and water is taken up by large intestine is called absorption.

Assimilation.

This absorbed food components is used by various organelles for different purposes inside cells of organs eg gulcose is used for generating energy amino acids for cell growth etc is called assimilation.

Egestion.

At last the undigested food is stored in rectum or large intestine for defecation this process is referred as egestion.

Digestive system of man consists of the following parts 

Mouth or buccal cavity.

It consists of mouth tongue teeth and salivary glands. Mouth ingests the food which is chewed by teeth and mixed with saliva by tongue mechanically broke down the food. Teeth are rooted in sockets in gums,each tooth has its own socket and such embedded teeth are called thecodont. Humans have thirty two teeth in total sixteen in upper jaw and other sixteen in lower jaw. They differ in appearance and perform different functions. The teeth are mainly of four types incisors, canines, molars and premolars. These perform the following functions like Cutting and biting, piercing and tearing, and grinding and chewing.

It also contains different types of exocrine glands which secrete digestive juices containing various enzymes which speed up digestion and some are given and describes below.

Salivary glands. 

These are of three kinds parotid gland(located on cheeks) sublingual gland(located below the front end of tongue) and sub mandibular gland(located under the lower jaw) according to their location in the mouth.

These are exocrine glands means they secrete their secretions directly into the digestive tract and are also called ducted glands as they have small tube like ducts from which they secrete enzymes. The secretions of these glands contain different chemical substance called enzymes which help in making digestive process quick and efficient.

Oesophagus or food pipe.

It is tube like structure which runs from mouth to stomach

Stomach.

It's a j shaped bag which can be divided into four parts viz cardia, Fundus, Body and Pylorus. It consists of different types of cells and glands. The outer layer is a mucous layer or mucosa whic protects itself and stomach from digestion by strong digestive juices present in the stomach. It received semi masticated or chewed food called bolus from oesophagus or food pipe and churns it strongly mixes it with gastric juices. This semi liquid partially digested food is called chyme. It also contains different types of exocrine glands which secrete digestive juices containing various enzymes which speed up digestion and some are given and describes below.

Gastric glands or stomach glands.

The outer layer of stomach is mucosa and It contains cardiac gastric glands in the beginning, the intermediate, or true, gastric glands or fundus or oxyntic glands in the central stomach and at last are pyloric glands present at the terminal or last portion of the stomach.

These glands are formed mainly of four types of cells mucous cells or mucosa neck cells (secretes mucous) parietal cells or oxyntic cells (secretes HCl) peptic or chief cells (secretes pepsin as inactive zymogen called pepsinogen)and endocrine cells. 

Pepsinogen comes into contact with HCl and converts to pepsin whic helps in digestion of proteins into proteoses and peptones or peptides.

Other enzyme Rennin which is a proteolytic enzyme found in the gastric juice of infants and It converts casein protein present in milk into Ca-paracaseinate.

The Gastric lipases enzyme present in the gastric juice helps in the digestion of fats, which converts fats into glycerol and fatty acids.

The pH of the stomach is 1.8 which is acidic in medium. This acidic medium of the stomach is optimal for activation of enzymes like pepsin.

HCl of gastric juice converts Fe3+into Fe2+ which is then easily absorbed. Gastric juice which contains mucus and bicarbonates protects the mucosal epithelium from excoriation by the hydrochloric acid.

The other peptide hormone called gastrin is released by the stomach which stimulates the gastric glands to secrete and release the gastric juice. It converts bolus into Chyme which is the thick acidic mixture of gastric juice and semi digested food formed in the stomach.

Small intestine.

It is long coiled tube like structure almost 6 meters or about 20feet in length,it helps in further digestion of chyme and also absorbs the digested food vitamins and minerals through small tube like structures called villi. It can be divided into duodenum, jejunum and ileum. It received the secretions of liver and pancreas also. The intestinal walls trigger its muscles to churn food back and forth (segmentation), mixing it with digestive juices, muscle movements (peristalsis) keep the food moving gradually forward.

Duodenum

The first part of the small intestine that the stomach feeds into is referred as duodenum, It’s a short, descending chute (about 10 inches long) that curves around the pancreas in a “C” shape before connecting to the rest of the coiled intestines.

Jejunum

After duodenum the remaining small intestine lays in many coils inside the lower abdominal cavity. Its in the middle section, which makes up a little less than half of this remaining length. It consists of many blood vessels, which give it a deep red color.

Ileum

The last and longest part is called ileum. It is the last and longest section of the small intestine and the walls of the small intestine begin to thin and narrow, and blood supply is reduced. Food or chyme spends the most time in the ileum, where the most water and nutrients are absorbed.

Large intestine.

The large intestine includes the colon, rectum and anus or anal canal. The large intestine is a long tube that continues from the small intestine as food nears the end of its journey through your digestive system, it turns food waste into stool and passes it from the body when you poop and large intestine receives food from the small intestine, the food has been liquified by the digestive process and most of the nutrients have been absorbed. The colon’s job is to reabsorb water or dehydrate what’s left of the food and form it into stool. It does this by slowly absorbing water and electrolytes as its muscle system moves the waste along. Meanwhile, bacteria living in your colon feed on the waste and break it down further, completing the chemical part of the digestive process.

Rectum.

It is a straight, 8-inch chamber that connects the colon to the anus and The rectum's job is to receive stool from the colon, let you know that there is stool to be evacuated (pooped out) and to hold the stool until evacuation happens. It acts a storage of undigested food which is the expelled out by voluntary muscles present in it through Anus Or anal canal which is located within the anal triangle of the perineum, between the right and left ischioanal fossa. It is also the final functional segment of the bowel, it functions to regulate release of excrement by two muscular sphincter complexes.

Liver.

It is also a exocrine gland which is essential for digestion of food and getting rid of the toxins from the body. It is just below beneath the diaphragm, and on top of the stomach, right kidney, and intestines in ribcage and is big as the size of football. It produces bile and helps in metabolism of fats proteins and carbohydrates it also excretes bilirubin hormones drugs and cholesterol. It receives the oxygenated blood through hepatic vein and nutrient rich blood is carried by portal vein.

Liver secretions are stored in a gallbladder which is a small, pear-shaped organ on the right side of your abdomen, just beneath your liver. It contains a digestive fluid called bile that's released into your small intestine.

Bile

Bile juice is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion, mostly breaks down fats into fatty acids, which can be taken into the body by the digestive tract. Bile contains: Mostly cholesterol.

Pancreas.

Pancreas is located in abdomen behind the  stomach, about the size of hand. During the process of  digestion, it makes pancreatic juices called enzymes which break down sugars, fats, and starches. These help our digestive system by making hormones. It contains Endocrine portion which is used to secrete the hormones, insulin, and glucagon which circulate into the bloodstream and 

Exocrine portion which is used to secrete the digestive enzymes into the small intestine which are called as pancreatic juice

Intestinal glands.

Brunner's glands and crypts of Liberkuhnare the two intestinal glands.

These are found in upper layer of small intestine and large intestine were they are called colonic crypts. These secrete intestinal juices which contains lot of enzymes 

These also secrete the mucous which gives lubrication to food.

Digestive system of cow.

The digestive system of a cow is composed of four main parts: the mouth, the oesophagus , the stomach (rumen, Reticulum, omasum and abomasum). The mouth is the first part of the digestive system where food enters and is partially chewed by the cow's teeth. The esophagus carries that half chewed food from the mouth to the rumen and Reticulum,where it is stored until later when the rumenants are full from this eating process, they rest and  later they coughs up bits of the unchewed food called cud and chews it completely this time before swallowing it again. This cud then goes to the third and fourth stomachs, the omasum and abomasum, where it is fully digested and Some of this digested food enters the bloodstream and travels to a bag called the udder, where it is made into milk that will come out of her teats, while the rest goes towards the cow's nourishment.

The digestive system of a cow is an incredibly complex and efficient system that allows cows to extract the most nutrients from their food. The rumen, or cuddle, is the first chamber of the cow's four-chamber stomach and is home to billions of bacteria and protozoa that help break down cellulose in plant material. This process allows cows to digest grasses, hay, and other plant material that humans cannot digest. Ruminants are animals with a four-chamber stomach like cows, sheep, goats, deer, elk, bison, and antelope. These animals have evolved over time to be able to extract more nutrients from their food than other animals can.