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Structure and Function of the Digestive System

Paper Type: Free Essay Subject: Biology
Wordcount: 2468 words Published: 23rd May 2018

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The function of each part of the digestive system

DigestiveSystemThe digestive system starts from mouth to the anus. The important parts of the digestive systems are mouth, teeth, tongue, oesophagus, liver, gall bladder, pancreas, stomach, small intestine, large intestine (colon), rectum and anus.

Digestive system is able to work with peristaltic movements- automatic compression and relaxation food pipe which pushes the food particles through the digestive system.

Mouth- is the entry point of the digestive system where the breakdown of the food substance taking place mechanically e.g., chewing and crushing.

Teeth – has four different types, they do different function cutting and biting done by the incisors and canine, chewing was done by (premolar and molar teeth).

Tongue- secrets the salivary glands which produce the bolus, mixes with the food and makes it easy to digest.

Oesophagus- is the main part of the food track; it allows the down way movement of food substances- this movement is called as peristalsis movement or alimentary canal.

Liver- which creates the bile from bile duct- cleanses and purifies the blood which is coming from the small intestine.

Gall bladder– stores and absorbs the chemicals, nutrients and the remaining liquid is send back to the small intestine.

Pancreas– secrets the enzyme called the insulin which breaks down the food substance into basic glucose.

Sphincter– is a connecting tube between stomach and oesophagus(phyloric sphincter).

Stomach- it is capable of holding food substances of 4 litres capacity and mixes & digests the food with hydrochloric acid.

Small intestine– 6-7 metres of length but tiny sized pipe like structure and is most important digestive organ which digests almost 90% of the food substances. There are 3 parts, duodenum, jejunum and ileum.

Large intestine (colon) – 1.5 metres in length, the remaining water and useful substances were absorbed; the waste substance is excreted out to the rectum and to the anus. Large intestine has ascending colon, descending colon, and transverse colon, Appendix which are connected to caecum and to small intestine.

Rectum- 8 inches base part of the large intestine, the faeces are stored here.


Anus- waste products are liquid and solid. The liquid waste excretes in the urinary bladder and solid wastes are goes out via anus.


Composition of proteins, fats and carbohydrates and how each of them are digested and absorbed by the body

Carbohydrates, fats and proteins make up 90% of the food, energy intake in the digestive system.

When we compare the food pyramid water and carbohydrates forms the base line, they are very much important to maintain the energy level in the body.

Carbohydrates they contain the basic elements of carbon, oxygen and hydrogen.

They are classified into monosaccharide’s, disaccharides, and poly-saccharides.

Poly-saccharides- poly means many, starch and cellulose are poly-saccharides glucose is stored in the form of poly-saccharides.

Maltose, sucrose intolerance some patients who were allergic to maltose they have to avoid taking cow milk items. They will go for soya milk or any other alternative available. Poly saccharides are divided into basic glucose.

Disaccharides- maltose, sucrose is a two unit of glucose

Our body consumes only the monosaccharide’s we call it as glucose.

We can find glucose in the following list produce.


They play important role in the process of cell building, muscle building, tissue building and body building.

Some of the enzymes, hormones and antibodies which were used in building hair, skin, cartilage, muscle and cells. They play important role in transport of oxygen and other substances like haemoglobin,


Proteins are made up of complex structure and contain amino acids; there are about 20 types of amino acids,






Sugars, dried fruit, cereals, rice flour, bread, pizza and potatoes.

  • Gives energy to the cells and to the total body.
  • Stored at mitochondria in a cell.

Carbohydrates were broken down into a single unit of glucose by insulin secreted by pancreas.


Fish, chicken, cheese, pork lion, lean beef, beans, egg white, milk, yogurt, soymilk and nuts/seeds

  • Provides structure and support for the cells.
  • Protect the body
  • fights the virus, bacteria foreign bodies.
  • Repairs the muscles and tissues

It is biological process of taking place in the cell, muscle, tissue and organs.

Proteins were present in Ribosomes, nucleolus and rough Endoplasmic reticulum

Proteins in plasma and blood cells


Avocados, cheese, dark chocolate, egg, fatty fish, nuts, butter from gross fed cows, virgin oil, coconut and coconut oil

  • Supplies energy to the body.
  • Twice the amount of energy we get from fat than the carbohydrates
  • LDL,HDL were taken through small intestine and liver
  • Excess food stored at subcutaneous layer of the skin.
  • Carries vitamins of A,D,E and k
  • Omega 3 fatty acid and omega 2 fatty acid
  • Triglycerides and glycerides are found in ATP cycle

Function of Organelles in the Cell

CELL is the smallest unit of the living organism, microscopic in size(visible only through microscope). Cell is classified into two 1. Animal cell and 2. Plant cell.

We deal with animal cell that includes the study of structure and function of the human cell we call that as anatomy and physiology of the cell.

Contents of the cell

Functions of the cell

Cell membrane

It is a cell wall like structure

It is a Protective membrane that maintains the structure, allows osmosis process, keep the organelles intact within the cell.


It is the brain of the cell

Contains DNA.


It is a round shaped

Plays a major role in making of protein.

Nuclear membrane

It is a semi permeable membrane

Separates nucleus and cytoplasm.


Deoxyribonucleic acid

Contains chromosomes.


23 pairs of chromosomes

Brings the genetic behaviour of the parent cell.


Gel like substance

Made up of water and nutrients.


Power house of the cell.

Releases the energy

It generates the ATP and energy for the entire cell. One molecule of glucose gives 28 molecules of adenosine triphosphate.


Ribbon like structure

Protein is prepared in the cell.



Digests the waste material in the cell.

Cilia and flagella

Moves the cell

In and around.



Storage area of the cell.

Endoplasmic reticulum- pathway to transfer of proteins

Rough endoplasmic reticulum

Protein associated- Studded with proteins.

Smooth endoplasmic reticulum

Fat associated.

Golgi apparatus

Act as a postal system

Used in packaging & secretion of energy

Cell division/


Mitosis– for normal cell

Time taken for division- 2hrs.

Life time for cells-

Wbc cells- 13 days

Rbc cells- 120 days

Liver cells- 18 months

Nerve cells- 100 years.

Cell divides one into two in four phases.at the end of these phases one cell is divided into two daughter cell.

Prophase, Metaphase, Anaphase, and Telophase (PMAT).

Meiosis-cell division takes place for reproductive cell

Multiplication of reproductive cells i.e, cells of sperms and eggs


Classification of Tissues

Types of tissues There are four types of tissues, epithelial tissues, connective tissues, muscle tissues and nerve tissues.


Epithelial tissues

Connective tissues

Muscle tissues

Nerve tissues


External area

Connects the tissue

Fills up space between organ and tissue.

Supports the body

Connects central nervous system


Covers large area, skin

Adipose tissue (helps to retain fat)

Biceps & tri ceps



Integumentary, lungs




Difference between benign and malignant tumours?

What are tumours?

Tumour is a sudden growth of cells, tissues which can happen anywhere in the whole body. It is capable of pushes the nearby cells and presses the neighbouring areas; therefore tumour causes sudden instability to the nearby organs.

Benign tumours- it is a tumour which is not a life threatening, non-cancerous and tumour will not spread.

Malignant tumour- it is a tumour which is a life threatening, it will spread in a very faster rate, the cancer cell can travel anywhere in the body and it can start growing at the place where it reaches. This process is called as metastasis.

There are different stages of malignant tumour they were primary stage, secondary stage, 3rd stage and 4th stage. If the patient identify the tumour and removes it in the primary stage the survival rate is high. They should continue the treatment to cure the caner.

If they find at later stages it is very difficult to cure completely.

Structure and function the urinary system

Urinary system is a system is to excrete the liquid waste product from the body, which were present in the blood. Urinary system has been placed between liver and to the urinary bladder and urethra (exit point).

Urinary system

Kidney, Ureters, Urinary Bladder and Urethra


Right kidney

Left kidney

Dark brown in colour

it acts like a filter, Cleanses the blood and sends back the pure blood into the stream.


Length(12cm)* breadth (6cm)* thick (4cm)

180 litres of blood enters and leaves the kidney per day.

Position of the kidneys

Left kidney placed near liver

Right kidney placed near spleen


Erythropoietin- hormone

Maintains stable balance of salt and other substance in the blood

Removes the urea in blood

filtering & cleaning unit in urinary system is nephrons

Each kidney contains one million nephrons, cortex and medulla have nephrons.


a glomerulus a small blood of capillaries(bed)

a small tube called a renal tubule


Two ureters- muscular tube, lined with mucus membrane

Carries urine from kidney to the bladder.


Triangular shaped, hollow sac, lined with mucus membrane.

In lower abdomen, it has two sphincter internal involuntary sphincter, external voluntary sphincter, circular rubber band in the bladder which tightens the urine pathway.

Nerves in the bladder

Nerves alert the brain when to urinate or empties the bladder

Controls the urination


Urine squeezes out

Through this tube. A final exit.





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