• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The Digestive System.

Extracts from this document...


THE DIGESTIVE SYSTEM The digestive system is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. Inside this tube is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food. Two solid organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes. In addition, parts of other organ systems (for instance, nerves and blood) play a major role in the digestive system. LIVER The liver is such an important organ in the human body that without it we'd only survive for 24 hours, and it's one of the few organs that has the power to regenerate when it gets damaged. ...read more.


It plays a dual role in helping us get the most out of food. The pancreas produces many of the digestive enzymes that we need, which are poured into the small intestine. It also produces bicarbonate (NaHCO3), which neutralizes the acid that comes from the stomach. Stomach acid is so strong that without the neutralizing effects of the bicarbonate it would destroy the digestive enzymes produced by the pancreas. The pancreas is an important member of the endocrine system, the body's mechanism for making hormones, which are then circulated around the body by the blood. The first hormone that it makes is called insulin, and its job is to help cells take up the sugar (glucose) which they need for energy. But if too much glucose is taken from the blood, a second hormone is released, called glucagons, which converts sugar stored in the liver (called glycogen), into glucose. ...read more.


As well as acting as a temporary storage facility, the stomach also continues the digestive process that begun in the mouth. The stomach produces enzymes that break down proteins in the food. Hydrochloric acid is also produced by the stomach, to activate the enzymes that break down the proteins. When the nerves in the stomach wall sense that the stomach has become stretched with food, the muscles of the stomach begin to work so that the food and enzymes mix together. This ensures that the first stage of digestion is completed before food moves on to the small intestine where the majority of digestion takes place. The stomach protects itself from being digested by its own enzymes, or attacked by the corrosive hydrochloric acid, by secreting a sticky neutralising mucus that clings to the stomach walls. However, if this layer becomes damaged in anyway it can result in painful and unpleasant stomach ulcers. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Exchange, Transport & Reproduction section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Human Reproductive System

    4 star(s)

    Endometrium The endometrium is the membrane lining the uterus. It prevents friction between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During menstrual cycle or estrous cycle, it grows to a thick, blood vessel rich, glandular tissue layer which provides an optimal environment for the implantation of a blastocyst upon arrival in the uterus.

  2. Marked by a teacher

    What is Type 1 diabetes

    3 star(s)

    level as close to normal as possible, can significantly reduce or even stop complications occurring. What is diabetic acidosis (ketoacidosis)? Diabetic acidosis is a life-threatening condition which can occur in patients with Type 1 (insulin-dependent) diabetes. It leads to high blood glucose levels and the presence of ketones in the urine, as well as certain acids in the blood.

  1. The Skeletal and Muscular System

    b. Lordosis. An abnormal forward curvature of the lumbar region of the vertebral column (aka hollow back or saddle back). It can be caused during pregnancy or extreme obesity, the main cause is poor posture. It can also be associated with rickets.

  2. Blood System Assignemnt

    Like arteries, veins have three layers: an outer layer of tissue, muscle in the middle, and a smooth inner layer of epithelial cells. However, the layers are thinner, containing less tissue. Veins receive blood from the capillaries after the exchange of oxygen and carbon dioxide has taken place.

  1. Journey of a hamburger from mouth to anus

    It's a pouch composed of sheets of muscle that encircle the stomach in different directions. When they contract, the stomach can mix the mush this way and that. The stomach muscles twist and churn the food like you would knead bread dough.

  2. The Endocrine System

    the mother and baby. It is formed from the uterine wall. Pineal Gland The pineal gland is variable in size. It is richly vascularised and whilst it has no direct link to the central nervous system, it is innervated by sympathetic neurones which are stimulated by centres of the brain controlled by light.

  1. the role of the microbiology department

    The advantages of this method are that staffs have the continuous experience of dealing with all kinds of specimens and are helped to correlate the results for different kinds of specimens received from the same patient. By the second method, all specimens of particular kinds are allocated to sections specializing in the examination of these kinds of specimen.

  2. The Reproductive System of a Cow

    Vestibule The vestibule is a part of the reproductive tract shared with the urinary system. It is approximately 4 inches long. Openings from the urinary bladder and a blind sac located below the opening of the urethra called the suburethral diverticulum are located on its floor.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work