Epithelial tissue is a barrier between the internal and external environment. Epithelial tissue has many functions such as protection, secretion, excretion, absorption, filtration, diffusion and sensory reception. It has little intracellular matrix. A good example of epithelial tissue from one extreme is the skin. The skin is none permeable, made up of dead cells, it has multiple layers and keratin is replaced continuously, this is a tough insoluble protein therefore it makes a good external barrier. The next extreme would be the lungs. The lungs are semi permeable, moist and extremely thin, its exchange mechanism is diffusion.
Connective tissues hold together organs and other tissue, which provide support. They form together in bundles which is part of the extracellular matrix, this is what provides the support and protection to keep the organs and tissue connected. An example of connective tissue is a tendon. A tendon has densely packed fibres which provides great strength. Another example would be bone. Bone also gives support and protection. It also produces red and white blood cells. The exchange mechanism is exocytosis.
Muscle tissue contains groups of cells or fibres which make the muscle contract and relax. The muscle contracts for force and movement. Muscle tissue aids us to walk, run, jump etc. Muscle tissue is rich in mitochondria, needed for energy. The exchange mechanism here is active transport.
Nervous tissue acts as a system within the body to communicate messages. Neurons or nerve cells are responsible for sending and receiving the messages. An example of nervous tissue may be found on the brain. This sends electrical messages down the spinal cord and into the body.
The two dishes chosen are Trinidad Pelau (Caribbean) and Linguine Amatriciana (Mediterranean). Here is a table of ingredients of each dish:
3 tbsp brown sugar
4 rashers of bacon or pancetta
450g stewing steak
1 clove of garlic
275g uncooked brown rice
Â¼ teaspoon of chillies
250ml coconut milk
500g peeled plum tomatoes
450g dry chickpeas
500g linguine pasta
Handful fresh basil
1 tbsp fresh parsley
2 tbsp grated parmesan cheese
Total Fat (g)
Saturated Fat (g)
The Caribbean dish is symbolic of its origin as meat, rice and peas form the main bulk of the dish. Notice the Caribbean dish is nearly 7 times higher in saturated fat than the Italian dish. There is a mix of fats in this dish, vegetable fat and animal fat.
The Italian dish is very symbolic of its origin as it is pasta and tomato based. Again there is a mix of fats in this dish, however the vegetable fat outweighs the animal fat.
It is probably politically incorrect to say there is a nutritional profile between the north and south of Britain, however the facts show there IS a difference. People from the north have a lower life expectancy than people from the south. The northerners love of processed meat products such as sausage, bacon, pies, pastries, cakes and biscuits have a detrimental effect towards their health. This is because processed meat products contain high level of saturated fat (which are found in meat and dairy products). Ailments for instance include diabetes, obesity and heart disease which is a major problem for people of the north. The recommended daily guideline states up to 20g of saturated fat is acceptable. The average amount for London and the south is 24g, where as in the north the average is 55g, which is more than double the recommended amount. Alcohol also plays a large part in the north's health problems, this is because alcohol has a lot of sugars, especially in beer. There are other factors as to why the north has a lower life expectancy compared to the south such as smoking. Unemployment is more common to the north as oppose to the south. The south also have higher wages compared to the north, which means they can afford better produce and the produce is more readily available. So to conclude on the above, It clearly defines that there is a nutritional difference across the north-south divide.
There are a range of factors that can affect peoples preferences for food. Personal reasons such as vegetarianism or the type of food a person has been brought up on for example savoury or sweet. Appearance is also a personal preference, an example of this would be baby octopus in a paella or seafood platter, this may be a persons idea of heaven and another persons idea of hell. Geographical and environmental issues have a major impact too. Potatoes are a staple product of the British diet, this is because potatoes are easily grown here. Rice is a staple product of the far east and Indian diet, this is because rice is easily grown there, where as it is not easy to grow it in Britain. So there are a range of factors that can affect peoples preferences for food.
The Eatwell Plate.
The Alimentary canal is adapted for the functions of digestion and absorption. When a human eats a piece of food, the teeth, tongue and cheeks are the first process of digestion as this process breaks the food down into small manageable pieces. The break down is helped along by the salivary glands or buccal cavity, which produces saliva that contains enzymes which start to break up the carbohydrates in the food. The food then passes down through the oesophagus and into the stomach. The stomach can store food and extend. The stomach secretes gastric juices which contain few enzymes and this is the start of the digestion of protein. The liver or part of the liver called the gall bladder produces bile this contains no enzymes, but the bile is an emulsifier which further helps break food down. The pancreas produces pancreatic juice which do contain enzymes and this further breaks the particles down. Although salivary glands, gall bladder and pancreas do aid digestion these are just accessory glands and all contribute to different secretions. The food then passes down from the stomach to the small intestine and this is where the bulk of the digestion takes place.
After the digestion has occurred the process of absorption takes place. From the stomach on to the small intestine (by this time the food has been turned into liquid form) this is where absorption takes place. In the small intestine there are folds which are circular and have villi, and the cells of the tissue have microvilli. This then makes the small intestine have a large surface area and it is very long. It also has a copious blood supply. For the absorption process to happen the walls of the intestine must be semi permeable, this then means the nutrients are more easily absorbed. The small intestine has circular and longitudinal muscles, not only are the muscles used for peristalsis, but for mixing the contents around so that all of the nutrients are absorbed. From the small intestine the matter then moves onto the large intestine, because most of the absorption has taken place in the small intestine, the large intestine absorbs the water in the matter. The matter is then turned into drier, compact faeces. If there were villi present in the large intestine they faeces would damage it, therefore this is why there aren't any villi present in the large intestine. So the alimentary canal is effective in the digestion and absorption of food.
The excretory system also called urinary system is adapted for the functions of salt and water balance as well as the excretion of waste products. The system consists of 2 kidneys, 2 ureters, 1 bladder and 1 urethra. The kidneys are thought to be the most functional organ of the urinary system. The kidneys remove waste product (urea) from the blood by filtration and this is responsible for the water and salt balance. Again the organ must have a large surface area for filtration and reabsorption. The kidneys acts as a sieve (see diagram) and filters out salts, water, urea, glucose, amino acids and hormones. The kidney has approximately a million tubules. Each tubule has a renal corpuscle, proximal tubule, a loop of Henle and a distal tubule. The renal corpuscle is the area in which the filtration takes place. Each renal corpuscle has its own blood supply and the capillaries in it filter out the waste products from the blood. The waste product then moves into the tubule for the reabsorption process. Blood pressure is the force behind the movement. Reabsorption requires carrier molecules and mitochondria for energy, the exchange mechanism here is active transport, because water always follows glucose and salt this term is called obligatory water reabsorption. Illness may have an effect on the reabsorpton of water and salts, therefore this makes salt and water variable. Hormones also can make the absorption of water variable too. Antidiuretic Hormone (ADH) reduces the amount of urine which means more water will be absorbed. People suffering from diabetes insipidus drink more water and urinate more, this is due to the lack of ADH. From the kidneys the urea passes down through the ureters, in to the bladder and down through the urethra and out of the body. After the kidneys, no more filtration or absorption takes place. So the kidneys are clearly the most functional part of the excretory system.
Blood cells and
Diagram of filtration