Part A

1. Digestive System

The digestive system is the system of organs that takes food in, the digestive system is a set of organs that transforms whatever we eat into substances that can be used in the body for energy, growth and repair. The main functions of the digestive system are ingestion, digestion, absorption, and defection.

Ref: (Class Notes 2015)

2. Explain the functions of each part of the digestive system identified in the diagram above?

The Mouth

The mouth is the first portion of the alimentary canal that receives food and saliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth. The tongue is a muscular organ and has many taste buds, which are accountable for the tastes: sweet, sour, bitter and salt. You would get a range of different flavours as the tongue moves the food around the mouth. The food in your mouth moves from tooth to tooth to have it made into a pulp with the aid of saliva. The tongue would then pass the pulp (bolus) down the throat.

There are four types of teeth. Individually they have their own functions in the breakdown of food. The first would be the incisors, there are four in each jaw. They are sharp, chisel shaped teeth that are used for cutting and biting. Next to these on both sides are the canines, canines are cone shaped teeth frequently called the eye-tooth. They have a sharp point and you would use them to tear food. There’s to in each jaw. Next are the premolars, there are four of them in each jaw, they would be used for crushing and crunching of food. There blunt broad teeth with two sharp ridges. Molars are similar to premolars and are six to each jaw, they are also blunt broad teeth but have a larger surface area. Each has four surface points. The salivary glands there are three parts of the salivary gland you have the parotid gland that is situated below the ear, the submandibular and the sublingual gland, they are situated below the tongue. Liquid called saliva is secreted from them. It contains water, mucus and the enzyme salivary amylase. The function of saliva is to lubricate the food with mucus, making it easier to swallow.

The Oesophagus

It’s a muscular tube that leads from the pharynx to the stomach. The food moves through it by a muscular contraction known as peristalsis. It’s part of the digestive system. It is the tube that carries food from your mouth to the stomach. The muscles contract and relax creating a wave like motion on the tube. The lining of the oesophagus secretes mucus to ease and oil the passage of food. Once food touches the end of the oesophagus it presses against the cardioesophageal sphincter.

The Stomach

The stomach is a C-shaped elastic sac. The wall of the stomach is a grouping of layers of muscle fibre with an inner mucous membrane. The mucous membrane has a lot of doublings called rugae. When the stomach is full is will stretch out allowing expansion, then it would contract when it empties. When the stomach is full it can hold up to approx. 4 litres (1 gallon) of food.

The Liver

The liver has numerous functions, its main function inside the digestive system is to process the nutrients absorbed from the small intestine. Bile from the liver secreted into the small intestine also plays a significant role in digesting fat. The liver only makes bile.

The Gallbladder

The gallbladder is a pear-shaped deep structure located under the liver and on the right side of the abdomen. Its main function is to store and concentrate bile, a yellow / brown digestive enzyme formed by the liver. The gallbladder is part of the biliary tract.

The Pancreas

The pancreas is a greyish pink gland organ it’s placed in the upper abdomen, it lies behind the stomach and intestines (guts). It is roughly the size of a hand. The pancreas has to major functions, one of them is to make digestive enzymes which help us to digest food. Enzymes are special chemicals which help speed up your body’s processes. The second one makes hormones which regulate our metabolism. Hormones are chemicals that can be released into the bloodstream.

The Large Intestine

The large intestine is a thick tube that’s approximately 1.5 metres (5 feet) long it receives waste from the small intestine, it hangs around the small intestine in an arch shape. It involves the caecum, colon, rectum, and the anal canal. The colon holds bacteria which breaks down any remaining food and makes some significant vitamins. It also deals with waste within the body.

Small Intestine

The small intestine is approximately six metres (18 feet) long. 90% of the digestive process takes place here in the small intestine. It’s a coiled tube that has three parts which are the duodenum, jejunum, and the ileum. The wall of the whole of the small intestine is significantly folded, each of the villi contains more projections called microvilli that absorbs food and passes it onto the capillaries. Muscles of the walls contract and relax so that the villi sway about.

Appendix

The appendix is a narrow tube attached to caecum and it is about 9 cm long. The appendix is not a vital organ you can live without it. The appendix sits at the junction of the small intestine and the large intestine, the appendix sits in the lower right abdomen. The function of the appendix is unknown. A theory is that the appendix acts as a storehouse for good bacteria “rebooting” the digestive system after diarrheal illnesses.

Rectum

The rectum is a short straight section of the alimentary canal, it leads from the colon to the anus and thus to the outside world. A human rectum is approximately 12cm long.The rectum is a chamber that begins at the end of the large intestine. It is usually empty only receiving the contents of the colon called faeces when they are ready to be passed out of the anus.

The Anus

The anus starts at the bottom of the rectum. The anorectal line separates the anus from the rectum. Tissue called fascia surrounds the anus and joins it to nearby structures. Circular muscles named the external sphincter form the wall of the anus and hold it closed. The glands in your body discharge fluid into the anus to keeps it surfaces moist.

3. Outline the composition of Proteins, Fats and Carbohydrates, and explain how each of them are digested and absorbed by the body.

Proteins, fats and carbohydrates are all in the body. Protein helps the body to grow, it builds muscle and gives you energy. Protein accounts for 16% of a person’s total body weight the reason for this is because connective tissue, skin, hair and muscle are all made up from protein. Carbohydrates are sugars the body uses for energy, simple carbohydrates give the body quick energy. Fat is also another way it helps the body grow, your body needs fat to process vitamins. Polyunsaturated and monosaturated fats are good for your body.

Part B

1. Draw a diagram of a typical cell, and state the function of each of its organelles?

Cells are the most important units of life. Our bodies contain over 100 trillion cells, they do everything in a human body from providing structure and stability to providing energy and a means of reproduction.

Ref: (Class Notes 2015)

Cell membrane

The cell membrane forms the outer edge of the cell and allows certain materials move in or out of the cell.

Cytoplasm

Cytoplasm is a gel-like material inside the cell that contains water and nutrients for the cell.

Nucleus

The nucleus directs the activity of the cell and contains chromosomes with DNA that contains all genetic information.

Nuclear Membrane

Nuclear membrane separates the nucleus from the cytoplasm.

Ribosomes

Ribosomes make protein for the cell.

Golgi Body

Golgi bodies are used in the cell for packaging and secreting of energy.

Lysosomes

Lysosomes are chemicals that are used to digest waste.

Vacuoles

Vacuoles are storage areas for the cell.

Mitochondria

Mitochondria breaks down food and releases energy to the cell, it’s like a powerhouse as it provides the cell with energy.

Endoplasmic Reticulum

Endoplasmic Reticulum moves materials around the cell.

2. Classify tissues into the four main groups; epithelial, connective, muscle, and nervous, give an example of each? (Table format will suffice)

There are four main tissue groups within the body, there are some functions and examples below for the four main groups of tissue within the body. All four cells work together in the body.

Ref: (Class Notes 2015)

(www.google.co.uk)

3. Explain the difference between benign and malignant tumours?

A tumour develops when a group of cells escape from their normal orderly process of cell division and they begin to multiply in an uncontrolled way, after a while plenty of these abnormal cells will be produced to form a lump, that is called a growth or a tumour. Two important differences between benign and malignant tumours are invasion and spread.

Benign

Benign tumours do not spread they can grow to a very large size, but it wouldn’t go to other parts of the body. Benign tumours push the surrounding normal tissues and organs out of their way. Occasionally pressure from a benign tumour could damage surrounding structures but the benign tumour never invades into those structures. There are several hundred different types of benign tumours that can develop in our bodies.

Malignant

Malignant Tumours have the power to spread by sending off seelings of tumour which can pass through the blood or lymphatic system to other parts of the body. The Seedlings would then settle in other organs and form what are called secondary tumours or metastases. A malignant brain tumour is a fast-growing cancer that spreads to other parts of the brain and spine, brain tumours are graded between 1 and 4, and a malignant brain tumour is either grade 3 or 4. Most malignant tumours are secondary cancers that mean it starts in one part of the body and spreads to the brain. The primary tumours are the ones that start in the brain. The word cancer only relates to malignant tumours. With malignant tumours it eats away and destroys the normal tissue around the affected area in which it has started off at.

The difference between benign and malignant tumours is that a benign tumour is non-cancerous were as a malignant tumour is cancerous. If has nothing to do with frequency in some of the organs of the body, benign tumours can be very large in size were a cancerous tumour can be very small.

Ref: (Class Notes 2015)

(www.google.co.uk)

Part C

1. Label the urinary system using the diagram overleaf.

The urinary system is one of the human’s body’s waste disposal units and its filtration unit. It contains the kidneys, ureters (tubes connecting the kidneys to the bladder), the bladder and the urethra. The urinary system helps empty the body from potentially harmful waste substances like urea and alcohol. It does this through filtration and excretion.

2. Explain the structure and function of each element of the urinary system?

The urinary system consists of the kidneys, the ureters, the bladder and the urethra. The major function of the urinary system is to get rid of all waste products and excess fluid from the body. The kidneys are the main organs of the urinary system. The urinary system produces a hormone which is responsible for controlling the rate at which red blood cells are made and an enzyme is responsible for controlling blood pressure. Inside each kidney there are approximately 1 million tiny nephrons, they are the units that clean the blood. All of the functions are needed for helping the body to maintain homeostasis also known as balance.

Ref: (www.google.co.uk) (Class Notes 2015)

3. Draw the structure of a nephron and explain how it produces urine?

A nephron is an important functional part of the kidneys. Both kidneys have around a million minute nephrons. Nephrons reside in the cortex and medulla it produces urine from filtrate, filtrate is the fluid that remains in the nephron after filtration its then removed from the bloodstream passing it to the bladder, a nephron is an intricate structure in the body it serves two purposes it filters and removes waste products and maintains the body’s water supply.

Ref: (Class Notes 2015)

4. Name and explain three diseases / disorders which affect the urinary system?

There are a lot of diseases and disorders that affect the urinary system in different ways.

Kidney Stones

Kidney stones are deposits of substances found in urine and would form solid stones in the renal pelvis, bladder or the ureters. It can be extremely painful and if they needed removing it would be done by surgery.

Glomerulonephritis

Glomerulonephritis is a type of glomerular kidney disease in the kidneys the filters become inflamed and scarred and would slowly lose their ability to remove waste and excess fluid from the blood to produce urine.

Cystitis

Cystitis is an inflammation on the bladder and would cause a person pain when passing urine. Sometimes it’s caused from infection. It’s very common in women because of the part of the shorter length of the female urethra.

Ref: (Class Notes 2015)

• Nicole O’Brien