body systems

P3+p4

Unit 10:- Human Physiology for Health and Social Care

P3+p4

For the human to survive and function properly, we need energy to let the cells repair themselves. To get this energy, we need to consume three main substances;

Carbohydrates (one of the three main classes of food and a source of energy. Carbohydrates are the sugars and starches found in breads, cereals, fruits, and vegetables, which, during digestion, are changed into a simple sugar called glucose. Glucose is stored in the liver until cells need it for energy.)
Protein (A naturally occurring combination of amino acids. Protein is one of the essential components of all living things and the diet of animal organisms.) and,
Lipids (Another term for fats that can be broken down into fatty acids.)

It is important to eat a healthy amount of the substances found above because food provides energy that the cells need to develop, change, and multiply. It also provides them with energy so they can repair themselves. Consecutively the carbohydrates, protein and lipids need to be digested and broken down so that the body can acquire the energy from them. Digestion occurs both physically and chemically.

Physical digestion involves the chewing of the food; (carbohydrates, protein and lipids) and the processes of moving food down the intestines by the muscles contracting and relaxing and in turn squeezing the food along the tubes. This is called peristalsis. The diagram below shows how the muscle movement moves the content of the intestine forwards:

Chemical digestion works with physical digestion, and it involves the enzymes that break up food. During the process of digestion, about 5 liters of liquids are produced to break the food down; this usually takes place in the large intestine. The liquid that is produced is made up of mainly water but it does contain important enzymes and other substances, which are vital during digestion.

The first sign of enzymes are when the food is in the mouth, and being chewed; amylase is found in the saliva and it breaks down carbohydrates in the food. An enzyme ...

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The first sign of enzymes are when the food is in the mouth, and being chewed; amylase is found in the saliva and it breaks down carbohydrates in the food. An enzyme called pepsin is released in the gastric gland, and this contains hydrochloric acid, which digests protein and breaks it down into amino acids, the pepsin digests protein by breaking it into smaller peptides that can be absorbed by the small intestine. In the liver, bile is produced, this breaks lipids into smaller droplets as they are to big to be absorbed by the blood in the beginning There aren’t any enzymes found in the bile salts because they act as warmth and melt the lipids so they form smaller droplets. Then they are absorbed through the intestine wall as small beads.

The pancreas produces a large amount of liquid, (insulin) shortly after food is eaten. The insulin that is produced contains three enzymes:

Lipase (digests lipids (fat))
Amylase (digests starch (carbohydrate))
Trypsin (digests protein)

The intestine glands complete the digestion process when the wall of the intestine absorbs all of the needed energy. They have a large surface area which means they can absorb large amounts of liquids at any time, meaning maximum energy is produced from the food eaten.

Below is a diagram showing the digestive system.

As part of a fully functioning human body, the body needs to maintain a constant internal environment. Homeostasis is when an organism maintains the constant internal conditions necessary for life. The heart rate, body temperature, breathing rate and the blood glucose levels all have constant internal conditions. The way this is achieved can be shown through flow charts; I am going to draw one for each of;

Heart rate
Body temperature
Breathing rate and,
Blood glucose.

This will help to explain how these homeostatic environments are attained. To be in homeostasis the organs internal environment must:

Contain the optimum concentration of gases, nutrients, ions and water
The optimum temperature
Have the optimum pressure for health cells.

Blood glucose

After you have eaten a carbohydrate rich meal, an excess of glucose is taken into the bloodstream at the small intestine. This then goes into the liver, where it is eventually absorbed and converted into glycogen. If the rate of glucose intake in the gut is higher than the rate of oxidisation then the sugar levels in the body may rise temporarily. When this happens, the pancreas secretes insulin to bring the sugar levels back down to normal. If there isn’t enough sugar in the body then an opposite reaction is caused; glycogen, along with other hormones, are stimulated to tell the body that there isn’t enough sugar there, this is when glucose is added to the bloodstream, therefore making the sugar levels go back to normal.

Heart and Breathing rate

Above is a diagram showing the breathing rate of a human,

The breathing rate is another system in the body that needs a constant rate in order to stay healthy. The stable breathing rate in an adult is between 15 and 25 breaths per minute this however; this increases when someone exercises and when someone becomes nervous or scared. Their breathing rate increases because there muscles and other cells in the body need more oxygen because they need to work harder… so larger amounts of oxygen is inhaled so the rate of breathing increases. The heart rate is the number of times the heart pumps blood around the body and the amount of beats per minute. In order to have a homeostatic heart rate it needs to be at a constant rate. The heart pumps blood around the body because the organs and tissues need oxygen to survive. This one function does have some inconsistency.

Body Temperature

The ability to control body temperature is extremely important if we are to survive, the bodily temperature is a system where there is room for slight variation, if our temperature rises or falls below or above 37°C (a human’s average body temperature) then we will begin to feel quite ill. There are lots of different factors that contribute to our body’s temperature. For example if we exercise, our body temperature goes up; this is when our sweat glands open so we can sweat. Sweating is a way our bodies cool down, which is inevitable. Below is a diagram that shows how our body reacts when our temperature drops and rises.

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