Human Body Systems

Monday, July 30, 2012

Dear Students,

Your wiki assignments are due tomorrow, Tuesday-July 31st, if you have any questions about your assigned topics please do not hesitate to ask before the deadline, and make sure you answer all the questions on the blog ( press comment to post your answers)to benefit from them before your exam. Have a great day.

Regards,

Miss Raya .J

Tuesday, July 24, 2012

Respiration / Ventilation

3D animation

This 3D animation is a detailed explaination of how the respiratory system works, this video will help you grasp the whole concept in general. However, i want you to focus on the contraction and relaxation of the muscles as we inhale and exhale and on how the Alveoli functions to have a better understanding.

Below are some interesting websites which i found to be quite helpful and which you could refer to for more information and animation

http://www.argosymedical.com/Respiratory/index.html

http://www.hcc.bcu.ac.uk/physiology/respiration2005.htm

http://netanimations.net/Moving_Animated_Heart_Beating_Lungs_Breathing_Organ_Animations.htm

Wednesday, July 18, 2012

Cellular respiration

The digestive system, breathing and circulation systems all exist to provide the cells of human body with what they need for respiration. During this process, glucose( a sugar produced as a result of digestion) reacts with oxygen to release energy which can be used by the cell. Carbon dioxide and water are produced as waste products.

This reaction can be summed up as follows:

Glucose + oxygen-à carbon dioxide + water (+energy)

The above is called aerobic respiration because it uses oxygen from the air

Aerobic respiration

This type of respiration takes place in mitochondria in cells. These tiny rod shaped bodies (organelles) which are almost found in every cell have folded membrane which provides a large surface area for enzymes involved in aerobic respiration. Muscle cells contain lots of mitochondria because they use a lot of energy.

Why is respiration needed?

Respiration releases energy from the food we eat so that the cells of the body can use it. The cells need energy to carry out the basic functions of life. One of their main functions is to build up large molecules from smaller ones to make new sell material. Much of the energy released in respiration is used for these building activities.

Another important use of energy from respiration is in making muscles contract, muscles are working all the time in our body, even when we’re unaware of using them. For example, when we’re asleep our heart is beating, our rib muscle and diaphragm are contracting as we breathe and so one, and all of these muscular activities use energy.

* Finally we are warm blooded meaning that our body has the same temperature inside almost regardless of the temperature around us.On cold days we use energy to keep our body warm and in hot days we use energy to sweat and keep our body cool.

Anaerobic respiration

The energy release in aerobic respiration in muscle cells allows them to move. However, during vigorous exercise the muscle cells may become short of oxygen- the blood simply canot supply it fast enough. When this happens the muscle cells can still obtain energy from glucose but they have to do it by a type of respiration which doesn’t use oxygen- anaerobic respiration.

This type of respiration produces a different waste product called lactic acid which the body cannot get rid of by breathing in out like it does with carbon dioxide, instead, it needs to be broken down. This needs oxygen and the amount of oxygen need to break down the lactic acid is knows as oxygen debt. Even though our leg muscle stopped working, our heart rate and breathing rate stay high to supply oxygen until we pay off the oxygen debt.

Anaerobic respiration:

Glucose -à lactic acid + energy

Oxygen debt repayment:

Lactic acid + oxygen -à carbon dioxide and water

Questions:

1-–Define both, aerobic and anaerobic respiration? And how do they differ?

2- Aerobic respiration provides energy for the cells of the body, explain why cells need this energy and what do they use it for?

3- If you exercise very hard you often puff for some time after you stop, explain what is happening.

References,

- Fullick, Ann (2001). Biology for AQA. Chicago: Heinemann Educational.

- Brain, J. D. (2006, August). The merck manual home health handbook. Retrieved from http://www.merckmanuals.com/home/lung_and_airway_disorders/biology_of_the_lungs_and_airways/exchanging_oxygen_and_carbon_dioxide.html

- Tamarakin, D. (2011, October 9). Stcc foundation press. Retrieved from http://faculty.stcc.edu/AandP/AP/AP2pages/Units21to23/respiration/alveolar.htm

- Peter. (2012). Anaerobic respiration articles. Retrieved from http://www.anaerobicrespiration.net/general/simple-definition-of-aerobic-and-anaerobic-respirations/

In relation to the breathing system

Gas exchange in the lungs

Breathing in supplies us with oxygen needed for cellular respiration, while breathing out removes waste carbon dioxide from our body, air is breathed to the lungs oxygen passes into the blood by diffusion (movement of molecules or particles from regions of higher concentration to regions of lower concentration)along a concentration gradient. At the same time, carbon passes out of the blood into the air of the lungs also by diffusion along a concentration gradient. This gas exchange takes place in the alveoli which are the tiny are sacs with large surface area that make up much of the structure of the lungs.
The movement of oxygen into the blood and carbon out of the blood take place at exactly the same time-there is swap or exchange between the two, so this process is known as gaseous exchange.

Gas exchange in Alveoli

Air in the lungs ends up in the alveoli which are tiny air sacs that provide an ideal site for most effective possible diffusion. They have a large surface are which is always kept moist. This is effective for most effective diffusion of the gases. The alveoli also have a rich blood supply so that a concentration gradient is maintained in both directions, oxygen is removed into the blood and more carbon dioxide is delivered to the lungs. This makes sure that the gas exchange can take place along the steep concentration gradients for it to occur as rapidly as effectively as possible.

Questions:

1- Explain fully, the function of the lungs, alveoli, diaphragm and ribs

2- True or false :

a) The breathing movements do not cause change in the volume only in the pressure of chest during ventilation.

b) The movement of air is brought about by both the ribs and the diaphragm.

c) Oxygen in the lungs from the air diffuses into the blood stream a while after carbon dioxide from the blood diffuses out of the bloodstream into the air.

d) The alveoli provides a very large moist surface area, richly supplied with blood capillaries to allow most efficient possible gas exchange.

References,

- Fullick, Ann (2001). Biology for AQA. Chicago: Heinemann Educational.

- Brain, J. D. (2006, August). The merck manual home health handbook. Retrieved from http://www.merckmanuals.com/home/lung_and_airway_disorders/biology_of_the_lungs_and_airways/exchanging_oxygen_and_carbon_dioxide.html

Thursday, July 12, 2012

Breathing System

How is air brought to lungs?

The job of the breathing system is to continually move air into the lungs and then move it out again. This is brought about by movement of the ribcage which we feel, and by movements of the diaphragm which unfortunately we cannot feel nor see.
When we breathe, our ribs move up and out, and the muscles of the diaphragm contracts so it flattens from its normal domed shape thus pulls air into the lungs. However, when we breathe out what happens is that the ribs move in and down and the diaphragm returns back to its domed shape, forcing air outside of the lungs.

This movement of air in and out of the body is known as ventilation

Ventilation as part of the breathing system

The breathing movements are brought about by
two different sets of muscles which change the pressure in the chest cavity. The intercorsal muscles between the ribs contracts pulling them upward and outward at the same time as the diaphragm muscles contract to flatten the diaphragm. These two movements increase the volume of the thorax and because the same amend of gas is now inside a much bigger space, the pressure inside the chest. This in return means the pressure inside chest is lower than the air outside therefore as a consequence, air moves into the lungs. Then, both the intercorsal and diaphragm muscles relax, the ribs drop and diaphragm domes up. The volume of the thorax is decreased and so the pressure inside the chest increases causing air to be squeezed and forced outside the lungs.

Questions:

1-– How are the lungs adapted to allow gas exchange to take place as effective as possible?

2- What is the difference in composition between inspired and expired air?

3- Explain fully how air is moved in and out of the lungs in human’s respiratory system?

References,