Explain the transportation of oxygen and carbon dioxide in the blood.

Oxygen is transported in the blood by (RBC). It binds with a substance in red blood cells called haemoglobin. Haemoglobin is made up of iron and simple proteins.
When oxygen and haemoglobin bind it is called oxyhaemoglobin. When the red blood cells reach cells in the body where oxygen is needed the process of binding is reversed and the oxygen diffuses into the cells once again leaving haemoglobin in the (RBC).
The waste product from the cells is called carbon dioxide. This diffuses into the (RBC) and it makes carbonic acid by combining with the water. This process is made faster by an enzyme called 'carbonic hydrase'

Ref:-www.miracleofthebloodandheart.com/4_dif_image006_0000.jpg

Edited by Parsons.R,Undated,GCSE Double Science Biology The Revision Guide Higher Level,Newcastle upon Tyne,Coordination Group Publications LTD.

CGP Class handouts.

Describe the structure of a red blood cell and explain how this relates to its function.

Red blood cells (RBC) are bio-concave in shape to give maximum surface area for the absorption of oxygen. They contain haemoglobin which when combined with oxygen makes oxyhaemoglobin which is what gives blood its bright red colour.
(RBC) have no nucleus to make more room for Haemoglobin.
(RBC) are very small. They are only 1/25,ooo of an inch big. They are also very flexible to enable them to squeeze there way through small spaces.
A(RBC) has a life span of aprox 120 days and then it is destroyed by the phagocyte cells. Old cells that are destroyed are constantly replaced by new (RBC) made in the bone marrow.

Ref:-Image from http://www.fi.edu/learn/heart/blood/images/red-blood-cells.jpg

CGP Handouts.

Describe the components of plasma and explain their functions.

Plasma is made up of mainly water, but it also carries Red blood cells, white blood cells, platelets, carbon dioxide, urea, hormones, antibody's and antitoxins and nutrients such as amino acids and glucose.

Red blood cells.

These carry oxygen from the lungs to all the cells in the body, in the form of oxyheamoglobin. They also carry carbon dioxide back to the lungs from the cells to be expirated.

White blood cells.

White blood cells defend the body against disease. They do this by consuming bad micro organisms and by producing anti body's that fight bacteria and anti toxins that neutralise toxins that bacteria have secreted into the body.

Platelets.

Platelets are very small bits of cells. They float around in plasma and are needed to help the blood clot and form a scab which stops the loss of blood and prevents infections from entering the body.

Urea.

Urea is secreted by the liver and is excreted in small amounts in sweat and also in urine.

Hormones.

Hormones are 'chemical messengers' that are carried in the blood. They are produced by the endocrine glands and only have an effect on target cells.

Nutrients.

These are needed by the body to repair it and to provide energy.

Some substances dissolve into the water in the blood and are carried in 'solution' and some do not dissolve and are carried in 'suspension'.

Ref:-Image from http://www.media-2.web.britannica.com.leb-media/71/91871-034-DA6BAO42.jpg

CGP Handouts

Edited by:-Parsons.R,Undated,GCSE Double Science Biology The Revision Guide Higher Level,Newcastle upon tyne, Coordination Group Publications LTD.

Describe the role of the nervous system in generating breathing rhythm.

Nerve impulses are passed from the brain down the brain stem and along the spinal nerves to the diaphragm and intercostal muscles. This causes the contraction and relaxation of the diaphragm and intercostal muscles during breathing.

The area of the brain that these spinal nerves carry impulses from is called the 'Medulla oblongata' also known as the Respiratory centers. The Respiratory is connected to a second Respiratory center in the 'Pons'.

The two respiratory centers allow for automatic breathing.

The respiratory centers can be over ridden by a part of the brain called the 'cerebella cortex'. This allows for us to control our breathing rate and hold our breath, all thoe this control can only be exerted for a short time at which point the medulla oblongata and the pons would override the cerebella cortex and automatic breathing would begin again.

The pons control the standard rate of breathing but it is also connected to the medulla and sensors that detect oxygen and carbon dioxide in the blood to allow for the breathing rate to change.

Ref:-Image from http://www.media-2.web.britannica.com/eb-media/71/91871-034-DA6BA042.jpg

Evaluate the conditions necessary for effective gaseous exchange.

There needs to be many alvoli in the lungs to provide a large surface area so that maximum gaseous exchange can take place.

The oxygen moves from the alveoli into the capillaries and carbon dioxide moves from the capillaries into the alviolis. This process is called diffusion. For diffusion to take place the walls of the alveoli and the capillaries are only 1 cell thick.

Inspiration (breathing in) and expiration(breathing out) is controlled by a part of the brain called the medulla.

Damage or disease to this part of the brain or any part of the airway can result in inadequate gaseous exchange.

Ref:-Image from http//:www.image.tutorvista.com/content/respiration/alveolus-of-man.jpeg

Describe the structure of the respiatory system and relate this to the process of ventilation.

The Nasal Passages.

Are two passages made up of cartilage through which the air is drawn into the body. They contain Goblet cells which produce mucus and cilia cells which keep the mucus moving. Mucus traps and prevents infections from entering the body. The nasal passages also moisten and warm air before it enters the Pharynx.

Pharynx.

This is the space behind the nasal cavity and above the Larynx.

Epiglottis.

Small flap of tissue that covers the trachea during swallowing to prevent foreign objects from entering and causing choking.

Larynx.

Also known as the voice box. It has two membranes and air passes through causing the vocal cords to vibrate and produce sound.

Trachea.

The Trachea is the airway also known as the windpipe. It is kept open by the rings of cartilage in its walls and allows the air to pass into the lungs.

Bronchi.

The Trachea splits into two tubes called Bronchi.

Bronchioles.

This is where the Bronchi branch off into smaller and more extensive tubes inside the lungs.

Alveoli.

Many small sacks at the end of the Bronchioles where gaseous exchange takes place. The walls of the Alveoli are only 1 cell thick to allow for the diffusion of oxygen and carbon dioxide and are numerous to provide greater surface area for gaseous exchange.

Lungs.

Located on either side of the heart. The right Lung has 3 sections and the left only 2. This enables room for the heart to sit in a space known as the cardiac notch. They are surrounded by a pleural membrane and in between is a pleural fluid that both protect the lungs from friction.

Ref:- Image from www.andrewparisi.com/tobacco/images/respiratorysystem.jpg

Evaluate the effects of smoking on body systems.

Nicotine is not carcinogenic but is toxic and in high doses can be lethal. Damage caused to the body is :-

• Lung diseases-chronic obstructive pulmonary disease, including corany heart disease, heart attacks and strokes are higher in smokers.
• Nicotine causes constriction of blood vessels resulting in high blood pressure and raising the heart rate.
• Smokers blood becomes thicker and stickier which puts extra stress on the heart and causes damage to the inside of blood vessels, which may lead to atheroma.
• Poor circulation to the extremities (hands and feet) can cause neuropathy.
• Smoking damages the mouth, teeth, gums and may cause ulcers of the digestive system.
• Osteoporosis caused by leeching of calcium from the bones leaves smokers more prone to fractures and Avascular Necrosis.
• Hydrogen cyanide damages the cilia in the respiratory tract and harmful chemicals can then collect in the lungs, stopping effective oxygenation of blood in the lungs.
• Carbon oxide binds with haemoglobin before oxygen. So because less oxygen is carried in the blood, more stress is put on the heart to pump blood around the body faster to deliver much needed oxygen.
• Tars can cause cancer of the throat and oesophagus .
• It causes the stomach to increase its secretion of acid which can cause heartburn and stomach ulcers.
• Bladder cancer can be caused by carcinogenic chemicals present in urine.
• High blood pressure causes damage to kidneys.
• Women's fertility can be lowered and an increase in cervical cancer.
• Men may suffer a low sperm count , abnormal sperm, low sperm mobility and decreased sex hormones. Decreased circulation may cause impotence.
• Immune system is impaired, making it harder for the body to fight infection.
• Skin becomes dry causing premature ageing.
• Miscarriage is more common in women who smoke.
• Smoking while pregnant or around children increases the risk of low birth weight, premature births, cleft lip palate, infections and Sudden Infant Death Syndrome (SIDS)

Looking at the risks above the amount of health risks associated with smoking far outweighs the reasons not to quit.

Ref:- Image from www.topnews.in/health/files/smoking-cigarette.jpg

www.free-online-health.com/smoking-health.htm (accessed 03/05/2010)