• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Control of Respiration

Extracts from this document...


Introduction The process of gas exchange within the body is know as respiration and has three fundamental stages: * Pulmonary ventilation - also known as breathing, is the inhalation and exhalation of gas between the air outside and the alveoli of the lungs * External respiration - refers to the exchange of gases in the alveoli of the lungs and the blood in pulmonary capillaries, where the capillary blood gains O� and loses CO� * Internal respiration - is the gas exchange between blood in systemic capillaries and tissue cells. This process can also be referred to as cellular respiration. Pulmonary ventilation is a result of alternating pressure differences, between the atmosphere and the alveoli of the lungs, due to contraction and relaxation of respiratory muscles. To enable air to flow into the lungs, the pressure within the alveoli must be lower than that of the atmosphere outside. This can be achieved by increasing the volume of the lungs. The process of pulmonary ventilation is organized by the CNS via the spinal nerves. These spinal nerves innervate the intercostals muscles and the diaphragm by fibers of the phrenic nerves which appear from the spinal cord at cervical levels C3, C4 & C5. The output of these fibers, also known as motor neurons, is controlled by the medullary ryhthmicity area located at the respiratory center in the medulla oblongata in the brain. ...read more.


This in turn causes no response to any input and results in a decrease in the breathing rate, which further lowers the concentration in PO� levels causing it to fall lower creating a positive feedback mechanism to occur. When this happens this could have a fatal result. The purpose of this practical is to determine which arterial gas pressure O� or CO� is the primary drive for respiration in an inactive person of good health. Also the effects of each gas mixtures on the rate of tidal ventilation will be investigated. Materials & Method Materials The equipment and materials used within this practical were as follows: * Dry flow head spirometer with anti-rebreathe valve * 1000L Douglas bag * Nose clip * Mouthpiece * PowerLab digital recording and analysis package * Three gas mixtures: Room Air (79% N�, 20% O�, 0.04% CO� 100% O� 95% O�/ 5% CO� Method Before starting the experiment ensure that the dry spirometer and the computer have been calibrated and that there is enough gas in the Douglas bag each time a new gas mixture is being utilized. The gas selection switch should primarily be set so that the subject is breathing in room air. As soon as the subject is relaxed and seated a nose clip should be placed upon the nose and a mouthpiece in their mouth. ...read more.


With the presence of carbonic anhydrase in the blood CO� is combined with H�O to form carbonic acid (H�CO�). If an increase of H+ molecules occur this causes the breakdown of carbonic acid into H+ and HCO�. This results in an increased amount of H+ present in the blood. When a high concentration of both CO� and H+ is detected the peripheral chemoreceptors become stimulated and initiate responses to brain to restore the concentrations back to normal. As the chemoreceptors participate in a negative feedback mechanism, they cause the inspiratory area to become highly active and produce a change in the rate and depth of breathing. Increased ventilation will occur when high concentrations of CO� are detected as it can be dangerous to have high levels within the body therefore the CO� molecules need to be exhaled out. The frequency of ventilation for each gas had increased; this could have been as a result of the subject hyperventilating slightly due to the conditions in which they were under. Therefore it was essential that that subject was given time to acclimatize each time before they started to breathe in each of the gas mixtures. The highest BPM reading was recorded under the room air gas. The reason as to why this may have occurred is also due to the fact the subject may not have entirely acclimatized before breathing in this air which then caused them to hyperventilate slightly. ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our University Degree Developmental & Reproductive Biology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related University Degree Developmental & Reproductive Biology essays

  1. Nutrition is the relationship of foods to the health of the human body.

    Some of this may be pulled from bone. Medical evidence shows that the body loses an average of 1.75 milligrams of calcium in the urine for every 1-gram increase in animal protein ingested. Additionally, as calcium and other minerals are leached from our bones, they are deposited in the kidneys and can form into painful kidney stones.

  2. Contrast the Biological Differences between Heterosexual Males and Homosexual Males

    After she gave birth, the male offspring exhibited same-sex behaviour (Ward, 1974, 1977, as cited in Ellis & Ames, 1987). This study has been replicated several times since then (Dahlof, Hard, and Larzzon, 1977; Whitney and Herrenkohl, 1977; Gotz and Dorner, 1980; Rhees and Fleming, 1981, as cited in Ellis & Ames, 1987).

  1. Mitochondrial genetics. Are there really only maternally inherited mitochondria in our cells? What happens ...

    So, the paternal mitochondria have some time within the egg when they potentially could distribute their mtDNA (Ankel-Simons, Cummins, 1996; Danan, 1999; Foley, 2003; Hayashida et al, 2005; Kunchithapadam, 1995). 2.2 If the sperm tail penetrates, does paternal mitochondria stay within the egg and automatically become inherited?

  2. The Female Orgasm: Adaptation, Artefact or culturally learned? ( Department of Psychology - University ...

    to seek sexual gratification. This is under the assumption that partial reinforcement produces more persistent behaviour than 100 per cent reinforcement (reward). Hence frustration might be reduced by engaging in additional coitus or different partners ensuring a more regular or varied supply of sperm to ensure conception (Diamond, 1980, p.

  1. The polymerase chain reaction (PCR) is an in vitro technique, which allows the amplification ...

    Individual primers should not contain sequences that are complementary. If they do, amplification of the target will not occur. Fig 3: The synthetic production of oligonucleotide primers6 The production of 5'-AT-3'. Phophoramidite nucleosides are modified with a dimethoxytrityl protecting group on the 5'-end and a �-cyanoethyl protected 3'-phosphite group.

  2. Discuss The Significance Of Normal And Abnormal Mitosis And Meiosis In The Lifecycle Of ...

    When Meiosis II is complete, there will be a total of four daughter cells, each with half the total number of chromosomes as the original cell. Meiosis facilitates stable sexual reproduction. Without the halving of ploidy, or chromosome count, fertilization would result in zygotes that have twice the number of chromosomes than the zygotes from the previous generation.

  1. Should reproductive hormones be used to alter fertility?

    This may explain why events that interrupt the constant cycle of ovulations, such as pregnancy, breastfeeding, and oral contraceptive use, are associated with a decreased risk of ovarian cancer. Another factor is that increased levels of certain hormones associated with ovulation, such as human chronic gonadotropin, increase the risk of ovarian cancer.

  2. The Endocrine systems involvement in the control of the female reproductive system.

    Oxytocin encourages the contraction of the smooth muscle cells in the uterus and around the milk glands in the breasts. Anti diuretic hormone (vasopressin) endorses the re-absorption of water from the urine in the kidney, consequently controlling the salt levels in the blood.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work