Saturday, October 31, 2009

The Regulatory Mechanism in Respiration

Relationship between the rate of respiration and the oxygen and carbon dioxide contents

  • Muscles require more Oxygen and glucose during vigorous exersice in order to release energy during cellular respiration
  • this lead to an increase in the heart beat which
  • caused the increase in the rate of respiration
  • as the rate of respiration increases, the supply of glucose and oxygen for cellular respiration increases
  • thus more carbon dioxide can be removed from the cell.

Explain the response of human respiratory toward different situation:

1. During vigorous activity such as running, aerobic exercise

  • Breathing rate increases
  • Heartbeat rate increases
  • the increased in heart beat helps the blood to deliver more oxygen
  • and more glucose to the respiring cells.

2. In fear

  • breathing rate increases
  • adrenal gland secrete adrenalin
  • causing an increase in heart beat

3. At high altitude

??

SPM 2007- essay No.6

  • Explain cellular respiration (aerobic and anaerobic ) in muscle tissue and yeast cell.

  • Explain the difference in physiological process of two individuals: vigorous activity and at rest. (lung, heart, kidney)

  • Explain the differences in % of dissolved oxygen and carbon dioxide in the pond based on graph given.

The regulatory mechanism of oxygen and carbon dioxide contents in the body.

  • Breathing is an involuntary action controlled by respiratory centre.

  • The respiratory centre is located in the medula oblongata.

  • Chemoreceptor function to monitor the chemical content of the blood

  • Both aortic and carotid bodies are sensitive to the oxygen exchange in the blood.

  • and also sensitive to pH values of the blood and carbon dioxide content.

Take note:
1.The regulatory mechanism during vigorous exercise. (The Flow chart showing the sequence of event )

2. The regulatory mechanism of the oxygen content in human body


The importance of maintaining a healthy respiratory system
..Smoking...........................Experiment in the Lab..

Related QS:


1. Explain how smoking would change the structure of alvelous [2 marks]


Answer:

F1-Damage the alveoli wall
P1-Reduces total surface area
F2-Heat (release by burning cigarette)
P2-(increase body temperature) damage the tissue lining of alveoli
F3-Tar
P3-Deposits on the alveolus, reduce the efficiency for gases exchange
F4-Acidic condition
P4-Corrodes/damages the alveolus


2. How would carbon monoxide in the cigarette smoke affect the rate of cellular respiration ? [3 marks]
Answer:

P1: Carbon monoxide competes with oxygen to bind with
Haemoglobin to form carboxyhaemoglobin
P2: It reduced the supply oxygen to cell
P3: thus reduce aerobic respiration


3. Explain how smoking can decrease the efficiency of the function of R in respiration. [3 marks]


Answer:
-Smoke contains tar, nicotine, carbon dioxide and heat / high temperature.
-tar deposited at alveolus wall / R decrease the permeability towards the respiratory gases/ rate of diffusion of respiratory gases / gaseous exchange.
- Air inhaled contains more CO2, decrease the gradient of oxygen and carbon dioxide diffusion.
-Alveolus wall less moist / dry, decrease the rate of diffusion of respiratory gaseous.

and you should be able to explain at least THREE diseases caused by cigarrate contents:

Tobacco smoke contains over 4,000 different chemicals. At least 50 are known carcinogens (cause cancer in humans) and many are poisonous.

i. benzene & Formldehyde

ii.Nicotine

iii.tar

eg: Lung cancer...actually caused by carcinogenic substances such as BENZENE and FORMALDEHYDEs in Tobacco. TAR can also cause lung cancer

Nicotine is a drug in tobacco causing addiction BUT NOT Lung cancer.

  • When a person smokes a cigarette, the body responds immediately to the chemical nicotine in the smoke.
  • Nicotine causes a short-term increase in blood pressure, heart rate and the flow of blood from the heart.
  • It also causes the arteries to narrow.
  • The smoke includes carbon monoxide, which reduces the amount of oxygen the blood can carry.
  • This, combined with the nicotine effects, creates an imbalance between the demand for oxygen by the cells and the amount of oxygen the blood can supply.
  • How does nicotine in cigarettes increase the risk of heart attack?
  • Cigarette smoking may increase the risk of developing hardening of the arteries and heart attacks in several ways.
  • First, carbon monoxide may damage the inner walls of the arteries,
  • encouraging fatty buildups in them.
  • Over time, this causes the vessels to narrow and harden.
  • Nicotine may also contribute to this process.
  • Smoking also causes several changes in the blood that make clots — and heart attack — more likely.

TAR- Particulate matter drawn into lungs when you inhale on a lighted cigarette.

  • Once inhaled, smoke condenses and about 70 per cent of the tar in the smoke is deposited in the smoker's lungs.
    Tar is a major cause of lung cancer, emphysema and bronchitis.
  • It also kills the cilia in the lining of the lungs.
  • The more visible effects are discoloring of the teeth, fingernails, gum disease, mouth cancer and many more very dangerous effects.

***Cigarretes do not cause asthma please...For your SPM, just take note of the above diseases...

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