Respiration

5/26/11
Yunsu Y.
Respiration notes:
** The respiration that we are talking about is not the same as cellular respiration!
1. Respiratory Surfaces:
** not all organisms have respiratory systems: bacteria don't have because their surface area to volume ration is large so diffusion can occur, but for humans our surface area is too small so we need respiratory systems.

• Earthworm: has moist skin=making diffusion across body surface easier.
  


• Aquatic Organisms: gills extend from the body which increases surface area and they are surrounded by water so that diffusion can occur.
  


• Terrestrial Organisms: respiratory surfaces fold into the body. The system is inside lined with moisture (mucus), needed for diffusion.


• Insects: tracheae and no circulatory system to transport O2.

2. Human Respiratory System:

• Breathing: the moist insides are exposed to air, then O2 dffuese into blood vessels and CO2 to the lungs.
  


• Circulatory System: trasnport O2 to all body cells and O2 back to lungs.


• Diaphragm: Sheet of muscle-important for breathing.


• Pharynx: where the digestive and respiratory systems meet.


• Larynx: voice box, we produce sounds by breathing out and the air moves the vocal cords making them vibrate.


• Trachea: windpipe, somtimes food gets caught here causing us to cough or choke.


• Bronchi: Lead to each lung


• Bronchioles: smaller branches


• Alveoli: cluster of air sacs. These are like the villi and microvilli found in the small intestine. This is where gas exchange occurs with blood vessels. These increase the surface area=more gas exchange.

Aveoli close up

3. Taking a Breath

• When the diaphragm contracts air is "PULLED" into the lungs. This is increasing the volume and decreasing the pressure. High pressure outside wants to get inside to the low pressure. (high to low!)--------- Negative Pressure breathing.
  


• When diaphragm relaxes when the air is "PUSHED" out of the lungs. There is a decrease in volume and an increase in pressure.
  

4. Controlling our breathing:

• Nerves in the brain regulate our breathing. Nerves tell the diaphragm when to contract and relax.
  


• 10-14 inhalations per minute. (average)


• This average will change depending on CO2 levels. The more CO2 in the blood, the faster the respiration rate.
  


• Hyperventilation: Purges blood of CO2 that brain stops sending messages to the diaphragm. This causes people to pass out but breathing into a paper bag helps by increasing the amount of CO2 taken in.

5. Hemoglobin: Binds to oxygen.

• Consists of 4 polypeptide chains, heme (chemical group) and iron- gives blood the red color.


• Each iron atom can bind to 1 O2 molecule=each hemoglobin can carry up to 4 O2 molecules.


• O2 rich blood is bright red and O2 poor blood is dark red or blue.

6. Problems:

• Iron deficiency cause anemia
  


• When hemoglobin binds to CO (carbon monoxide)=Bad! Now the hemoglobin cannot bind with oxygen because the bond is too strong on the CO. This interferes with the delivery of O2 to the body cells and cellular respiration=death. Also found in cigarette smoke. \

7. Effects of Smoking:

• Pollutes air


• Contains many harmful chemicals damaging mucus and cilia making it hard to remove foreign particles. = smokers cough.


• Smoking kills ~430,000 Americans per year.


• Emphysema: disease that causes alveoli to disintegrate. = reduces lungs' ability to exchange gas and causes breathlessness and fatigue.
  

HW: Study for Fetal Pig Dissection Test TOM!!
Lab 54&55 due tom with cover page and color code the pictures
U.P 47-51 and 55-56 due TUESDAY

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