Summary of the topic gas exchange from Campbell Biology a Global Approach, 11th edition. This summary includes notes of accompanying MasteringBiology assignments, lectures and any lectures.
Summary of the topic of gas exchange from Campbell Biology a Global Approach, 11th edition. This summary inc...
Gaswisseling (BOOK)
43.5
Partial pressure is the pressure exerted by a particular gas in a mixture of gases. A gas
always undergoes net diffusion from a region of higher partial pressure to a region of lower
partial pressure.
Gills are outfoldings of the body surface that are suspended in the water. In fishes, the
efficiency of gas exchange is maximized by countercurrent exchange, the blood flows in a
direction opposite to that of water passing over the gills. As the blood continues it passage
its Po2 steadily increases, but so does that of the water (countercurrent exchange). This
results in a partial pressure gradient that favors the diffusion of O2 from water to blood
along the entire length of the capillary.
A tracheal system (insects) is a network of air tubes that branch throughout the body. The
biggest parts are the trachea which are exposed to air.
In addition to tracheal systems, lungs are localized respiratory organs. In humans air passes
the trachea from the larynx. The trachea branches into two bronchi, which branch into finer
tubes called bronchioles. Alveoli are air sacs clustered at the tips of the tiniest bronchioles.
Alveoli produce a mixture of phospholipids and proteins called surfactant, which coats the
alveoli and reduces surface tension, which prevents the alveoli form collapsing due to the
high pressure.
43.6
Amphibian
Positive pressure breathing is inflating the lungs with forced airflow.
Birds
Passage of air through the entire system requires two cycles of inhalation and exhalation;
43.7
Mammals
, Negative pressure breathing is pulling air into the lungs.
The lungs are surrounded by two membranes, the inner one adheres to the outside of the
lungs and the outer one two the wall of the thoracic cavity. The two layers are separated by
a piece of fluid which makes it impossible to separate them (like two plates with water
between it).
The tidal volume is the volume of air inhaled and exhaled with one breath (about 500mL in
rest). The vital capacity is the vital volume during maximum inhalation and exhalation (about
3.4 (v) and 4.8 (m) L). The air that remains after forced exhalation is called the residual
volume.
The most neurons which are responsible for regulating breathing are located in the medulla
oblongata, near the base of the brain. The medulla uses pH as an indicator of CO2
concentration. CO2 can react with H2O and form H2CO3 which can react to HCO3- and H+,
which lowers the pH. So when CO2 rises the pH rises. O2 has almost no effect on regulating
the breathing system, but when O2 levels drop very low, O2 sensors in the aorta and the
carotid arteries in the neck send signals to the breathing control centers.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller stijnvantrijp. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R68,65. You're not tied to anything after your purchase.
