Essay
Biological cycles essay
- Course
- Institution
A cycle is a biological pathway or process in which the end product of one cycle becomes the starting point for the next. Write an essay about cycles in biology.
[Show more]
Seller
Follow
sophiemitchell1
Reviews received
Content preview
A cycle is a biological pathway or process in which the end product of one cycle becomes thestarting point for the next. Write an essay bout cycles in biology.
Cycles play a massive part in biology. In humans, the cardiac cycle is essential for maintaining life,
using oxygen from the mechanism of breathing to sustain aerobic respiration. This, in turn,
producing ATP from ADP and Pi, allowing phosphate to be incorporated into an organism biomass,
providing a starting point/product for the phosphorous cycle.
Oxygen is present in many biological cycles; aerobic respiration, photosynthesis and the mechanism
of breathing in humans. In order to receive the oxygen needed for aerobic respiration, humans must
take in oxygen from the air. This is done through the mechanism of breathing. Breathing is an active
process, requiring muscle contraction and relaxation to occur. For inspiration to occur, the external
intercostal muscles must contract, and as muscles work in pairs, the internal intercostal muscles
relax. This causes the ribs to be pulled upwards and outwards, increasing the volume of the thorax.
The diaphragm muscles also contract, causing it to flatten, further increasing the thoracic volume.
This increased volume results in a reduction of pressure in the lungs. Atmospheric pressure is now
greater than pulmonary pressure, causing air to be forced into the lungs. Once air is forced into the
lungs, oxygen diffuses across the alveoli epithelium and into the red blood cells found surrounding
the alveoli. Carbon dioxide diffuses out of the red blood cells into the alveoli, down its concentration
gradient. This carbon dioxide then leaves to leave the lungs so the cycle can restart. The external
intercostal muscles relax and the internal intercostal muscles contract. This pulls the ribcage down
and in, increasing thoracic pressure. The diaphragm also relaxes, so is pushed up against the
contents of the abdomen, further increasing the thoracic pressure. Atmospheric pressure is then less
than pulmonary pressure, resulting in air being forced out of the lungs. The cycle then starts again,
meaning the lungs are ventilated to maintain a steep concentration gradient of oxygen into the red
blood cells and carbon dioxide out of them. During normal breathing, the recoil of elastic tissue in
the lungs is the main cause of air being forced out. This is known as passive breathing. When
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 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 these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller sophiemitchell1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $8.39. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
53022 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now