Summary
Summary Transport in Animals A Level Biology
- Module
- Transport in Animals
- Institution
- OCR
Revision notes for Biology Transport in Animals OCR Biology A As/A Level
[Show more]
Seller
Follow
Content preview
TRANSPORT IN ANIMALSOPEN CLOSED
Explain the need for transport systems in multicellular Very few vessels to contain transport medium Blood enclosed in blood vessels
animals Pumped stsraight from heart to body cavity Doesn't come directly into contact with body cells
In body cavity (haemocoel) medium is under low pressure Heart pumps blood around body under pressure
• Low SA:V as we get bigger, diffusion not enough. Comes into direct contact with the tissues and the cells Substances enter & leave blood by diffusion through vessels
Medium returns to heart through open-ended vessel Blood flow adjusted by widening/narrowing vessels
• Increased metabolism – more O2 and nutrients required. Invertibrate animals; most insects All vertibrates and starfish.
• To remove waste e.g. CO2.
SINGLE DOUBLE
Fish; annelid worms Birds and most mammals
Blood flows through heart once for each circulation Blood flows twice through heart for each complete circulation
Blood flows through two sets of capillaries Blood pumped from heart to lungs = get O2 and unload CO2
Blood returns to heart slowly due to very narrow vessels Blood flowws through heart and is pumped around the body
Low pressure = low efficiency of exchange so activity in these High activity of these animals maintained by high pressure
animals are low except for fishes as there are 3 vessels
Exception: fish = countercurrent gas exchange; don't maintain
their body temp.
Describe how tissue fluid is formed from plasma
• At arterial end of capillary, blood is under high pressure
(hydrostatic pressure).
• This tends to push out blood fluid from the capillaries.
• Can leave through tiny gaps in capillary wall
• Contains plasma with dissolved nutrients and O2.
ARTERIES CAPILLARIES VEINS
Carry blood at high pressure Once cell thick - short diffusion diffusion Carry blood at low pressure
Carry oxygenated blood (except pulm. artery) Where most exchange occurs Carry deocygenated blood (except pulm. vein)
Small lumen = maintain pressure Lumen same size as RBCs Large lumen = ease blood flow
Thick wall with collagen - withstand pressure Many of them - large SA for diffusion Thin walls - no pressure to maintain
Elastic tissue- allow wall to stretch and recoil (pulse) Valves - prevent backflow of blood
Smooth muscle - constrict and contract Carry blood to heart
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 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 maroagbaire. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £5.00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
66579 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now