Lecture notes
Circulatory Systems in Animals
- Institution
- University Of Lincoln (UoL)
Covers the different types of circulatory systems in different animals and how they function.
[Show more]
Seller
Follow
Content preview
Comparative Anatomy and Physiology in AnimalsLecture 3 Circulatory Systems of Animals 20/10/20
- All cells need nutrients and oxygen and to have waste products, such as CO2, to be removed.
- Size and structural complexity is critical to the evolution and organisation of circulatory
systems.
Definitions
- Blood vessel- a tubular structure carrying blood through the tissues and organs (a vein, an
artery, or a capillary).
- Heart- a muscular organ in most animals, which pumps blood through the blood vessels of
the circulatory system.
- Blood- a body fluid in animals that delivers necessary substances such as nutrients and
oxygen to the cells and transports metabolic waste products away from those same cells.
- Haemolymph- a body fluid that is a mixture of blood and interstitial fluid.
Platyhelminthes and Nematoda
- Flatworms have relatively short distances between organs and so rely on diffusion for gas
exchange and nutrient delivery.
- In large turbellaria, diffusion distances are increased so they have gut ceca in which cilia
move digestion products nearer the edges of the body.
- Nematodes are small (most <2.5mm long) and do not need a circulatory system.
Annelida
- Annelid worms are large and segmented and require a circulatory system.
- Each segment has a coelom filled with fluid, which is circulated by cilia on the internal walls,
and muscle contractions.
- Body organisation requires a well-developed haemal system of blood vessels and hearts to
provide transport through the body.
- Annelids have blood enclosed in a network of blood vessels that is a closed system. Blood is
pushed through the dorsal blood vessel from the anterior (head) end by the contractile walls
of the blood vessel itself.
- Within a segment blood then flows into a capillary network around the gut and then enters
the ventral blood vessel, in which it moves towards the posterior (tail) end of the worm. In
this way respiratory gases, nutrients, and waste products can be transported around the
body to all tissues.
- The blood is pushed through the vessel via peristalsis.
Molluscs
- Increased size and body plan complexity mean that molluscs have a well-developed
circulatory system.
- Heart with pair of atria and a medial ventricle with a dorsal aorta. Other vessels transport
haemolymph but connect to haemocoel, such as the dorsal aorta, blood vessels and
haemolymph.
- The heart has one or more pairs of atria, which receive oxygenated blood from the gills.
- These empty into the medial ventricle, which is continuous aorta, which branches to smaller
vessels to deliver blood to haemocoelic sinuses in the head, foot and bathe the visceral
mass.
- Blood then passes over the nephridia and returns to the heart by afferent branchial vessels.
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 chloegalvin. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £6.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
64438 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