Chapter 8 Circulatory Systems Flashcards
Why do animals need a specialised transport system?
High metabolic demands
Small SA:V so
Large diffusion distances between exchange surfaces are inner most cells
Transport of substances within the body e.g enzymes moving about
Rate of diffusion too slow to sustain metabolism
What features do transport systems share in animals?
Liquid transport medium
Vessels that transport this medium
A pumping mechanism
What is an open circulatory system? Where is it found and does what?
Blood pumped from the heart into the body cavity of an animal, entering the enlonged heart freely
Invertebrates like insects
Transports glucose and removes waste, does not transport CO2 and O2
What is a Haemocoel and Haemolymph?
Coel- body cavity of the organism in open circulatory
Haemolymph- transport medium of OC
What are disadvantages of an open circulatory system?
Steep diffusion concentration gradient is not maintainable- not efficient
Amount of haemolymph cannot be controlled like with humans
What is a closed circulatory system? What types exist. e.g?
Blood is transported enclosed in blood vessels, and does not directly come in contact with the body cells
Single=Fish Double=Mammals
Describe what happens in single circulatory, how is it different from double, including structures
In single, blood travels through the heart once in a complete circulation- 1 ventricle and 1 atrium
In double, blood travels through the heart twice in a complete circuit- 2 ventricles and 2 atria
Why is a double circulatory more efficient than single?
Pumped twice, meaning high pressures can be maintained, so a faster flow of blood
In single, the two sets of capillaries with only one pump slow it down
Why are fish an exception of the impact of single circulatory?
Efficient circulation, very active
Counter current, body weight supported by water, and they do not need to maintain their body temperatures so lower metabolic demands
What is the order of components of blood vessels, outer to inner
Collagen
Smooth Muscle
Elastic fibres
Thin layer of epithelium
Lumen
How is the structure of arteries linked to function?
Carry (oxygenated) blood at high pressures
Collagen layer thick, provides strength to withstand pressure
Smooth muscle controlling the amount of blood flow, thinner, and to provide strength
Elastic fibres which stretch, and recoil= elastic recoil, to push blood between pulses to help keep constant movement
Thin layer of epithelium to provide a smooth surface, reducing friction
Narrow lumen to maintain pressure
How do arterioles differ to arteries?
Thinner elastic and collagen layer as hydrostatic force less, lower pressure
More smooth muscle to allow more vasodilation and vasoconstriction
How are capillaries adapted to their function?
Producing tissue fluid to exchange useful substances to tissues
Fenestrated to form tissue fluid
Allows movement of one cell at a time, slower movement through, increases time for diffusion
Thin walls as a single layer of endothelial cells, so small diffusion distances, heightened by RBC pushing against
Extensively branched as a bed to increase SA for exchange
How are veins and venules adapted to their function?
Transport low pressure blood back to the heart
Little elastic fibres as low pressures, no pulses so no elastic recoil
Collagen present to provide support as large volumes of blood often travelling
Still has some endothelium, smooth muscle
Medium sized veins have Valves to prevent backflow
Wide lumen- increase blood flow
How does deoxygenated blood return to the heart, often against gravity?
Most (medium) veins have valves, one way system
Larger veins next to skeletal muscle, contractions move blood along
Inhaling, lowers pressure in thoracic cavity, blood in chest veins to heart
