Transport In Animals Flashcards
Need for a transport system
Size
SA:volume
Level of metabolic activity
Good transport system properties
Fluid carry nutrients/oxygen/waste (blood)
Pump to create pressure of the fluid (heart)
Exchange surface to transfer substances through blood (capillaries)
Tubes/vessels to carry blood
2 circuits, pick up O₂ and deliver to tissues
In single circulatory systems…
Blood flow rate is slow and there’s low pressure
Circuit where blood flows to lungs
Pulmonary circulation
Circuit where oxygen is transported around body and tissues
Systemic circulation
Open circulatory system
Blood not in vessels
Fluid bathes tissues/cells
Movement of body/muscular pumping circulates
What’s bad about open circulatory systems?
Low blood pressure so slow flow
Circulation affects by body movements or lack of
What’s good about closed circulatory systems?
High pressure so quick flow and rapid delivery/rapid removal
Transport is separate from body movements
Vessels’ inner layer, single layer of cells
Endothelium
Arteries take blood ____ ____ ___ _____ with ____ ________
Away from the heart
High pressure
Artery structure to deal with high pressure
Standard structure of artery
Thick wall to withstand it
Small lumen to keep it
Inner layer is elastic tissue/fibre to stretch wall and maintain pressure
Middle layer is smooth muscle
Outer layer is collagen fibres for strength for pressure
Veins carry blood ____ __ ___ ____ at ___ ________
Back to the heart
Low pressure
Vein structure
Thin walls
Large lumen
No need to stretch/ recoil because has valves
Venules carry blood from…
Capillaries to veins
Walls consist of thin muscle/elastic tissue outside endothelium and thin outer collagen
Arterioles are…
Small vessels that carry blood from the artery to capillaries
Smooth muscle constricts arterioles to direct blood to parts
WBC
Leucocytes + platelets
Capillary structure
Thin walls
Narrow lumen
Walls are a single layer of endothelial cells
Leaky walls to allow blood plasma and dissolved substances through
Tissue fluid is…
Plasma leaking from capillaries and surrounding tissues
Supplies tissues with oxygen and nutrients
Happens by mass flow not diffusion
When exchange at capillaries occurs, diffusion happens between
Tissue fluid and cells
Nutrients and O₂ goes into cells and waste comes out of cells
Hydrostatic pressure is…
It pushes…
What the fluid exerts when pushing sides of vessel
Blood fluid out of capillaries at the arteriole end, only dissolved O₂ and nutrients pass because RBC and WBC are too big
At the venous part of the capillary the…
So…
Pressure is low
Allows tissue fluid back with the waste CO₂
Some tissue fluid goes to the……… which……
Lymphatic system
returns excess fluid back to the blood system
Why does size affect the need for a transport system?
A bigger size means cells are further from the surface so increased diffusion path
