3.2 - Transport In Animals Flashcards
What are three features of an effective transport system?
- A fluid to carry nutrients/oxygen/wastes around the body (blood)
- A pump to create pressure that will push the fluid around the body (heart)
- Exchange surfaces (capillaries)
What is the role of arterioles?
Take blood from artery to capillary; they have a layer of smooth muscle which contracts restricting and slowing blood flow
How are capillaries adapted for exchange?
- Narrow lumen (squeezes red blood cells against walls so transfer of oxygen is better to the tissues)
- Walls consist of single layer of endothelial cells (reduces diffusion distance)
- Walls are permeable (allows blood plasma and dissolved substances to leave the blood)
What are the factors that affect the efficiency of transport systems?
- Size
- SA:Vol
- Metabolic activity
What are the characteristics of an open circulatory system? (insects)
- No blood vessels
- Fluid is called haemolymph
- Not as efficient
- Blood pressure is lower
- Blood/fluid cannot be directed to where it is needed as the body movements can influence the flow of the fluid
- Locusts have an adapted system with tubes that can direct the fluid flow
- Peristalsis is a wave of contraction used to squeeze the fluid one way along the heart
What are the characteristics of an closed circulatory system? (fish/human)
- Have blood vessels (In humans: arteries, capillaries and veins)
- The blood vessels allow the blood to be directed to where it is needed
- Blood pressure is higher
How is blood pressure affected by having a single, closed circulatory system? (fish)
-Blood pressure declines as it is further away from the heart and after going through the gills
-Rate of flow at tissues is low
Heart=High
Pre-gills=High
Post-gills=Low
Pre-tissues=Low
Post-tissues=Very low
Pre-Heart=Very low
Post-heart=High
Why is blood pressure lost at the gills?
The gills are a network of fine capillaries so blood pressure is lost to the capillaries
How is blood pressure affected by having a double, closed circulatory system? (humans)
-Blood pressure in the lungs is not too high
-Heart can boost pressure before blood goes to the rest of the body
-Body circulation is at a higher pressure
Post-heart=High (out Left side)
Pre-lungs=High (but not too high)
Post-lungs=Low
Pre-Heart=Low
Post-heart=Very high (out right side to whole body)
Pre-tissues=High
Post-tissues=Low
Pre-Heart=low
Post-heart=High (out Left side)
What is the circulation to the body called?
Systemic circulation (Pumped from the aorta)
What is the circulation to the lungs called?
Pulmonary circulation (Pumped from the pulmonary artery)
What is the structure and function of arteries?
STRUCTURE:
- Lumen, where blood flows through
- Endothelial layer, smooth layer of flattened cells
- Elastic fibres, stretches and recoils as the heart pulses
- Smooth muscle fibres, constrict to narrow/dilate to expand the artery and divert the blood flow to where it is needed the most
- Collagen fibres, enables the artery to withstand the high pressures
FUNCTION:
-Arteries carry blood away from the heart (HIGH BP)
What is the structure and function of veins?
STRUCTURE:
-Wider lumen, where blood flows through
-Endothelium, smooth single layer of flattened cells
-Thinner layer of elastic fibres, stretches and recoils
-Less smooth muscle fibres, constrict/dilate the artery and divert the blood flow to where it is needed the most
-Thinner layer of collagen fibres, enables the vein to
withstand pressure
-Contain valves to stop backflow and ensure blood
moves in one direction towards the heart
FUNCTION:
-Veins carry blood towards the heart (LOW BP)
What is the structure and function of capillaries?
STRUCTURE:
- Lumen, where blood flows through the diameter of a RBC (7micrometer)
- Endothelium, smooth single layer of flattened cells
- Can be:
- Continuous, thinner and less leaky
- Fenestrated, most leaky (Found in the kidney)
- Discontinuous, wider and less leaky
FUNCTION:
- Capillaries are the site of exchange (Glucose, oxygen, amino acids, various nutrients or waste products etc)
- Produce tissue fluid
What is the purpose of tissue fluid?
It bathes the cells, supplies what they need and removes what they don’t need
What is plasma made up of?
Water, ions, sugars, gases, small proteins