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
How is plasma and tissue fluid different?
- Plasma is when the fluid is inside of the blood vessel and it is the liquid component of the blood
- Rather tissue fluid is when it exits the capillary and bathes the cells
What happens to the tissue fluid after it has bathed the cells?
- Most the tissue fluid returns to the capillaries and becomes plasma again
- However the excess tissue fluid is drained into the lymphatic system then to the heart
What is oncotic pressure?
The pressure caused due to osmosis so the movement of water from a high WP to a low WP down the WP
gradient
What is hydrostatic pressure?
The physical pressure
What is the movement of water and plasma in the capillaries due to oncotic and hydrostatic pressure? (at the arteriole end)
-There is a higher hydrostatic pressure than the oncotic pressure
The plasma is forced out of the capillaries
The water is moved in to the capillaries
What is the movement water and plasma in the capillaries due to oncotic and hydrostatic pressure? (At the venule end)
- There is a higher oncotic pressure than the hydrostatic pressure
- This is because the oncotic pressure is maintained but the hydrostatic pressure slowly decreases as it moves along the capillaries to the venule end with plasma leaking out
- The plasma continues to slowly leak out the capillaries
- The water is moved into the capillaries
What is the flow of the blood through the heart in order?
- Deoxygenated blood enters the heart through the vena cava (From the body)
- The blood enters the right atrium
- Blood is pushed through the atrioventricular valve to the right ventricle
- The right ventricle contracts forcing the blood up, through the semi-lunar valves and out the pulmonary artery (To the lungs)
- Oxygenated blood enters the heart through the pulmonary vein (From the lungs)
- The blood enters the left atrium
- Blood is pushed through the atrioventricular valve to the left, thicker ventricle (At a higher pressure)
- The left ventricle contracts forcing the blood up, through the semi-lunar valves and out the aorta (to the rest of the body)
What is the process of the cardiac cycle?
ATRIAL SYSTOLE
-The atria is filled with blood from the vena cava (R) and the pulmonary veins (L)
-The atria contract, forcing the blood to pass the atrioventricular valves and into the ventricles
VENTRICULAR SYSTOLE
-The ventricles contract, forcing the blood up through semilunar valves and inti the aorta
-The force of the ventricles contracting, shuts the atrioventricular valves, thus preventing backflow into the atria
