Module 3.2 Transport in Animals Flashcards
3 main factors that influence the need for a transport system:
1) Size
2) Surface area to volume ratio
3) Level of metabolic activity
What happens to the diffusion pathway as the size of an organism increases?
The cells inside a large organism are further away from the surface - the diffusion pathway is increased. The diffusion rate is reduced, diffusion is too slow to supply the need. The outer layers use up the supplies so less reach the cells deep in the body.
Features of a good transport system:
1) Fluid (to carry the nutrients, oxygen and waste around the body)
2) A pump
3) Exchange surfaces
Extra good features:
1) Tubes or vessels
2) Two circuits
What happens in a single circulatory system?
The blood flows through the 💗 ONCE for each circuit of the body
Give an example of an organism that has a single circulatory system
Fish 🐠🐟🐡
What happens in a double circulatory system?
Blood flows through the 💗 TWICE for each circuit of the body
Do mammals have a single or double circulatory system?
Double
Name the 2 circuits in mammals
Pulmonary and systemic
Advantages of a double circulatory system?
Will deliver oxygen and nutrients quickly to the parts of the body that need it, the blood can flow more quickly by increasing the pressure of the 💗
In the single circulatory system of 🐟…
- The blood pressure drops as blood passes through the capillaries of the gill
- The blood has low pressure as it flows towards the body, and will be flowing fairly slowly
- Limited rate at which oxygen and nutrients can be delivered and wastes removed
In the double circulatory system of mammals…🚶🏽
- Blood pressure can’t be too high in pulmonary circuit otherwise it could damage the capillaries in the lungs
- The heart can increase the pressure of the blood so the blood flowing to the body can be under high pressure
- The systemic circuit can carry blood at a higher pressure than the pulmonary circuit
Why is it necessary that mammals have a good circulatory system?
Because they are active and need to maintain their body temperature. They require a lot of energy and need a good supply of oxygen and nutrients and they also need waste removed rapidly.
What does an open circulatory system mean?
Blood isn’t always in the blood vessels
Disadvantages of an open circulatory system:
- Low blood pressure
- Slow blood flow
- Circulation of the blood may be affected by body movements/ or lack thereof
Advantages of closed circulatory systems:
- Higher pressure
- Blood flows faster
- More rapid delivery of oxygen and nutrients
- More rapid removal of waste
What do all blood vessels have?
An inner layer of lining called Endothelium
Why is the wall of the left ventricle so much thicker than the wall of the right ventricle?
The left ventricle has to pump blood through the aorta then to the whole body via the systemic circuit and this is a great distance so a lot of pressure needs to be created.
The right ventricle only has to pump blood to the lungs which is a shorter distance so not as much pressure is required.
What would happen if your coronary artery became blocked?
The flow of blood would be restricted so less oxygen would get to the cardiac muscle, causing a heart attack.
Describe how blood flows around the heart and body
THE RIGHT HAND SIDE IS DEOXYGENATED:
Blood enters via the vena cava
It moves into the right atrium
It goes through the right atrioventricular valve
It moves into the right ventricle
It goes through the semilunar valve
Blood exits the heart via the pulmonary artery and goes to the lungs to be oxygenated
THE LEFT HAND SIDE IS OXYGENATED:
Blood enters via the pulmonary vein
It moves into the left atrium
It moves through the left atrioventricular valve
It moves into the left ventricle
It goes through the semilunar valve and goes to the body
External features of the heart
- Made out of cardiac muscle
- Most of the heart is made of 2 ventricles which have very thick muscular walls
- Above the ventricles are the atria, they have thinner walls
- The coronary arteries supply the cardiac muscle with oxygen for aerobic respiration
- The arteries carry blood away from the heart
- Veins carry blood into the heart
- The bottom of the heart is called the apex
All blood vessels are lined with endothelium to
Reduce friction
🌟Arteries
Take blood away from the heart at high pressure
Have a small lumen to maintain pressure
Have thick walls containing collagen to help withstand the high pressure
Have elastic tissue which stretches and recoils to maintain pressure
The smooth muscle contracts, constricting the airway and narrowing the lumen e.g. can redirect blood flow
🌟Veins
Take blood into the heart at low pressure
Large lumen = less friction
Thinner walls than arteries
Walls have thin layers of collagen, elastic tissue and smooth muscle
Valves = blood flows in one direction
🌟Capillaries
V small
Allow exchange of materials
Thin walls of flattened endothelial cells (squamous epithelial) to reduce the diffusion distance
Narrow lumen - squeezes RBCs up next to the wall to reduce diffusion distance further
