3.4.1 Mass transport in animals Flashcards
What type of organisms can rely on diffusion alone
Small organisms
Why do large organisms have to develop a transport system
Due to increasing size, their surface area to volume ratio has decreased to the point where the demand of the organism cannot be met by the body surface alone
What is a transport system required to do
To take materials from cells to exchange surfaces and from exchange surfaces to cells
What type of circulatory system do mammals have
A closed, double circulatory system
What does the term ‘closed’ mean when describing the circulatory system
All the blood vessels are connected in a circuit, meaning that the blood always remains in those blood vessels as long as there is no damage to the blood vessels
What does the term ‘double’ mean when describing the circulatory system
The blood passes through the heart twice in each circuit.
In mammals, where do the circuits deliver the blood to
- Delivers blood to the lungs
- Deliver blood to the rest of the body
Why do mammals require a double circulatory system
To manage the pressure of the blood
Why does the blood need to return to the heart after going to the lungs
Because when blood is passed through the heart, its pressure is reduced
Why does the blood flow through the lungs at a lower pressure (2 reasons)
- To prevent damage to the capillaries surrounding the alveoli
- Lower pressure = moving more slowly, enabling more time for gas exchange
What is the name of the circuit between the heart and the lungs
Pulmonary circulation
Why does the blood need be pumped again at the heart in order to get a higher pressure
To ensure that the blood reaches all the respiring cells in the body
In a circulatory system, what are the 3 key features
- Transport fluid
- Pump
- Series of tubes
In mammals, what is their pump
Heart
In mammals, what is their transport fluid
Blood plasma
In mammals, what is their series of tubes
Blood vessels
What is the name of the circuit between the heart and the rest of the body called
The systemic circulation
In pulmonary circulation, what type of blood is carried from the heart to the lungs
Deoxygenated
In pulmonary circulation, what type of blood is carried from the lungs to the heart
Oxygenated
In pulmonary circulation what vessel carries blood from the heart to the lungs
Pulmonary artery
In pulmonary circulation, what vessel carries blood from the lungs to the heart
Pulmonary vein
In systemic circulation, what type of blood is transported from the heart to the rest of the blood
Oxygenated
In systemic circulation, what type of blood is transported from the rest of the body to the heart
Deoxygenated
In systemic circulation, what vessel carries blood from the heart to the rest of the body
Aorta
In systemic circulation, what vessel carries blood from the rest of the body back to the heart
Vena cava
Where does the coronary arteries carry blood to
Supply the heart, the cardiac muscle, with oxygenated blood
What are the 4 major blood vessels that enter/ exit the heart
- Veins - Vena cava, Pulmonary vein
- Arteries- Aorta, Pulmonary artery
What are the 2 blood vessels connected to the lungs
- Pulmonary artery
- Pulmonary vein
What are the 2 blood vessels connected to the kidneys
- Renal artery
- Renal vein
What type of muscle is the heart made of
Cardiac muscle
What does the word ‘myogenic’ mean when describing the heart
Meaning that the muscle can contract or relax without any input from nervous system or hormones
What are the 2 unique properties of the cardiac muscle
- It myogenic (it can contract and relax without stimulation)
- It never fatigues, as long as it has a supply of oxygen
Where do the coronary arteries branch off from
The aorta
What is myocardial infarction
A heart attack
What causes a heart attack
Blockages in the coronary arteries- since oxygenated blood is not being supplied to the cardiac muscle so they can not respire
What are the 4 chambers in the heart called
- Left atrium
- Right atrium
- Left ventricle
- Right ventricle
Are the walls of the atria or the ventricle thicker
The ventricles have thicker muscular walls
Why are the muscular walls of the atria thinner than the muscular walls of the ventricles
As they don’t need to contract as hard as they aren’t pumping blood far (only to the ventricles)
Why does the atria have elastic walls
To stretch when the blood enters
Why do ventricles have thicker muscular walls compared to atria
To contract with greater force to push to blood out at higher pressure
Why do the ventricles need to create a higher blood pressure when contracting than atria
To enable blood to flow a longer distance (R ventricle to the lungs, L ventricle to the rest of the body)
Which ventricle wall is thinner the left or right
The right ventricle wall is thinner
Why does the right ventricle have thinner walls
Because it pumps blood to the lungs, and we don’t want too high of a pressure in the lungs (could damage capillaries, and it needs to be slow for gas exchange)
Why does the left ventricle have a thicker muscular wall
It needs to contract with the highest force to pump the blood out at the highest pressure. The blood is going to the rest of the body
What type of blood vessels bring blood into the heart
Veins
What type of blood vessels take blood away from the heart
Arteries
What are the 2 veins into the heart
- Vena cava
- Pulmonary vein
What type of blood does the vena cava carry
Deoxygenated blood
Where does the vena cava carry blood from and to in the heart
From the blood
Into the right atrium
What type of blood does the pulmonary vein carry
Oxygenated blood
Where does the pulmonary vein carry blood from and to in the heart
From the lungs
Into the left atrium
What are the 2 arteries connected to the heart
- Pulmonary artery
- Aorta
What type of blood does the pulmonary artery carry
Deoxygenated blood
Where does the pulmonary artery carry blood from and to
From the right ventricle
To the lungs (to become oxygenated)
What type of blood does the aorta carry
Oxygenated blood
Where does the aorta carry blood to and from
From the left ventricle
To the rest of the body
What are the 2 types of valves in the heart
- Semi- lunar valves
- Atrioventricular valves
Where are the semi-lunar valves located
Between ventricle and artery
Where are the atrioventricular valves found
Between the atrium and the ventricles
What is another name for the atrioventricular valves on the right side of the heart
Tricuspid valve
What is another name for the atrioventricular valves on the left side of the heart
- Bicuspid valves
- Mitral valve
How many flaps / membranes are on the left atrioventricular valve
2
How many flaps / membranes are on the right atrioventricular valve
3
What is the role of valves
To prevent back flow of blood
When do valves open
When there is a higher pressure from behind
When do valves close
When there is a higher pressure from in front
What is the septum (in the heart)
A piece of cardiac muscle that runs all the way down the middle, separating the left and right side of the heart, separating the oxygenated blood from the deoxygenated blood
Why is separating the oxygenated and deoxygenated blood (the septum) important
The oxygenated blood isn’t being diluted by the deoxygenated blood. There is a very high concentration of oxygen within the oxygenated blood, this maintains concentration gradient which enables diffusion at respiring cells
What are the 3 stages of the cardiac cycle
- Diastole
- Atrial systole
- Ventricular systole