4 Mass Transport (Heart and stuff) Flashcards
Where is the heart? What is it nestled in, what are the diff layers called and what are the features and purpose? What are the two layers seperated by and why? What are the three layers of the heart? (Hint- epi, myo, endo)
In the mediastinum cavity between your lungs
Double walled sac called the pericardium:
Fibrous pericardium- tough outer layer, made of dense connective tissue. Purpose is to protect and anchor it to surrounding stuctures.
Inner serous pericardium- two layers
Visceral pericardium (part of heart wall)(also epicardium)
Outer parietal pericardium
By thick film of fluid to reduce friction at heart beats
Epicardium (outside), myocardium(middle- mostly cardiac muscle), innermoste endocardium (thin white layer of squamous epthelial tissue)
Different Mass Transport Systems, if positive or negative
To get the substances from the exchange surfaces to the cells of an organism a mass transport system is needed. Substances are transported by mass flow of water
Differences in pressure are needed
Human circulatory system (positive pressure)
Transport of water in plants (negative pressure)
Transport of sugar in plants (positive pressure)
Circulatory system in mammals:
How does it solve the problems? Distance to diffuse? Surface area? Maintaining concentration gradient?
DtD- capillaries network: 1 cell thick, lots of them, branching (any cell in body is always close to a capillary)
SA- large no. of capillaries
Conc. grad- constant movement of blood in capillaries: pumped by heart
Define the following: Arteries Arterioles Veins Venules Capillaries Hepatic Portal vein Systemic circulation Pulmonary circulation
Why hepaptic is unusual
What connects arteries to the heart? Same with veins
Why is a double circulatory system required?
Arteries- (high P) carry blood AWAY from the heart
Arteries- artrioles-capillaries-venules-heart
Veins (Low P) carry blood TO the heart
Veins-venules-capillaries-artrioles-heart
Hepaptic- cap to cap- SI to Liver
Systemic AND pulmonary req bc pressure is lost in complex systems/through capillaries so when reaches lungs, not enough P, need to reach heart and be pumped out to increase P
Features of a transport system and how achieved?
- A suitable medium in which to carry materials, for example blood. This is normally a liquid based on water because water readily dissolves substances and can be moved around easily, but can be a gas such as air breathed in and out of the lungs.
- A form of mass transport in which the transport medium is moved around in bulk over large distances - more rapid than diffusion.
- A closed system of tubular vessels that contains the transport medium and forms a branching network to distribute it to all pans of the organism.
- A mechanism for moving the transport medium within vessels. This requires a pressure difference between one part of the system and another.
It is achieved in two main ways:
a Animals use muscular contraction either of the body muscles or of a specialised pumping organ, such as the heart (see Topic 7.4) .
b Plants rely on natural, passive processes such as the evaporation of water {see Topic 7.8).
• A mechanism to maintain the mass flow movement in one direction, for example, valves.
• A means of controlling the flow of the transpon medium to suit the changing needs of different pans of the organism.
• A mechanism for the mass flow of water or gases, for example, intercostal muscles and diaphragm during breathing in mammals.
Why are there two seperate pumps in the human heart, not just one like fish? Use the diagram to help you answer
The problem with such a system is that the blood has to pass through tiny capillaries in the lungs in order to present a large surface area for the exchange of gases (see Topic 6.8). In doing so, there is a very large drop in pressure and so the blood flow to the rest of the body would be very slow. This drop in pressure is illustrated in Figure l. Mammals therefore have a system in which the blood is returned to the heart 10 increase its pressure before it is distributed to the rest of the body. It is essenrial to keep the oxygenated blood in the pump on the left side separate from the deoxygenated blood in the pump on the right.
Which ventricle has a thinner wall and why?
The right ventricle pumps blood only to the lungs, and it has a thinner muscular wall than the left ventricle.
The left ventricle has a thick muscular wall, enabling it to contract to create
enough pressure to pump blood to the rest of the body
What are the roles of the aorta, vena cava, pulmonary artery and pumlonary vein? What ventricle/atrium are they connected to?
- The aorta is connected to the left ventricle and carries oxygenated blood to all parts of the body except the lungs.
- The vena cava is connected to the right atrium and brings deoxygenated blood back from the tissues of the body (except the lungs).
- The pulmonary artery is connected to the right ventricle and carries deoxygenated blood to the lungs. where its oxygen is replenished and its carbon dioxide is removed. Unusually for an artery, it carries deoxygenated blood.
- The pulmonary vein is connected to the left atrium and brings oxygenated blood back from the lungs. Unusually for a vein, it carries oxygena ted blood.
1 Name the blood vessel that supplies the heart muscle with oxygenated blood.
2 State whether the blood in each of the following structures is oxygenated or deoxygenated:
a vena cava
b pulmonary artery
c left atrium.
3 List the correct sequence of four main blood vessels and four heart chambers that a red blood cell passes through on its journey from the lungs, though the heart and body, and back again to the lungs.
4 Suggest why it is important to prevent mixing of the blood in the two sides of the heart.
1 coronary artery
2 a deoxygenatcd;
b deoxygenated;
c oxygenated
3 pulmonary vein left atrium left ventricle aorta vena cava right atrium right ventricle pulmonary artery
4 The mixing of oxygenated and deoxygenated blood would result in only partially oxygenated blood reaching the tissues and lungs. This would mean the supply of oxygen to the tissues would be inadequate and there would be a reduced diffusion gradient in the lungs, limiting the rate of oxygen uptake.
How can stress cause cardiovascular disease e.g heart attacks?
High blood pressure increases the risk of heart disease for the following reasons:
- As there is already a higher pressure in the arteries, the heart must work harder to pump blood into them and is therefore more prone to failure.
- Higher blood pressure within the arteries means that they are more likely to develop an aneurysm (weakening of the wall) and burst, causing haemorrhage.
- To resist the higher pressure within them, the walls of the arteries tend to become thickened and may harden, restricting the flow of blood.
What is the function of the coronary arteries? What happens if they get blocked?
Coronary arteries supply blood to the heart muscle. Like all other tissues in the body, the heart muscle needs oxygen-rich blood to function.
Decreased blood flow to your heart. Eventually, the reduced blood flow may cause chest pain (angina), shortness of breath, or other coronary artery disease signs and symptoms. A complete blockage can cause a heart attack
Describe what happens to the atrium, ventricles, AV valves, SL valves and cardiac muscles during each stage of the cardiac cycle
1) Diastole- heart muscle relaxed
SLV shut- stop rev blood flow from arteries
Blood enters from veins
Cardiac muscle relaxed
Atria and ventricles fill with blood
2) Atrial Systole- atria contract
SLV shut Atria mucles contract AV open Blood flows from atria to ventricles Blood squeezed out of atria (only point where atria aren't filled with blood)
3) Ventricular systole
SLV open Ventricles contract AV shut Blood flows from ventricles into arteries Ventricle muscles contract Blood squeezed out of ventricles
Where are the semi lunar valves and atrioventricular valves located? What cause them to open and close?
SLV- in aorta and pumonary artery
AV- between atria and ventricles
Prevent backflow
Generally- open when pressure is higher BEHIND the valve, close when pressure is higher IN FRONT of the valve
AV valves- open when P higher in atra than vent
close when P higher in vent than atr
SLV- open when P higher in vent than arteries (aorta or pul artery)
close when P higher in arteries than vent
Why is there a higher pressure change in the ventricles than the atria?
Ventricles have far thicker muscular wall than in the atria, so can contract with a greater force, and generate much hugher pressure
Draw and label cardiac ouput pressure graph.
Lines- left ventricle pressure, aortic pressure, atrial pressure
Label: Diastole Atrial systole Ventricular systole AV valves closing AV valves opening Aortic valve closing Aortic valve opening Isovolumetric contraction
See Miss Estruch vid
