1.1- what is cardiovascular disease ? Flashcards
1
Q
what is a cardiovascular disease (CVDs) ?
A
a disease of the heart and circulation and are the main cause of death in the UK
2
Q
what is an open circulatory system
A
- when blood circulates in a large open system, normally in insects
- the heart pumps blood into cavities surrounding the animals organs
- substances can then diffuse between the blood and the cell
- when the heart relaxes blood is drawn back into the cavities through valved openings along its length
3
Q
what is a closed circulatory system
A
- the blood is enclosed in blood vessels, in many animals and all vertebrates
- generates higher blood pressures as blood is forced along the the blood vessels
- means blood travels faster and so the blood system is more efficient
- animals with closed circulatory systems are normally bigger and more active
4
Q
The general path of blood by a closed system
A
- blood leaves heart under pressure and flows along arteries and then arterioles to capillaries
- there are lots of capillaries which come into close contact with most of the cells in the body where substances are exchanged
- then blood returns to the heart by venules and then veins
- valves make sure the blood flows in only one direction
5
Q
path of blood in a single circulatory system
A
- fish used as an example
- heart pumps blood to the gills
- gaseous exchange takes place; there is diffusion of CO2 from the blood into the water that surrounds the gills and then diffusion of oxygen from water to the gills
- the blood leaves the gills and then flows around the rest of the body before returning to the heart
- they have one ventricle and one atrium
6
Q
what is a double circulatory system
A
- birds and mammals have one
- the right ventricle pumps de-oxygenated blood to the lungs where it receives oxygen
- oxygenated blood then returns to the heart to be pumped a second time by the left ventricle out to the rest of the body
- the blood gets an extra boost that reduces time taken for blood to circulate to the rest of the body
- therefore birds and mammals have a high metabolic rate
7
Q
why do many animals need a circulatory system
A
- in multicellular organisms they are too large for substances to diffuse and move around their body quick enough unlike uni-cellular organisms that are small enough for diffusion to be adequate
- they have to rely on a mass transport system to move substances efficiently by mass flow- a circulatory system
8
Q
what is mass flow
A
The transport medium in animals is blood, mass flow means that blood is transported in one direction due to a difference in pressure
9
Q
what does it mean when water is described as having a dipole nature
A
- has an unevenly distributed electrical charge
- hydrogen end is slightly positive and oxygen end slightly negative
- the slightly positive end is attracted to the slightly negative end of other water molecules
- hydrogen bonding holds water molecules together
10
Q
what are the properties of water that make it an ideal transport medium
A
Solvent-
- many chemicals dissolve easily in water
- allows vital biochemical reactions to occur as the chemicals are free to move around in the aqueous environment
- dissolved substances can be transported around organisms
- ionic and polar substances can dissolve easily as they get surrounded by water due to its dipole nature
Thermal properties-
- specific heat capacity of water very high
- large amount of energy required to break hydrogen bonds
- water warms up and cools down slowly
- helps organisms to avoid rapid changes in internal temp
11
Q
Basic heart structure
A
- made of carciac muscle
- right side receives deoxygenated from body and pumps to lungs
- left side receives oxygenated from lungs and pumps to body
12
Q
what are the similarities between arteries and veins
A
- walls of both vessels contain collagen to make them strong and durable
- contain elastic fibres to allow stretch and recoil
- smooth muscle cells in walls allows to constrict and dialate
13
Q
differences between veins and arteries
A
- arteries narrow lumen- veins wide lumen
- arteries thicker walls- veins thinner walls
- arteries more collagen,smooth muscle and elastic fibres- veins less
- arteries have no valves- veins do
14
Q
how does blood move through the vessels
A
- during systole blood is forced into arteries and walls stretch to accommodate
- during diastole elasticity of artery walls causes them to recoil behind blood, pushing blood forward and smoothing blood flow
- when blood reaches capillaries blood flow is steady
- blood flows slower in capillaries as smaller lumen and friction from walls
- allows for exchange
- blood flows steady through veins- no pulses
- assisted by contraction of nearby muscles
- backflow prevented in veins due to semi lunar
15
Q
what happens during atrial systole
A
- blood returns to heart due to action of skeletal muscles and breathing
- blood under low pressure into left and right atria from pulmonary veins and vena cava
- as they fill increased pressure forces tricuspid and bicuspid valve open and leaks into ventricles
- atria then contract to push blood into ventricles
