1.1 - What is cardiovascular disease? Flashcards
Define single cellular organisms.
organisms that are made up of only one cell
Define multi cellular organisms.
organisms that are made up of more than one cell
Why don’t single cellular organisms need circulatory systems?
- lrgr SA:V ratio
- take in nutrients by dffsn
- as hve shrter dffsn dstncs
What is the main reason multi cellular organisms need circulatory systems?
- smllr SA:V ratio
- have mr cmplx srtcrs
- so hv lngr dffsn dstncs
Why does an increased level of activity lead to a need for circulatory systems?
High mtblc rate = needs lrg O2 supply
crcltry systms needed as dffsn dstncs for O2 = too far
What has a bigger SA:V ratio? Mouse or elephant?
mouse
What are the 2 types of circulatory systems?
- open
- closed
What is an open circulatory system?
consists of a heart that pumps a fluid around that is not enclosed in vessels
What is a closed circulatory system?
blood is fully enclosed within blood vessels at all times
Why do only small animals have an open system?
-do not have complex structures
-so fluids do not need to be enclosed in vessels
- & travel long dstncs & thus small animals can use diffusion
What are 2 advantages of a double circulatory system?
- blood can pass slowly through region of gaseous exchange maximising transfer of O2 & CO2
- blood flows at a higher pressure to body
What is an advantage of a closed circulatory system?
allows blood to flow @ higher pressures, so blood travels faster around body
What is a disadvantage of this 3 chambered system?
do not seperate oxygenated & deoxygenated blood - allows less effcnt trnsprt of O2 -> body cells
Which blood vessel has valves?
veins
Which 2 blood vessels carry oxygenated blood from the heart to the body cells?
arteries & arterioles
Which 2 blood vessels carry deoxygenated blood from the body cells to the heart?
veins & venules
What is the biggest artery in the body?
aorta
What 3 things are the artery walls made up of?
- elastin fibres
- smooth muscle
- colllagen
What is the function of elastin fibres?
made of elastin - allow arteries & veins to stretch & recoil providing vessel with flexibility
What is the function of smooth muscle?
contracts & relaxes changing size of lumen
What are the walls of veins made up of? What is the difference between the walls of veins & arteries?
- elastin fibres
- smooth muscle
- collagen
(all in smaller proportions to arteries= larger lumen)
Due to low blood pressure, what do veins not have?
pulse
How thick is the endothelium of a capillary? Why does this help the endothelium be adapted to its function?
1 cell thick - short dffsn dstnc
How thick is the lumen of the capillary? What does this ensure?
1 blood cell thick - red blood cells travel in single file
Why is it important that red blood cells travel single file in the capillaries?
allows oxygen & glucose to diffuse out of blood cells efficiently
How are substances exchanged in the capillaries?
from blood cells -> surrounding tissue thrgh gaps in endothelium
How are capillaries adapted for diffusion?
- large surface area
- lumen = one blood cell thick
- endothelium = one blood cell thick
What happens during atrial systole?
- both atria contract
- blood flows from atria -> ventricles
- atrio-ventricular valves open & semilunar valves close
- closure of semilunar valves prevents backflow of blood into veins
What happens during ventricular systole?
- both ventricles contract
- atrio-ventricular valves are pushed shut by pressurised blood in ventricles
- seminlunar valves open
- blood flows from ventricles into arteries
What happens during ventricular diastole?
- atria & ventricles relax
- semilunar valves close
- atrio-ventricular valves open
- blood flows from veins through the atria & into ventricles
What are the 4 components of the blood?
- red blood cells
- white blood cells
- plasma
- platelets
State all 6 stages of the blood clotting cascade.
- Damage to blood vessel walls exposes collagen
- Platelets = fragments of blood cells which bind to exposed collagen & release clotting factors. platelets also adhere to each other & form temporary blockage known as a platelet plug.
- One of these clotting factors is thromboplastin, & once this enzyme is activated, it catalyses conversion of prothrombin -> thrombin. This occurs in the presence of calcium ions
- Thrombin is an active protease enzyme which catalyses reaction that converts fibrinogen into fibrin.
- Fibrin is an insoluble protein consisting of a mesh of fibres & these attach to the platelets in plug
- Red blood cells & other platelets are trapped by the mesh, forming the clot
Describe the structure of an enzyme.
a protein which has a specific shape with an active site which is complementary to the substrate that binds to the enzyme’s active site.
Which vitamin is needed for clotting?
vitamin K
What type of ions are needed for clotting?
calcium
Define positive feedback.
continuous circle when something keeps increasing
What type of feedback loop is blood clotting?
positive
What is coronary heart disease?
disease of arteries supplying blood -> heart
What is atherosclerosis?
thickening of arteries inside walls caused by a build up of fatty plaques, called atheromas
What can atherosclerosis lead to?
rdcd blood supply (ischaemia) to tissues, which can have ptntlly fatal consequences
What is an atheroma? What sort of cholesterol are atheroma’s mostly made up of?
build up of fatty plaques in arteries, made up of mainly LDL cholesterol
State the stages of atherosclerosis.
- endothelium in the artery wall becomes damaged. This endothelial damage is a result of high blood pressure of the blood
- Cholesterol builds up in the blood and oxidises, which results in an inflammatory response
- inflammatory response is where white blood cells enter the artery wall.
- White blood cells take in these chemicals, including cholesterol and fatty deposits build up. fatty deposits are called an atheroma.
- Calcium salts and fibrous tissue build up at the site of the atheroma & hard plaque forms on the artery walls. This means that artery wall elasticity is reduced and the artery lumen narrows. This causes blood pressure to increase.
- endothelium ruptures over the hard plaque, exposing the collagen. Platelets come into contact with the collagen and become sticky. They stick together to form a platelet plug
platelet plug sticks tgthr w proteins & becomes a blood clot - increase in blood pressure leads to an increase in damage of the endothelial tissue in other areas. This makes it more likely that other plaques will form in the coronary arteries.
What sort of molecule is water?
polar
What type of bonding occurs between the hydrogen and oxygen atoms in water?
covalent bonds
How strong is the charge on the oxygen atom in water?
weakly negative (δ-)
How strong are the charges on the hydrogen atoms in water?
weakly positive (δ+)
What is the separation of charge due to electrons in covalent bonds being unevenly shared called?
a dipole
Why is water a polar molecule?
has one positively charged end & one negatively charged end
What type of bond form between the water molecules?
hyrogen bonds
What contributes to many properties of water molecules?
hydrogen bonds
How strong are hydrogen bonds? What does this result in?
weak when few in number - so they are constantly breaking & reforming, so water molecules move around each other in a liquid state
What is it called when water molecules are attracted to each other? What causes this property?
cohesion - hydrogen bonds
What is it called when water can form hydrogen bonds with other molecules?
adhesion
Why is cohesion and adhesion so important?
allows water to flow easily
- water molecules can pull other water molecules along
- water can adhere to side of vessel bc of adhesion
How is the loss of heat when sweating related to the dipole nature of water molecules?
- water has an uneven distribution of charge
- so water forms hydrogen bonds with other water molecules
- and it requires a lot of heat energy to break these bonds & allow water to evaporate
How do the properties of water make it an ideal transport medium?
- water is a solvent
- because water molecules surround polar molecules, hydrogen bonds form between water & solute molecules
- water is a liquid so has the ability to flow and transport substances
