Lifestyle & Risk Flashcards
What is an open circulatory system common to?
Molluses and arthropods
What is blood flow like in an open circulatory system?
- Blood is pumped by a heart into body cavities, where tissues are surrounded by the blood
- Still relies on diffusion of substances from blood to cells
What is blood flow like in a close circulatory system?
- The blood does not make direct contact with the tissue cells
- The blood is retained in the blood vessels
- A closed system is very responsive to the changing needs of the oxygen and is highly efficient
How many times does blood flow to complete a complete cycle in single circulation?
One
How many times does blood flow to complete a cycle in double circulation?
Two
What are the advantages of a double circulatory system?
- Prevent mixing of oxygenated and deoxygenated blood so oxygen supply is highly efficient
- Pressure can be maintained
- Cells can have a high metabolic
rate
What is mass transport?
Mass transport is the bulk movement of gases or liquids in one direction, usually via a system of vessels and tubes
What are the features of mass transport systems?
- A system of vessels - usually tubes which follow a specific route
- A way of making sure substances move in the right direction
- A means of moving material quickly to meet the organisms needs
- A transport medium - usually water carries dissolved substances
What are the benefits of mass transport?
- Mass transport systems help to bring substances quickly from one exchange site to another
- They also help to maintain concentration gradients at exchange sites
- Mass transport systems ensure effective cell activity by keeping the immediate fluid environment of cells within a suitable metabolic range
What is a pulmonary circuit?
A system of blood vessels that forms a closed circuit between the heart and the lungs
What is a systemic circuit?
A system of blood vessels that form a closed circuit between the heart and the rest of the body
What are the features of arteries?
- Narrow lumen
- Thick walls
- High amount of collagen
- High mount of elastic fibres
- High amount of smooth fibres
- No valves present
What are the features of veins?
- Wide lumen
- Thin walls
- Less collagen
- Low amount of collagen
- Low amount of elastic fibres
- Low amount of smooth fibres
- Valves are present
What are the features of capillaries?
- Narrow lumen
- 1 cell thick walls
- No collagen
- No elastic fibres
- No smooth fibres
- No valves present
What are the main functions of blood?
- Transports digested food products for use or storage
- Transports excretory products
- Transport chemical messengers to target organs
- Helps maintain body temperature
What are red blood cells?
- The main role of RBCs is to transport oxygen from the lungs to the respiring tissues
- Haemoglobin transports mostly oxygen but it does also transport some carbon dioxide
- When haemoglobin combines with oxygen it becomes oxygen haemoglobin
How is oxygen transported?
- Each haemoglobin molecule can bind to 4 oxygen molecules
- Since oxygen binds to haemoglobin, it ensures free oxygen in cytoplasm remains low - this maintain a steep conc gradient from the air in the lungs to the blood (high affinity)
- Oxygen conc in the body tissues is also relatively low to maintain a conc gradient between the RBCs and body tissues (low affinity)
How is carbon dioxide transported?
- Around 5% of CO2 is carried in solution in the plasma. 10-20% combines with haemoglobin to from carbaminohaemoglobin
- The rest of the CO2 reacts with water in the blood to form carbonic acid with the help of carbonic anhydrase
-The carbonic acid then separates to form H+ ions and hydrogen carbonate ions which are held in the cytoplasm of RBCs - At the lungs, where CO2 conc is low, carbonic anhydrase catalyses the reverse reaction and free CO2 diffuses out of the blood and into the lungs
What is affinity?
Ease with which O2 binds with haemoglobin
What is partial pressure?
A measure of concentration of O2
What is oxygen association?
Binding of O2 to haemoglobin
What is oxygen disassociation?
Releasing of O2 to haemoglobin
What is the purpose of platelets?
Organism have a limited volume of blood
- If a blood vessel is damaged, it must be blocked for two reasons:
1) Prevent blood loss
2) Prevent the entry of pathogens
The body has a built-in damage limitation system in the clotting mechanism of the blood to seal up the vessels called THROMBOSIS
What important substances are released when platelets break open in large numbers?
- Seretonin
- Thromboplastin
What is serotonin?
Causes smooth muscle to contract which narrows the blood vessels
What is thromboplastin?
Thromboplastin initites a CASCADE SYSTEM which leads to the formation of a clot
1) Thromboplastin CATALYSES THE CONVERSION OF PROTHROMBIN INTO ANOTHER ENZYME CALLED THROMBIN using CALCIUM IONS
2) Thrombin acts on another plasma protein called FIBRIGEN which is converted into fibrin which forms a mesh of fibres
3)More platelets and blood cless pour from the wound, GETTING TRAPPED IN THE MESH - FORMING A CLOT
4) Special PROTEINS IN THE PLATELETS CONTRACT, TIGHTENING THE CLOT
What happens when clotting goes wrong?
THROMBOSIS is the term given to the formation of a blood clot (thrombus) inside a blood vessel. If a THROMBUS breaks loose it forms an embolus which travels in the bloodstream where it may end up blocking a blood vessel completely
If the embolus block a CORONARY ARTERY it may lead to:
1) A heart attack
2) A stroke if it blocks an artery supplying the brain.
In either case, tissue death an occur due to a lack of oxygen
What is the blood clotting mechanism?
1) Damaged tissue releases platelets
2) Platelets release thromboplstin, prothrombin and calcium ions
3) These catalyse thrombin
4) Thrombin catalyses fibrigen
5) Fibrigen is converted to fibrin
6) Fibrin forms a clot
What are white blood cells?
White blood cells are responsible for the body’s immune response
- LYMPHOCYTES produce specific ANTIBODIES AND ANTITOXINS
- PHAGOCYTES engulf pathogen and destroy them through PHAGOCYTOSIS
Where is the tricuspid valve located
Between right atrium and right ventricle
Where is the bicuspid valve located?
Between left atrium and left ventricle
Where are the semi-lunar valves located?
Between the right ventricle and pulmonary artery and between left ventricle and the aorta
What is the function of valves?
Ensure that blood flows in only one direction
What is the function of tendinous cords
Ensure valves are not turned inside out when high pressures are exerted by the ventricle
What is systole?
The contraction of the heart
What is diastole?
The relaxation of the heart
What is atrial systole?
The period when the atria are contracting
What is ventricular systole?
When the ventricles are contracting
What is the cardiac cycle?
One complete cycle of filling and pumping of blood
How is the cardiac cycle controlled?
Heart muscle is MYOGENIC which means it can initiate its own contraction.
In the heart, there are TWO NODES that are responsible for keeping the cardiac cycle running correctly
- A heartbeat starts off at the SINOATRIAL NODE (SAN) located above the right atrium
- The second node is knows as the ATRIOVENTRICULAR NODE (AVN) which is located near the AV valve
What are nodes?
Nodes are masses of tissues from which are electrical impulses can be generated
What are the pressure changes in the cardiac cycle?
- As a chamber fills with blood, the pressure is going to rise. When a chamber contracts the pressure also rises
- Changes in pressure affect whether a valve is open or close because fluids always move from areas of high pressure to areas of low pressure
What is atherosclerosis?
- Damage to endothelium and artery causes inflammatory response
- WBC and lipids from the blood clump together under endothelium
- WBC lipids and connective tissues form a plaque called an atheroma
- Plaque blocks the lumen and restrict blood flow (Atherosclerosis)
How does atherosclerosis happen?
Fatty deposits (atheroma) cause an artery to become narrower, increasing its chances of being blocked completely by a clot (thrombosis)
What are the results of atherosclerosis?
Blood supply to cells can be reduced or cut off. If arteries supplying the heart are blocked, this results in a heart attack. A stroke is caused by clots in arteries leading to the brain. An artery can even burst as blood builds up behind a clot. (aneurism)
What is deposition?
A process which substances are added to a surface
What is a plaque?
An abnormal build up of substances or tissue on a body part or organ
What is endothelium?
The tissue which forms a single layer of cells lining various organs and cavities of the body
What is cholesterol?
A type of lipid made in the liver; found in the blood and in all cells of the body
How does atheroma form
- Endothelium is damaged by high blood pressure
- Inflammatory response including white blood cells and cholesterol deposition
- Atheroma builds up
- Plaque forms due to calcium salt and fibrous tissue deposition
- Artery hardens and narrows resulting in higher blood pressure
- Positive feedback
What is the equation for blood pressure?
Force/Area
Where is blood pressure the highest?
Arteries
Where is blood pressure the lowest?
Capillaries
How is blood pressure measured?
A SPHYGMOMANOMETER or BLOOD PRESSURE METER is a divide used to measure blood pressure: composed of an inflatable cuff to restrict blood flow, and a mercury or mechanical manometer to measure the pressure
What is systolic pressure?
The force at which your heart pumps blood around the body
What is a normal blood pressure measurement?
120/80
What are symptoms of a high blood pressure?
- Headaches
What are risk factors of high blood pressure?
- Smoking & Alcohol
- Overweight
What are symptoms of low blood pressure?
- Dehydration
- Heart problems
What are the risk factors of low blood pressure?
- Some medication
What is diastole?
The muscles of the atria and ventricles is relaxed
- Pressure against the atrioventricular valves pushes them open - 70% of the blood flows passively into the ventricles
SEMI-LUNAR VALVES CLOSE (‘dub’) to prevent backflow
What is atrial systole?
The ATRIA CONTRACT forcing the remaining blood into the ventricles.
The atrioventricular valves the close to prevent back flow into the atria
What is ventricular systole?
Happens immediately after atrial systole
- VENTRICLES CONTRACT from the base of the heart upwards
- Blood pushed up and out through the arteries through SEMI-LUNAR VALVES
- Pressure also CLOSES THE ATRIOVENTRICULR VALVES (‘lub’) preventing backflow
When is overestimation of the risk common?
When the risk is:
- Involuntary
- Not natural
- Unfamiliar
- Dreaded
- Unfair
- Very small
What drives people’s actions and behaviours?
Perception of riskW
What are the features of a well-designed study?
- Clearly stated aim, hypothesis or question to be answered
- Participant in the sample are representative of the population, to which the results will be applied
- A sufficiently large sample size
- Symptoms of people with disease are clearly defined
- Any measurements made truly reflect what ‘they aim to measure
- Method that are used are reliable
- Other variables that might affect the results are controlled for
- There is a suitable time-scale of the study
What is cholesterol?
Cholesterol is transported in your body in high-density lipoproteins (HDLs) or low-density lipoproteins (LDLs), they each have a different effect on cholesterol levels and are formed in different types of food
What are the treatments of CVD?
- Antihypertensives
- Statins
- Anticoagulants
- Platelet inhibitors
What are antihypertensives?
- Keeps heart from becoming overworked
- Used to treat high blood pressure
- Change electrolyte levels
- Older adults can get dizzy and fall
- Help to lower blood pressure
What are statins?
- Lower levels of LDLs
- Reduce chances of heart attacks or stroke
- Need to be taken everyday
- Can cause sleep problems and muscle pain
- No surgery required
What are anticoagulants?
- Decreases blood clotting
- Reduced chances of strokes
What are platelets inhibitors?
Stop platlets from binding to form clots
Reduces incidence of thrombosis
Why is water important?
- Human body is around 60% water
- 80% of cells are water
- It is a reactant in many reactions
- It is a solvent
- Helps transport substances
- It helps to regulate body temperature
What is the structure of a water molecule
- Oxygen and hydrogen covalently share electrons. The O pulls the shared electrons closer to it, leaving the H slightly more negative
- This is polar
- and- attract forming H bonds
What is hydrogen bonding?
- Hydrogen bonding is what gives water its unique properties
- The slightly negative oxygen is attracted to the slightly positive hydrogen
What is specific heat capacity?
- Hydrogen bonds give water a high specific heat capacity
- Specific heat capacity is the energy required to raise the temperature of 1g of a substance by 1’C
What is latent heat capacity?
A lot of energy (heat) is required to break the hydrogen bonds between water molecules meaning water has a high latent heat capacity for evaporation
This is useful for living organisms because it means water is greater for cooling things
What is cohesion?
H2O stick to other H2O molecules via H bonds
What is adhesion?
Water sticks to non water molecules via H bonds
How is water a solvent?
- Water acts as a solvent in which many of the solutes an organism requires can be dissolved
- Many of these substances are ionic
- Because water is dipolar the slightly positive end of a water molecule will be slightly attracted to the negative ion, and the slightly negative end of a water molecule will be attracted to the positive ions
The cystol of prokaryotes and eukaryotes is mainly water. Water acts as a medium for chemical reactions and helps transport dissolved compound both in and out of the cell
How is water important as a habitat?
- Water provides a habitat for a huge number of organisms, many organisms cannot survive out of water
- Because water has a relatively stable temperature and doesn’t change into a gas easily it provides a constant environment for organisms to live in
What are carbohydrates?
- Carbohydrates are organic molecules composed of carbon, hydrogen and oxygen atoms
- They act as a source and storage of energy
- Often referred to a sugars
What are monosaccharides?
- Monosaccharides are single sugar monomers, they are the simplest carbohydrates
- When we add monosaccharides together we form a disaccharide
- When we add more and more monosaccharides together we form a polysaccharide - a long repeating chai of molecules joined together
What is glucose?
- Main source of fuel for many organisms
- It is used in respiration to release energy
- It is used as a building block for larger CHO structures like amylase which makes up starch (spiral structure)
- It is very small so can be easily transported into and out of cells by carrier proteins in the cell surface membrane
- It is very soluble so can be transported around the body in blood very easily
What are isomers?
Isomers are molecules that have the same chemical formulas but have a different arrangement of atoms in space
What is the general formula of carbohydrates?
(CH2O)n OR Cx(H2O)y
(CH2O)n - the n represent the number of times the basic CH2O unit is repeated
Cx(H2O)y - in a ratio of 2:1
What is the difference between alpha and beta glucose structures?
In alpha glucose the hydrogen is above
In beta glucose the hydrogen is below
How are sugars drawn?
Carbons are numbered clockwise, starting from the carbon on the far right
Diagrams must:
- be neat and clear
- be drawn in pencil
- show clearly which atoms the bonds join
What are the properties of disaccharides?
- Disaccharides are sweet-tasting sugars and soluble
- Disaccharides are sugars that are composed of two monosaccharides joined together in a condensation reaction
- Disaccharides are also soluble (not as soluble as monosaccharides and their chemical)
What are condensation reactions?
- Condensation reactions involve the formation of a strong covalent bond know as a glycosidic bond
- This occurs when the two hydroxyl groups on different monosaccharides interact
- The name of the glycosidic bond depends on the location of the hydroxyl groups interacting
- Water is released in a condensation reaction
- Maltose and Amylopectin are example of disaccharides formed by condensation reaction
What are the different formations of disaccharides?
The disaccharide formed depends on the specific combination of monosaccharide
Glucose + Glucose -> Maltose
Glucose + Fructose -> Sucrose
Glucose + Galactose -> Lactose
What is maltose?
- Formed between 2 alpha glucose molecules
- The bonds form between the carbon 1 of the first monosaccharide and carbon 4 of the second, so its called a 1-4 glycosidic bond
What is lactose?
- Formed between beta glucose molecule and a galactose molecule
- The bond form between the carbon 1 of the first monosaccharide and carbon 4 of the second, so its called a 1-4 glycosidic bond
What is sucrose?
- Formed between an alpha glucose molecule and a fructose molecule
- The bond form between the carbon 1 of the first monosaccharide and carbon 2 of the second, so it a
1-2 glycosidic bond
What are lipids?
- Lipids are organic molecules, there are two main types
- Triglycerides - source of energy
- Phospholipids - structural role in cell membranes
- Lipids are made of mostly carbon and hydrogen with some oxygen atoms
- They are large complex macromolecules - but are NOT polymers
- They consist of a carboxyl group with a hydrocarbon chain attached
- They are non polar and hence, don’t dissolve in water
What are triglycerides?
Simple naturally occurring fat
What molecules are triglyceride made from?
1 glycerol
3 fatty acids
What diseases can be caused by high triglyceride levels?
Atherosclerosis, heart disease, stroke
