Topic 1: Lifestyle, Health and Risk Flashcards
give features of a mass transport system
vessels
transport
maintains speed
Define a double circulatory system.
Right ventricle pumps deoxygenated blood to the lungs, left ventricle pumps oxygenated blood round the body. Leads to a high metabolic rate.
why do some organisms require a mass transport
larger animals have a smaller SA:V ratio and a higher metabolic rate.
Diffusion alone is insufficient to supply all cells with the substances they need
Why may larger organisms use more energy
they are more complex, so more nutrients, gases and wastes have to be exchanged by diffusion.
They have a higher demand for oxygen in and waste out.
what makes water a dipole molecule
uneven distribution of charge
O attracts the electron density making it slightly more negative
how is water used in transport
water acts as a solvent due to its polar nature, allowing the transport of biological molecules
Other polar substances, as well as ionic and hydrophilic substances, can easily dissolve in water.
The specific heat capacity of water is very high to maintain homeostasis.
Water has a high boiling point due to the hydrogen bonds.
how does water act as a solvent
water molecules surround the charged particles,
H+ attracted to negative ions
O- attracted to positive ions
The surrounded ions break appart
what is cohesion
attraction of water molecules to eachother
what is adhesion
water hydrogen bonding to other molecules
how does a public perception of risk differ from actual risk
- people overestimate risk if something is not under their control / is unfamiliar or has particularly severe consequences
- people underestimate risk if something only has an effect in the long term
what is the systemic circuit in our circulatory system
blood returns to the left side of the heart and oxygenated blood is pumped around the body
what is the pulmonary circuit in our circulatory system
right side of the heart pumps deoxygenated bloodto the lungs
what is the structure of the atria and how does this relate to their function?
thin walled + elastic = can stretch when filled with blood
what is the structure of the ventricles and how does this relate to their function?
thick muscular walls pump blood under high pressure
the left ventricle is thicker than the right because it has to pump blood all the way around the body
what are the 4 major blood vessels in the heart
vena cava
pulmonary artery
pulmonary vein
aorta
what is the function of the vena cava
brings deoxygenated blood from the body TO THE HEART
what is the function of the pulmonary artery
takes blood from the heart TO THE LUNGS
what is the function of the pulmonary vein
brings oxygenated blood from the lungs TO THE HEART
what is the function of the aorta
takes blood from the heart AROUND THE BODY
what is the structure of the ARTERIES and how does this relate to their function?
thick muscular walls to handle high pressure w/o tearing.
Elastic tissue allows recoil
Narrow lumen to maintain pressure
what is the structure of the VEINS and how does this relate to their function?
thin walls due to lower pressure
valves to prevent backflow
less muscular and elastic tissue as they dont have to control blood flow
what is the structure of the CAPILARIES and how does this relate to their function?
- one cell thick walls - short diffusion pathway
- can form large capillary networks to provide a large surface area
2 main circuits in the mammalian circ system
pulmonary - to and from lungs
systemic - to and from rest of body
describe what happens during cardiac diastole
- heart is relaxed
- blood enters atria , increasing the pressure
- opens the AV valves
- blood flows into ventricles
SL valves remain closed
what happens during atrial systole
- atria contract
- pushing any remaining blood into the ventricles
- pressure increases in the ventricles so AV valves close
describe what happens during ventricular systole
ventricles contract, pressure increases, AV valves close, SL valves open,
blood flows into the arteries
what is atherosclerosis
the hardening of the arteries
what are the steps involved in athersclerosis
- damage to the endothelium
- an inflammatory response occurs and white blood cells accumulate in the damaged area
- lipids and cholesterol clump w the WBC under the endothelium, platelets can also be involved sometimes
- this clump of macrophages, cholesterol, lipids and platelets is forms a plaque called an atheroma
what effect does an atheroma have on the blood pressure
atheromas narrow the lumen of the artery, reducing and restricting blood flow … therefore increasing BP
consequences of CVD
Narrowed coronary arteries may lead to angina.
Heart muscle lacks oxygen and has to respire anaerobically.
Arteries blocked and are ischaemic (not enough blood flowing).
If muscle cells are starved of oxygen for too long it results in an infraction.
why does blood need to clot
prevent blood loss
prevent entry of pathogens
provides a framework for repair
what is thrombosis
the process of blood clotting
Describe the process of thrombosis
- platelets release (protein) thromboplastin in response to damage
- calcium ions (from the plasma) and thromboplastin trigger the conversion of prothrombin(P) into enzyme thrombin
- thrombin catalyses conversion of soluble protein fibrinogen to the insoluble protein fibrin
- fibrin forms a network of fibres that traps platelets and blood cells
how are blood clots dangerous?
may restrict blood flow, therefore, reduces oxygen supply to cells
how does the formation of atheromas and blood clots cause a heart attack
blood flow to the heart is restricted
less oxygen reaches cells in heart cells
rate of respiration decreases
cells no longer produce ATP
cells can no longer contract, reducing the force generated by the heart
what are some factors that increase the risk of CVD
genetics
age
gender (men more likely)
high blood pressure
high cholesterol levels
smoking
obesity
what can we use to identify obesity?
BMI over 30
waist to hip ratio
how to calculate BMI
Mass/ height^2
4 treatments for CVD
Antihypertensives
Statins
anticoagulants
Platelet inhibitors
how do antihypertensives work?
by lowering blood pressure which in turn reduces the risk of arterial endothelia damage
examples of antihypertensives
beta blockers - prevent heart rate increases
vasodilators - increase diameter of blood vessels
diuretics - reduce blood volume
how do statins work
lowering blood cholesterol by blocking an enzyme in the liver which is needed to make cholesterol
which lowers the LDL conc
how do anticoagulants work?
reduce blood clotting, therefore decreases the likelihood of thrombosis
how do platelet inhibitors work?
substances which reduce blood clotting
they prevent the clumping together of platelets
e.g aspirin
difference between correlation and causation
correlation = where a change in one variable occurs at the same time as a change in another variable
causation = where a change in one variable CAUSES a change in another variable
features of a good scientific study
clear aim or hypothesis
representative sample
valid and reliable results
peer review
how to ensure results are valid and reliable
control extraneous variables
repeat study using the same method
use a representative sample
consequences of energy imbalance
more energy burned than consumed = weight loss
more energy consumed than burned = weight gain
what do carbohydrates consist of
chains of monosaccharides
contains only carbon hydrogen and oxygen
what is an example of a monosaccharide
glucose - hexose sugar coz 6 carbons
on alpha glucose what are the locations of the H and OH groups
H = above C1
OH = below C1
difference between disaccharide and polysaccharide
di = two monosaccharides
poly = many monosaccharides
how are di and polysaccharides formed
monosaccharides join through a condensation reaction
glycosidic bonds are formed
what are the 2 types of glycosidic bonds
1,4 and 1,6
1,6 = for branches
2 examples of monosaccharides and their functions
glucose - main substrate for respiration
ribose - component of DNA and RNA
3 examples of disaccharides + their component monosaccharides
maltose = two glucose
sucrose = glucose + fructose
lactose = glucose + galactose
what is the function of disaccharides
provide the body with a quick release source of energy
they are soluble in water
properties of polysaccharides that allow them to be good for storage
compact
insoluble
2 examples of polysaccharides and their function
glycogen - energy store in animals
starch - energy store in plants
formation of glycogen
(structure)
Made up of alpha glucose. Has numerous side branches allowing rapid hydrolysis. 1,4 and 1,6 glycosidic bonds. Stored in liver and muscles. Used by bacteria, fungi and animals as an energy store.
relate the structure of glycogen to its function
highly branched, terminal ends can be easily hydrolysed into glucose to release energy quickly
how is starch formed?
(structure)
Starch is made up of amylose, which is an unbranched chain, 1,4 glycosidic bonds and is coiled into a spiral, and amylopectin, which has side branches and 1,6 glycosidic bonds. Starch is low solubility in water and compact.
what are the 2 different polysaccharides that make up starch
amylose and amylopectin
relate the structure of starch to its function
mixture of 2 polysaccharides
amylose -not branched but coiled to make molecule compact so large amounts can be stored
amylopectin = highly branched, so energy can be released quickly
how is a triglyceride formed
one molecule of glycerol forms ester bonds with three fatty acids through condensation reaction
properties of triglycerides
non polar
hydrophobic
what is the difference between unsaturated and saturated fats
saturated = no C=C bonds, solid at room temp due to strong intermolecular forces
form unbranched linear chains
unsaturated = 1+ C=C bonds, liquid at room temp due to weak intermolecular forces
difference between cis-fatty acids and trans-fatty acids
cis = H atoms are on the same side of the double bond - can be metabolised by enzymes
trans = H atoms are on opposite sides of the double bond - cannot form enzyme-substrate complexes - not metabolised - linked to CHD
what bond do triglycerides have
ester bonds formed via condensation reaction, +3H20 molecules
what is meant by HDL + function and structure
High density lipoprotein = GOOD
made of triglycerides from unsaturated fats combined with protein.
Reduces blood cholesterol by transporting it to liver to be broken down
what is meant by LDL + structure and function
low density lipoproteins = BAD
made of triglycerides from saturated fats combined with protein
Blocks receptor sites, reducing cholesterol absorption
how do LDLs contribute to risk of CVD
high blood cholesterol levels caused by LDLs leads to the formation of atherosclerosis plaques
= causal relationship
