Topic 1 Flashcards
Heart function
-To generate pressure to pump blood around the body
-allow mass transport/ mass flow
-To overcome the limitations of diffusion to ensure fast enough delivery of oxygen gas to all body cells
What is the function of the coronary arteries
Transports oxygenated blood from the heart into the cardiac muscle
What are the heart walls made of?
Cardiac muscle
Define ‘cardiac cycle’
The pattern of contraction and relaxation of the heart during one complete heartbeat
Artery structure - outer collagen coat
Strong to withstand high blood pressure
Artery structure - Thick smooth muscle layer
Muscle contracts to allow vasoconstriction to maintain high blood pressure
Artery structure - Thick elastic fibre layer
Allow artery to stretch and recoil to maintain high blood pressure
Artery structure - Smooth endothelium
Reduces resistance to blood flow
Artery structure - narrow lumen
Maintains high blood pressure
Vein structure - outer collagen coat
strength
Vein structure - valves
to prevent back flow of blood
Vein structure - thin smooth muscle layer
less construction of vein needed
Vein structure - thin elastic fibre layer
less elastic recoil needed as blood is moved by contraction of skeletal muscles
Vein structure - smooth endothelium
reduces resistance to blood flow
Vein structure - large lumen
reduces resistance to blood flow to prevent low blood pressure slowing down
Capillary structure - one cell thick wall
reduced diffusion distance speeds up exchange of substances between the blood and tissue cells
Capillary structure - walls have pores
to allow the passage of molecules through the wall, aiding formation of tissue fluid
Capillary structure - very narrow lumen
decreases the rate of flow of blood to allow more time for exchange of oxygen/ glucose between blood and cells by diffusion
Walls of red blood cells can be in contact with capillary wall, reduction distance for oxygen to diffuse to enter cells
Diffusion
The movement of molecules or ions from a region of high concentration to a region of low concentration, down a concentration gradient
Diffusion
The movement of molecules or ions from a region of high concentration to a region of low concentration, down a concentration gradient
Open circulatory system
There are no blood vessels, instead the blood is held within a body cavity and the organs are bathed in blood. Diffusion takes place between blood and organs. Blood is under low pressure
Closed circulatory system
Blood is held within blood vessels and is under high pressure
Single closed circulatory system
Blood flows once through the heart during each complete circuit of the body. blood is at low pressure when reaching body capillaries
Double closed circulatory system
Blood flows twice through the heart during each complete circuit of the body. Blood is at high pressure when reaching body capillaries
Advantages of double closed circulatory system
-Oxygenated and deoxygenated blood do not mix
-blood can be pumped at different pressures
-repressurisation
Dipolar nature of water
Oxygen is delta negative
Hydrogen is delta positive
Bonding between water molecules
Hydrogen bonding between delta positive of hydrogen and delta negative of oxygen
Properties of water
-good solvent
-high latent heat of vaporisation
-high specific heat capacity
Specific heat capacity
how much energy it takes for 1kg of material by 1 degrees celsius
solvent
something other substances can dissolve in
Hydrophobic
Repels water (non-polar) molecules eg lipids)
Hydrophilic
Attracts water (polar molecules/ions eg glucose)
What is blood pressure the measure of?
The hydrostatic force of the blood against the walls of a blood vessel
What is elevated pressure known as?
Hypertension
What are the units of blood pressure
mmHg
What is peripheral resistance?
Contact between blood and the walls of the blood vessels causes friction and this impedes the blood flow
When is blood pressure highest in artery blood
during systole - this is called systolic pressure
When is blood pressure lowest in artery blood
during diastole - this is called diastolic pressure
What is oedema
fluid building up in tissues and causing swelling
which type of blood vessel does atherosclerosis usually occur in
arteries
Two main risk factors for atherosclerosis
1)high blood pressure
2)high blood cholesterol
What is a blood clot also known as
a thrombus
platelets in blood clotting
cell fragment releases thromboplastin, found in blood plasma, can change shape
thromboplastin in blood clotting
soluble enzyme, catalyses conversion of prothrombin into thrombin, globular
prothrombin in blood clotting
soluble plasma protein, globular, present in blood
thrombin in blood clotting
soluble enzyme, globular, catalyses the conversion of fibrinogen to fibrin
fibrinogen in blood clotting
soluble, plasma protein present in blood, globular
fibrin in blood clotting
insoluble protein, fibrous, forms a mesh to trap red blood cells and platelets
which artery becomes blocked which leads to a heart attack
coronary
what effect does a blocker coronary artery have on the blood flow and oxygen to the heart muscle
reduces flow of oxygenated blood to heart muscle
General formula for a monosaccharide
CnH2nOn
Two structural differences between a monosaccharide and a disaccharide
-monosaccharide is a single sugar unit, disaccharide is a double sugar unit
-A disaccharide has a glycosidic bond, monosaccharide does not
condensation reaction definition
joining of monomers or smaller molecules to make a larger molecule
water is removed and a bond is formed
hydrolysis reaction definition
splitting of polymers or large molecules into smaller molecules
water is added and a bond is broken
what is a hexose sugar
six carbon sugar
function of glucose
-immediate respiration source
-joined to form starch or glycogen for energy storage
function of galactose
a component of disaccharide lactose
fructose function
sweet sugar which attracts animals to eat the fruit and therefore helps seed dispersal
how does the structure of glucose relate to its function
-doesn’t need to be hydrolysed as is a single sugar unit
-polar with many hydrophilic OH groups making it soluble in water - transport
-small so diffuses quickly into blood
maltose (glucose+glucose) function
found in germinating seeds (when starch is broken down by enzyme amylase)
sucrose (glucose+fructose) function
used for transporting energy in plants (sugar in the phloem)
lactose (glucose+galactose) function
sugar in milk - for energy
polysaccharide definition
many sugar units joined together by glycosidic bonds formed in condensation reactions
starch structure
-alpha glucose
-amylose - unbranched, 1,4 glycosidic bonds
-amylopectin - branched, 1,4 and 1,6 glycosidic bonds
function and properties of starch
-energy storage in plants
-rapidly hydrolysed to release glucose quickly due to many branches
-insoluble so no osmotic effect
-compact - more starch and therefore more glucose can be stored in smaller space
glycogen structure
-alpha glucose
-branched
-1,4 and 1,6 glycosidic bonds
glycogen function and properties
-energy storage molecule in animals
-rapidly hydrolyses to release glucose quickly due to many branches
-insoluble - no osmotic effect
-compact - more glycogen and so more glucose can be stored in a smaller space
cellulose structure
-beta glucose
-unbranched
-1,4 glycosidic bonds
cellulose function and properties
-provides strength in the plant cell wall
Describe the structure of a fatty acid
long straight hydrocarbon chain and a carboxylic acid group.
Function of cholesterol
Found in cell membrane, where its function is to regulate fluidity
what is a lipoprotein
a molecule made up of cholesterol combined with triglycerides and protein
is LDL saturated or unsaturated fatty acid
saturated
is HDL saturated or unsaturated fatty acid
Unsaturated
Role of LDL in cholesterol transport
Transports cholesterol from liver to body tissues where cholesterol binds to LDL receptors on cell membranes to be taken up into cells
Role of HDL in cholesterol transport
Transports cholesterol from body tissues to liver where cholesterol is broken down
Important in reducing blood cholesterol levels
consequences of increased saturated fats in the diet
Too many LDLs can cause LDL receptors on cells and tissues to overload so LDLs accumulate in blood causing high blood LDL cholesterol
does saturated fatty acid have higher or lower H:C ratio?
higher
does unsaturated fatty acid have higher or lower H:C ratio?
Lower
