Topic 1 - Lifestyle, Health and Risk Flashcards
(53 cards)
Open circulatory system
Consists of a heart, fluid and large cavity.
e.g. insects
The heart pumps blood into cavities that surround organs. Substances are able to diffuse between blood and cells. When the heart relaxes, blood is moved into the heart from the cavity through small, valved spaces.
Closed circulatory systems
Where blood is enclosed in blood vessels.
Generates higher blood pressure, forcing blood along narrow vessels instead of large cavities. Therefore the blood travels quicker and is more efficient at delivering substances to places in the body.
e.g. vertebrates
heart -> arteries -> aterioles -> capillaries -> venules -> veins -> heart
Single circulatory systems
The heart pumps deoxygenated blood to the gills.
Gaseous exchange happens in the gills - diffusion of CO2 from blood into the water surrounding the gills, and diffusion of O2 from the water to the blood into the gills.
e.g. fish
Double circulatory systems
Right ventricle pumps deoxygenated blood to the lungs where it is given O2.
The oxygenated blood travels back to the heart to be pumped (a second time) by the left ventricle into the body.
The blood flows through the heart twice for each full circuit of the body.
e.g. birds and mammals
Mass flow
Blood moves because of mass flow.
Movement of fluid down a pressure gradient (in one direction), through blood vessels, from a high pressure to low pressure.
Allows organisms to maintain their metabolic rate because it makes sure there is fast delivery of respiratory substances.
Why larger organisms need a closed circulatory system
To overcome diffusion limitations - diffusion isn’t sufficient on its own for oxygen/glucose transport.
SA:V ratio - larger organisms have a smaller SA:V ratio, meaning substances aren’t able to be diffused in fast enough.
Metabolic rate - larger organisms have a higher metabolic rate so require quicker delivery of substances.
What blood is and its functions
A specialised transport transport medium.
Functions:
- transport
- immunity/defence
- thermoregulation
- maintaining pH of bodily fluids
Composition of blood
Cells - 45%:
- RBCs - transport oxygen
- WBCs - immunity
- Platelets - blood clotting
Plasma - 55%:
- Water
- Proteins
- Ions
- Nutrients
- Waste products
- Hormones
- Gases
Water and electronegativity
Water = a polar molecule.
Electronegativity is the level of which atoms attract electrons in a covalent bond.
Electronegative is a high tendency to pull electrons.
Intermolecular bonding
Polar molecules form hydrogen bonds form between molecules.
Why water is a liquid
Has negative oxygen ends and positive hydrogen ends (dipole).
This allows each molecule to bond to another molecule through weak hydrogen bonding.
Waters traits - Good solvent
Water attracts/dissolves polar solute.
Waters traits - High specific heat capacity
Organisms need to keep a constant temperature.
The hydrogen bonds in water need a lot of energy to break.
Specific heat capacity - how much energy needed to raise the temperature of 1cm3 of volume by 1 degree celsius’s.
Waters traits - High tension
Hydrogen bonds are weak, but there are lots in water, which produces cohesion and tension.
Cohesion - weak hydrogen bonds hold water together.
Adhesion - water binds to different surfaces.
Tension - if one molecules moves, all of them move.
Valves of the heart
Atrioventricular valves - separate atrium and ventricle. also called tricuspid (right) and bicuspid (left) valves.
Semilunar valves - prevents the backflow of blood from the arteries into the ventricles.
Valves - prevent the back flow of blood.
Blood vessels
Arteries have thicker walls, narrowser lumen, more collagen and more smooth muscle with elastic fibres.
Veins have thinner walls, wider lumen, less collagen and less smooth muscle with elastic fibres. They also have valves.
Capillaries have one cell thick walls, no valves, collagen or smooth muscle. They have narrow lumen and are porous.
Using a stage micrometer and eyepiece graticule
- Line up eyepiece with stage micrometer. (1mm = 1000µm)
- Count the number of eyepiece units that are in 1000 µm. e.g. five eyepiece units in 1000 µm.
- Work out the length of one eyepiece unit in µm. e.g. 1000 µm ÷ 5 = 200 µm
- Take away the stage micrometer.
- Use the calculation to measure the width of the artery. e.g. if the width is twelve eyepiece units, the calculation is 12 x 200 = 2400 µm
Microscopy
- Set the objective lens to the lowest magnification. (x4)
- Use stage controls to move the slide across the stage until the light is shining through the specimen.
- Focus using the coarse focus.
- Adjust the focus using fine focus.
- Increase the objective lens magnification.
- Refine the image using the fine focus.
Cardiac cycle - Cardiac diastole
All the chambers are relaxed, allowing blood to flow into the heart.
Cardiac cycle - Atrial systole (Ventricular diastole)
The left atrium contracts, which increases pressure in the atria, forcing blood into the ventricles. AV valves are open - due to pressure being higher in the atrium than the ventricle.
Cardiac cycle - Ventricular systole (Atrial diastole)
The atria relax and the left ventricle contracts, increasing the pressure in the ventricle. AV valves are shut. Ventricle keeps contracting, forcing blood into the aorta. SL valves open.
Heart Attack
Myocardial Infarcation.
Lack of oxygen to heart tissue.
Leads to tissue damage or death.
Stroke
Lack of oxygen to brain tissue.
Leads to tissue damage or death.
Aneurysm
Swelling of an artery.
Can burst, the blood loss can be fatal.
