Topic 1 Ford Flashcards
Respiration
Oxygen + Glucose –> Carbon Dioxide + Water (+Energy)
Purpose of a circulatory system
delivers oxygen and glucose to your cells for respiration and removes carbon dioxide and water
Why do we need a circulatory system?
because diffusion is not fast enough to transport the amount of molecules we need. Also organisms maintaining their body temp. have a higher metabolic demand so they need a more efficient system
Circulatory system
allows for MASS FLOW which overcomes the limitations of diffusion in meeting the requirements of an organism
Factors affecting need for a transport system
- size
- surface area to volume ratio
- metabolic rate
Mass Flow
the particles in a fluid move in one direction through tubes due to a difference in PRESSURE; high to low valves permitting
Types of circulatory system
- Open
- Closed - single
- Closed - double
Open circulatory system
-blood not always held in vessels
-blood circulates through the body cavity and tissues
Generally occurs in smaller animals that have separate tubes for gases
Closed circulatory system
- blood stays in vessels
- this generates a higher blood pressure so the blood travels faster and is more efficient at delivering nutrients and removing waste
Which organisms don’t need a circulatory systems?
Smaller organisms with a larger surface area to volume ratio don’t need a circulatory system because their cells are close enough that diffusion can occur
What is an advantage of having two separate circuits?
There will be no mixing of oxygenated and deoxygenated blood - higher concentration gradient. It also allows the blood to be pumped at two different pressures so there’s no damage to lungs or body tissues
Arteries
carry blood Away from the heart
veINs
carry blood INto the heart
Capillaries
exchange substances with body Cells (link arterioles to venules)
Venules
collect blood from capillaries and lead it back to veins
Arterioles
control blood flow from arteries to capillaries
veins
- wider lumen
- valves
- thinner muscle layer
- less elastic fibres
arteries
- narrower lumen
- no valves
- thicker muscle layer
- more elastic fibres
- more collagen fibres
capillaries
- very narrow lumen
- single cell layer endothelium
Blood
Fluid in our circulatory system containing:
- red blood cells
- white blood cells
- platelets
- plasma
Water
is a polar molecule - oxygen slightly negative, hydrogen slightly positive
Why is water a good solvent?
because it is a polar molecule, charged or polar ions cover all sides of a water molecule due to the different charges.
Water’s hydrogen bonds
- one hydrogen bond is weak but multiple are very strong
- means water has a high specific heat capacity helping organisms to maintain a steady temperature
Typical blood pressure
120/80
Blood pressure
hydrostatic force of the blood against the walls of a blood vessel
Systolic blood pressure
when the ventricles are contracting - maximum blood pressure when heart contracts
Diastolic blood pressure
when both atria and ventricles are relaxed - minimum blood pressure in an artery
Hypertension
elevated blood pressure
oedema
a sign of high blood pressure - fluid building up in tissues and causing swelling
Peripheral resistance
friction between the blood and the artery wall will slow down blood flow, is highest in capillaries
Red blood cells
carries oxygen
Platelets
blood clotting
White blood cells
immune system - antitoxins, antibodies, engulf pathogens
Plasma
water based fluid carrying: glucose, CO2, urea, lactic acid, vitamins, amino acids, hormones
Risk Factor: Genetics
- tendency to high blood pressure and poor cholesterol metabolism
- arteries that damage easily
- mutations in genes that control HDL:LDL ratio
Risk Factor: Gender
-oestrogen gives women some protection before menopause, post menopause this protection is lost and CVD risk increases
Risk Factor: Ageing
-elasticity and width of arteries decreases
Risk Factor: Diet
-many correlations; saturated fat, cholesterol, lipoprotein
Risk Factor: High blood pressure
-leads to damage of arteries
Risk Factor: Smoking
-correlation and causation; chemicals cause damage to arteries and cause them to constrict
Risk Factor: Inactivity
-regular exercise reduces blood pressure and raises HDL levels
Risk Factor: Obesity
-increases risk of CVD and type 2 diabetes
