1A: Circulatory System Flashcards
why is water a polar molecule?
it has a slightly negative charge and a slightly positive charge
how are water molecules held together ?
hydrogen bonds hold the molecules together
what does water cohesion mean?
water is attracted to other water molecules via H+ bonds
what does water adhesion mean?
water molecules attracted to other surfaces
what molecules can easily dissolve in water ??
polar / charged molecules
why does hydrophilic mean?
attracted to water (polar molecules)
what does hydrophobic mean?
repelled by water (non-polar molecules)
what is the benefit of many polar substances being able to readily dissolve in water?
it is easy for them to be transported around the body and in plants
why does water have a high heat capacity?
strong hydrogen bonds between the water molecules - more energy needed to break the bonds. Some of the energy supplied is used to break the bonds between the water molecules instead of to raise the temperature
what is water potential?
the ability for water to move - from a high potential to a low potential
how can you reduce water potential?
by adding solutes to the water
how is water a good solvent?
it’s a polar molecule therefore easily dissolvable- this aids in the transport of substances around the body/plants for respiratory purposes
what is mass transport?
the bulk movement of gases or liquids in one direction , usually the light a system of vessels and tubes
what is a circulatory system?
a system in which substances are transported in a flowing fluid through vessels and tubes
what are the two types of circulatory systems?
open and closed circulatory systems
what is an open circulatory system?
where the blood is pumped by a heart into body cavities/tissues. This process relies on diffusion of substances from blood to cells
what is a closed circulatory system?
where the blood is enclosed within the blood vessels and it does not make direct contact with the tissue cells
why is a double pump better than a singular one (pressure) ?
easier to maintain blood pressure (high) as more blood is being pumped at once
why is a double pump better than a singular one ( blood) ?
prevents the mixing of oxygenated and deoxygenated blood. This results in the oxygen supply being highly efficient
why is a double pump better than a singular one (metabolic rate)?
the substances can be transported around the body through the blood at a quicker rate- processes happen quicker therefore body processes happen at a more efficient rate.
what are the main features of a mass transport system? (4)
- a system of vessels that follow a specific route
- a way of making substances move in the right directions (waste out, nutrients in)
- a means of moving materials quickly to meet organism needs
- a transport medium (usually water as it carries dissolved substances)
what are the benefits of a mass transport system? (3)
- helps to bring substances quickly from one exchange site to another
- to maintain concentration gradients at exchange sites
- to ensure effective cell activity (keeping waste products out and nutrients in)
what is a pulmonary circuit
circuit between the heart and the lungs
what is a systematic circuit
a circuit between the heart and the rest of the body
what is the benefit/purpose of elastic fibres in blood vessels?
they can stretch and recoil - providing vessel walls with flexibility
what is the benefit/purpose of smooth muscle in blood vessels?
when contracting / relaxing - it changes the size of the lumen (affects blood flow/pressure)
what is the benefit/ purpose of collagen in blood vessels ?
provides structural support to maintain the shape and volume of the vessel
what is the function of arteries?
they carry blood from the heart to the rest of the body
what is the benefit of thick tough tissue in the arteries?
to withstand high blood pressure
what is the benefit of elastic fibres in the arteries?
helps withstand the force of the blood as the lumen can stretch to maintain blood pressure
what is the benefit of smooth muscle in the arteries?
to make blood flow easier
what is the benefit of collagen in the arteries ?
to help the lumen stretch to adapt to blood flow
does the arteries have a narrow or wide lumen?
narrow lumen
what is the function of vein?
to carry blood away from body cells and to the heart
why do veins have less elastic fibres and muscle tissue in comparison to arteries?
veins carry blood at lower blood pressure
does the vein have a narrow or wide lumen?
wide lumen
why do veins have less collagen, less elastic fibres, and less smooth muscle?
blood is being carried at a lower pressure
what is the function of valve?
to prevent the back flow of blood and to prevent the mixing of oxygenated and deoxygenated blood
name the three valves
• bicuspid valve
• tricuspid valve
• semi lunar valve
where is the tricuspid valve located?
between the right atrium and right ventricle
where is the bicuspid valve located?
between the left atrium and the left ventricle
where is the semi lunar valve located?
between the ventricles and the arteries and follow it (aorta/pulmonary artery)
why are there larger veins aside large muscles?
to assist in squeezing the blood towards the heart each time the muscle contracts
what is the function of capillaries?
the link blood vessels together to form a network. they are where exchange of substances between tissues take place
why are capillaries one cell thick?
to increase rate of diffusion as it’s a short diffusion distance for substances
why do capillaries have a narrow lumen?
to slow down the blood flow therefore the substances have enough time to exchange efficiently
what are the four components of blood?
red blood cells, White blood cells, platelets and plasma
what is function of blood?
to transport digested food products for use and/or storage
- also acts as a buffer to PH changes and helps to maintain body temp (thermoregulation)
what is the function of red blood cells?
to carry oxygen from the lungs to the rest of the body
how is a red blood cell adapted to its function?
no nucleus + biconcave disc shape therefore they have a large surface area therefore they can carry more haemoglobin
haemoglobin + oxygen ??
oxyhaemoglobin
haemoglobin + CO2??
carbaminohaemoglobin
how many molecules of oxygen can bind or haemoglobin?
4
how is a steep concentration gradient maintained from oxygen in the lungs to the blood?
oxygen binds to haemoglobin, ensuring free oxygen in the cytoplasm remains low
do the lungs have a high or low affinity for oxygen?
high affinity
what does high affinity mean?
substance binds easily but dissociates slowly
what does low affinity mean?
substance binds slowly but dissociates easily
what is oxygen dissociation?
the relationship between the partial pressure of oxygen and oxygen saturation of haemoglobin
what is partial pressure?
the measure of oxygen concentration (PO2)
what does an oxygen dissociation curve show?
the rate at which oxygen associates and dissociates with haemoglobin a certain PO2’s
what happens to the haemoglobin as oxygen associates to it?
after the first oxygen binds, the haemoglobin changes shape so that more oxygen can bind rapidly
how does haemoglobin changing shape affect the graphs shape?
the graphs line steepens (looks like an S)
if the curve on the oxygen dissociating graph shifts to the left…
haemoglobin has a higher affinity for oxygen therefore oxygen loads easier in the lungs. this means that there is less oxygen present
if the oxygen dissociation curve shifts to the right…
haemoglobin has a lower affinity for oxygen therefore oxygen unloads quicker . this means that there is more oxygen present
where in CO2 within the body?
• plasma carries 5%
• 10-20% combines with haemoglobin
• rest of CO2 reacts with water in the blood
CO2 + water …
carbonic acid
what concerts CO2 and H2O into carbonic acid?
enzyme called carbonic anhydrase
what happens once carbonic acid is formed?
it separates into H+ ions and hydrocarbonate ions which are held in the RBC’s cytoplasm
what can lower your bloods oxygen affinity?
if your blood is too acidic
what is the blood flow of the heart?
Vena Cava, Right Atrium, Right Ventricle, Pulmonary Artery, Lungs, Pulmonary Vien, Left Atrium, Left Ventricle, Aorta
what is the importance of valves and the septum in the heart?
to prevent the back flow of blood and the mixing of oxygenated and deoxygenated blood
what is the tendinous cords?
to prevent the valves from turning inside out when high pressure of blood are exegetes by the ventricles
what is the cardiac cycle?
the events of a single heart beat
what are the main steps in the cardiac cycle?
atrial systole , ventricular systole and diastole
what is systole?
a contraction of the heart
what is a diastole?
the relaxation of the heart
what happens during a diastole?
the atria and ventricles relax as the the atria’s fill with blood. Semi lunar valve closes and the AV valve opens
what happens during the atrial systole?
blood is forced into the ventricles as the atria contracts and the AV valve closes to prevent the back flow of blood back into the atria
what happens during a ventricular systole?
the semi lunar valve opens as blood is pushed up the arteries due to the ventricle contracting
what is the pressure during atrial systole? Why?
the pressure is high as the muscle is contracting , filling with blood and valves are opening and closing.
After the blood has left the atria, pressure reduces
what is the pressure during ventricular systole?
high as the muscle is contracting, filling with blood and valves are opening and closing.
Once blood has left the ventricles pressure reduces
what is the pressure during a diastole?
overall heart pressure is low but the pressure in the aorta is high bc blood had been pumped into it
why is there a tiny delay between AS and VS?
it allows the atria to relax before the ventricle contracts
why is the heart myogenic?
it initiates it’s own contractions (no conscious effort involved)
what nodes are involved in the cardiac cycle?
sinoatrial node (SAN) and the atrioventricular node (AVN)
what is the rhythm of the heart? (SAN + AVN)
• the SAN sends an electrical excitation wave
• the atria contracts, forcing blood through the AV valve
• after a short delay, a AVN sends out a wave of excitation
• the bundle of his (a bundle of tissues) transfers the electrical impulses down the septum
• the impulses are conducted via the purkynje fibres
• the ventricles contract from the back upwards which forces blood out the heart
how do you calculate stroke volume?
cardiac Output X Heart Rate
what is stroke volume?
amount of blood that’s ejected by the left ventricle in one cycle
what is cardiac output ?
the volume of blood pumped by the heart per minute
how does CO2 concentration affect haemoglobin?
the acid changes the shape of it and lowers its affinity for oxygen
in the cardiac cycle, when is blood pressure highest
during systole
what is hypertension
when blood pressure is over 140Hg
what is the issue with hypertension
if blood pressure if over 140Hg for log periods of time, it can damage the artery lining leading to atheroscolosis
what is a sphygmomanometer
a blood pressure moniter machine
