Circulatory System Flashcards
can single-celled organisms gain oxygen and glucose directly
Single-celled organisms can gain oxygen and glucose directly from their surroundings, and the molecules can diffuse to all parts of the cell quickly due to short diffusion distances
Why do larger organisms require mass transport system
The diffusion distances involved are too great
Large organisms often have high energy requirements, so the delivery of reactants for metabolism needs to happen quickly
what does mass transport system allow
Bring substances quickly from one exchange site to another
Maintain diffusion gradients at exchange sites
Ensure effective cell activity by supplying reactants and removing waste products
how are atoms composed in water
hydrogen and oxygen. One atom of oxygen combines with two atoms of hydrogen by sharing electrons; this is covalent bonding
The sharing of the electrons is uneven between the oxygen and hydrogen atoms
what does oxygen atom attract in H2O bond
he oxygen atom attracts the electrons more strongly than the hydrogen atoms, resulting in a weak negatively charged region on the oxygen atom (δ-) and a weak positively charged region on the hydrogen atoms (δ+)
This separation of charge due to the electrons in the covalent bonds being unevenly shared is called a dipole
When a molecule has one end that is negatively charged and one end that is positively charged it is said to be a polar molecule
Water is a polar molecule
why does water dipole nature make it good at transporting
Water is cohesive making it good to transport substances
Water is a solvent
explain cohesion and adhesion in water
Hydrogen bonds between water molecules allow for strong cohesion between water molecules
Water is also able to hydrogen bond to other molecules; this is known as adhesion
The forces of cohesion and adhesion within a body of water and between water and its surroundings means that water flows easily
why is water a solvent
since polar molecule many ions will dissolve in it
Water molecules surround charged particles; the positive parts of water are attracted to negatively charged particles and the negative parts of water are attracted to positively charged particles
The surrounded molecules break apart
The ions surrounded by water molecules have dissolved
what happens in closed circulatory system
blood is pumped around the body and is always contained within a network of blood vessels
what happens in open circulatory system
the blood, or blood equivalent, is inside the body cavity and bathes the organs
what does the right side of the heart pump
deoxygenated blood to the lungs for gas exchange; this is the pulmonary circulatory system
what does the left side of the heart pump
Blood then returns to the left side of the heart, so that oxygenated blood can be pumped at high pressure around the body; this is the systemic circulatory system
what is the heart divided into
four chambers
The two top chambers are atria
The bottom two chambers are ventricles
what are the left and ride side of the heart separated by
a wall of muscular tissue called the septum
what are the right atrium and right ventricle separated by
atrioventricular (AV) valve known as the tricuspid valve
what are the left atrium and ventricle separated by
another AV known as the bicuspid valve
what are right ventricle and pulmonary artery separated by
semilunar valve known as pulmonary valve
what are left ventricle and aorta seperated by
another SL valve known as the aortic valve
what are valves attached to
heart walls by valve tendons, or cords; these prevent the valves from flipping inside out under high pressure
what is the function and structure of the left ventricle
thicker muscle than right for strong contraction to pump blood around the body.
what is the function of AV valves
prevent back flow of blood from ventricles to atria
what is the function of the semi lunar valves
prevent back flow of blood from aorta or pulmonary artery to the ventricles
what two blood vessels bring blood into heart
vena cava: blood from body
pulmonary vein: from lungs
what two blood vessels take blood away from the heart
The pulmonary artery takes blood to the lungs
The aorta takes blood to the body
what is coronary arteries
a series of blood vessels in the muscle of the heart
what are arterioles
arteries branch into narrower blood vessels called arterioles which transport blood into capillaries
what are venules
these narrow blood vessels transport blood from capillaries into veins
what blood vessel has narrow lumen and wider lumen
arteries have narrow lumen and veins have wider lumen
what is the endothelium in artieries
once cell thick and lines the lumen. Very smooth and reduces friction for blood flow. Folded enabling it to expand under high pressure.
Do arteries have smooth muscle and elastic tissue
This layer is thick in arteries
The layer of muscle cells strengthen the arteries so they can withstand high pressure
It also enables them to constrict and narrow the lumen for reduced blood flow
what does contraction of the muscle cause
constriction of the lumen
This is useful for diverting blood flow away from certain locations
what does elastic tissue help
maintain blood pressure in the arteries
It stretches and recoils to even out any fluctuations in pressure
what does outer wall of artery contain
Contains the structural protein collagen protects blood vessels from damage by over-stretching
why is smooth muscle layer and elastic layer thinner in veins
no need for a thick muscular layer as veins don’t have to withstand high pressure
how structure of vein relate to its function
A larger lumen helps to ensure that blood returns to the heart at an adequate speed preventss resistance to blood flow back to the heart
valves prevent backflow of blood
thin layer of muscular and elastic tissue to maintain blood pressure
smooth endothelium to prevent resistance to blood flow
why is there no pulse in veins
increased distance from the heart
why do capillaries have a narrow lumen
Red blood cells need to pass through the capillaries in single file
This forces the blood to travel slowly which provides more time for diffusion to occur
structure of capillary walls
wall of the capillary is a single layer of endothelial cells
This layer also lines the lumen in arteries and veins
The wall is only one cell thick; this reduces the diffusion distance for oxygen and carbon dioxide between the blood and the tissues of the body
what is the contraction/relaxation of the heart called
systole and diastole
what are the volume and pressure changes during systole and diastole
Contraction of the heart muscle causes a decrease in volume in the corresponding chamber of the heart, which then increases again when the muscle relaxes
Volume changes lead to corresponding pressure changes
When volume decreases, pressure increases
When volume increases, pressure decreases
Throughout the cardiac cycle, heart valves open and close as a result of pressure changes in different regions of the heart
explain atrial systole
The walls of the atria contract
Atrial volume decreases
Atrial pressure increases
The pressure in the atria rises above that in the ventricles, forcing the atrioventricular (AV) valves open
explain ventricular systole
The walls of the ventricles contract. The pressure in the ventricles rises above that in the atria. This forces the AV valves to close, preventing back flow of blood. The pressure in the ventricles rises above that in the aorta and pulmonary artery
This forces the semilunar (SL) valves open so blood is forced into the arteries and out of the heart. Relaxed atria begin to fill with blood again
Explain Diastole
The ventricles and atria are both relaxed
The pressure in the ventricles drops below that in the aorta and pulmonary artery, forcing the SL valves to close
The atria continue to fill with blood
Blood returns to the heart via the vena cava and pulmonary vein
Pressure in the atria rises above that in the ventricles, forcing the AV valves open
Blood flows passively into the ventricles without need of atrial systole
The cycle then begins again with atrial systole
why are daphnia suitable to investigate effect of caffeine on heart rate
having transparent bodies; their internal organs, such as the heart, can be observed using a light microscope
what is the method to investigate effect of caffeine on heart rate
- five different concentrations of caffeine and control of distilled water
- add cotton wool on slide and add daphnia using pipette and add some distilled water
- use stop clock to time a minute and record number of heartbeats/ dots on paper
- repeat with different concentrations and daphnia
results of daphnia experiment
caffeine increases heart rate of Daphnia by release of stimulatory neurotransmitters.
steps of atherosclerosis
Damage by high blood pressure, is caused to the endothelium
inflammatory response occurs and white blood cells such as macrophages accumulate in the damaged area
Lipids and cholesterol clump together with macrophages under endothelium and form fatty streaks
platelets (fragments of blood cells) can add to fatty deposit.
Platelets, cholesterol lipids and macrophages accumulate under endothelium forming plaque knows as atheroma. This plaque can harden reducing elasticity of artery wall and increasing blood pressure
what is the process of blood clotting known as
thrombosis
steps of thrombosis
damaged blood vessels release protein called thromboplastin
calcium ions from plasma and thromboplastin trigger conversion of soluble prothrombin into enzyme thrombin
thrombin catalyses conversion of soluble protein fibrinogen into insoluble protein protein fibrin.
fibrin fibres mesh and tangle trapping platelets and red blood cells
blood clot formed
how can atheroma increase risk of blood clotting
plaque deposit rupture through endothelium damaging it and forming rough surface triggering thrombosis
why is atheroma and blood clotting dangerous
blood clot that forms can completely block the artery
Blood clots reduce blood flow which restricts the movement of oxygen in the blood, therefore reducing respiration of the surrounding cells, tissues and organs
if they reach the brain this can cause a stroke to occur
Heart attack
Deep vein thrombosis
How is coronary hear disease caused
formation of atheroma and blood clots in the coronary arteries
Blood flow to certain areas of the heart is restricted and delivery of oxygen to the affected cells decreases, thereby reducing respiration in these cells
The cells can no longer produce ATP
The cells can no longer contract, reducing the force generated by the heart when it beats
The cells can die, causing permanent damage to heart tissue leading to heart attack
two factod to control with caffeine and ghost shrimps
temperature of solution if too cold can decrease heart rate
same size so caffeine affect equally
why will a mammal born with a hole between ventricles have lack of energy
deoxygenated and oxygenated blood will mix as the deoxygenated blood from right ventricle will be transferred to left ventricle reducing the concentration of oxygen in the blood circulating around the body and to respiring tissues and muscle cells hence less oxygen for aerobic respiration
control for daphnia investigation
use distilled water only no caffeine to show that the solvent had no effect on heart rate and to compare with caffeine concentrations
how does blood clot cause heart attack
blood clot can clog/block the artery so oxygen cannot reach the heart/muscle cells preventing aerobic respiration from occurring. Therefore cardiac muscles cant contract
myogenic
stimulation generated within the muscle resulting in depolarisation
How does SAN ensure oxygenated blood enters aorta
sinoatrial
initiates impulses and electrical activity over atria
causes atria to contract and pump oxygenated blood into left ventricle. Electrical activity from the SAN causes left ventricle to contract.
four differences between arteries and capillaries
capillaries are one cell thick / arteries have multiple layers
arteries contain collagen and capillaries dont
lots of muscle in arteries no muscle in capilaries
pores in capillaries none in arteries
elastic tissue in arteries none in capillaries
lumen one cell wide in capillaries
why does frequent use of cocaine increase blood clot formation
von willebrand
fibrinogen
idea that von Willebrand factor results in platelets sticking to {the endothelium /each other};
2. reference to release of thromboplastin (from platelets) ;
3. (as a result) the blood clotting process is triggered / eq;
4. credit one correct detail of clotting process;
5. reference to more fibrinogen resulting in the clot {being larger / growing faster } ;
6. reference to von Willebrand factor making the platelets stickier;
7. as a result of {platelet stickiness /platelets sticking together} the {clot grows faster / blood flow is decreased / eg} ;
8. If the blood is flowing slower then there is an increased chance of blood clotting / eq;
why is water a good transport medium
it is a solvent so it can surround polar molecules and form hydrogen bonds.
water is a liquid so it can flow
left side of heart structure in comparison to right side
aorta which has thicker layer of muscular tissue / collagen and elastic tissue
collagen withstands high blood pressure
muscular tissue maintains high blood pressure and elastic tissue recoils to maintain blood pressure
Describe how av valves work in one cardiac cycle
the valves are open { when atria contract / atrial systole / when blood pressure greater in atria (than ventricles) } (1)
• the valves close { when ventricles contract / during ventricular systole/when pressure greater in ventricles (than atria) } (1)
• valves prevent backflow of blood into the atria during ventricular systole (1)
explain how a blood clot can cause a heart attack
prevents oxygen reaching the heart {muscle / cells / tissue / eq};
prevents (aerobic) respiration;
(cardiac) muscle unable to contract / dies / eq } ;
two differences between fibrin and fibrinogen
Idea that fibrinogen is globular and fibrin is fibrous;
. fibrinogen is soluble and fibrin is insoluble
what happens during diastole
atria and ventricles relax
blood enters atria
semilunar close and atrioventricular open
Describe the roles of the atrioventricular (bicuspid and tricuspid) valves during the
cardiac cycle.
valves {separate / eq} atria from ventricles ;
2. open during atrial {systole / contraction } /
eq ;
3. so that blood can pass through to ventricles /
eq ;
4. closed during ventricular {systole /
contraction} eq ;
5. to prevent {blood being forced back / backflow
/ eq} (up into atria) / to maintain pressure in
ventricles ;
6. open during diastole / eq ;
7. so that ventricles can start to fill up (as atria
are filling)
Describe the structure of collagen.
primary structure described as a repeating amino acid sequence (1)
three polypeptide chains (1)
chains coiled around each other (1)
cross-linking between the chains
