The Circulatory System Flashcards
The need for circulatory system
Why do larger organisms need a mass transport system
3 points
1
- made of many layers of cells
- Diffusion distances involved too great
- High energy requirements, so delivery of reactants for metabolism needs to be quick
Need for a Circulatory system
Mass transport system
1 point
2
Bulk movement of gasses and liquids in one direction
usually through a system of vessels and tubes
Need for a circulatory system
What does the mass transport system help with
3 points
3
- Bring substances quickly from one exchange site to another
- maintain diffusion gradients at exchange sites and between cellls and their fluid surroundings
- ensure effective cell activity, supplying reactants and remove waste products
Need for a circulatory system
Double circulatory system
3 points
4
- blood passes through heart twice.
- Right ventricle of heart pumps deoxygenated blood to lungs where it receives oxygem
- oxygenated blood returns to heart to be pumped second time - blood receives extra push to circulate around body faster
For both birds and mammals
Need for a circulatory system
Single Circulatory system
4 points
5
- Blood passes through heart once
- heart pumps deoxygenated blood to gills
- gaseous exchange occurs in gills - diffusion of oxygen from water into blood/ carbon dioxide from blood to water
- oxygenated blood leaves gills and flows round body back to heart.
usually in fish
Need for a circulatory system
Open circulatory system
3 points
6
- blood circulates in large open spaces
- a heart pumps blood into cavities, substances diffuse between blood and cell
- heart relaxes and blood is drawn back from cavities into heart through valved openening in its lengths
In insects and other small groups
Need for a Circulatory system
Closed circulatory system
3 points
7
- blood is enclosed within blood vessels
- generates higher blood pressure, blood is forced along narrow channels
- blood travels faster and so more efficient
Water in transport
What makes water cohesive
1 point
8
Hydrogen bonds form between positively charged Hydrogens and negatively charged oxygen in water
Water in transport
Why is water good at transporting substances
1 point ( but two factors)
9
Polar nature means water is cohesive and a solvent
Water in transport
Cohesion and adhesion of water
10
- cohesion is attraction of water molecules to each other
- adhesion is the ability of water to hydrogen bond to other molecules
- cohesion allows watermolcules to pull other water molecules along
- adhesion allos water to adhere to the sides of vessels
both require hydrogen bonds and ensure that water flows easily
Water in transport
Water as solvent
2 points
11
- positive regions of water attracted to negatively charged particles, negative regions of water attracted to positively charged particles
- surrounded molecules break apart to form ions, and are dissolved
Mammalian Heart
Heart structure
3 points
12
- Heart is protected in chestcavity by pericardium - though and fibrous sac
- 4 chambers, left atria and ventricle, right atria and ventricle
- Left and right sides are seperated by septum (ensures blood doesn;t mix between the right and left sides)
Mammalian Heart
Importance of valves
2 points
13
- Keeps blood flowing in right direction
- maintains correct pressures in the chambers of heart
Mammalian Heart
Valves between ventricle and atrium
3 points
14
- atrioventricular valve
- between right atrium and ventricle: tricuspid valve
- between left atrium and ventricle: bicuspid valve
Mammalian Heart
Valves between arteries and ventricles
3 points
15
Semilunar valves,
* separates right ventricle and pulmonary artery
* separates left ventricle and aorta
Mammalian Heart
Valves, open and close
16
- open when pressure of blood behind them is greater than pressure in front of them
- close when pressure of blood in front of them is greater than the pressure behind them.
prevents backflow of blood
Mammalian Heart
Valves attached to heart
2 points
17
By valve tendons or cords.
* They prevent valves from flipping inside out under high pressure.
mammalian heart
Left ventricle
2 points
18
Thicker muscle than right ventricle
* for strong contraction to pump blood all the way around the body
right ventricle only needs to pump blood to nearby lungs
Mammalian Heart
Ventricles
1 point
19
Thicker walls than atria to pump blood out of the heart
the atria only pumps blood into ventricles
Blood Vessels
Order of vessels from heart
-
20
Heart > Artery > arterioles > capillaries > venules > veins > heart
arteries carry blood from heart, veins to heart, capillaries to cells
Blood Vessels
Arteries structure
6 points - remember muscle Tissue CONTRACTS, elastic tissue RECOILS
21
one cell thick Endothelium lining the lumen
* reduces friction for free bloodflow
* highly folded, enabling it to expand under pressure
thick smooth and elastic tisssue - tunica media
* strengthens the arteries so they can withstand high perssure
* also alllows it to constrict and narrow the lumen - directs blood flow away from certain locations
elastic tissue maintains blood pressure streches and recoils to even out fluctuations in pressure
tunica externa containing collagen
* collagen is a strong protein that protectd blood vessels from damage by overstretching
narrow lumen to maintain high blood pressure
stretch to accomadate an increase volume of blood per heartbeat: pulse
Blood Vessels
veins structure
6 points
22
- smooth muscle and elastic layer is muchthinner in veins as they don’t need to withstand high pressures
- wide(r) lumen - ensures blood return to heart is at adequate speed
- reduces friction between blood and endothelium
- rate of blood flow is slower in beins but larger lumen means volume of blood delevered/time is equal to arteries
- valves to prevent backflow of blood
- no pulse due to increased distance from heart
Mamillian Heart
Capillaries structure
23
- very narrow lumen, red blood cells pas through capilaries in single file
- this forces blood to travel slowls, so more time for diffusion to occur
- single layer of endothelial cells, reducing diffusion distances for oxygen and CO2
- cells of wall have gaps called poors, allows blood plasma to leak out and form tissue fluid
capillaries form networks callled capillary beds
Cardiac cycle
Cardiac cycle
24
series of events that take place one heart beat, including muscle contraction and relaxation
cardiac cycle
systole
25
contraction of the heart
cardiac cycle
diastole
26
relaxation of the heart
Cardiac cycle
Atrial systole
4 points
27
- The walls of the atria contract - atrial volume decreases, atrial pressure increases.
- the pressure in the atria rises above rgat in the ventricle, forcing the AV valves open
- blood forced into the ventricle. slight increase in Ventricular pressure and chamber volume as Ventricles receive blood from atria
- ventricles relaxed atp. ventricular diastole coincides with atrial systole
Cardiac Cycle
Ventricular systole
4 points
28
- walls of the ventricle contract, volume decreasing and pressure is increasing
- pressure in ventricle rises above that in the atria, forcing the AV valves to close
- pressure in ventricles rises above that in the aorta and pulmonary artery and SL valves open and blood is forced into arteries out the heart
- atria is relaxing in this periiod. bloos flow to heart continues and the relaxed atria fills with blood again
Cardiac Cycle
Diastole
5 points
29
- Both ventricles and artria are both relaxed
- pressure in ventricles drop below that in aorta and pulmonary artery, forcing SL valves to close
- atria continues to fill with blood from vena cava.
- pressure in the atra rises above tghat in in the ventricle, av valves forced open
- blood flows passively into ventricles without atrial systole
Atherosclerosis
Atherosclerosis process
6 points
30
- Damage by high blood pressure, is caused to the endothelium
- An inflammatory response occurs and white blood cells such as macrophages accumulate in the damaged area
- Lipids and cholesterol clump together with the macrophages under the endothelium and form fatty streaks first signs of atherosclerosis
Platelets can also add to the fatty deposit - cholesterol, lipids, macrophages and platelets accumulate under the endothelium The structure forms a plaque known as an atheroma
- The atheroma narrows the lumen of the artery, restricting blood flow and thereby raising blood pressure
- Over time, the plaque can calcify and harden, reducing elasticity of the artery wall and further increasing blood pressure
Blood clotting
Process of thrombosis
