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Biology A level > The Circulatory System > Flashcards

The Circulatory System Flashcards

(61 cards)

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1
Q

Why is a circulatory system needed in larger animals

A

In single celled o2 and glucose can diffuse by across the cell membrane fast enough due to the short diffusion pathway

Larger organisms are made up of many layers of cells and therefore the diffusion distance is too long

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2
Q

What is mass transport

A

Bulk movement of gases or liquids in one direction

Usually via a system of vessels / tubes

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3
Q

What is a closed system

A

Where blood is pumped around the body
And maintained in a network of blood vessels

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4
Q

What is an open circulatory system

A

Blood is not contained within blood vessels but is pumped directly into the body cavities

Molluscs are one of the only organisms with this

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5
Q

What type of circulatory system do humans have and how do we know

A

Double closed circulatory system meaning in one complete circuit of the body , blood passes through the heart twice

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6
Q

What does the right side of the heart do

A

Pumps deoxygenated blood to the lungs
This is the pulmonary exchange system

Blood then returns to the left side and this newly oxygenated blood is pumped to the rest of the body.

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7
Q
A
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8
Q

Flow of blood from deoxygenated blood entering heart through vena cava

A

Blood come from body and vena cava into right atrium then enters the right ventricle

This is attached to the pulmonary artery which transport the deoxygenated blood to the lungs

Pulmonary vein carries oxygenated blood away from the lungs and into left atrium

Left atrium to left ventricle

Left ventricle through aorta to the body

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9
Q

Function of the heart

A

Hollow muscular organ which pumps blood.
Cardiac muscle is specialised for repeated involuntary contractions without rest

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10
Q

Function of arteries

A

Carry blood away from the heart .
Thick muscle wall and narrow lumen to maintain and withstand high pressure

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11
Q

Function of arterioles

A

Small arteries which branch from larger ones and connect to capillaries

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12
Q

Capillaries function

A

Tiny blood vessels which connect to arterioles and venules

Their small diameter allows them to pass directly past cells to perform gas exchange and exchange of substances such as glucose

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13
Q

Venules function

A

Small veins which join to capillaries

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14
Q

Veins function

A

Blood vessels which carry blood back towards the heart .
Thinner walls
Wider lumen
Less muscle compared to arteries
Valves - prevent backflow

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15
Q

function of the pulmonary artery

A

carries deoxygenated blood away from the heart, towards the lungs

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16
Q

function of the pulmonary vein

A

carries oxygenated blood away from the lungs towards the heart

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17
Q

function of the coronary arteries

A

supply the heart with oxygenated blood

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18
Q

function of the aorta

A

carries oxygenated blood from the heart to the body

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19
Q

function of the vena cava

A

carries deoxygenated blood from the body to the right atrium

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20
Q

function of the renal artery

A

supplies the kidneys with oxygenated blood

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21
Q

function of the renal vein

A

carries deoxygenated blood away from the kidneys towards the heart

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22
Q

genrally do veins or arteries carry oxygenated blood

A

genrally arteries do with the exception of the pulmonary vein

therefore veins usually carry deoxygenated blood

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23
Q

what is the centre muscular tissue that seperates the two sides of th heart

A

the septum
(interatrial and interventricular)

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24
Q

function of the septum

A

ensures that the blood in the right and left sides doesnt mix

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25
when do the valves in the heart open
when the pressure of blood behind them is greater than the pressure in front of them
26
function of valves in the heart
ensures blood keeps flowing forward maintains correct pressure in the chambers of the heart
27
what valve seperates the right atrium and right ventricle
tricuspid valve
28
which valve seperates the left atrium and ventricle
bicuspid valve
29
which valve seperates the right ventricle and pulmonary artery
pulmonary valve
30
which valve seperates the aorta and left ventricle
aortic valve
31
how to tell valves position
the vein / artery leaving the heart and -tic eg. aortic bicuspid - left tricuspid - right
32
why does the heart need its own blood supply
it is a muscle
33
what brings the blood heart for contraction
coronary arteries on its surface must be clear of plaque ( no CHD)
34
why are the walls of the atria thinner than that of the ventricles
ventricles must contract to push blood out of the heart atria only push blood into the ventricles
35
why is the left muscle on the left ventricle much thicker than the right
blood leaving the left ventricle goes to the whole body - a far distance so needs a higher pressure created by the muscular contraction
36
what is the cardiac cycle
the series of events that take place in one heart beat - including muscular contraction and relaxation
37
technical names for the conraction and relaxation of the heart
systole - contraction diastole - relaxation
38
what happens in contraction
the heart muscle causes a decrease in volume in the chambers of the heart pressure increases valves open and close
39
is contraction the exact opposire of relaxation
yes yes
40
how does blood get moved into the ventricles
the atria walls contract atria volume decreases pressure increases AV valves open blood into the V's
41
what is ventricular systole
walls of ventricles contract vol decreases pressure increases AV valves close to prevent backflow of blood Semil;unar valves are opened and blood leaves
42
what occurs in diastole
ventricles and atria are relaxed pressure in the ventricles drops below that in the aorta and pulmonary artery forces SL to close blood returns to the heart pressure changes opens AV valves blood also enters ventricles
43
method of investigating various factors affect on heart rate
use Heart rate monitor on individuals at rest give each 200ml caffeine solution wait 15 mins use Hr monitors to record heart rates at each individual at rest repeat measurements every 15 mins put in graph
44
limitations of investigating various factors affect on heart rate method
too much caffeine = dangerous not enough wont work ensure that samples in a sample group are similar
45
structure of arteries
thick wall with layers of collagen elastic fibres to allow the artery wall to expand around high pressure blood
46
structure of veins
thin wall larger lumen valves
47
structure of arterioles
can contract to partially cut off blood flow to specific organs can stop blood flow completely
48
main function of capillaries
form exchange surfaces
49
Structure and function of capillaries
very small diameter - forces blood to travel slowly so more time for diffusion to occur branch between cells - substances can diffuse between the blood and cells quickly as ther is a short diffusion distance one cell thick pores that allow blood plasma to leak out
50
what is plasma
a straw coloured liquid that is mostly made up of water as it is the solvent tissue fuid is ths same but with less proteins and is the site of exchange of substances
51
how does tissue flkuid form
plasma leaves capillaries pushed by hydrostatic pressure and the increased protein conc in blood results in a water potential between capillary and tissue fluid resulting in the plasma leaving
52
how is lymph formed
some tissue fluid reenters the capillaries while some inter sthe lymph capillaries this lymph system has larger vessels which move by body movement and have valves lymph eventually reenters the bloodstream
53
another function of lymph
after digestion , lipids are transported from the intestines to the bloodstream by lymph
54
things that increase CHD risk
genetics age sex high blood pressure smoking
55
high blood pressure increases CHD bc
arteries develop tghicker walls and the lumens narrow which results in atheromas
56
smoking increases CHD bc
tobacco damages heart and lungs reducing blood pressure
57
correlation -
is an association or relationship between variables
58
causation -
occurs when one variable has an influence or is influenced by, another
59
what does correlation and causation have to do with CHD
important when evaluating data on risk factors that you state that a factor increases or descreases the risk or that there is a correlation between a factor and an outcome but that this one factor is not necessarily the (only) cause
60
method of heart dissection
Place the specimen on the dissecting board Use the tools to access the desired structure When using the scalpel cut away from your body and keep your fingers far from the blade to reduce the chance of cutting yourself Scissors can be used for cutting large sections of tissue (cuts do not need to be precise) Scalpel enables finer, more precise cutting and needs to be sharpe to ensure this Use pins to move the other sections of the specimen aside to leave the desired structure exposed
61
limitations of heart dissection
t can be hard to see some of the smaller, finer structures within organs The specimens do not reflect how the tissue would look in a living organism If only a single specimen is dissected then anomalies found within that specimen may be ignored or glossed over

Biology A level (21 decks)

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