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topic 3 Flashcards

1
Q

describe the relationship between a small organism and its surface area to volume ratio

A

small organisms have a very large surface area in comparison to their volume.
this means that there is a big surface for exchanging substances but also there is a small distance from the outside of the organism to the middle of it.
so small organisms can simply exchange substances across their membranes using simple diffusion.

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2
Q

describe the relationship between a large organism and its surface area to volume ratio

A

the larger an organism, the smaller its surface area compared to its volume and the larger the distance from the middle to the outside.
larger organisms typically have a higher metabolic rate, which demands efficient transport of waste out of cells and reactants into the cells.
they have adaptations that help make the exchange across surfaces more efficient.

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3
Q

describe the cardiac muscle

A

the walls of the heart have a thick muscular layer.
this muscle is called the cardiac muscle.

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4
Q

what are the properties of the cardiac muscle?

A

its myogenic meaning it can contract without nervous or hormonal stimulation.
it never fatigues as long as it has a supply of blood.

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5
Q

describe the coronary arteries and its role and what will happen to it if its blocked

A

they supply the cardiac muscle with oxygenated blood.
these branch off from the aorta.
if they become blocked the cardiac muscle wont receive oxygen, therefore it will not respire and the cells will die. This results in myocardial infarction (a heart attack).

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6
Q

what are the four chambers of the heart?

A

left and right atrium.
left and right ventricles.

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7
Q

describe the atria

A

thinner muscular walls.
do not need to contract as hard as not pumping blood far only to ventricles.
elastic walls to stretch when blood enters.

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8
Q

describe the ventricles

A

thicker muscular wall to enable bigger contraction.
this creates a higher blood pressure to enable blood flow to flow to longer distances (to lungs and rest of the body).

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9
Q

describe the role of the right ventricle

A

pumps blood to the lungs.
at low pressure to prevent damage to the capillaries in the lungs and so blood flows slowly to allow time for gas exchange.
therefore thinner muscular wall in comparison to the left ventricle.

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10
Q

describe the left ventricle

A

pumps blood to the body.
at a higher pressure to enable blood reaches all the cells in the body.
therefore much thicker muscular wall in comparison to the right ventricle to enable larger contractions of the muscle to create higher pressure.

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11
Q

describe the role of the vena cave

A

carries deoxygenated blood from the body into the right atrium.

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12
Q

describe the role of the pulmonary vein

A

carries oxygenated blood from the lungs to the left atrium.

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13
Q

describe the role of the pulmonary artery

A

carries deoxygenated blood from the hearts right ventricle to the lungs to become oxygenated.

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14
Q

describe the aorta

A

carries oxygenated blood from the left ventricle to the rest of the body.

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15
Q

where is the semi-lunar valve found?

A

in the aorta and pulmonary artery.

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16
Q

where is the atrioventricular valves found?

A

between the atrium and the ventricles.

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17
Q

where is the bicuspid and tricuspid valve?

A

bicuspid is on the left side.
tricuspid is on the right side.

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18
Q

when do valves open?

A

when the pressure behind the valve is high.

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19
Q

when do valves close?

A

when the pressure infront of the valve is high.

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20
Q

what is the role of the vavles?

A

they prevent the backflow of blood.

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21
Q

what is the role of septum?

A

separates the oxygenated blood and deoxygenated blood.
maintains high concentration of oxygen in oxygenated blood to maintain concentration gradient to enable diffusion at respiring cells.

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22
Q

what are the three stages of the cardiac cycle?

A

diastole.
atrial systole.
ventricular systole.

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23
Q

what is meant by diastole?

A

the atria and ventricular muscles are relaxed.
this is when blood will enter the atria via the vena cava and pulmonary vein.
the blood flowing into the atria increases the pressure within the atria.

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24
Q

what is the cardiac output?

A

the volume of blood which leaves one ventricle in one minute.

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25
what is meant by atrial systole?
the atria muscles walls contracts increasing the pressure further. this causes the atrioventricular valves to open and blood to flow into the ventricles. the ventricular muscular walls are relaxed (ventricular diastole).
26
what is meant by ventricular systole?
after a short delay the ventricle muscular walls contract, increasing the pressure beyond that of the atria. this causes the atrioventricular valves to close and the semi-lunar valves to open. the blood is pushed out of the ventricles into the arteries (pulmonary and aorta).
27
how do you calculate the cardiac output?
cardiac output= stroke volume x heart rate.
28
when do the atrioventricular valves open?
when the pressure is higher in the atria compared to the ventricles.
29
when do the atrioventricular valves close?
when the pressure is higher in the ventricles compared to the atria.
30
when do the semi lunar valves open?
when the pressure in the ventricles is higher compared to in the arteries.
31
when do the semi lunar valves close?
when the pressure in the arteries is higher compared to in the ventricles.
32
what is meant by a closed system?
the blood remains within the blood vessels.
33
what is a double circulatory system?
the blood vessels pass through the heart twice in each circuit. there is one circuit which delivers blood to the lungs and another circuit which delivers blood to the rest of the body.
34
why do mammals require a double circulatory system?
to manage the pressure of blood flow. the blood flows through the lungs at low pressure. this prevents damage to the capillaries in the alveoli. and also reduces the speed of blood flow enabling more time for gas exchange.
35
why is oxygenated blood from the lungs pumped out at a higher pressure?
to ensure all the blood reaches all the respiring cells in the body.
36
what is the roles of the arteries?
arteries carry blood away from the heart and into arterioles.
37
describe the arterioles.
they are smaller than arteries and connect to the capillaries.
38
describe the capillaries.
they connect arterioles to the veins.
39
describe veins.
they carry blood back into the heart.
40
describe the muscule layer of arteries.
thicker than veins so that constriction and dilation can occur to control the volume of blood.
41
describe the muscle layer of veins.
relatively thin so it can control the blood flow.
42
do capillaries have a muscle and elastic layer?
no.
43
describe the muscle layer of arterioles.
thicker than in arteries to belp restrict blood flow into the capillaries.
44
describe the elastic layer of arteries.
thicker than in veins to help maintain blood pressure. the walls can stretch and recoil in response to the heart beat.
45
describe the elastic layer of veins.
relatively thin as the pressure is much lower.
46
describe the elastic layer in arterioles.
thinner than in arteries as the pressure is lower.
47
describe the wall thickness of arteries.
thicker walls than veins to help prevent the vessels bursting due to the high pressure.
48
describe the wall thickness of veins.
thin as the pressure is much lower as there is a low risk of bursting. the thinness mean the vessels are easily flattened which means the vessels are easily flattened, which helps the flow of blood up to the heart.
49
describe the wall thickness of capillaries.
one cell thick consisting of only a lining layer. this provides a short diffusion distance for exchange materials between the blood and cells.
50
describe the wall thickness of arterioles.
thinner as pressure is slightly lower.
51
which blood vessel has valves?
veins.
52
describe the importance of capillary beds.
this is how gases and nutrients are supplied to the body's cells. At the venule end of the capillary, carbon dioxide and wastes are reabsorbed into the blood.
53
what is haemoglobins?
haemoglobin are groups of globular protein found in different organisms. haemoglobin is a protein with a quaternary structure. haemoglobin and red blood cells transport oxygen.
54
what is meant by the affinity of haemoglobin for oxygen?
the ability for haemoglobin to attract or bind to oxygen.
55
what is meant by the saturation of haemoglobin with oxygen?
when haemoglobin is holding the maximum oxygen it can bind.
56
what is loading/association of haemoglobin?
the binding of oxygen to heamoglobin.
57
what is unloading/dissociation of haemoglobin?
when oxygen detaches or unbinds to haemoglobin.
58
describe the oxyhaemoglobin curve.
oxygen is loaded in regions with a high partial pressure of oxygen (e.g. alveoli). oxygen is unloaded in regions with a low partial pressure of oxygen.
59
what is meant by cooperative nature?
the cooperative nature of oxygen binding to haemoglobin causes the haemoglobin to change shape when the first oxygen binds. this makes it easier for further oxygen to bind.
60
what is meant by the Bohr effect?
The Bohr effect is when a high carbon dioxide concentration causes the oxyhaemoglobin curve to shift to the right. the affinity for oxygen decreases as the acidic carbon dioxide changes the shape of haemoglobin slightly.
61
what happens in areas with low partial pressure of carbon dioxide?
low partial pressure of CO2 in the alveoli causes the oxyhaemoglobin curve shifts to the left, increasing the affinity and therefore loads more oxygen.
62
what happens in areas with high partial pressure of carbon dioxide?
high partial pressure of CO2 in respring cells cause the curve to shift to the right, decreasing affinity and therefore unloads more oxygen.
63
why do animals have different types of haemoglobin?
animals have different types of haemoglobin which have different affinities for oxygen, which is an adaptation to their environments.
64
what is tissue fluid?
the fluid containing water, glucose, amino acids, fatty acids, ions, and oxygen which bathes the tissues.
65
how do capillaries allow liquid and small molecules to be forced out?
capillaries have small gaps in the walls so that liquid and small molecules can be forced out. as blood enters the capillaries from arterioles, the smaller diameter results in a high hydrostatic pressure so water, glucose, amino acids, fatty acids, ions and oxygen are forced out. this is called ultrafiltration.
66
what is forced out the capillary?
water molecules. dissolved minerals and salts. glucose. small proteins and amino acids. fatty acids. oxygen.
67
what remains in the capillary?
red blood cells. platelets. large proteins.
68
how is a lowered water potential created?
large molecules remain in the capillaries and therefore create a lowered water potential.
69
why is the water potential low?
towards the venule end of the capillaries, the hydrostatic pressure is lowered due to the loss of water, but the water potential is very low.
70
how is water reabsorbed?
water re-enters the capillaries by osmosis.
71
why is not all the liquid reabsorbed by osmosis?
not all the liquid reabsorbed by osmosis, as equilibrium will be absorbed. the rest of the tissue fluid is absorbed into the lymphatic system and eventually drains back into the bloodstream near the heart.
72
define digestion.
during digestion large insoluble biological molecules are hydrolysed into smaller soluble molecules that can be absorbed across cell membrane.
73
what are carbohydrates hydrolysed by?
amylase. membrane bound disaccharides.
74
where is amylase produced?
salivary glands. pancreas.
75
what is the role of amylase?
amylase hydrolyses polysaccharides into the disaccharide maltose by hydrolysing the glycosidic bonds.
76
what are the roles of the membrane bound disaccharides?
sucrase and lactase are membrane bound disaccharides which hydrolyse sucrose and lactose into monosaccharides.
77
what are proteins hydrolysed by?
endopeptidases (hydrolyse peptide bonds between amino acids in the middle of a polypeptide chain). exopeptidases (hydrolyse peptide bonds between amino acids at the end of a polypeptide chain). membrane-bound dipeptidases (hydrolyse peptide bonds between two amino acids).
78
how are lipids digested?
lipids are digested by lipase and the action of bile salts.
79
where are lipase produced?
the pancreas.
80
what do lipase hydrolyse and what is formed?
they hydrolyse the ester bonds in triglycerides to form monoglycerides and fatty acids.
81
where are bile salts produced and what do they do?
liver. bile salts can emulsify lipids into tiny droplets called micelles. this increases the surface area for lipases to work on.
82
describe emulsification and micelle formation.
lipids are covered in bile salts to create an emulsion. many small droplets of lipids provides a large surface area to enable faster hydrolysis action by lipase.
83
describe the chemical digestion of lipase.
lipases hydrolyse the lipids into glycerol and fatty acids to form monoglycerides.
84
what are micelles and what do they do?
micelles are water soluble vesicles formed of the fatty acids, glycerol and monoglycerides and bile salts. micelles deliver the glycerol, fatty acids and monoglycerides to the epithelial cells of the ileum for absorption.
85
where are the products of digestion absorbed?
in mammals the products of digestion are absorbed across the cell lining the ileum.
86
how is the ileum wall adapted for its function?
the ileum wall is covered in villi, which have thin walls surrounded by a network of capillaries and epithelial cells have even smaller microvilli. these feature maximise absorption, by increasing the surface area, decreasing the diffusion distance and maintaining a concentration gradient.
87
how are glucose and amino acids absorbed?
to absorb glucose and amino acids from the lumen to the gut there must be a higher concentration in the lumen compared to the epithelial cells. but there is usually more in the epithelial cell (for facilitated diffusion). this is why active and co transport are required.
88
how are lipids absorbed?
lipids are digested into monoglycerides and fatty acids by the action of lipase and bile salts. these form tiny structure called micelles. when the micelles encounter the ileum epithelial cells, due to the non polar nature of the fatty acids and monoglycerides, they can simply diffuse across the cell surface membrane to enter the cells of the epithelial cells. once in the cells, these will be modified back into triglycerides in the endoplasmic reticulum.
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biology 1 (12 decks)

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