transport in animals

Question 1

why do multicellular organism require a transport system

Answer 1

They are big and have a low surface area to volume ratio and a high metabolic rate and are very active so most of the respiring cells need a rapid supply of glucose and oxygen so to make sure the cells have enough oxygen and glucose multicellular organism need a transport system.

Question 2

what is a single circulatory system

Answer 2

Blood only passes through the heart once for each complete circuit of the body

Question 3

what is a double circulatory system

Answer 3

Blood passes through the heart twice for each complete circuit of the body

Question 4

what is a open circulatory system

Answer 4

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

Question 5

what is a closed circulatory system

Answer 5

blood is pumped around the body and is always contained within a network of blood vessels

Question 6

“how is blood transported in fish
”

Answer 6

Heart pumps blood to the gills to pick up oxygen and then to the rest of the body to delivery oxygen in a single circulatory system

Question 7

“how is blood transported in mammals
”

Answer 7

The right side of the heart pumps blood to the lungs and then it travels to the left side of the heart which then pumps blood to the rest of the body and is returned to the right side of the heart

Question 8

“how is blood transported in insects


“

Answer 8

The heart is segmented. It contracts in a wave starting from the back pumping blood into a single main artery. The artery opens up into the body cavity . the blood flows around the insects organs gradually making it back into the heart segment through a series of valves

Question 9

“structure and function of arteries


“

Answer 9

To transport blood away from the heart to the arterioles. Walls are thick and muscular and have elastic tissues to recoil and stretch as the heart beats which helps maintain the high pressure. The inner endothelium is folded which allows the arteries to expand which also helps maintain the high pressure and avoids tearing when the vessel stretches. The smooth muscles contract to constrict the lumen making it narrower to maintain pressure.

Question 10

“structure and function of arterioles
”

Answer 10

To transport blood from the arteries to the capillaries. They have a layer of smooth muscles and have less elastic tissue

Question 11

“structure and function of capillaries
”

Answer 11

They are one cell thick for small distance of diffusion

Question 12

“structure and function of venules
”

Answer 12

To transport blood from the capillaries to the veins. They have very thin walls that contain some muscle cells

Question 13

“structure and function of veins


“

Answer 13

Transport blood from venules to the heart. They have a wider lumen than arteries with very little elastic and muscle tissue. They have low pressure of blood and blood flow is helped by the contraction of muscles . They contain valves to stop the backflow of blood. The large lumen provide as much space as possible for low pressure blood to flow

Question 14

“how is tissue fluid formed


“

Answer 14

The hydrostatic pressure at the arterial end of the capillaries is greater than the hydrostatic pressure in the tissue fluid so fluid is forced out of the capillaries and into the space around cells. As the proteins are too big to move out of the capillaries the protein content creates a water potential gradient between the capillaries and the tissue fluid. The high hydrostatic pressure is greater than the octonic pressure which forces water out of the capillaries. As fluid leaves the hydrostatic pressure at the venous end is lower and the water potential in the capillaries is lower then the water pressure in the tissue fluid so water moves back into the capillaries by osmosis.

Question 15

“formation of lymph


“

Answer 15

Excess tissue fluid passes into lymph vessels and once they’re inside they are called lymph. Lymph gradually move toward the main lymph vessels in the thorax which return to the blood near the heart

Question 16

“What is pericardium
”

Answer 16

A double layer of inelastic membranes surrounding the heart to prevent it from stretching too much.

Question 17

“cardiac cycle

“

Answer 17

“Atrial and ventricular diastole- atrial and ventricle relaxed and blood moves into the atria from the veins cava and the pulmonary vein. Atrioventricular valves open and the atrial pressure is slowly Building and the semilunar valves are closed as there’s lower pressure in ventricles then in the pulmonary artery and aorta.
Atrial systole- muscles in the wall of the atria contract and the atrioventricular valves open as the atrial pressure is much higher than the pressure in the ventricles l. Blood is forced from the atria into the ventricles. Semilunar valve remains closed as there’s lower pressure in ventricles then in the pulmonary artery and aorta.
Ventricular systole- atria is relaxed and the atrioventricular valves close as the pressure in the ventricles is much greater than in the atria and the tendinous cord stops them from turning inside out. The muscles in the ventricles contract and the semilunar valves open as there is much higher pressure in the ventricles then in the pulmonary artery and aorta. “

Question 18

“How is a heart beat initiated
”

Answer 18

Starts in the Sino atrial node which is in the right atrium. It sends out regular waves of electrical activity to the atrial walls. This cause the right and left atria to contract at the same time. A band of non-conducting collagen tissue prevents the waves of electrical activity being passes directly from the atria to the ventricles. Instead they are transferred from the SAN to the atrioventricular node. It is responsive for passing waves of electrical activity on to the bundle of his but there is a slight delay before the AVN reacts to make sure the ventricles contract after the atria is emptied. The bundle of his conducts the electrical impulses to the purkyne tissue on the right and left ventricle walls. The purkyne tissue carries the waves of the electrical activity into the muscular wall on the right and left ventricle causing them to contract simultaneously from the bottom up.

Question 19

Describe ECG

Answer 19

P wave caused by contraction and depolarisation of the atria. The main peak of the heartbeat is called the QRS complex and is caused by the contraction and depolarisation of the ventricles. The T wave is due to the relaxation and repolarisation of the ventricles. The height of the wave indicates how much electrical charge is passing through the heart.

Question 20

“What is tachycardia
”

Answer 20

When the heartbeat is too fast which is ok for exercise but at rest it shows that the heart isn’t pumping blood efficiently

Question 21

“What is bradycardia
”

Answer 21

When the heartbeat is too slow. Common in athletes but can show that the heart isn’t pumping blood efficiently

Question 22

What is ectopic heart beat

Answer 22

An extra heart beat caused by an earlier contraction of the atria or ventricle. Occasion ectopic heartbeats in healthy people don’t cause a problem

Question 23

What is fibrillation

Answer 23

A irregular heartbeat. The atria or ventricle lose their rhythm and stop contracting properly. This can result in chest pain and fainting due to lack of pulse and death.

Question 24

structure of haemoglobin

Answer 24

It is a globular protein with quaternary structure. It has four polypeptide chains (two alpha, two beta) Each chain has a haem group. Each haem group contains an iron ion. Each of the four haem groups can combine with 1 molecule of O2 : Hb + 4O2 ⇌ Hb(O2)4

Question 25

What’s the relationship between haemoglobin saturation and partial pressure of oxygen?

Answer 25

Oxygen loads onto haemoglobin to form oxyhemoglobin where there’s a high pO2 (Alveoli) . Oxyhemoglobin unloads its oxygen where there’s a lower pO2. (Respiring tissue)

Question 26

what are the three ways carbon dioxide is transported around the body?

Answer 26

“1. ~ 10 % dissolves in blood plasma.
2. ~ 20 % binds with haemoglobin to form carboaminoheamogolobin
3. ~ 70 % dissolves in the cytoplasm of red blood cells where the enzyme carbonic anhydrase catalyses the reaction between carbon dioxide and water
CO2 + H2O ⇌ H2CO3 ⇌ HCO3– + H+ “

Question 27

“Why is the oxygen dissociation curve s-shaped?
”

Answer 27

When haemoglobin combines with the first O2 molecule, its shape alters in a way that makes it easier for other molecules to join to. As the Hb starts to become saturated, it gets harder for more O2 molecules to join.

Question 28

why is the a steep increase in % haemoglobin saturation as the pO2 rises?

Answer 28

because after one O2 molecule binds the haemoglobin molecule changes shape, exposing the other three haem groups. Affinity of Hb for O2 increases.

Question 29

why is the % saturation of haemoglobin higher for fetal hb than for adult hb at every pO2?

Answer 29

because fetal Hb has a higher affinity for O2 than maternal Hb. This ensures that foetal blood can load oxygen from maternal blood.

Question 30

What happens at low and high pCO2?

Answer 30

lower pCO2
oxygen saturation of haemoglobin would be higher because there are fewer H+ ions, so oxygen is less readily dissociating from the
haemoglobin. Higher pCO2
At higher pCO2, oxygen saturation of haemoglobin would
be lower because there are more H+ ions, so oxygen is more readily dissociating from the haemoglobin. Hb has a higher affinity for H+ than O2

Question 31

“What happens at low temperature?
”

Answer 31

oxygen saturation of haemoglobin would be higher because respiration is occurring less rapidly and therefore PCO2 would be lower

Question 32

Higher temperature

Answer 32

At higher temperature, oxygen saturation of haemoglobin would be lower because respiration is occurring more rapidly and therefore PCO2 would be higher

Question 33

“What happens the animals living at high altitude and small/fast metabolism animal?

“

Answer 33

“High altitude animal
oxygen saturation of haemoglobin would be higher because respiration is occurring less rapidly and therefore PCO2 would be lower
AND their haemoglobin has a higher affinity for oxygen (same as foetal Hb) so that oxygen can pick up oxygen more readily in the lungs.
Small/fast metabolism animal
In smaller animals, or those with fast metabolisms, oxygen saturation of haemoglobin would be lower because respiration is occurring more rapidly and therefore PCO2 would be higher (see above).
AND their haemoglobin has a lower affinity for oxygen (opposite of foetal Hb) so that oxygen can dissociate to respiring tissues more readily. “

Question 34

“Why would the line for myoglobin be far to the left of line 3 so it’s % O2 saturation is much higher than that of line 2/ Hb?
”

Answer 34

because it has a much higher affinity for oxygen than haemoglobin, so it can load oxygen very readily from haemoglobin, and will release it reluctantly (so will only release it to respiring cells if surrounding oxygen levels drop to low levels).

Question 35

What’s the Bohr effect?

Answer 35

At higher CO2 concentration there are more H+ ions (greater acidity) which cause oxygen to dissociate from haemoglobin. The increased CO2 means cells are respiring faster and they need the more readily dissociated oxygen. This effect is called the Bohr effect. On an oxygen dissociated curve, the line will move further to the right the more CO2 is present.
The Bohr effect: High PCO2 = High oxygen dissociation.

Question 36

chloride shift

Answer 36

carbon dioxide react with water to form carbonic acid
carbonic acid dissociates into hydrogen carbonate and hydrogen ions
hydrogen ions combines with haemoglobin too for haemoglobinic acid
hydrogen carbonate ions diffuse out of the red blood cell into blood plasma
chloride ions diffuse into the red blood cell

Question 37

what caused lub sound in lub dub

Answer 37

av valves closing

Question 38

what causes dub sound in lub dub

Answer 38

semi lunar valves closing