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Bio Mod 3 > Transport In Animals > Flashcards

Transport In Animals Flashcards

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1
Q

What are the 3 main factors that influence the need for a transport system?

A

Size
Sa:V ratio
Level of metabolic activity(increases with physical activity)

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2
Q

What is a single circulatory system?

A
  • when the circulatory system is a single circuit

- in fish, blood is pumped from the heart to the gills and then through the rest of the body

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3
Q

What is a double circulatory system?

A

When the system has two separate circuits:

  • pulmonary circulation(heart to lungs)
  • systemic circulation(around the body to the tissues)
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4
Q

What is the advantage of having a double circulatory system?

A

The heart can increase the blood pressure after it has passed through the lungs so that it can flow round the body more quickly

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5
Q

What is an open circulatory system?

What are some disadvantages of this?

A
  • When blood is not enclosed within blood vessels but instead flows through the body cavity so that cells are bathed directly in blood.
  • low blood pressure
  • dependant on body movements
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6
Q

What is the structure of an artery?

A

-tunica intima: A layer of folded endothelium elastic tissue(to allow the artery to expand)
-surrounded by tunica media: a thick layer of muscle
-surrounded by tunica adventitia: elastic tissue to allow the artery to stretch and recoil
Narrow lumen

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7
Q

What is the structure of a vein?

A

They have a layer of endothelium surrounded by a thin layer of muscle tissue surrounded by a thin layer of elastic tissue.
Wide lumen to allow more blood flow.

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8
Q

What tissue do arteriole walls contain?

A

A layer of smooth muscle but less elastic tissue

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9
Q

What do venule walls contain?

A

Thin walls containing some muscle tissue

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10
Q

What is the difference between tissue fluid and blood plasma?

A

Blood plasma is a component of blood, when it leaves the blood through the capillary wall it becomes tissue fluid
Although, tissue fluid doesn’t contain proteins as they are too large
Tissue fluid bathes cells to allow exchange of gas and nutrients

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11
Q

What happens to the tissue fluid that doesn’t re-enter the blood?

A

It is directed into the lymphatic system which returns tissue fluid to the blood system in the subclavian vein in the chest

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12
Q

What are some external features of the mammalian heart?

A

Consists of cardiac muscle, lying over the surface of the heart are coronary arteries that supply oxygenated blood to the heart muscle

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13
Q

What is the features and structure of the heart?

A

Divided into 4 chambers:
-Right atrium
-Right ventricle
-left atrium
-left ventricle
Atrio-ventricular valves seperate the ventricles and atria
Semilunar valves are at the base of the major arteries; aorta, pulmonary artery where blood leaves the heart.
Blood enters the heart via the vena cava and the pulmonary vein

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14
Q

What separates the ventricles from one another?

What prevents the valves from turning inside out?

A

A wall of muscle called the septum

Tendinous cords

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15
Q

How is blood pressure maintained in different areas of the heart?

A
  • atria walls are very thin as they simply receive blood that gets pushed into the atria
  • right ventricle wall is thick to enable blood to be pumped to the lungs
  • left ventricle wall is thicker than that of the right ventricle as blood needs sufficient pressure to carry out systemic circulation
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16
Q

Explain the changes in pressure and therefore the action of atrio-ventricular valves

A
  • During diastole muscular walls of all chambers relax, blood flows in from the veins. Pressure in the ventricles rapidly drops below the pressure in the atria
  • atrial systole begins: blood in the atria pushes atrio-ventricular valves open, blood entering the heart flows straight through atria into ventricles.
  • pressure in atria and ventricles rise as they fill with blood
  • when the atria begins to relax the valves close
  • ventricular systole begins where the ventricles begin to contract which increases pressure to keep the atrio-ventricular valves closed
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17
Q

Explain the changes in pressure and therefore the action of semilunar valves

A
  • Pressure in the major arteries is higher than the pressure in the ventricles so semilunar valves are closed
  • ventricular systole raises the blood pressure in the ventricles quickly
  • the semilunar valves are pushed open once the pressure of the ventricles exceeds that of the major arteries
  • This pushes blood at a high pressure into the major arteries
  • once the ventricle walls have finished contracting the heart begins diastole, elastic recoil
  • this causes the pressure in the ventricles to drop as they return to their normal size
  • This causes blood to flow back towards the ventricles however the valve prevents back flow and so blood collects
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18
Q

What steps does the cardiac cycle consist of?

A

Diastole: elastic recoil, chambers increase in size blood flows in.
Atrial systole: left and right atria contract pushing blood through atrio-ventricular valves.
Ventricular systole:left and right ventricles contract at the apex so blood is pushed towards arteries.

19
Q

How does the pressure changes in the heart chambers and aorta appear on a graph?

A
  • Big peak - ventricle pressure
  • higher line - aortic pressure
  • lower line - atrial pressure
20
Q

Why is the heart myogenic?

A

Because it can initiate its own contraction and will still contract rhythmically outside of the body

21
Q

What controls the contractions/heart beat in the heart?

A
  • The sino-atrial node: it’s a small patch of tissue which generates electrical activity
  • The SAN initiates a wave of excitation at regular intervals
22
Q

How does the SAN control the contraction of the atria?

A

The wave of excitation quickly spreads over the walls of both atria, as it passes it creates an atrial systole.
The tissue at the base of the atria does not conduct the wave of excitation so it cannot spread to the ventricles

23
Q

How does the SAN control the contraction of the ventricles?

A
  • The wave of excitation spreads to the atrio-ventricular node (at the top of the septum) which conducts it and carries it down the purkyne tissue
  • At the base of the septum the wave of excitation spreads through the ventricle walls
  • this creates a contraction from the base upwards
24
Q

What is bradycardia?

A

Slow heart rate

25
Q

What is tachycardia?

A

Fast heart rate

26
Q

What is atrial fibrillation?

A

The atria contracting more frequently than the ventricles

27
Q

What is an ectopic heart beat?

A

An early ventricular beat

28
Q

How can we measure electrical activity of the heart?

A

Using an electrocardiogram(ECG). Attaching a number of sensors to the skin which detect the electrical activity after spreading from the heart through tissues to the skin.
This is converted into a trace

29
Q

What does the p (initial) wave show on an ECG trace?

A

Atrial stimulation

30
Q

What does the T (final) wave show on an ECG trace?

A

Diastole

31
Q

What does the QRS complex show on an ECG trace?

A

The excitation of the ventricles

32
Q

What is the structure of haemoglobin?

A
  • A protein consisting of 4 polypeptide chains
  • Each peptide chain has a haem (prosthetic) group consisting of one Fe^2+ ion (so 4 in total)
  • this provides a high oxygen affinity
33
Q

What is dissociation?

A

After oxygen and haemoglobin bind reversibly, red blood cells reach body tissues where oxygen gets released from oxyhemoglobin

34
Q

What does the high affinity for oxygen of the haem group lead to?

A

When red blood cells reach the lungs oxygen diffuses into the red blood cells and binds to haemoglobin. Four molecules of oxygen bind to one molecule of haemoglobin forming oxyhemoglobin.

35
Q

What is pO2?

What happens if it’s…
A) high?
B) low?

What does this help to maintain?

A

Oxygen partial pressure; the concentration of oxygen in the cells

A)Haemoglobin has a high oxygen affinity, so binds to it eg. From the lungs

B)haemoglobin has a low oxygen affinity because the haem group is in the centre of the molecule so oxygen dissociates from haemoglobin eg. In respiring tissue

A concentration gradient so a constant oxygen supply

36
Q

How is carbon dioxide transported?

A
  • In the form of hydrogencarbonate ions.
  • some is combined directly with haemoglobin.
  • some is dissolved in blood plasma
37
Q

How are hydrogencarbonate ions formed?

A

Carbonic anhydrase catalyses the reaction between water and carbon dioxide to make carbonic acid.
This carbonic acid then dissociates into hydrogencarbonate (HCO3-) ions and H+ ions

38
Q

What is the chloride shift?

A

After hydrogen carbonate ions leave the cell the charge inside the RBC is maintained by the movement of chloride ions Cl- from the plasma into the RBC

39
Q

How is the pH maintained within the RBC after dissociation of carbonic anhydrase?

A

To prevent the cell from becoming too acidic due to the build up of H+ ions, they bond with/associate with haemoglobin that has dissociates from oxygen.
This forms haemoglobinic acid (HHb)
The haemoglobin is acting as a buffer

40
Q

What is the Bohr effect?

A

Carbon dioxide enters RBC’s forming carbonic acid which dissociates tk release H+ ions.
These H+ ions effect the pH of the cytoplasm making it more acidic
This change in pH is said o alter the tertiary structure of haemoglobin and reduce the affinity for oxygen
Oxygen is released from the oxyhaemoglobin to the tissues.
Bohr shift occurs where the dissociation curve moves down and right as there is less saturation with oxygen.

41
Q

What is the hydrostatic pressure like at the arterial end? What does this lead to?

A

(Hydrostatic pressure refers to bp)
It is high at the arterial end, this forces blood plasma through the capillary endothelium into the existing tissue fluid

41
Q

What is oncotic pressure?

A

It refers to the concentration of solutes or proteins in a solution.
Higher oncotic pressure encourages flow back into the vessel and resists flow out of the vessel.
Oncotic pressure is highest in the blood that in the tissue fluid at both ends of the capillary bed

41
Q

What is the hydrostatic pressure like at the venule end? What does this lead to?

A

The hydrostatic pressure is low so oncotic pressure outweighs the hydrostatic pressure allowing tissue fluid containing carbon dioxide and waste products to enter the blood

42
Q

What are capillary walls made of?

A

Endothelium

Bio Mod 3 (2 decks)

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