3.2 - Transport In Animals Flashcards

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1
Q

What are three features of an effective transport system?

A
  • A fluid to carry nutrients/oxygen/wastes around the body (blood)
  • A pump to create pressure that will push the fluid around the body (heart)
  • Exchange surfaces (capillaries)
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2
Q

What is the role of arterioles?

A

Take blood from artery to capillary; they have a layer of smooth muscle which contracts restricting and slowing blood flow

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3
Q

How are capillaries adapted for exchange?

A
  • Narrow lumen (squeezes red blood cells against walls so transfer of oxygen is better to the tissues)
  • Walls consist of single layer of endothelial cells (reduces diffusion distance)
  • Walls are permeable (allows blood plasma and dissolved substances to leave the blood)
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4
Q

What are the factors that affect the efficiency of transport systems?

A
  • Size
  • SA:Vol
  • Metabolic activity
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5
Q

What are the characteristics of an open circulatory system? (insects)

A
  • No blood vessels
  • Fluid is called haemolymph
  • Not as efficient
  • Blood pressure is lower
  • Blood/fluid cannot be directed to where it is needed as the body movements can influence the flow of the fluid
  • Locusts have an adapted system with tubes that can direct the fluid flow
  • Peristalsis is a wave of contraction used to squeeze the fluid one way along the heart
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6
Q

What are the characteristics of an closed circulatory system? (fish/human)

A
  • Have blood vessels (In humans: arteries, capillaries and veins)
  • The blood vessels allow the blood to be directed to where it is needed
  • Blood pressure is higher
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7
Q

How is blood pressure affected by having a single, closed circulatory system? (fish)

A

-Blood pressure declines as it is further away from the heart and after going through the gills
-Rate of flow at tissues is low
Heart=High
Pre-gills=High
Post-gills=Low
Pre-tissues=Low
Post-tissues=Very low
Pre-Heart=Very low
Post-heart=High

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8
Q

Why is blood pressure lost at the gills?

A

The gills are a network of fine capillaries so blood pressure is lost to the capillaries

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9
Q

How is blood pressure affected by having a double, closed circulatory system? (humans)

A

-Blood pressure in the lungs is not too high
-Heart can boost pressure before blood goes to the rest of the body
-Body circulation is at a higher pressure
Post-heart=High (out Left side)
Pre-lungs=High (but not too high)
Post-lungs=Low
Pre-Heart=Low
Post-heart=Very high (out right side to whole body)
Pre-tissues=High
Post-tissues=Low
Pre-Heart=low
Post-heart=High (out Left side)

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10
Q

What is the circulation to the body called?

A

Systemic circulation (Pumped from the aorta)

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11
Q

What is the circulation to the lungs called?

A

Pulmonary circulation (Pumped from the pulmonary artery)

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12
Q

What is the structure and function of arteries?

A

STRUCTURE:

  • Lumen, where blood flows through
  • Endothelial layer, smooth layer of flattened cells
  • Elastic fibres, stretches and recoils as the heart pulses
  • Smooth muscle fibres, constrict to narrow/dilate to expand the artery and divert the blood flow to where it is needed the most
  • Collagen fibres, enables the artery to withstand the high pressures

FUNCTION:
-Arteries carry blood away from the heart (HIGH BP)

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13
Q

What is the structure and function of veins?

A

STRUCTURE:
-Wider lumen, where blood flows through
-Endothelium, smooth single layer of flattened cells
-Thinner layer of elastic fibres, stretches and recoils
-Less smooth muscle fibres, constrict/dilate the artery and divert the blood flow to where it is needed the most
-Thinner layer of collagen fibres, enables the vein to
withstand pressure
-Contain valves to stop backflow and ensure blood
moves in one direction towards the heart

FUNCTION:
-Veins carry blood towards the heart (LOW BP)

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14
Q

What is the structure and function of capillaries?

A

STRUCTURE:

  • Lumen, where blood flows through the diameter of a RBC (7micrometer)
  • Endothelium, smooth single layer of flattened cells
  • Can be:
  • Continuous, thinner and less leaky
  • Fenestrated, most leaky (Found in the kidney)
  • Discontinuous, wider and less leaky

FUNCTION:

  • Capillaries are the site of exchange (Glucose, oxygen, amino acids, various nutrients or waste products etc)
  • Produce tissue fluid
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15
Q

What is the purpose of tissue fluid?

A

It bathes the cells, supplies what they need and removes what they don’t need

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16
Q

What is plasma made up of?

A

Water, ions, sugars, gases, small proteins

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17
Q

How is plasma and tissue fluid different?

A
  • Plasma is when the fluid is inside of the blood vessel and it is the liquid component of the blood
  • Rather tissue fluid is when it exits the capillary and bathes the cells
18
Q

What happens to the tissue fluid after it has bathed the cells?

A
  • Most the tissue fluid returns to the capillaries and becomes plasma again
  • However the excess tissue fluid is drained into the lymphatic system then to the heart
19
Q

What is oncotic pressure?

A

The pressure caused due to osmosis so the movement of water from a high WP to a low WP down the WP
gradient

20
Q

What is hydrostatic pressure?

A

The physical pressure

21
Q

What is the movement of water and plasma in the capillaries due to oncotic and hydrostatic pressure? (at the arteriole end)

A

-There is a higher hydrostatic pressure than the oncotic pressure
The plasma is forced out of the capillaries
The water is moved in to the capillaries

22
Q

What is the movement water and plasma in the capillaries due to oncotic and hydrostatic pressure? (At the venule end)

A
  • There is a higher oncotic pressure than the hydrostatic pressure
  • This is because the oncotic pressure is maintained but the hydrostatic pressure slowly decreases as it moves along the capillaries to the venule end with plasma leaking out
  • The plasma continues to slowly leak out the capillaries
  • The water is moved into the capillaries
23
Q

What is the flow of the blood through the heart in order?

A
  • Deoxygenated blood enters the heart through the vena cava (From the body)
  • The blood enters the right atrium
  • Blood is pushed through the atrioventricular valve to the right ventricle
  • The right ventricle contracts forcing the blood up, through the semi-lunar valves and out the pulmonary artery (To the lungs)
  • Oxygenated blood enters the heart through the pulmonary vein (From the lungs)
  • The blood enters the left atrium
  • Blood is pushed through the atrioventricular valve to the left, thicker ventricle (At a higher pressure)
  • The left ventricle contracts forcing the blood up, through the semi-lunar valves and out the aorta (to the rest of the body)
24
Q

What is the process of the cardiac cycle?

A

ATRIAL SYSTOLE
-The atria is filled with blood from the vena cava (R) and the pulmonary veins (L)
-The atria contract, forcing the blood to pass the atrioventricular valves and into the ventricles
VENTRICULAR SYSTOLE
-The ventricles contract, forcing the blood up through semilunar valves and inti the aorta
-The force of the ventricles contracting, shuts the atrioventricular valves, thus preventing backflow into the atria

25
Q

What is the process of the cardiac cycle?

A

ATRIAL SYSTOLE
-The atria is filled with blood from the vena cava (R) and the pulmonary veins (L)
-The atria contract, forcing the blood to pass through the atrioventricular valves and into the ventricles
VENTRICULAR SYSTOLE
-The ventricles contract, forcing the blood up through semilunar valves and inti the aorta
-The force of the ventricles contracting, shuts the atrioventricular valves, thus preventing backflow into the atria
DIASTOLE
-As the ventricles relax it causes a drop in blood pressure, this causes the semilunar valves to shut
The atria start to fill with blood and as the pressure increases, blood starts trickling down into the ventricles again

26
Q

What is the electrical activity of the heart?

A
  • The myogenic cells in the SAN (The hearts pacemaker) fire a wave of depolarization
  • The wave of depolarisation spreads over the atria causing it to contract, but it is blocked to go to the ventricles
  • The wave then goes to the atrioventricular node, there is then a slight delay (0.1 seconds)
  • The wave then travels down the bundle of His to the septum and then it travels up the ventricle walls from the bottom carried by the purkinje fibres
  • The ventricles contract and the blood is forced up and out the aorta or pulmonary artery
27
Q

What does myogenic mean?

A

The cells are capable of keeping their own rhythm

28
Q

What is an ECG?

A

An electro cardio gram, it is used to measures the electrical activity of the heart

29
Q

What do the parts of the ECG on a graph mean?

A

P = Atrial excitation (Contraction of the atria)
QRS complex = Ventricle excitation
(Contraction of the ventricles)
T = Repolarisation (Resting)

30
Q

What are the conditions that are shown through an abnormal ECG reading?

A

Fast = Tachycardia
Slow = Bradycardia
Atrial fibrillation = No atrial excitation (P) present so it only shows the QRS complex and the T
Ectopic = Not rhythmical (Skipping of beats so the rhythm is irregular)

31
Q

How is the cardiac cycle shown on a graph?

A
Pressure in the aorta (1)
Pressure in the left ventricle (2)
Pressure in the left atrium (3)
-1,3,2 (blood into ventricle)
[AV valve closes]
-1,2,3
[SL opens)
-2,1,3
[SL closes]
-1,2,3
[AV opens]
-1,3,2
32
Q

How is oxygen transported in the blood?

A

Inside the capillaries, inside RBC’s bound to haemoglobin

33
Q

What is the equation for the process of loading and unloading oxygen onto/off haemoglobin?

A

Hb + 4O2 -> OxyHb (LOADING)

Hb + 4O2

34
Q

When does loading and unloading occur?

A
  • Loading occurs at a high partial pressure of O2 (High concentration of O2)
  • Unloading occurs at a low partial pressure of O2 (low concentration of O2)
35
Q

When does loading and unloading occur?

A
  • Loading occurs at a high partial pressure of O2 (High concentration of O2)
  • Unloading occurs at a low partial pressure of O2 (low concentration of O2)
36
Q

What is the partial pressure of O2 in the lungs, and how does this affect the O2 saturation of haemoglobin?

A

12-14kPa, as there is more O2 available the haemoglobins more saturated (100%) and picks up
oxygen more easily

37
Q

What is the partial pressure of O2 in the tissues, and how does this affect the O2 saturation of haemoglobin?

A

2-4kPa, as there is a lower concentration of O2 in the tissues the haemoglobin unloads the oxygen, thus providing oxygen for the tissue that needs it

38
Q

What is the Bohr shift?

A

When CO2 is present due to increased levels of exercise, haemoglobin loses affinity for O2 in order for it to unload the O2 onto cells that need it

39
Q

What is the process that causes the Bohr shift?

A

1) Cells produce CO2, carbonic anhydrase catalyses a reaction between CO2 and water to make carbonic acid
2) The carbonic acid dissociates into: H+ and HCO3-
3) The HCO3- ion leaves the RBC and goes into the plasma
4) The oxyhaemoglobin unloads oxygen so it dissociates into Hb and 4O2
5) The oxygen leaves the cell and the Hb that is left binds to the H+ ion from the dissociation of carbonic acid
6) The H+ binds to Hb and changes its conformational shape (haemoglobinic acid is formed)
7) The binding of the H+ makes it more difficult for O2 to bind so it reduces the haemoglobin’s affinity for O2

40
Q

How is most of the CO2 transported?

A

-Most of the CO2 is transported as an ion in the plasma

41
Q

Why does the faetal haemoglobin have a higher affinity for O2 than normal adult haemoglobin?

A
  • The baby must have a higher affinity for oxygen than the mother
  • This is because the baby must get the oxygen from the mothers blood
42
Q

What is the purpose of the slight delay at the AVN?

A

-The delay permits the atria to finish contracting so that the ventricles completely fill with blood before the ventricles themselves begin to contract