3.2- Transport in animals Flashcards
What is the difference between a single and double circulatory system?
In a single circulatory system, blood only passes through the heart once for each complete circuit of the body
In a double circulatory system, the blood passes through the heart twice for each complete circuit of the body
Which organisms has a single circulatory system?
Fish
Which organisms has a double circulatory system?
Mammals
What is the pulmonary system?
The side of the circulatory system that sends blood to the lungs from the heart
What is the systemic system?
The side of the circulatory system that sends blood from the heart to the rest of the body
What is an advantage of the mammalian doubles system?
It gives the blood an extra push so blocking travel faster and oxygen can be delivered more quickly
What type of circulatory system do all vertebrates have?
Closed - blood is enclosed inside blood vessels
What type of circulatory system do insects and some invertebrates have?
Open - blood isn’t enclosed in blood vessels and flows freely through the body cavity
How does blood flow around the body in an open circulatory system?
The heart is segmented and contracts like a wave
This pumps the blood into a single main artery
This artery opens up into the body cavity
The blood flows around the insect organs before going through valves back to the heart
What is the system that supplies insects with oxygen?
Tracheal system- not the circulatory system
What is the role of the circulatory system in insects?
Supplies the insects cells with nutrients and transport things like hormones around the insect
What are the 5 types of blood vessels called?
Arteries Arterioles Capillaries Venules Veins
How are arteries adapted for their functions?
They have thick and muscular walls and elastic tissue which maintains a high pressure
The endothelium is folded which allows the artery to expand under high pressure
How are arterioles adapted for their functions?
Arterioles have a layer of Smooth muscle but less elastic tissue.
The smooth muscle allows and to expand or contract and control the amount of blood flowing to tissues
How are capillaries adapted for their functions?
Capillary walls have an endothelium which is only one cell thick.
This allows efficient diffusion to a car
How are venules adapted for their functions?
Venues have very thin walls that contain some muscle cell
This allows them to form veins
How are veins adapted for their functions?
Veins have a large lumen and very little elastic or muscle tissue
They contain valves to stop blood flowing backwards
This helps them take blood back to the heart under low pressure
What is tissue fluid?
The fluid that surrounds cells in tissues
It is made from substances that leave the blood plasma but doesn’t contain red blood cells or big proteins
How is tissue fluid formed?
At the start of the capillary bed, the hydrostatic pressure in the capillaries is greater than the hydrostatic pressure in the tissue fluid which forces fluid out of the capillaries and into the spaces around cells
What happens after tissue fluid is formed around the cells?
The hydrostatic pressure reduces in the capillaries so it is much lower at the end of the capillary bed
This means oncotic pressure is high at the venule end so some watery enter from the tissue fluid by osmosis
What happens to excess tissue fluid that doesn’t re-enter the capillaries?
It is returned to the blood through the lymphatic system
How is lymph returned to the blood?
valves in the lymph vessels stop the lymph going backwards
Lymph moves towards the main lymph vessel in the thorax where it’s returned to the blood near the heart
Are red blood cells found in blood, tissue fluid and lymph?
Blood: Yes
Tissue fluid: No
Lymph: No
They are too big to get through the capillary walls
Are white blood cells found in blood, tissue fluid and lymph?
Blood: Yes
Tissue fluid: Very few - only enter tissue fluid when there’s an infection
Lymph: Yes- most of found here
Are platelets found in blood, tissue fluid and lymph?
Blood: Yes
Tissue fluid: No- only if the capillaries are damaged
Lymph: No
Are proteins found in blood, tissue fluid and lymph?
Blood: Yes
Tissue fluid: Very few- most of too big to get through
Lymph: Only antibodies
Is water found in blood, tissue fluid and lymph?
Yes! all 3
Are dissolved solids found in blood, tissue fluid and lymph?
Yes!
Solutes it’s to move freely between blood, tissue fluid and lymph
What’s the first stage of the cardiac cycle?
The ventricles are relaxed and the atria contract which pushes blood through the atrioventricular valves to the ventricles
What’s the second stage of the cardiac cycle?
The atria relax and the ventricles contract
This forces the atrioventricular valve shut to prevent backflow and the semilunar valves open
Blood is forced out the pulmonary artery and aorta
What is the third stage of the cardiac cycle?
The ventricles and atria both relax
The semilunar valves close
The atrioventricular valves open and blood flows passively
What causes the lub-dub sound of a human heartbeat?
Lub- atrioventricular valves close
Dub- semilunar valves close
Cardiac muscle is myogenic. What does this mean?
It can contract and relax without receiving signals from nerves
How can doctors check heart function?
By using an electrocardiograph
What’s the trace produced by an electrocardiograph called?
An electrocardiogram (ECG)
What is the p wave of an ECG caused by?
Contraption / depolarisation of the atria
What is the qrs complex of an ECG caused by?
Contraction / depolarisation of the ventricles
What is the t wave of an ECG caused by?
Relaxation / repolarization of the ventricles
In an ECG Trace, the heart muscle depolarises when it ———— repolarises when it————.
Contracts
Relaxes
What is tachycardia?
When the heartbeat is too fast - around 120 beats per minute
It shows the heart isn’t pumping efficiently
What is bradycardia
Where the heartbeat is too slow- around 60 beats a minute
What is an ectopic heartbeat?
An extra heartbeat caused by the earlier contraction of the atria or ventricles
They normally don’t cause problems in healthy people
What is fibrillation?
A really irregular heartbeat
It can result in anything from chest pain and fainting to lack of pulse and death
How is oxygen carried around the body?
As oxyhaemoglobin
Haemoglobin has a high affinity for oxygen
How does haemoglobins affinity for oxygen change when there’s a high partial pressure of oxygen?
When there’s a high partial pressure, oxygen loads onto haemoglobin to form oxyhaemoglobin
How does haemoglobins affinity for oxygen change when there’s a low partial pressure of oxygen?
When there’s a lower partial pressure, oxyhaemoglobin unloads it’s oxygen
Where in the human body is there a high partial oxygen and low partial pressure of oxygen?
High partial pressure of oxygen- lungs
Low partial pressure of oxygen- Respiring Cells
How many oxygen molecules can each hemoglobin molecule carry?
4
How many haemoglobin molecules are in an erythrocyte?
Millions- not 4
Why is a dissociation curve for adult human haemoglobin s-shaped?
When haemoglobin combines with the first oxygen molecule, it’s shape alters in a way that makes it easier for other molecules to join too
But as haemoglobin starts become saturated, it gets harder for more oxygen molecules to join
Label the x and y axis on a dissociation curve for the affinity of oxygen?
X-axis- partial pressure of oxygen(kPa)
Y-axis- percentage saturation of haemoglobin with oxygen
What is different about fetal haemoglobin compared to adult haemoglobin?
Fetal haemoglobin have a higher affinity for oxygen than adult haemoglobin
Why is fetal haemoglobin’s high affinity for oxygen important?
The foetus get oxygen from its mother’s blood
By the time the mother’s blood has reach the placenta, it’s oxygen saturation has decreased
For the foetus to get enough oxygen to survive, its haemoglobin have to have a higher affinity for oxygen
Can you draw a dissociation curve for fetal haemoglobin compared to adult haemoglobin?
Fetal Curve is higher and less S-shaped
What two things affect oxygen unloading from haemoglobin?
A low partial pressure of oxygen
A high partial pressure of carbon dioxide - this is important
What occurs when there’s a higher partial pressure of carbon dioxide inside cells?
The rate of oxygen unloading increases
What happened to most (90%) of the carbon dioxide from respiring tissues?
90%- It diffuses directly into Red blood cells where it reacts with water to form carbonic acid, catalyzed by carbonic anhydrase
The carbonic acid dissociates to give hydrogen ions and hydrogencarbonate ions
This forms haemoglobinic acid
The hydrogen carbonate ions are transported away in the blood plasma and to compensate for the loss, chloride ions diffuse in
When the blood reaches the lungs, the low CO2 concentration causes the ions to Recombine into CO2 and then it is breathed out
What happened to some (10%) of the carbon dioxide from respiring tissues?
10%- Binds directly to haemoglobin and is carried to the lungs where it is breathed out
