Transport in Animals Flashcards
Why do animals need a transport system?
The need to supply cells with oxygen
Remove waste products
They are too large to perform these actions by simple diffusion (SA : V)
What are the 3 factors that influence the need for a transport system?
Size
Surface area to volume ratio
Level of metabolic activity
How does size affect the need for a transport system?
If an organism is large the pathway for diffusion to their cells becomes too large
Therefore a transport system is required to supply cells with oxygen and to remove waste
How does surface area to volume ratio affect the need for a transport system?
When an organism has a low surface area to volume ratio the rate of diffusion is slow
Therefore it would take too long for oxygen to diffuse into the cells and so a transport system is required
How does the level of metabolic activity affect the need for a transport system?
Metabolic activity requires energy
Energy is produced in respiration
Aerobic respiration requires a lot of oxygen
Highly active organisms require lots of oxygen and thus need a transport system to provide it
What is a single circulatory system?
Where the blood flows through the hear once per circuit of the body
Give an example of a type of animal with a single circulatory system
Fish
Heart -> Gills -> Body -> Heart
What is a double circulatory system?
Where there are two different circuits performing different roles
One takes blood to the lungs to pick up oxygen
The other takes this oxygenated blood the working muscles
Describe the route of blood in a double circulatory system
Heart -> Lungs -> Heart -> Body -> Heart
What are the names of the two circuits in humans?
Pulmonary circuit
Systemic circuit
What are the advantages of a double circulatory system?
Can deliver the nutrients more quickly
The heart is able to increase the pressure of the blood after it has passed through the lungs so damage isn’t caused to delicate capillaries
Can remove waste products more efficiently
What is an open circulatory system?
Where the blood is not always held in blood vessels
Instead the blood can flow freely through the body cavity
What are the disadvantages of open circulatory systems?
Blood pressure is low and blood flow is slow
Circulation of blood may be affected by movement or lack of movement
What is a closed circulatory system?
Where blood flows in specialised blood vessels
What are the advantages of a closed circulatory system?
High pressure so blood moves quickly
More rapid delivery of oxygen and nutrients
More rapid removal of CO2 and waste
Transport is unaffected by body movements
What is the name of the thin single cell layer on the inside of blood blood vessels?
Endothelium
Describe and explain the differences in structure between veins and arteries
Arteries have thick layer of smooth muscle and thick layers of collagen whereas veins have thinner layers of smooth muscle and collagen
Arteries have a narrow lumen to maintain high blood pressure whereas veins have a wider lumen to allow ease of flow
Veins have valves to prevent back flow of blood because the blood is maintained at a lower pressure. Arteries don’t need this as the blood is much higher in pressure
What are the names of the 3 layers of an artery?
Tunica intima - a thin layer of elastic tissue
Tunica media - thick layer of smooth muscle
Tunica adventitia - Thick layer of collagen and elastic tissue
Describe the structure of capillaries?
Very narrow lumen - helps oxygen transfer as it reduces the diffusion distance
Very thin walls - consist of 1 layer of flattened endothelium, reduces diffusion distance
Walls are leaky - allows blood plasma and dissolved substances to leave the blood
What does blood plasma contain?
Oxygen Carbon dioxide Mineral ions Glucose Amino acids Hormones Clotting Factors
RBC’s
WBC’s (leucocytes)
What is tissue fluid made of and how is it formed?
Similar to plasma but without any blood cells in it
Formed by plasma leaking out of the capillaries
What is hydrostatic pressure?
The pressure pushing out on the walls of a blood vessel from the blood inside
What is oncotic pressure?
The pressure from water trying to move into the blood vessel due to solute concentrations inside
Oncotic pressure opposes hydrostatic pressure
What’s the function of the lymphatic system?
To drain excess tissue fluid out of the tissues and return it to the blood
How does the composition of lymph fluid differ to tissue fluid?
Lymph fluid contains more lymphocytes
Where are the lymphocytes in lymph fluid produced?
In the lymph nodes
At the arterial end of a capillary bed what is higher; hydrostatic pressure or oncotic pressure?
Hydrostatic pressure
At the venous end of a capillary bed what is higher; hydrostatic pressure or oncotic pressure?
Oncotic pressure
What is the role of the coronary arteries?
To supply oxygenated blood to the cardiac muscle
Which vessel delivers deoxygenated blood from the body to the hear?
Vena Cava
Which vessel delivers Oxygenated blood from the lungs to the heart?
Pulmonary vein
Which vessel delivers oxygenated blood from the heart to the rest of the body?
Aorta
Which vessel delivers deoxygenated blood from the heart to the lungs?
Pulmonary artery
Which chamber does blood from the vena cava flow into?
Right atrium
Which chamber does blood from the pulmonary vein flow into?
Left atrium
What are there names of the valves which separate the atria and the ventricles
Atrio-ventricular valves
What chamber does the pulmonary artery take blood from?
Right Ventricle
What chamber does the Aorta take blood from?
Left Ventricle
What valves are found at the base of the arteries leaving the heart?
Semilunar valves
What is systole?
When the ventricles contract and force blood out of the heart
What is diastole?
After systole the ventricles and atria relax and the heart fill back up with blood
Where is the Sino-atrial node located?
In the right atrium
What is the role of Sino-atrial node (SAN)?
To act as the pacemaker by initiating a wave of excitation in the heart
Why does the bottom wall of the atria not conduct the wave of excitation but the side walls do?
To prevent the wave of excitation spreading to the ventricular walls too quickly which would cause an unsynchronised contraction
What is the name of the area by which the wave of excitation is able to pass from the atria to the ventricles?
The atrio-ventricular node (AVN)
Why does the atrio-ventricular node delay the wave of excitation?
To ensure that the ventricles don’t contract too soon
This would cause an unsynchronised heartbeat leading to back-flow
What is the name of the tissue in the septum which carries the wave of excitation?
Purkyne tissue
What is the name of the graph showing electrical activity in the heart?
Electrocardiogram (ECG)
In an ECG, what does the P wave represent?
Excitation of the atria (atrial systole)
In an ECG, what does the QRS complex represent?
Ventricular systole
In an ECG, what does the T wave represent?
Diastole
What is the name of the condition where someones heart rate is slower than normal?
Bradycardia
What is the name of the condition where someones heart rate is faster than normal?
Tachycardia
What is the name of the condition where someones heart rate is beating at irregular intervals?
Ectopic heartbeat
What would an ECG of a patient with atrial fibrillation look like?
No clear P wave (atrial systole)
What protein carry oxygen?
Haemoglobin
What gives haemoglobin its affinity for oxygen?
Fe2+ Prosthetic group
How many molecules of oxygen can be carried per molecule of Haemoglobin?
4
Describe the shape of the line on a graph showing saturation at different partial pressures of oxygen
Starts low and rises steeply as oxygen enters haemoglobin easily
As saturations reaches 100% the curve flattens off as it becomes harder to add oxygen against a concentration gradient
Compare the haemoglobin dissociation curves of adult and feral haemoglobin
Fetal haemoglobin has a higher affinity than adult haemoglobin
so fetal haemoglobin increases slightly quicker than adult haemoglobin
Still has the same S-shape
How is a majority of carbon dioxide transported in the body?
Hydrogencarbonate ions (HCO3^-)
Describe the formation of hydrogencarbonate ions
CO2 combine with water to form Carbonic acid (H2CO3)
Carbonic acid dissociates into HCO3- and H+
What is the name of the enzyme which catalyses the reaction between water and CO2 to form carbonic acid?
Carbonic anhydrase
What is the Chloride shift?
The movement of Cl- ions into the red blood cell as HCO3- ions move out
Aims to maintain a constant charge inside the cell
What is formed inside the red blood cell to prevent a build of of H+ ions (which could cause pH change)?
Haemoglobinic acid
What is the Bohr effect?
Describes the effect of CO2 concentration on the ability of haemoglobin to take up oxygen
At higher CO2 concentrations uptake is less effective
Why does the Bohr effect occur?
When CO2 combines with water in RBC’s it forms carbonic acid
Carbonic acid dissociates to form H+ ions which lowers pH
this causes change in the shape of haemoglobin so it is less effective at holding oxygen
