Unit 3 - Transport In Animals Flashcards
What are features of an EFFECTIVE transport system?
- Fluid or medium to carry nutrients
- A pump to create pressure
- Exchange surfaces
What are features of an EFFICIENT transport system?
- Tubes or vessels to carry the blood via mass flow
- 2 circuits
Which animals have a double circulatory system?
Mammals
What are the advantages of a double circulatory system?
- Delivers oxygen and nutrients after
- The blood can flow quicker increasing pressure to the heart
What are the disadvantages to a single circulatory system?
The rate at which Oxygen and Nutrients are delivered to the tissues and waste products removed is limited
What’s the BP like in a single circulatory system of a fish? 🐠
- Drops as the blood passes through the capillaries in the gills
- Low pressure and speed as it flows towards the body
Why are fish not as metabolically active as mammals?
They are cold blooded so there is no need to maintain energy
Why do mammals need a double pump system?
They have to maintain their body temperature
Arteriolar
Small blood vessels that distribute blood from an artery to the capillaries
Venules
Small blood vessels that collect blood from the capillaries and lead into the veins
What are the DISADVANTAGES to an open circulatory system?
- Blood pressure and speed is slow
- Circulation can be affected by body movement
What are the advantages of a closed circulatory system?
- Higher pressure, faster blood flow
- Quicker delivery of Oxygen and Nutrients
- Quicker removal of Carbon Dioxide and other wastes
- Transport is independent of body movement
What layer do all blood vessels have?
Endothelium- Inner lining made of a single layer of cells.
Smooth to reduce friction with the blood
What layers do capillaries have?
- Endothelial
- Lumen
What layers do Arteries and Veins have?
- Collagen fibres
- Smooth muscle
- Elastic fibres
- Endothelium
- Lumen
What are the features of Arteries?
- Small lumen to maintain high BP
- Folded inner layer to allow lumen to expand as blood flow increases
Features of Arterioles?
- Contains a layer of smooth muscle which can contract to reduce blood flow
- Can be used to divert the blood flow to parts of the body requiring more Oxygen
What are the features of capillaries?
- Very thin walls to allow the exchange of nutrients and waste products
- Lumen around 7um (about the diameter of a erythrocyte)
- This squeeze the erythrocytes against the walls reducing diffusion distance
- Reduces rate of flow
- Leaky walls
What are the features of veins?
- Large lumen to ease blood flow
- Thin walls as they don’t need to constrict lumen
- Valves because of low pressure
- Think walls can be flattened by skeletal muscles which applies pressure to blood
Hydrostatic Pressure
The pressure that a fluid exerts when pushing against the sides of a vessel
What is the lymphatic system?
A system of tubes that returns excess tissue fluid to the blood system
Oncotic pressure
The pressure created by external fluid pushing on the blood vessels
How is tissue fluid different to blood plasma?
- Doesn’t contain many of the cells found in blood
- Doesn’t contain plasma proteins
What kind of movement is the flow of blood plasma into tissue fluid?
Mass Movement
How is blood out of the capillaries at the arterial end of the capillary bed?
The blood is at a relatively high hydrostatic pressure which forces the blood out
Through what processes does the exchange substances in and out of the cell take place?
- Diffusion
- Facilitated Diffusion
- Active Transport
How are waste products able to return to the blood?
The blood pressure is much lower at the ventless end of the capillary
What happens to tissue fluid that doesn’t return to the blood?
It enters the lymphatic system
Why does tissue fluid go into the lymphatic system?
It drains the excess tissue fluid out of the tissues and returns it to the blood system in the subclavian vein in the chest
What makes up the lymphatic in the lymphatic system?
Similar composition to tissue fluid but contains more lymphocytes as these are produced in the lymph nodes
Lymph
The fluid held in the lymphatic system
Lymph nodes
Swellings found intervals along the lymphatic system. They have an important play in the immune response
What kind of hydrostatic pressure do blood plasma, tissue fluid and lymph have?
Blood plasma – High
Tissue fluid and Lymph - low
What is oncotic pressure like in the blood plasma, tissue fluid and lymph?
Blood plasma – more negative
Tissue fluid and length – less negative
Does lymph contain fats?
Yes especially near the digestive system
How does the hydrostatic pressure change along the capillary bed?
In the capillaries – high at the arterial end, low at the venule
In the tissue fluid – lower than on the capillaries, the same at both ends
How does oncotic pressure changed throughout a capillary bed?
The same for the whole stretch, bit more negative in the capillaries and less negative in tissue fluid
How does oncotic pressure move the substances in the blood?
– Oncotic pressure of the blood pulls water into the blood
– Oncotic pressure of tissue fluid pulls water into the tissue fluid
Cardiac muscle
Specialise muscle found in the walls of the heart chambers
What do Semilunar valves do?
Stop blood re-entering the heart and arteries
Why are the walls of the atria very thin?
The chambers do not need to create much pressure because they only have to push the blood into the ventricles
What is the thickness of the wall of the right atria like?
Thicker than the atria so the blood can be pumped to the lungs, but not too thick because The alveoli in the lungs are very delicate and could be damaged by high blood pressure
What is the thickness of the walls in the left ventricle like?
Two or three times thicker than in the right ventricle.
The blood need sufficient pressure to overcome the resistance of the systematic circulation
What is the bicuspid valve?
Left atrioventricular valve
What is the tricuspid valve?
Right atrioventricular valve
What does the electro cardiogram (ECG) do?
Records the rhythm, rate and electrical activity of your heart
How does an electrocardiogram monitor the activity of the heart?
Record the electrical signals from your heart.
Electrodes placed on your chest record the signals
What does the bit to the left of the spike of a heart trace show?
P-wave – SA node fires
What does the spike on a heart trace show?
QRS – AV node and ventricles fire
What does the bit to the right of the spike of a heart trace show?
T-wave - Ventricles recharge
What are slow heart rates called?
Bradycardia
Less than 60 bpm
What is a fast heart rate called?
Tachycardia
More than 100 bpm
What kind of heart trace is it where the P-wave is not clear?
Atrial fibrillation
What kind of heart rate is it when a beat has been skipped?
Ectopic heartbeat
Cardiac cycle?
The performance of the human heart from ending of one heartbeat to beginning of the next
What are the three stages of cardiac cycle?
Atrial and ventricular diastole
Atrial systole
Ventricular systole
What is it Atrial and ventricular diastole?
Chambers are relaxed and filling with blood
What is it Atrial systole?
Atria contract and the remaining blood is pushed into the ventricles
What is ventricular systole?
Ventricles contract and push blood out through the aorta and pulmonary artery
Myogenic muscle
Originating in or produced by muscle cells
Purkyne tissue
Is a network of the Pukyne fibres that carry the cardiac impulses from the atrioventricular node to the ventricles of the heart and causing it to contract
Sino atrial node
Natural pacemaker of the heart
Electrical impulses are generated here
Do the atria or ventricles contract at a higher rate?
They contract at the same time
How many times a minute does the SAN send out electrical waves?
At rest the SA node sends out between 60 and 100 bpm
How do you the atria contract?
When the SA node sends a electrical impulse the electrical signal travels from your SA node through muscle cells in your right and left atria the signal triggers muscle cells that make your atria contract
How did the ventricles contract?
The signal travels down a bundle of conduction cells called bundle of HIS which divides the signal into two branches one going to each ventricle
These branches divide further into a system of conducting fibres that spreads the signal through your left and right ventricle is causing them to contract
What happens in Atrial systole?
The Atrium contracts and tops off the volume in the ventricle with only a small amount of blood
Atrial contraction is complete before the ventricle begins to contract
What happens in ventricular systole?
Pressure rises in the ventricles pumping blood into the aorta from the left ventricle
What happens in diastole?
Period of relaxation of the heart muscles accompanied by the filling of the chambers of blood
How do the atrioventricular valves work?
When the ventricles relax atrial pressure exceeds ventricular pressure the AV valves are pushed open
What prevents valves from turning inside out?
They’re attached a small papillary muscles by tough tendons
How do you the semilunar valves work?
When the atrioventricular valves open the semilunar valves are shut and blood is forced into the ventricles. When the AV valves shut the semilunar valves open for some blood into the aorta and pulmonary artery
What causes the pulse we can feel?
As your heart pumps blood through your body you can feel a pulse in some of the blood vessels close to the skin surface such as your Wrist, neck, or upper arm
What does the elastic recoil of the walls of the aorta help to maintain?
The elastic recall of the arteries allows the artery to expand as normal but then exert an inward forced to create blood pressure
Affinity
The strength by which to a more molecules interact or behind
Dissociation
The process in which molecules or compounds separate or split into smaller particles
Fetal haemoglobin
Fetal haemoglobin is the main oxygen carrier protein in the human fetus
What does haemoglobin come when it takes of oxygen?
Oxyhemoglobin
Is the oxygen + haemoglobin reaction reversible?
Yes
How does the diameter of capillaries increase rate of diffusion?
Capillaries are only a few micro metres in diameter They have only one endothelial cell wall in thickness
What percentage of a Erythrocyte is made up of haemoglobin?
About 95%
What does haemoglobin consist of?
Haemoglobin is a protein made up of four polypeptide chains
Each chain is attached to heme group composed of porphyry attached to a Iron atom
What kind of affinity for oxygen does haem group have?
As one oxygen molecule binds to warn haem group, the oxygen affinity for the other groups increase
What is partial pressure?
Partial pressure is the pressure of a single type of gas in a mixture of gases
What is the saturation of haemoglobin measured in?
Grams per decilitre
g/dl
What shape is the haemoglobin dissociation curve?
Sigmoidal
Why does haemoglobin not readily associate with oxygen molecules that at a low oxygen tension?
As the blood circulates to other body tissues in which the partial pressure of oxygen is less the haemoglobin releases oxygen into the tissues because the haemoglobin cannot maintain its full band capacity of oxygen in the presence of lower oxygen partial pressures
Why does the haemoglobin dissociation curve eventually plateau?
Molecules bind as oxygen partial pressure increases until the maximum amount that can be bound is reached as this limit is approach very little additional binding occurs and the curve levels out as the haemoglobin becomes saturated with oxygen
How is fetal haemoglobin different adult haemoglobin?
Fetal haemoglobin has a different conversation from the adult forms of haemoglobin which allows it to bind oxygen stronger.
Why does fetal haemoglobin need a stronger affinity for oxygen than than the adult haemoglobin?
By the time the blood reaches of the centre there is a lower concentration of oxygen in the blood
Carbonic anhydrate
An enzyme that catalyse is the in-conversion of dissolved bicarbonates and carbon dioxide
Chloride shift
And exchange of ions it takes place in our red blood cells in order to ensure that no buildup of electric change takes place during gas exchange
Bohr effect
The effect of carbon dioxide on the oxygen dissociation curve for haemoglobin
Haemoglobinic acid
A very weak acid from inside red blood cells when hydrogen ions combine with haemoglobin
What are the three ways carbon dioxide is transported to the lungs?
- Dissolved in solution
- Buffered with water as carbonic acid
- Bound to proteins
How are hydrogen carbonate ions formed?
And in the cytoplasm of the red blood cells there are high levels of the enzyme carbonic anhydrase
This enzyme catalyse of the reversible reaction between carbon dioxide and water form carbonic acid
Carbonic acid and associates to form hydrogen carbonate ions and hydrogen ions
What does carbonic acid dissociate to release?
Hydrogen ions and bicarbonate ions
What do the hydrogen carbonate ions do after they’ve been produced?
Transport carbon dioxide to the lungs
How is the charge inside the erythrocyte maintained after the hydrogen ions leave?
Negatively charged chloride ions move into the Erythrocyte
This is known as the chloride shift
What happens if hydrogen ions builds up in a Erythrocyte?
Hydrogen ions in the red blood cells would prevent further conversion and production of Bicarbonate ions
Why is haemoglobin able to take up hydrogen ions in the dying tissues?
At a great concentration of hydrogen ions haemoglobin stabilises and has a reduced affinity to oxygen helps delivering it to tissues in need
What causes the change in PH of haemoglobin?
An increase of CO2
