Module 3 Transport In Animals Flashcards
Describe open circulatory systems
Blood not contained in a blood vessel, pumped directly into body cavity, haemocoel, the blood is a fluid called haemolymph. Heart runs down length of thorax. In the haemocoel, the haemolymph bathes organs and tissues, enabling diffusion of substances. When heart relaxes, haemolymph blood is sucked back in via pores called Ostia. Haemolymph moves around haemocoel due to movement of organism and amount of haemolymph cannot be varied with changing demands. Examples are insects.
Q-explain why insect circulatory system is described as open
Because blood isn’t enclosed in blood vessels all the time, it flows freely through the body cavity.
Describe closed circulatory systems
Blood is enclosed inside blood vessels. Blood is pumped through a series of progressively smaller vessels, capillaries, substances diffuse in and out of blood and into cells, blood is then returned to heart via a series of progressively larger vessels. Examples are fish and mammals.
Describe single circulatory systems
Blood passes through heart once for each complete circuit of the body. Examples are fish. Advantages is less complex and doesn’t require complex organs. Disadvantages are low blood pressure, slow movement of blood, activity level of animal tends to be low.
Q- Describe the circulation system of fish
Have single, blood flows from heart to gills and then on to body before returning to heart.
Describe double circulatory systems
Blood passes through the heart twice for each complete circuit of body. Examples are birds/mammals. Advantages are heart can pump blood further around the body, high pressure, fast flow of blood. Disadvantages are more complex. Pulmonary circuit carries blood from heart to lungs for gas exchange, systematic circuit carries blood from rest of body to deliver oxygen and nutrients.
What is the circulatory system compromised of
Heart, fluid in which substances are transported, vessels
Why are fish so active
They have a single circulatory systems which is not as effective as double but works for fish, they have a specialised gas exchange system in gills which allows them to take in more oxygen. They don’t need to maintain body temperature.
What are the advantages of the mammalian system
Heart can increase blood pressure after blood passes through lungs, increased speed of delivery, increased blood pressure in systemic system, lower blood pressure in pulmonary system decrease change of damaging capillaries.
Describe the mammalian system
Have double, pulmonary takes blood from heart to lungs and back, the systemic takes blood from heart to body tissues and back.
Q-compare circulatory system of mammals and fish
Fish have single circulation, mammals have double. Both are closed systems. In fish blood pressure is lower, mammals have higher pressure. Fish are less efficient at transporting oxygen to tissues, mammals are more. Both have a heart. In fish, blood passes through 2 sets of capillaries, mammals pass through 1.
What are the five types of blood vessels
Arteries, arterioles, capillaries,venules,veins
Describe arteries
Carry oxygenated blood from the heart to the bodies cells. Thick(1mm), High muscle, high elasticity, inner surface is endothelium, size of lumen is smaller than veins(2.5cm-0.4cm), no valves, enables blood to be at high pressure. narrow lumen maintains high pressure, thick elastic and muscle layers allow the vessel expand with heart beats and then recoil(gives pulse).
Describe arterioles
Carry oxygenated blood from the heart to the bodies cells. Thick(30um), high muscularity, medium elasticity, endothelium inner surface, no valves, carry’s blood under high pressure, more muscle and less elastic fibres which have little pulse surge and constrict and dilate to move blood flow.
Describe capillaries
7-8um thickness, no muscles, no elasticity, one cell thick(to ensure blood cells travel through singly), no valves, substances are exchanged from blood cells to surrounding tissue through gaps in endothelium, have large SA.
Describe venules
Carry deoxygenated blood from bodies cells to heart, thin(0.1mm), low muscularity, low elasticity, endothelium inner surface, there is valves, no elastin fibres or smooth muscle
Describe veins
Carry deoxygenated blood from bodies cells to heart, thin walls(0.5mm), low muscularity, low elasticity, endothelium inner surface, 1cm lumen, there is valves. Do not have pulses as blood pressure is low, walls contain lots of collagen and few elastic fibres and muscle
What is order of vessels
Arteries lead into arterioles, into capillaries, where gas exchange takes place, move into venules, then into veins and back to heart
What is the role of elastic fibres in blood vessels
Made of elastin. They stretch and recoil providing the vessel with flexibility
What is the role of smooth muscle in blood vessels
Contracts and relaxes changing the size of the lumen
What is the role of the collagen in blood vessels
Provides structural support to maintain shape and volume of the vessel
Describe the transverse section of an artery
Connective tissue on outside, then smooth muscle and elastic tissue, with thin inner layer of endothelium
What are the adaptions of the capillary
Large SA, cross sectional area is small(to reduce rate of blood flow from the artery supplying them), endothelium is one cell thick(shorter distance of diffusion)
What helps blood flow
Valves(prevents back flow of blood), large valves(have active muscle moving blood), breathing movements(in chest aids movement of blood)
What are the 4 components of blood
Plasma- carries other stuff like glucose, hormones,protein called albumin for maintaining balance of fluid, protein called fibrinogen for clotting etc. white blood cells- immune support, phagocytes and lymphocytes. Platelets- clotting. Red blood cells- carries oxygen.
What are the features of a red blood cell(erythrocyte)
Biconcave shape-large SA:V, lots of haemoglobin- transporting oxygen, no nucleus- maximises space for haemoglobin so more oxygen can be transported, diameter- larger than a capillary diameter so slows blood flow to enable diffusion of oxygen.
What is tissue fluid
Fluid found outside cells and outside blood cells, bathes and surrounds body cells so that exchange of gases and nutrients can occur, contains everything plasma does except red blood cells, lymphocytes, proteins.
What is the hydrostatic pressure at arteriole end of capillary and venule end
4.3 and 1.6
EQ- suggest why the hydrostatic pressure of the blood decreases as it moved from the arteriole end to venule end of capillary(2 marks)
Small molecules including water are forced out of the capillary at the arteriole end due to hydrostatic pressure. This causes volume of fluid to decrease and therefore the hydrostatic pressure decreases.
What does hydrostatic pressure do
Forces small molecules like water, glucose,urea out of capillary.
What is the hydrostatic pressure in the tissue fluid
1.1
What is oncotic pressure
If water moves out of an area, the oncotic pressure of that area will decrease and the value will become more negative. Any substances which remain in a solution like the blood, such as plasma proteins, will have an osmotic effect and therefore lower the oncotic pressure. Forces fluid in capillary.
What is the overall net movement of the capillary
4.1-1.1=3.2, Hydrostatic pressure moves fluid out of capillary. -3.3- -1.3=-2, oncotic pressure moves fluid into capillary. 3.2- - 2=1.2
How does the return of tissue fluid in the capillaries
Most is returned to blood via the capillaries due to oncotic pressure, fluid loss causes water potential in blood capillaries to become lower than that of tissue fluid, fluid moves back into capillaries at venous end via osmosis, remaining enter lymph vessels.
Describe lymph
Tissue fluid flows into lymph system through valves and nodes. These valves are large enough to allow large protein molecules to pass through. Without the lymph system you would die as rate of water loss would be too large. This would lead to a build up of tissue fluid in tissues called oedema. Not all tissue fluid returns to capillaries. Excess drains into lymphatic system where it forms lymph which is a colourless/pale yellow fluid similar to tissue fluid but containing more lipids. The lymphatic system drains into circulatory system near vena cava via the thoracic duct.
What is the tissue composition of blood
Erythrocytes etc, hormones, plasma proteins, fats transported as lipoproteins, glucose, more amino acids, more oxygen, little carbon dioxide
What is the tissue composition of tissue fluid
Some white blood cells, some hormones and proteins, no fats, less glucose, amino acids, oxygen, more carbon dioxide.
What is the tissue composition of lymph
Lymphocytes, some proteins, more fats than in the blood, less glucose,amino acids,oxygen, more carbon dioxide.
Describe the heart
Consists of cardiac muscle tissue, like smooth muscle and contracts involuntarily. Cardiac muscle is made up of cells that are connected to cytoplasmic bridges which enables electrical impulses to pass through the tissue, contains mitochondria. Cardiac muscle cells are myotonic- they twitch.
What are the three stages of the cardiac cycle
Atrial systole, ventricular systole, diastole
What does systole mean
Contracting
What does diastole mean
Filing
Describe atrial systole
Muscle of the atria contract and pressure inside increases. Semi lunar valves in the vena cava and the pulmonary vein close. Tricuspid and bicuspid atrioventricular valves open, allowing blood into ventricles. Volume of blood is high to low.
Describe ventricular systole
Muscles of ventricles contract and the pressure inside increases. Tricuspid and bicuspid atrioventricular valves close. Semi lunar valves in aorta and pulmonary arteries open. Volume of blood is high to low.
Describe diastole
Semi lunar valves in aorta and pulmonary arteries close. All heart muscles relax. Blood flows into atria from vena cava and pulmonary vein. Blood pressure remains low inside atria and ventricles.
Describe valves
Prevent back flow, controlled by pressure changes in the heart , high pressure behind valve forces it open, high pressure in front of valve closes it.
What are the 2 nodes in the heart
Sino atrial node(SAN), atrio ventricular node(AVN)
Describe the function of the SAN and AVN
SAN is upper left wall of the right atrium sends a wave of electrical activity throughout the atria. Causes walls of atria to contract. Blood is forced through bicuspid and tricuspid valves into the ventricles. Layer of non conducting tissue prevents excitation passing directly to ventricles. AVN picks up the wave and delay activity before it sends its own wave of excitation down bundle of his, into purkinje fibres. Cause ventricular walls to contract. This forces blood out of aorta and pulmonary (semi-lunar) valves.
Dissection of heart
Wear aprons and lab coats, place heart on tray, look at outside of heart and feel the muscles, identify the chambers, cut open atria and ventricle and valves, draw a biological drawing, wash hands and disinfectant.
What does myogenic mean
Twitch
What are ECG’s
Measures electrical activity of the heart by attaching electrodes to the skin. Used to diagnose problems with the heart. May be taken before/after exercise or when relaxed.
What is bradycardia
Heart rate is slow below 60bpm. May need artificial pacemaker
What is tachycardia
Heart rate is very rapid, over 100bpm
What is an ectopic heartbeat
Extra heartbeats out of normal rhythm, can be normal but frequent may require treatment
What is atrial fibrillation
Example of arrhythmia, abnormal rhythm, rapid impulses generated in atria, inefficient blood pumping
Why is bradycardia common in diving animals
Because it conserves more oxygen, as heart rate is slower
Why is tachycardia common if you visit high altitudes
There is lower concentration of oxygen in air the higher you get due to air pressure decreasing, so your heart beats faster to supply more oxygen
Why is there a delay of the heart during AVN
Stops atria and ventricle contracting at the same time
What is a pulse oximeter
Measure blood oxygen levels and pulse. Observes oxygen saturation
What is a colorimeter
Difference in blood colour according to saturation with oxygen, changes colour due to light transmitted through a patients fingers
How is oxygen carried around the body
Haem groups contain an Fe2+ which attracts o2 (affinity). Each haem group can combine with one molecule of oxygen,o2. One molecule of haemoglobin can combine with max four oxygen molecules, 4o2. When haemoglobin has bound oxygen it forms a molecule called oxyhaemoglobin.
What is partial pressure
Relative amount of oxygen present in pascals
What is affinity and its relevance to oxygen
Tendency a molecule has to bind with oxygen. Haemoglobin affinity depends on concentration of oxygen.concentration/partial pressure. As partial pressure of oxygen increases, Hb’s affinity for O2 increases.
What is association/loading
In lungs, O2 joins to the iron in haemoglobin
What is disassociation/unloading
In tissue, O2 leaves the iron
Why is oxygen association and dissociation efficient
Readily associates with oxygen at surface where gas exchange takes place, readily dissociates from oxygen at the respiring tissues
Describe what happens during association
When the first oxygen molecule binds to first haem group and distorts the shape(conformational change) of the whole molecule so that second,third oxygen molecule is taken up at an increasing rate. Fourth is harder and sometimes doesn’t happen.
Describe what happens during dissociation
First oxygen molecule is released to tissues very rapidly but then the rest are released at a slower rate and only at very reduced partial pressure of oxygen.
Describe conformational change
Difficult first O2 to bind. The binding causes a conformational change which makes it easier for next to bind, cooperative binding. Large P02 required to bind 4th.
What happens when carbon dioxide is present to haemoglobin
Haemoglobin changes its affinity for oxygen in different conditions. In presence of carbon dioxide the new shape of haemoglobin binds less tightly to oxygen, so releases its oxygen. This is good as oxygen moves to areas it needs.
Describe oxygen dissociation curve
Helps understand how blood carries and releases oxygen. The greater the partial pressure of oxygen the greater the saturation of the haemoglobin. In lungs partial pressure is high. At respiring tissue partial pressure is low.
Describe foetal haemoglobin
Has a higher affinity for oxygen than adult haemoglobin. This is important as it helps maximise oxygen uptake from mothers blood stream which has already lost some of its oxygen by the time it reaches the placenta.
Describe myoglobin
Molecule with similar structure to haemoglobin but with only 1 haem group. Myoglobin has a high affinity for oxygen. This means oxymyglobin will only dissociate when oxygen levels are low. It is found in muscle cells where it acts as an oxygen reserve.
What are the 3 ways carbon dioxide is transported
5% carried dissolved in the plasma, 10-20% is combined with amino groups of haemoglobin to form carbaminohaemoglobin, HbCO2, 75-80% is converted to hydrogen carbonate ions in the cytoplasm of the red blood cells. Red blood cells contain enzyme carbonic anhydrase which catalyses reaction between carbon dioxide and water.
What is the chloride shift
Negatively charged hydrogen carbonate ions move out of the cell the red blood cell becomes more positive. Chloride ions move into the red blood cell.
How is carbon dioxide released
Converting co2 into HCO3- the rbc keeps a steep concentration gradient for more co2 to diffuse into the rbc. When blood reaches the lungs which has low carbon dioxide concentration, carbonic anhydrase catalyses the breakdown of carbonic acid into carbon dioxide and water. HCO3- diffuses back in and chloride ions out.
Describe the Bohr effect/shift
Carbon dioxide in the blood reacts with water to form bicarbonate and hydrogen ions. As level of carbon dioxide increases more H+ is released and PH increases. High CO2 concentrations are found at respiring cells. The high CO2 concentration causes Hb to release O2 which enters body cells for respiration. When carbon dioxide increases oxygen dissociation curve move to right. As partial pressure of carbon dioxide rises, haemoglobin gives up oxygen more easily.
What is the equation for cardiac output
Heart rate x stroke volume
What is stroke volume
Volume of blood pumped during each heartbeat, in cm3.
What is the equation for heart rate
60 / time taken for one heartbeat
