transport in animals Flashcards
why do multicellular organism require a transport system
They are big and have a low surface area to volume ratio and a high metabolic rate and are very active so most of the respiring cells need a rapid supply of glucose and oxygen so to make sure the cells have enough oxygen and glucose multicellular organism need a transport system.
what is a single circulatory system
Blood only passes through the heart once for each complete circuit of the body
what is a double circulatory system
Blood passes through the heart twice for each complete circuit of the body
what is a open circulatory system
blood is not contained within blood vessels but is pumped directly into body cavities
what is a closed circulatory system
blood is pumped around the body and is always contained within a network of blood vessels
“how is blood transported in fish ”
Heart pumps blood to the gills to pick up oxygen and then to the rest of the body to delivery oxygen in a single circulatory system
“how is blood transported in mammals ”
The right side of the heart pumps blood to the lungs and then it travels to the left side of the heart which then pumps blood to the rest of the body and is returned to the right side of the heart
“how is blood transported in insects
“
The heart is segmented. It contracts in a wave starting from the back pumping blood into a single main artery. The artery opens up into the body cavity . the blood flows around the insects organs gradually making it back into the heart segment through a series of valves
“structure and function of arteries
“
To transport blood away from the heart to the arterioles. Walls are thick and muscular and have elastic tissues to recoil and stretch as the heart beats which helps maintain the high pressure. The inner endothelium is folded which allows the arteries to expand which also helps maintain the high pressure and avoids tearing when the vessel stretches. The smooth muscles contract to constrict the lumen making it narrower to maintain pressure.
“structure and function of arterioles ”
To transport blood from the arteries to the capillaries. They have a layer of smooth muscles and have less elastic tissue
“structure and function of capillaries ”
They are one cell thick for small distance of diffusion
“structure and function of venules ”
To transport blood from the capillaries to the veins. They have very thin walls that contain some muscle cells
“structure and function of veins
“
Transport blood from venules to the heart. They have a wider lumen than arteries with very little elastic and muscle tissue. They have low pressure of blood and blood flow is helped by the contraction of muscles . They contain valves to stop the backflow of blood. The large lumen provide as much space as possible for low pressure blood to flow
“how is tissue fluid formed
“
The hydrostatic pressure at the arterial end of the capillaries is greater than the hydrostatic pressure in the tissue fluid so fluid is forced out of the capillaries and into the space around cells. As the proteins are too big to move out of the capillaries the protein content creates a water potential gradient between the capillaries and the tissue fluid. The high hydrostatic pressure is greater than the octonic pressure which forces water out of the capillaries. As fluid leaves the hydrostatic pressure at the venous end is lower and the water potential in the capillaries is lower then the water pressure in the tissue fluid so water moves back into the capillaries by osmosis.
“formation of lymph
“
Excess tissue fluid passes into lymph vessels and once they’re inside they are called lymph. Lymph gradually move toward the main lymph vessels in the thorax which return to the blood near the heart
“What is pericardium ”
A double layer of inelastic membranes surrounding the heart to prevent it from stretching too much.
“cardiac cycle
“
“Atrial and ventricular diastole- atrial and ventricle relaxed and blood moves into the atria from the veins cava and the pulmonary vein. Atrioventricular valves open and the atrial pressure is slowly Building and the semilunar valves are closed as there’s lower pressure in ventricles then in the pulmonary artery and aorta.
Atrial systole- muscles in the wall of the atria contract and the atrioventricular valves open as the atrial pressure is much higher than the pressure in the ventricles l. Blood is forced from the atria into the ventricles. Semilunar valve remains closed as there’s lower pressure in ventricles then in the pulmonary artery and aorta.
Ventricular systole- atria is relaxed and the atrioventricular valves close as the pressure in the ventricles is much greater than in the atria and the tendinous cord stops them from turning inside out. The muscles in the ventricles contract and the semilunar valves open as there is much higher pressure in the ventricles then in the pulmonary artery and aorta. “
“How is a heart beat initiated ”
Starts in the Sino atrial node which is in the right atrium. It sends out regular waves of electrical activity to the atrial walls. This cause the right and left atria to contract at the same time. A band of non-conducting collagen tissue prevents the waves of electrical activity being passes directly from the atria to the ventricles. Instead they are transferred from the SAN to the atrioventricular node. It is responsive for passing waves of electrical activity on to the bundle of his but there is a slight delay before the AVN reacts to make sure the ventricles contract after the atria is emptied. The bundle of his conducts the electrical impulses to the purkyne tissue on the right and left ventricle walls. The purkyne tissue carries the waves of the electrical activity into the muscular wall on the right and left ventricle causing them to contract simultaneously from the bottom up.
Describe ECG
P wave caused by contraction and depolarisation of the atria. The main peak of the heartbeat is called the QRS complex and is caused by the contraction and depolarisation of the ventricles. The T wave is due to the relaxation and repolarisation of the ventricles. The height of the wave indicates how much electrical charge is passing through the heart.
“What is tachycardia ”
When the heartbeat is too fast which is ok for exercise but at rest it shows that the heart isn’t pumping blood efficiently
“What is bradycardia ”
When the heartbeat is too slow. Common in athletes but can show that the heart isn’t pumping blood efficiently
What is ectopic heart beat
An extra heart beat caused by an earlier contraction of the atria or ventricle. Occasion ectopic heartbeats in healthy people don’t cause a problem
What is fibrillation
A irregular heartbeat. The atria or ventricle lose their rhythm and stop contracting properly. This can result in chest pain and fainting due to lack of pulse and death.
structure of haemoglobin
It is a globular protein with quaternary structure. It has four polypeptide chains (two alpha, two beta) Each chain has a haem group. Each haem group contains an iron ion. Each of the four haem groups can combine with 1 molecule of O2 : Hb + 4O2 ⇌ Hb(O2)4
