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.