Mass Transport In Animals Flashcards
Why do large multi cellular organisms need transport systems to carry substances between exchange substances
Most cells to far away from exchange surfaces or each bother for Diffusion alone to maintain composition of tissue fluid within suitable metabolic range
What is the function of the circulatory system
Transports raw materials from specialised exchange organs to body cells
Describe the 2 circuits the closed double circulatory system is made of
1 takes blood from heart to the lungs
Other loop takes blood around the rest of the body
What is pulmonary circulation
Deoxygenated blood in the right side of the heart is pumped to lungs
Oxygenated blood is returned to the left side of the heart
What is systematic circulation
Oxygenated blood in the left side of the heart is pumped to tissues and organs in the body
Deoxygenated blood returns to the right side of the heart
Why is pulmonary and systematic circulation important for mammals
Prevents the mixing of oxygenated and deoxygenated blood
Blood pumped to the body is fully saturated with oxygen
Efficient delivery of oxygen anf glucose for respiration
Blood pumped at higher pressure
What do coronary arteries do
Deliver oxygenated blood to the cardiac muscle
What blood vessels enter and leave the heart
Aorta, vena cava and pulmonary artery
Pulmonary vein
What is the function of the blood vessels that enter and leave the heart ?
(Aorta, vena cava and pulmonary artery, pulmonary vein
Aorta - takes oxygenated blood from the heart to the body (respiring tissues)
Vena cava - takes deoxygenated blood from respiring tissues to the heart
Pulmonary artery - takes deoxygenated from the heart to the lungs
Pulmonary vein- takes oxygenated blood from the lungs to the heart
What are blood vessels that enter and leave the kidney
Renal arteries and veins
What is the function of the renal veins and arteries
Renal vein - takes deoxygenated blood to the vena cava from the kidney
Renal arteries- takes oxygenated to the kidneys
What does the cardiac muscle contain a lot of ?
Large numbers of mitochondria and myoglobin
Describe the gross structure of the heart
The aorta is right at the top and is mostly to the right of the picture - attached to left ventricle
Pulmonary artery is the one in the middle that loops in aorta and comes of to the right - attached to right ventricle
Pulmonary vein is on the right side of the picture below pulmonary artery
The vena cava comes out on the left side of picture next to aorta Right atrium - top left side Right ventricle - bottom left side Left atrium - top right side Left ventricle - bottom right side
Describe where the valves are in the heart
The atrioventricular vale is the valve between the right ventricle and right atrium and same for the left side of heart
Semilunar valves are in the pulmonary artery and aorta
Describe how blood flows into heart
Right atrium -> AV valve -> right ventricle -> semilunar valve into pulmonary artery and away from the heart
Blood taken to lungs where it is oxygenated and is returned to the heart through the pulmonary vein
Enters in left atrium and passes through AV valve into left ventricle
Blood passes into semi lunar valve into aorta which takes blood into aorta and the whole body
What do the av and semi lunar valves do
Atrioventricular- prevent back flow of blood from ventricles to atria when ventricles contract
Semi lunar valves - prevent back flow of blood from arteries to ventricles and back into heart when ventricles contract
Link ventricle to pulmonary artery and aorta
Why does the left side of the heart have thicker muscular wall
Generates higher blood pressure
For oxygenated blood to travel greater distance all around the body
Why does the right side of the heart have a thinner wall ?
Generates lower pressure
For deoxygenated blood to travel a small distance to the lungs where high blood pressure would damage the alveoli
What is the function of a vein
Take blood back to heart under low pressure
Describe the structure of a vein
Large lumen (wider than arteries)
Very little elastic or muscle tissue
Thin walls - carry blood away from tissues as pressure of blood is low (wont burst)
Valves - prevent back flow of blood
Contraction of skeletal muscles surrounding veins, squeezes
Maintaining blood flow
What is the function of the arteries
To carry oxygenated blood from the heart to the rest of the body
Describe the structure of the arteries
Thick smooth muscle layer-
Can contract pushing blood along
Can control blood flow
Thick elastic tissue layer
Stretches as ventricle contracts under high pressure and recoils when ventricle relaxes at low pressure
Smooth pressure surges and maintained high pressure
Thick wall
Withstand high pressure and prevents artery bursting
Smooth endothelium
Narrow lumen - increases and maintain high blood pressure
Arteries divide into smaller vessels called
Arterioles
What is the function of arterioles
Control blood flow from arteries to capillaries
Describe how arterioles control blood flow
They have thicker muscle layer than arteries
This muscle can contract and restrict blood flow to capillaries by narrowing lumen
Or
Dilate to increase blood flow to capillaries by enlarging lumen
What is the function of capillaries
Exchange substances between blood and body tissues
What are 4 adaptations of capillaries for efficient exchanging of substances
Thin walls (one cell thick of endothelial cells) Short diffusion pathway -> rapid diffusion
Large number of branched capillaries -> increases surface area to vol ratio
Narrow lumen -> rbc squeezed flat against capillary -> reduces diffusion distance
Capillaries are found near cells -> short diffusion pathway
Pores in walls -> substances can escape
Why do capillaries have gaps between lining (pores) of endothelial cells ?
They acts as sieve controlling which molecules can leave the capillaries
Allows white blood cells to escape