Answer: Capillaries
Explanation: Blood vessels have the same basic structures used to circulate blood of different composition to and away from the heart to the body. Blood vessels are arteries, veins and capillaries. Arteries carry oxygenated blood from the heart to the body and veins carry deoxygenated blood from the tissues to the heart.
Capillaries are the ones that work with body cells for exchange.They collect nutrients and oxygen from the blood to the cell and also collect carbon dioxide and waste from the cell to the blood which is transported to the vein where it travels via the venous system and goes through the heart, then to the lungs for gaseous exchange.
Therefore the enswer is, capillaries.
Hormones glucagon and insulin are produced in the alpha and beta cells respectively in the Islet of Langerhan in the pancreas. They are involved in the negative feedback system of blood glucose regulation in homeostasis.
GLUCAGON: when there is a low blood glucose concentration, the pancreas detect this and alpha cells produce and release glucagon. Glucagon causes the cells of the body to absorb less glucose from the blood. It also inhibits the process of converting glucose into glycogen (glycogenesis) and cause gluconeogenesis (process of converting amino acids/proteins and lipids/fats into glucose) and glycogenolysis (conversion of glycogen to glucose). Finally, glucagon decreases the rate of respiration so less glucose is required.
INSULIN: when blood glucose is high, insulin is released. Insulin binds with cell surface receptors of cells and activates the enzymes attached to the receptor. The enzymes cause a conformational change in the structural proteins that surround glucose transport protein containing vesicles, causing them to move out of the way so the vesicles migrate up to the cell membrane and glucose transport proteins can fuse with it. Thus, more glucose can be taken in by cells. Insulin also cause glycogenesis (converting glucose into glycogen) and inhibits gluconeogenesis and glycogenolysis.
Basically insulin decreases blood glucose concentration (eg. after eating) and glucagon increases it (eg. skipping breakfast in the morning)
Answer:
A) Elastin
Explanation:
Elastin is the principle load-bearing protien present in the wall of aorta. It is the protien which coil and recoils like a spring within the elastic fibres and accounts for elasticity of blood vessels. As during excerise , afterload is increased ,thus a stretch is produced in the vessels. Similarly im warm environment the vessels dilate this this stretch is produced by elastin.
Without predators in an ecosystem, the ecosystem would be dominated by consumers. more consumers in an ecosystem would lead to eating more producers. predators keep an ecosystem in check, to make sure that there isn't overpopulation. hope this helps!
