erythropoiesis is triggered by low oxygen levels.
Hemorrhage or living at high altitude
The exact word for this would be ''erythropoiesis''.
Kidneys
A reduced blood flow to the kidneys
Stimuli itself is of two types - external stimuli and internal stimuli. External stimuli refers to touch, pressure, heat etc. Internal stimuli refers to the stimuli produced by body components - like hormones etc.
There are many types of stimuli, it all depends on what the body is reacting to. There may be stimuli from someone smacking you, which would result in a pain response. There can also be visual stimuli, like seeing old pictures, which results in a nostalgic feeling.
Increased erythropoiesis can be stimulated by conditions like hypoxia (low oxygen levels), anemia, high altitude, chronic kidney disease, or certain medications like erythropoietin. These conditions trigger the release of erythropoietin, a hormone that stimulates the production of red blood cells in the bone marrow.
Stimuli is basically what would initiate the functioning of something. say for example smell of good food makes your mouth water? Here Food is the stimulant which act as a STIMULI for your tongue!
Hemoglobin in blood carries about 280 ml of oxygen/ liter. That bond is tight enough to carry oxygen and loose enough to give at pressure gradient difference. If erythropoiesis does not occur in body you can carry only 4 ml / liter of oxygen/ liter in body and you will not survive with such a low supply of oxygen.
because its responding to stimuli
Perceptual defense is the process of blocking certain stimuli from being perceived. This is due to the offensive, threatening or unpleasant nature of the stimuli.
internal is in and external is out