Year 1 Childhood Hormones

What is not true regarding osteoclasts?

Binding of RANK-L and RANK reduces osteoblast activity.

[blank_start]OPG[blank_end], whose production is stimulated by estrogen, plays a big role in bone homeostasis. It inhibits RANK-L from binding to RANK by acting as a competitive inhibitor. Doing this disengages [blank_start]osteoclast[blank_end] activity, thus promoting [blank_start]osteoblast[blank_end] activity.

The parathyroid releases [blank_start]calcitonin[blank_end] (which is actually made in the thyroid) which [blank_start]decreases[blank_end] calcium concentration in the blood. This means there is increased [blank_start]osteoblast[blank_end] activity. The parathyroid releases [blank_start]parathyroid[blank_end] [blank_start]hormone[blank_end] ([blank_start]PTH[blank_end]) which [blank_start]increases[blank_end] calcium concentration in the blood. This eans there is increased [blank_start]osteoclast[blank_end] activity.

Bone Growth: 1. Hypothalamus: [blank_start]Growth[blank_end] [blank_start]Hormone[blank_end] [blank_start]Releasing[blank_end] [blank_start]Hormone[blank_end] | v 2. Anterior Pituitary Gland: [blank_start]Growth[blank_end] [blank_start]Hormone[blank_end] | V 3. [blank_start]Liver[blank_end]: [blank_start]Insulin-like[blank_end] [blank_start]Growth[blank_end] [blank_start]Factor[blank_end] [blank_start]1[blank_end]

Bone Growth pt. 2: Liver makes IGF-1 and will also produce more [blank_start]GH[blank_end] b/c IGF-1 has [blank_start]positive[blank_end] feedback loop on GH but IGF-1 has a [blank_start]negative[blank_end] feedback loop for GHRH, which maintains balance b/c it can shut down GH

Vitamin D helps with [blank_start]calcium[blank_end] [blank_start]absorption[blank_end]. That is, if you have low vitamin D, you might have a harder time depositing calcium into your bones, therefore having [blank_start]weaker[blank_end] bones. Vitamin D comes primarily from the sun but can also be obtained from the diet (eggs, dairy, [blank_start]seafood[blank_end].) Vitamin D specifically is metabolized in 3 different places: first, the [blank_start]skin[blank_end] where it is initially absorbed, then the [blank_start]liver[blank_end] where it's converted into a useable form, and finally the [blank_start]kidneys[blank_end] where it's activated for usage.

Hormones in exercise: When you first begin exercise, most of your energy is from burning carbohydrates and lipids. This is because [blank_start]catecholamines[blank_end] (from the adrenal medulla and NOT steroids,) [blank_start]growth[blank_end] hormone (anterior pituitary gland), and [blank_start]cortisol[blank_end] (from zona fasiculata of adrenal cortex) promote breaking down of [blank_start]glycerol[blank_end] and fatty acids. (BTW: The pancreas stores [blank_start]insulin[blank_end]. [blank_start]Insulin[blank_end] decreases blood glucose levels by promoting cellular uptake of glucose from the blood. The liver stores [blank_start]glycogen[blank_end]. [blank_start]Glycogen[blank_end] increases blood glucose levels by having more glucose released into the blood.) During exercise, there is an [blank_start]increased[blank_end] muscle sensitivity to insulin due to the [blank_start]GLUT-4[blank_end] receptors which leads to [blank_start]increased[blank_end] glucose uptake by muscle cells.