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In this IBDP Biology blog post, we will be discussing the further physiological processes within human bodies and how we control these processes.
Control of ADH by negative feedback
- Neurosecretory cells in the hypothalamus synthesise and transport ADH to the posterior pituitary gland where it is stored
- Osmoreceptors in the hypothalamus detect an increase in blood solute concentration when levels of water in the blood drop
- In response to this nervous activation, ADH is released from the posterior pituitary and travels in the blood to the kidneys
- ADH makes the epithelium of the collecting ducts more permeable to water
- This increases the amount of water reabsorption by the kidneys, causing blood solute concentration to drop
- With a drop in blood solute concentration, ADH secretion is inhibited (negative feedback)
- If blood solute concentration is low (due to excessive water intake), the collecting duct remains impermeable to water and urine is dilute
The structural features of an exocrine glands
- Exocrine glands have ducts through which they secrete their product
- The ducts / ductules arise from a cluster of cells called an acinus
- Acini are lined by a single layer of secretory cells which release the exocrine product into the lumen of the duct via secretory vesicles
- Secretory cells are held together by tight junctions, and possess a highly developed RER and golgi network for material secretion
That is all for this post!
References:
https://www.google.com/url?sa=i&url=https%3A%2F%2Fvasopressin.wordpress.com%2Frelease-and-feedback%2F&psig=AOvVaw0RmsL_UGt4fZmPotJgZbm_&ust=1627663439514000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCIjlgf_ciPICFQAAAAAdAAAAABAD
https://www.google.com/url?sa=i&url=http%3A%2F%2Fib.bioninja.com.au%2Foptions%2Foption-d-human-physiology%2Fd2-digestion%2Fexocrine-glands.html&psig=AOvVaw0cAFxZC4JXqA4ebDgyw0B2&ust=1627663498979000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCICFyZfdiPICFQAAAAAdAAAAABAD
Drafted by Venetia (Biology)