Regulation of Endocrine System

What is the hypothalamus?

The interface between nervous and endocrine system. Its regulatory hormones affect pituitary function

What happens in the hypothalamus?

What are the two lobes of the pituitary?

The anterior pituitary lobe and the posterior pituitary lobe

What is released from the anterior pituitary?

Hormones that control other endocrine glands

What is released from the posterior pituitary?

Oxytocin and ADH

How is the hypothalamus and anterior pituitary linked?

Production occurs in the hypothalamus before release into the hypophyseal portal system to anterior pituitary

What do the anterior pituitary hormones released do?

What is a portal system?

A system where the vein from one capillary bed travels to a second capillary bed before returning to the heart

What happens in the hypophyseal portal system?

Neurosecretory neurons at median secrete regulatory factors

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Enter fenestrated capillaries in capillary bed in hypothalamus

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Portal veins

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Capillary bed in anterior pituitary

What is involved in feedback control of endorcine secretion via negative feedback?

What is involved in feedback control of endocrine secretion via additional pathways?

• Prolactin (PRL) regulation: hypothalamus produces releasing factor (PRF) and inhibiting hormone (PIH)

• Growth hormone regulation: hypothalamus produces releasing hormone (GH-RH) and inhibiting hormone (GH-IH)

What do the anterior pituitary hormones do?

Act on the liver to promote the release of somatomedins. Eg. insulin like growth factors which:

• Stimulate tissue growth (particularly skeletal muscle and cartilage)

• Increase amino acid uptake/protein synthesis

What does growth hormone do?

Acts directly on tissue to:

• Stimulate cell division in epithelial and connective tissue

• Stimulate triglyceride breakdown in adipocytes

• Stimulate liver glycogen breakdown