BVMS1 Veterinary Endocrinology: Hormones and Feedback

What is the endocrine system?

A collection of glands that produce hormones to regulate physiological functions.

List some physiological functions regulated by hormones.

Metabolism, growth and development, tissue function, sexual function, reproduction, sleep, mood.

How do hormone signals differ from neuron signals?

Hormone signals are broadly distributed throughout the body, while neuron signals are precisely targeted.

What are target cells?

Cells that possess specific receptor proteins for a hormone and respond to it.

What happens if a target cell has no or the wrong receptor?

There will be no effect on the target cell.

What are the three main classes of hormones?

Steroid hormones, peptide and protein hormones, amine hormones.

What is the half-life of steroid hormones?

Hours.

From what are steroid hormones synthesized?

Cholesterol.

How are peptide and protein hormones structured?

They are structured from chains of amino acids, varying in size from 3 to over 200 amino acids.

What is the half-life of peptide and protein hormones?

Minutes.

Describe the synthesis process of peptide hormones.

Prepropeptides are synthesized in the rough ER, cleaved to propeptides, packaged in vesicles, and released by exocytosis.

What are amine hormones derived from?

Amino acids tyrosine and tryptophan.

What is the role of transport proteins for steroid hormones?

They protect hormones from metabolism and assist in maintaining hormone concentration in circulation.

What is the primary feedback control for hormones?

Negative feedback system.

What is the function of the hypothalamus in the endocrine system?

It acts as the master gland, receiving information and regulating hormone secretion.

What are the two lobes of the pituitary gland?

Anterior (adenohypophysis) and posterior (neurohypophysis).

What is an example of hormonal regulation not involving the hypothalamus-pituitary axis?

Glucose homeostasis.

What triggers the release of melatonin from the pineal gland?

Darkness.

What is the role of parathyroid hormone?

It is involved in blood calcium homeostasis.

What is homeostasis in the context of hormone regulation?

The maintenance of a constant internal environment through feedback mechanisms.

What is the significance of hormone feedback?

Hormones released from target organs feedback to regulate their own release.

How do steroid hormones elicit their effects?

They bind to specific receptors, translocate to the nucleus, and interact with response elements to produce mRNA/protein.

What is the role of the anterior pituitary?

It secretes tropic hormones regulated by the hypothalamus.

What is the function of gastrointestinal endocrine hormones?

They regulate digestive processes and include various peptides and amine hormones.

What is the difference between endocrine and paracrine signaling?

Endocrine signaling involves hormones released into the bloodstream, while paracrine signaling involves local signaling between nearby cells.

What is the primary mode of secretion for peptide hormones?

Exocytosis.

What is the effect of increased hormone concentration in the negative feedback system?

It leads to decreased production of the hormone.