Anatomy and Cell Biology 3309 Lecture Notes - Lecture 35: Adrenal Medulla, Zona Fasciculata, Adrenal Gland
2 May 2018
School
Department
Professor
Histology Lecture 12 – Semester 2
Endocrine System
- Endocrine system hormones regulate and integrate activity of many physiological things that go on in
the body
o Various different organs in the body that produce a plethora of different hormones
- There are cells that produce different products
o Each cell produces a specific product – products are released into the blood stream
- Glands are divided into endocrine and eocrine glands
o Exocrine = attached by a duct to the surface onto which their product is emptied
â–Ş Exocrine substances are released to the outside surface or duct system (which
represents outside surface)
o Endocrine = ductless glands and secrete their product into the blood stream
â–Ş Endocrine cells secrete products into circulation (fenestrated capillaries)
â–Ş Secrete hormone (chemical product that is transported by the blood or body fluids
and has a specific regulatory effect on cells remote from its origin)
â–Ş Purely endocrine: adrenals, thyroid, parathyroid, pituitary and pineal
â–Ş Endocrine + other functions: testes, ovaries, and pancreas
- Products circulate throughout the body
o Sorting out happens at the target organ – there are specific cells that express specific
receptors for those hormones so they catch only the hormones they require
- Target cells at distant sites are affected by receptor-mediated signalling
find more resources at oneclass.com
find more resources at oneclass.com
- Two types of hormones
o Protein hormone
o Steroid hormone
- Protein hormone bind external membrane receptor or transmembrane receptor
o Recognition invokes a conformational change in the receptor at the intraceullar part of the
receptor. Allows docking molecuels to come on and kick off a secondary signalling response
o Require intracellular secondary messengers to evoke physiological response
- Steroid hormone are freely diffusavle through the PM
o Do not require receptors at the cell surface
o Transorted through the blood sequestered or bound to carrier proteins. Carrier proteins
deliver the hormone to the cell
o The cells have receptor for the carrier protein (sometimes) –as it binds, the hormone
diffuses through the cell membrane and goes to the nucleus
o Have DNA response element that binds the hormone – results in physilogical effects
â–Ş Transcription of genes
o Have lipid precursors (made by glycerol and lipids)
o Membrane diffusable hormone binds to nuclear receptors affecting gene transcription
find more resources at oneclass.com
find more resources at oneclass.com
Location of Endocrine Cells
- Major endocrine glands (+ 2 glands that are situated in the brain-pituitary and pineal gland)
o Thyroid gland
o Parathyroid gland
o Adrenal gland
- Have endocrine cells situated throughout the body
o Ex. In the pancreas (endocrine), there are Islets of Langerhans
o Locaed in the ovaries and testes (gonads)
â–Ş Reproductive organs are also endocrine organs
- Endocrine organs are regulated by the pituitary gland, which is the master control endocrine gland
Learning Objectives
- Distinguish between endocrine and exocrine glands giving examples
- Describe the location and organization of the adrenal gland
- Name 3 layers in the adrenal cortex and describe their arrangement
- Name the type of hormones produced in the adrenal gland
- Describe the adrenal blood supply
- Describe the location and organization of the thyroid gland
- Identify 2 cell types in the thyroid gland and name the hormones they produce
- Outline the steps in the synthesis, storage and secretion of thyroid hormone
- State the function of thyroid hormone and calcitonin
- Describe the histology of the parathyroid glands
- Identify the cell type secreting parathyroid hormone
- State the function of PTH.
Adrenal Gland
- Adjacent or beside the kidney
o Sits at the superior aspect of the kidney (on top)
o Triangular bodies at the cranial pole of each kidney
- Produces five different hormones (KNOW THESE)
o Named according to the structure of hormone, and where they are produced
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Endocrine system hormones regulate and integrate activity of many physiological things that go on in the body: various different organs in the body that produce a plethora of different hormones. There are cells that produce different products: each cell produces a specific product products are released into the blood stream, exocrine = attached by a duct to the surface onto which their product is emptied. Secrete hormone (chemical product that is transported by the blood or body fluids and has a specific regulatory effect on cells remote from its origin) Target cells at distant sites are affected by receptor-mediated signalling. Two types of hormones: protein hormone, steroid hormone. Protein hormone bind external membrane receptor or transmembrane receptor: recognition invokes a conformational change in the receptor at the intraceullar part of the receptor. Allows docking molecuels to come on and kick off a secondary signalling response: require intracellular secondary messengers to evoke physiological response.
