Hormones

Secretion is regulated by:

Signals from the nervous system (neural stimulus) Chemical changes in the blood (humoral stimulus) Other hormones

Pancreas function

The pancreas is both an endocrine and exocrine gland.

Secretion of insulin and glucagon are controlled

by negative feedback.

The posterior pituitary gland role

does not synthesise any hormones, but stores and releases two hormones produced by the neurosecretory cells of the hypothalamus: oxytocin (OT) and anti-diuretic hormone (ADH).

Hormones are secreted

in short bursts when needed.

Connected by

infundibulum.

These hormones regulates

the secretory activities of the anterior pituitary gland

The anterior pituitary secretes

7 hormones.

There are also

Certain organs and tissues that are not part of the endocrine system also secrete hormones

What is the endocrine glands consist of

Endocrine glands consists of secretory cells surrounded by extensive network of capillaries that facilitates the diffusion of hormones from the secretory cells into the bloodstream.

Role of hormones and example of functions

Hormones produces widespread changes and control and integrate various processes like: Reproduction, Growth and Development, Regulation of cellular metabolism and energy balance and many more..

Hormones only affect

Hormones travelling throughout the body will only affect target cells that possess specific protein receptors.

Location of the pancreas

It is located in the curve of the duodenum.

How they act

Most hormones circulate through the blood and bind to receptors on "target cells." Neurotransmitters also bind to receptors on "target" cells.

Receptor are

Receptors are continually being synthesized and broken down.

Receptors can be

Receptors may be down-regulated in the presence of high concentrations of hormone. Receptors may be up-regulated in the presence of low concentrations of hormone.

What does each system release

Releases neurotransmitters; the endocrine system releases hormones.

Endocrine pancreas

Scattered among the acini are clusters of endocrine tissue called pancreatic islets (islets of Langerhans).

What is the endocrine system consist of

The endocrine system consists of glands widely separated from each other with no physical connections.

What happen after that

The hormones diffuse into the blood stream through capillaries and are carried to target cells throughout the body.

How each type of hormone circulates

Water-soluble hormones circulate freely in the plasma. Lipid-soluble hormones circulate bound to transport proteins

Nervous and endocrine systems

Work together to coordinate all systems of the body.

Regulation of Hormone Secretion

achieved via negative feedback or a few by positive feedback

Water-soluble hormones mechanism

bind to receptors on the exterior surface of the target cell.

How a target cell responds to a hormone is based on:

concentration The number of hormone receptors on the target cell Influences exerted by other hormones Some hormones work more effectively when a second hormone is present to assist them (synergistic effect). Some hormones oppose the action of others (antagonistic effect). (CSIAN)

The anterior pituitary gland secretes:

human growth hormone (hGH), thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), adrenocorticotropic hormone (ACTH) melanocyte-stimulating hormone (MSH)

E.g.

hypothalamus, thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small intestine, heart, adipose tissue and placenta.

Two types of hormones

lipid-soluble (steroid hormones, thyroid hormones) or water-soluble (amine hormones, peptide and protein hormones).

Endocrine glands include

pituitary, thyroid, parathyroid, adrenal and pineal glands.

The hypothalamus secretes

releasing hormones and inhibiting hormones

Endocrine glands function

secrete hormones. They do not have ducts and secrete their hormones directly into the interstitial fluid that surrounds them.

Two regions of the pituitary gland

the anterior pituitary and the posterior pituitary.

They reach

the anterior pituitary gland via the hypophyseal portal system

The neurosecretory cells in the hypothalamus secretes

two hormones.

The hypothalamus and pituitary gland role

work together to control other endocrine glands

How do steroid hormones act?

Bind to receptors within target cells and affect gene expression by binding to cytoplasm receptors. Complex then moves to the nucleus and then binds to regulatory section of the target gene which activates transcription

Hormone activity diagram

(slide 10)

Hypothalamus and Pituitary Gland diagram

(slide 21)

An example :Thyroid Gland diagram

(slide 22)

Hormones table

(slide 24)

Pancreatic Islets

(slide 29)

Pancreatic Islets tables

(slide 30 + 31)

Endocrine Disorders photos

(slide 33)

Comparison of Control by the Nervous and Endocrine Systems

(slide 5)

Gland location diagram

(slide 8)

Exocrine pancreas

Almost all of the exocrine cells of the pancreas are arranged in clusters called acini. These produce digestive enzymes that are delivered to the gastrointestinal tract through ducts.

The islets include 4 types of cells that secrete different hormones:

Alpha (A) cells - glucagon Beta (B) cells - insulin Delta (D) cells - somatostatin F cells - pancreatic polypeptide