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Chemical Coordination Cheat Sheet (DRAFT) by

Chemical Coordination

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Terms

Certain chemicals are involved in commun­ica­tio­ns,­which are neurot­ran­smi­tte­rs,­Phe­romones & hormones
Neurot­ran­smi­tters: Chemical messanger between neurons
Pherom­ones: Chemicals secreted by an organism in minute amounts to stimulate particular reaction from another organism of the same species.
Hormon­e(G­r.H­orm­on:­Exc­ite): chemical messenger that is secreted by specia­lized tissues called glands­,that is transp­orted in the blood stream.
3 primary chemical categories of hormones are:
1.Peptide and Protein hormones (short chain amino acid hormones and long chain amino acid hormones
Peptide hormones example ADH and Protein hormones example Growth hormone & Insulin
2.Amino acid derivate hormones 3.Steroid hormones
Hormones may be catego­rized as hydrop­hilic (polar) or protein nature hormones & lipophilic (non-p­olar) steroid and thyroid hormones.

Hypoth­alamus

Part of brain that contains clusters of specia­lized cells called neuros­ecr­etory cells
A set of neuros­ecr­etory cells in the hypoth­alamus exerts control over the anterior pituitary lobe by secreting 2 kinds of hormones into the blood releasing hormones make the anterior pituitary lobe to secrete its hormones
Inhibiting hormones from the hypoth­alamus make the anterior pituitary lobe stop secreting hormone.
Another set of neuros­ecr­etory cells produce 2 hormones ADH & Oxytocin which are stored and secreted from posterior pituitary glands
Releasing and inhibiting hormones of hypoth­alamus, TRH,CR­H,G­nRH­,GH­RH,­GHI­H,P­IH,MIH.

Pituitary Gland

Also known as hypoph­ysis,is a pea sized gland.
Consists of 2 distinct lobes or parts
1.Aden­ohy­pop­hysis: appears glandular & also called anterior pituitary lobe
2.Neur­ohy­pop­hysis: appears fibrous & also called posterior pituitary lobe
Anterior pituitary: indepe­ndent endocrine gland.P­ro­duces at least 7 essential hormon­es.S­everal hormones of anterior pituitary are collec­tively termed as tropic hormones or tropin
1.ACTH: Stimulates the adrenal cortex to produce cortic­ost­eroids
2.Mela­nocyte stimul­ating hormone (MSH): Stimulate the synthesis and dispersion of melanin pigment in the skin.
3.Growth hormone (GH) OR Somato­tropic hormone (STH): The growth of muscles, bone and other tissues.
4.Prol­actin: Stimulate the mammary glands to produce milk.
5.Thyroid Stimul­ating hormone (TSH): Stimulates thyroid gland to produce thyroxin.
6.Lute­inizing hormone (LH): Stimulate gonads (teste­s/o­varies) for production of steroid hormone estrogen and proges­terone from ovaries and testos­terone from testes.
7.Follicle stimul­ating hormone (FSH): Stimulate develo­pment of ovarian follicles in females. In males it is required for the develo­pment of sperm. FSH and LH are called gonado­tropins (GnTH) because they stimulate the activities of the male and female gonads.
Posterior pituitary gland: the hormones released from here are actually stored secretion of hypoth­ala­mus,ADH & Oxytocin
ADH literally means hormone that prevents urination helps prevent dehydr­ation.
Oxytocin has 2 physio­logical effects;it stimulates uterine contra­ctions during labour & stimulates breast tissue contra­ctions to promote lactation after childb­irth.

Thyroid galnd

Located at the base of neck in front of tracheae.
Comprised of 2 lobes & isthmus that binds them together.
Produce 3 major hormones: T3,T4 or thyroxin & Calcit­onin.
Thyroxin contains 4 atoms of iodine, secreted in greater amount but is less potent than T3.
Thyroxin release is stimulated by TSH from anterior pituit­ary­,which in turn is stimulated by releasing hormone from hypoth­alamus TRH.
Excessive secretion of thyroid hormone known as hypoth­yro­idism
Children born with hypoth­yro­idism are stunted in their growth and suffer severe intell­ectual disabi­lity,a condition called cretinism
Shortage of thyroid hormones is an enlarg­ement of thyroid called goiter.

Parath­yroid gland

4 small glands attached to the back of thyroid gland.
Hormone produced by parath­yroid is a peptide hormone called parath­ormone or parath­yroid hormone

Pancreas

Located adjacent to the stomach
Performs both endocrine and exocrine functions
Endocrine cells make up only 2% of the weight of the pancre­as,rest of the organ is exocrine tissues
In 1869,a German medical student student named Paul Langerhans described some unusual clusters of cells scattered throughout the pancre­as,­these clusters came to be called Islets of Langer­hans.
Clusters of endocrine cells that secrete 2 hormones directly into the circul­atory system.
Each islet has a population of alpha cells,­which secrete the peptide hormone glucogon.
Population of beta cells which secrete the peptide hormone insulin.
Insulin & Glucogon are antago­nistic hormones that regulate the concen­tration of glucose in the blood.
Defect in insulin produc­tio­n,r­elease or reception by target cells result in diabetes mellitus
Diabetes mellitus: condition in which blood glucose levels are high and fluctuate wildly with sugar intake.
Diabetes type -1: autoimmune disorder i-e the immune system attacks and destroys its own beta cells.
Diabetes type 2: Associated with genetic histor­y,o­bes­ity­,st­res­s,lack of exercise and old age

Adrenal gland

Located just above each kidney
Each adrenal gland is composed to an inner portio­n,the adrenal medulla & an outer portion the adrenal cortex
Adrenal medulla: produce 2 hormones epinep­hrine (adren­aline) & nor epinep­hrine (nor adrena­line) in response to stress.
Adrenal cortex : all hormones from it are steroids and referred collec­tively as cortic­ost­eroids.
Many cortic­ost­eroids have been isolated from the adrenal cortex,the 3 main types are glucoc­ort­icoids such as cortis­ol,and the minera­loc­ort­icoids such as aldost­erone & Androgen
Over secretion of cortisol cause Cushing's syndrome (Hyper­cor­tis­olism)
Low secretions of adrenal cortex hormone cause Addison's disease
Aldost­erone: helps to regulate mineral balance.
Androgen: sex hormon­e,s­imilar to testos­terone present in both male & female bodies.

Gonads

Produce and secrete 3 major categories of steroid hormones,a testos­ter­one­,es­trogen & proges­terone.
All 3 types are found in both males and females but in different propor­tions
Testes: male gonads produce both sperm & male sex hormon­e.FSH stimulates Sertoli cells of testes to facilitate sperm develo­pment and LH stimulates Leydig cells of testes to release testos­terone
Ovaries: female gonads,lie in the abdominal cavity produce both egg & female sex hormon­es.O­varies secrete 2 lipophilic hormones estrogen & proges­terone.

Feedback Mechanism

Chemical coordi­nation or most of bodily functions are regulated by a series of complex feedback mechanism
Postive feedback mechanism: rare in endocrine system­,when release of a hormone initiates action that leads to an additional release of that hormon­e.E­xample Oxytocin
Negative feedback mechanism: one way that endocrine system tries to keep homeos­tasis (stabi­lity) in the body.E­xample control of blood sugar(­glu­cose) by insulin