When our professor told us to make an edublog, I was like “Aww, seriously?!” Haha J Honestly, I don’t really like blogging. It wasn’t easy for me to write a blog. Why? First of all you have to read a lot of books, articles, or any reliable sources about the topic that you want to write. Sad to say, it’s not my hobby to read. I’d rather watch movies or listen to music than reading. And also, I admit that I’m not good in writing. Haha. But since it’s a part of our requirement (in Clinical Chemistry III), I tried.

At first, I don’t know how will I start or where to start. So what I did was, I visited some of my classmates’ blog and other writers’ blog. From them, I got ideas on how will I create my own blog.

Through writing this blog, I’ve learned a lot of things. Here are some of the things that I have learned:

First, I found out that edublogging is not just simply posting anything you want. Edublogging is sharing of what you have learned from school or from what you have read.

Second, I learned how to gather information from different reliable sources through internet and books. Of course, as a writer, we would like to give our readers information base on facts. And as a part of that, we have to give credits to those writers or webpages where we got those ideas. By doing so, readers can also visit those references if they would like to gather more information.

Third, I learned how to be more creative. As a blogger, we want to make our own blog as unique as we can. We decorate it by inserting some photos, graphics, or videos. It is necessary so that readers will be more interested in reading our blogs.

And, oh another thing, it will also help you to improve your writing skills and English grammar J

If it wasn’t because of our professor, maybe I wouldn’t try doing this stuff. And maybe I wouldn’t say “kaya ko naman pala”. And for that, I would like to thank her, Mrs. Virginia Gaces, for encouraging us to do this and for believing in us.

Thank you Ma’am Gaces! May God bless you always J

INTRODUCTION

Photo credit to: http://sciencegames.4you4free.com/poisons_toxicologist.gif

“All substances are poisons; there is none which is not a poison. The right dose differentiates a poison from a remedy.”

 – Paracelsus (1493-1541)

The quotation above illustrates that all chemicals could be toxic but the degree of the effect depends on the dose or degree of exposure.

            Toxicology is defined as the scientific study of toxins or poisons, which may cause adverse effects when administered by a living organism.  An adverse effect is the abnormal or harmful effect following exposure to the toxic substance. The effect can be a severe injury or death. On the other hand, these substances can also be used safely. In other words, the risk from these substances depends on the dose and exposure. (And this explains the above quotation).

AREAS OF TOXICOLOGY

The field of toxicology can be divided into following disciplines:

Mechanistic toxicology – it focuses on understanding specific chemical, biochemical and molecular mechanisms by which toxicants have their effects.

Descriptive toxicology – it focuses on the testing of chemicals and it provides information for safety evaluation and regulatory requirements.

Regulatory toxicology – deals with the risk decision-making based on data from mechanistic and descriptive toxicology. It sets standards for “safe” exposure.

Forensic toxicology – deals with the medical and legal aspects of toxicants on humans and animals.

Clinical toxicology – application of toxicological principles within a diagnostic setting, usually to determine whether a presenting adverse effect or disease or injury is due to some type of chemical exposure.

Occupational toxicology – concerned with health effects from exposure to chemicals in the workplace.

Environmental toxicology – deals with the study of the effects of chemicals in the body.

ROUTES OF EXPOSURE

Photo credit to: http://www.docstoc.com/docs/568884/General-diagram-of-routes-of-exposure-and-Module-Two-Routes-of-Exposure

Toxicity may depend on the route of exposure at which the substance is absorbed.

·            Dermal (Skin contact) – it is the common route of exposure. Skin acts as a barrier against entry of most chemicals thus reduces the toxic exposure.

·        Inhalation – it is said to be the most dangerous route of entry because it readily allows passage of chemicals to the lungs.

·    Ingestion – chemicals that are ingested may be absorbed into circulation along the gastrointestinal tract.

TYPES OF TOXIC EFFECTS ACCORDING TO EXPOSURE

ACUTE TOXICITY	CHRONIC TOXICITY
Exposure to a single large dose Associated with short-term exposure to  a substance Effects: often reversible Example: Carbon monoxide or cyanide poisoning	Exposure to multiple doses Associated with prolonged/repeated exposure to a substance Effects: often irreversible Example: lead or mercury poisoning

PHYSIOLOGICAL CLASSIFICATION OF TOXIC RESPONSES

Class	Effect
Irritant	Causes inflammation of the skin and mucous membranes (skin, eyes, nose, or respiratory system).
Corrosive	A material that can destroy human tissue. Includes both acids and bases and may be a solid liquid or gas. Most common toxic material encountered in the laboratory.
Asphyxiant	A material that deprives tissue of oxygen and causes suffocation by displacing oxygen or interfering chemically with oxygen absorption, transport or utilization.
Anesthetic	Depresses the central nervous system Example: alcohols, halogenated hydrocarbons
Hepatotoxin	Causes liver damage. Example: carbon tetrachloride
Nephrotoxin	Causes kidney damage. Example: chloroform, mercury, dimethyl sulfate
Neurotoxin	Affects the nervous system. Example: mercury, lead, carbon disulfide
Hematopoietic toxin	affects the cellular components of blood or its ability to function Example: benzene, xylene, CO, cyanides
Pulmonary toxin	Irritates or damages the lungs. Example: asbestos, silica ozone. chromium
Reproductive toxins	Causes impotence or sterility in men and women. Example: lead, dibromodichloropropane
Carcinogen	A material which can cause cancer. Example: asbestos, Bis-chloromethyl ether, benzene, acrylonitrile
Mutagen	Anything which causes a change in the genetic material of a living cell. Many mutagens are also carcinogens.
Teratogen	A material which interferes with the developing embryo when a pregnant female is exposed to that substance. Example: lead, thalidomide

Table from: http://learn.caim.yale.edu/chemsafe/references/classification.html

The importance of studying toxicology is that, understanding toxicology could reduce the possibility of human exposure to the harmful effects of toxicants. So I hope that somehow, you’ve learned something from this article and share it to others.

Thank you for reading, and watch out for my next article. :)

God Bless!!!

“Let the wise hear and increase in learning, and the one who understands obtain guidance”  - Proverbs 1:5

 References:

Duffus, John H. and Worth, Howarth G.J. Fundamental Toxicology

Hodgson, Ernest. A Textbook of Modern Toxicology 4^th Edition

Bishop, M., Fody, E., and Schoeff, L., Clinical Chemistry: Techniques, Principles, Correlations, 6th Edition

http://www.merckmanuals.com/vet/toxicology/toxicology_introduction/absorption_distribution_metabolism_and_excretion.html

http://www.agius.com/hew/resource/toxicol.htm

http://safety.science.tamu.edu/toxics.html

http://www.toxicologyguide.com/871-Environmental-Toxicology/

http://learn.caim.yale.edu/chemsafe/references/classification.html

Here's a brief introduction about Endocrinology.

When we hear the word “Endocrinology”, the first thing that comes into our mind is the endocrine system. As we all know, endocrine system consists of glands that produces and secretes hormones. These hormones are chemicals that help regulate the body’s growth, metabolism, maturation, and even sexual development. Glands that are responsible for the production and secretion of these hormones include the thyroid gland, adrenal gland, pituitary gland, hypothalamus, pancreas, pineal, thymus, and also the testicles and ovaries.

 Photo taken from: http://www.emedicinehealth.com/anatomy_of_the_endocrine_system/article_em.htm

Below is the list or summary of the hormones and their functions.

Hormones Produced by the Major Hormone-Producing Glands and Their Primary Functions
Endocrine Gland	Hormone	Primary Hormone Function
Hypothalamus	Corticotropin-releasing hormone (CRH)	Stimulates the pituitary to release adrenocorticotropic hormone (ACTH)
	Gonadotropin-releasing hormone (GnRH)	Stimulates the pituitary to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
	Thyrotropin-releasing hormone (TRH)	Stimulates the pituitary to release thyroid-stimulating hormone (TSH)
	Growth hormone-releasing hormone (GHRH)	Stimulates the release of growth hormone (GH) from the pituitary
	Somatostatin	Inhibits the release of GH from the pituitary
	Dopamine	Inhibits the release of prolactin from the pituitary
Anterior pituitary gland	ACTH	Stimulates the release of hormones from the adrenal cortex
	LH	In women, stimulates the production of sex hormones (i.e., estrogen) in the ovaries as wll as during ovulation; in men, stimulates testosterone production in the testes
	FSH	In women, stimulates follicle development; in men, stimulates sperm production
	TSH	Stimulates the release of thyroid hormone
	GH	Promotes the body’s growth and development
	Prolactin	Controls milk production (i.e., lactation)
Posterior pituitary gland1	Vasopressin	Helps control the body’s water and electrolyte levels
	Oxytocin	Promotes uterine contraction during labor and activates milk ejection in nursing women
Adrenal cortex	Cortisol	Helps control carbohydrate, protein, and lipid metabolism; protects against stress
	Aldosterone	Helps control the body’s water and electrolyte regulation
Testes	Testosterone	Stimulates development of the male reproductive organs
Ovaries	Estrogen (produced by the follicle)	Stimulates development of the female reproductive organ
	Progesterone (produced by the corpus luteum)	Prepares uterus for pregnancy and mammary glands for lactation
Thyroid gland	Thyroid hormone (i.e., thryoxine [T4] and triiodothyronine [T3])	Controls metabolic processes in all cells
	Calcitonin	Helps control calcium metabolism (i.e., lowers calcium levels in the blood)
Parathyroid gland	Parathyroid hormone (PTH)	Helps control calcium metabolism (i.e., increases calcium levels in the blood)
Pancreas	Insulin	Helps control carbohydrate metabolism (i.e., lowers blood sugar levels)
	Glucagon	Helps control carbohydrate metabolism (i.e., increases blood sugar levels)
1These hormones are produced in the hypothalamus but stored in and released from the posterior pituitary gland.

Table from http://pubs.niaaa.nih.gov/publications/arh22-3/153.pdf (Endocrine System: An Overview by Susanne Hiller-Sturmhöfel, Ph.D., and Andrzej Bartke, Ph.D.)

References:

Bishop, M., Fody, E., and Schoeff, L., Clinical Chemistry: Techniques, Principles, Correlations, 6^th Edition

http://pubs.niaaa.nih.gov/publications/arh22-3/153.pdf

http://www.news-medical.net/health/Endocrinology-What-is-Endocrinology.aspx