ENDOCRINE SYSTEM

DefinitionEndocrine System refers to the collection of glands of an organism that secrete hormones directly into the circulatory system to be carried toward a distant target organ.

includes all of the glands of the body and the hormones produced by those glands.

Major endocrine glands pineal gland

pituitary gland

pancreas

ovaries

testes

thyroid gland

parathyroid gland

hypothalamus

gastrointestinal tract

adrenal glands

There are up to 20 major hormones secreted by the gland in the endocrine system which are essential to different tasks throughout the body.

Here are a few of the areas governed by the endocrine system

Reproduction Responses to stress and injuries Growth and sexual development Body energy levels Internal balance of body systems Bone and muscle strength

Functions of the Endocrine System

Controls the processes involved in movement and physiological equilibrium

Includes all tissues or glands that secrete hormones into the blood

Secrete hormones directly into the bloodstream.

Integrate body systems

TERMS

ENDOCRINE GLAND a gland that secretes hormones directly into the bloodstream; a ductless gland.

HORMONES is a very powerful substance secreted by an endocrine gland into the bloodstream, that affects the function of another cell or "target cell".

HOMEOSTASIS is the maintenance of the constant internal environment which include the function of kidney, liver, skin, etc.

Major Endocrine Glands

Pituitary Gland(Hypophysis)

Is located at the base of the brain or just below the hypothalamus

It is also known as the “master gland” It is a master in controlling other glands

of the body ( thyroid, adrenal glands, and gonads

It is consists of anterior pituitary and posterior pituitary glands.

Anterior Pituitary Glands( Adenohypophysis)

Hormone stimulates the thyroid gland, adrenal glands and gonads

It secretes other hormones like melanocyte stimulating hormone responsible for skin color

Prolactin stimulating milk production for lactating mothers

Somatotropin (growth hormone) Giantism and dwarfism LH,MSH, FLH

Anterior Pituitary Glands

It has three region :

1. Pars distalis – It is the largest and vascular lobe, it is the major secretory of the gland

2. Pars tuberalis – it joins the pituitary stalk arising from the posterior gland

3. Pars intermedia – it is located between the pars distalis and posterior gland, it serves as the boundary between anterior and posterior gland ( it is very small and indistinct to humans)

Posterior Pituitary Glands(Neurohypophysis)

It releases vasopressin hormones to control the amount of water

Oxytocin secreted during childbirth in stimulating muscular contraction of the uterus and ejection of milk from lactating mammary gland

2 Regions of the Posterior Pituitary Gland

Pars Nervosa- It is also called as “posterior lobe”- Is the storage site of Oxytocin and

Vasopressin

Infundibular stalk

- the connection between the hypothalamus and the posterior pituitary.

Thyroid Glands It is located in the neck at the back of the

Adam’s apple

It secretes three hormones :

- T3 (triiodothyronine)

- T4 (thyroxin)- Calcitonin – lowers down the blood

calcium level of the body

Both T3 and T4 contain the iodine element which regulate the metabolism and play a crucial role in development ad maturation.

Hyperthyroidism- excess of T3 and T4

Hypothyroidism- insufficient of T3 and T4

HYPOTHYROIDISM

-is an underactivity of the thyroid gland causing laziness, dullness, and goiter.

HYPERTHYROIDISM

- having an active behavior resulting to loss of weight and insomnia.

Parathyroid Gland

It is located at the back of the thyroid gland

The parathormone regulates the utilization of calcium and phosphorus in the blood level of the body

Too much secretion of the parathormone presents poor physical coordination

Less secretion can lead to “tetany” is the intermittent, involuntary twitching and spasms of the muscle

Adrenal Glands It is located at the top or above the kidney

Adrenalin, the hormone it produces

It has two parts the inner part which is the “medulla” and the outer part which is the “cortex”

Medulla is the source of epinephrine(adrenalin) and Non-epinephrine. Epinephrine raises blood sugar levels, cause nervousness and perspirations on acute emergencies.

Cortex releases cortisone which is essential for adapting to stress and maintaining blood

sugar level and aldosterone that regulates the salt and water balance of the body.

Gonads It stimulates the secondary sex

characteristics for boys and girls during puberty stage

The appearance of pubic hair, hair at the armpit etc.

The male gonads secrete the hormone “androgen” that contain testosterone which influences the growth of prostate, seminal vesicles, the production of sperm

The female gonads secrete the hormones “estrogen” which is necessary for the development of the reproductive organ and “ progesterone” which is essential for maintaining pregnancy located at the paired ovaries

Pancreas It is located near the stomach at the

right side of the abdomen at the level of the umbilicus

The hormones and insulin are found at the “Islets of Langerhans” of the pancreas.

Insulin plays an important role in keeping the levels of sugar(glucose) in the bloodstream under control.

Glucagon increases the level of sugar in the body if the insulin is absent or lacking.

Pineal Gland It is situated at the mid-

cerebrum

It releases melatonin that regulates body rhythms and sleeping patterns.

THE

END!!!

Prepared By:Prepared by:

Patricia FranciscoMonique Burgos