T he Endocrine System

The Endocrine System

Epically Made By: Morgan DiStasio and Falcon Jakiela

“What is it?” Simply put the Endocrine System can be easily

linked to the Nervous System based upon the similarities (i.e. sending signals through the body).

The effects it has on a horse consists of changes in metabolism, stress, growth, and sexual development.

The Glands There are 9 glands within the Endocrine

System:◦ Hypothalamus◦ Pituitary◦ Thyroid◦ Parathyroid◦ Thymus◦ Pancreas◦ Adrenal◦ Ovaries◦ Testes

The Hypothalamus Gland Location?

◦ At the brain. What does it do/What is it?

◦ Controls autonomic functions.◦ Controls emotions.◦ Controls homeostasis.◦ Regulates sleep and wake cycles as well as the water

and food intake systems.◦ Controls motor functions (i.e. movement)

This gland controls the entire Endocrine System, therefore it can be properly called the “President” of the Endocrine.

The Pituitary Gland Location?

◦ At the base of the horse’s brain. This Gland contains 3 Sections; Anterior, Intermediate and Posterior. What does it do?/What is it?

◦ The anterior section controls the most: Stimulates thyroid w/ THS (thyroid stimulus hormone). Releases growth hormone for cell reproduction/regeneration

and general body growth (GH). Stimulates milk for nursing mothers using Prolactin (PRL) and

produces Luteinizing hormone (LH) to help release eggs during birth.

It releases Follicle stimulus hormone to effect growth, development, maturing and the reproduction process.

Using Adrenocorticotropic, it activates the adrenal cortex. Within males this gland stimulates Leydig cell production to

cause testosterone.

The Pituitary Gland (Cont.) Next is the intermediate section which controls only one function:

◦ This section produces Melanocyte stimulus hormones (MSH). MHS works on the skin cells containing black pigment.

The last is the Posterior section:◦ This section releases the Oxytocin hormone.

This hormone is required to assist during labor and birth.◦ It stimulates the Antidiuretic hormone (ADH) release to regulate

water balance and causes and increase in absorption of water into the blood by the kidneys.

The entire Pituitary Gland is known as the ‘Master Gland’ and for a good reason, seeing as it controls the rest of the Endocrine System as does the Hypothalamus Gland. But this gland is more like the CEO rather than a president, it simply directs and sends out messages.

The Thyroid Gland Location?

◦ Around the larynx, consisting of two lobes on either side of the windpipe.

What does it do?/What is it?◦ This gland is a regulator more than anything:

It regulates metabolism using a hormone Triiodothyronine (T3).

It regulates the manner by which tissues utilize food for the production of energy and to expand that throughout the body.

Thyroid Gland (Cont.) Also, it uses a chemical called Thyroxine (T4) which

regulates oxygen levels/oxygen consumption of tissue in the body.

Using Calcitonin, this gland regulates the phosphate metabolism within the horses bones and also assists in regulating the blood calcium levels.

Regulates hormonal levels.◦ Problems producing any of those hormones can effect bodily

functions (i.e. chronic fatigue, muscle weakening, ect).

The Parathyroid Gland Location?

◦ Near the thyroid. What does it do?/What is it?

The Thymus Gland This gland virtually disappears once a horse grows into an

adult. Location?

◦ Between the trachea and the heart of a horse. What does it do?/What is it?

The Adrenal Gland This gland is also known as “The shock organ”. This gland also has multiple parts; The adrenal cortex and the adrenal

medulla. Location?

◦ Near the kidneys. What does it do?/What is it?

◦ A.c.: Is the outer layer derived from genital-tract cells and is divided

into three zone that produce steroid hormones. ◦ A.M.:

Is the interior derived from neurological cells which produces catecholamines, organic compounds that act as hormones in the blood stream as well as a transmitter for the nervous system.

Adrenal Gland (Cont.)◦ This gland helps regulate body salt levels, blood pressure, and blood

volume.◦ Its glucocorticoids helps to regulate energy, protein, fat and mineral

use as well as help to reduce inflammation.◦ Its gonadocorticoids influences gender-specific behavior in mares and

stallions; within stallions it also participates in sperm production.◦ Catecholamines influence the “fight or flight” response to a threat.

The Ovaries and Testes Glands Location(s)?

◦ Self-explanatory. What do they do?/What are they?

◦ The Ovaries gland is a female reproductive organ, whereas, the Testes gland is a male reproductive organ.

The ProcessStimulus (change in temperature, ect.)

Detection of stimulus

Release of hormone which travels through bloodstream

Arrival of hormone at target cell

Response to stimulus occurs

Disease Found in The Endocrine Equine Cushing’s Syndrome: This

occurs when signals from other glands begin to stop and fail which cause the Pituitary Gland to stimulate overproduction of the steroid hormone cortisol by the adrenal glands. This leads to a domino-effect of over-activity of other endocrine metabolic disturbances which has outcomes of obesity, behavioral changes, weakening in muscles, and also an abnormally long or curly coat which fails to shed.◦ This disease can also be called:

Pituitary Pars Intermedia Dysfunction.

Sites Used http://www.oxymega.com/thyroid_gland.html http://www.equisearch.com/horses_care/health/anatomy/endocrines

ystem_062907/ http://www.agriscience.msu.edu/3000/3180/3184/3184E/3184E.htm http://www.buzzle.com/articles/pituitary-gland-function.html