Download Endocrine System

Endocrine System
Objectives
 State the structures that make up the endocrine
system
 Describe the functions of the endocrine system
Introduction
 The body needs to coordinate and integrate all of ifs
functions into one harmonious whole. This is called
homeostasis. The maintenance of homeostasis
involves the growth, maturation, reproduction, and
metabolism. The body system responsible for this
coordination is the endocrine system.
Structures
 Composed of numerous glands throughout the body
that secrete hormones into the bloodstream and
excrete chemicals to rid the bod of wastes
 These chemicals are passed in the body through
blood and tissues
 Chemicals and hormones provide changes in the
body that regulate growth, regulate sexual
production and development, metabolize nutrients
in cells, and maintain a homeostasis in the body
allowing for a balance in the body system.
Endocrine Glands
 Secrete hormones directly into the bloodstream
 Then transported to all areas of the body
 Glands include:
 Pituitary
 Thyroid
 Parathyroid
 Adrenal
 Thymus
 Pancreas
 Pineal
 Gonads
Pituitary Gland
 Main gland
 Works with the hypothalamus to control the
endocrine system and create a link with the nervous
system
 Lies at the base of the brain and has an anterior and
posterior lobe
 Posterior lobe connects to the hypothalamus


Develops from brain tissue while an animal is in the embryo
stage
Serves as a reservoir for hormones and allows for the release
and regulation of hormones
Pituitary Gland Continued
 The posterior or black lobe releases two peptide
hormones: oxytocin and antidiuretic hormone
(ADH)
 Oxytocin plays vital role in parturition or labor

Hormone releases and causes muscles of the uterine wall to
contract and milk production to begin in the mammary gland
 ADH promotes urine formation, water absorption,
controls blood pressure and changes control in water
content
Pituitary Gland Continued
 The anterior lobe is controlled by the hypothalamus
 Main function is to release hormones into bloodstream
and produce and regulate growth hormones within the
body
 Major growth hormone somatotropin increases protein
synthesis within the body, thus increasing the size of the
animal
 Produces the hormone prolactin, which controls milk
production
 Pituitary Gland is often called the master gland as it
controls the thyroid gland which regulates and secretes
hormones within the body
Thyroid Gland
 Can become overactive or underactive in animals,
causing many conditions that can affect them
 Produces thyroid stimulating hormone (TSH) and tells
the thyroid when to produce thyroxine

controls the actions of the thyroid gland and cell metabolism
 Two hormones found in the bloodstream that help
identify normal or abnormal thyroid gland production
are T3 and T4


T3 hormone is more potent and a more active hormone
T4 hormone is converted into tissues and breaks down fats and helps
control cholesterol
 Located in the neck and contains two lobes
Parathyroid Glands
 Located on the surface of the thyroid gland
 Secrete parathormone
 Helps regulate blood calcium and phosphorous levels
Adrenal Glands
 Lie cranial to the kidneys
 Produce and release adrenaline and other hormones
 Adrenaline is a chemical that is released by the nervous system
in times of stress to create a response in an animals fight or
flight instinct reaction
 Also regulate function of ACTH or
adrenocorticotropic hormone

Controls blood pressure, releases cholesterol, and also controls
the body’s production of steroids
Pancreas
 Serves a dual role in endocrine and exocrine
production and functions
 Produces and regulates insulin production
 Insulin is regulated by the blood glucose level (AKA
blood sugar)
Thymus
 A gland in young animals
 Has immunologic functions through maturation of t-
lymphocytes
Pineal Gland
 Located in a central portion of the brain
 Plays a role in the regulation of body rhythms
Hormones
 Made up of four major chemical groups that regulate
parts of the body


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Fatty acids control hormones involved in estrus in the female
animal’s heat cycle
Steroids occur naturally in the body and regulate chemicals,
such as cholesterol, in the body that control essential life
functions
Amino acids are the simplest hormones and control the
thyroid gland functions
Peptides are the largest hormones and control the proteins in
the body