Endocrine System : Priscilla DiNapoli
Eddie McLaughlin Endocrine System Endocrine System : Endocrine System Controls many body functions
Releases special chemical substances called hormones into the bloodstream
Hormones affect other glands in the endocrine system and other body systems Exocrine system
Transports hormones via ducts to target tissues
Consists of several glands located in various parts of the body
Secrete chemicals such as sweat, mucus, and digestive enzymes, into ducts that send the products to the appropriate location Pituitary Gland : Pituitary Gland Pituitary gland: a small gland located on a stalk hanging from the base of the brain
Known as the “master gland”
Primary function is to control other glands
Produces many hormones.
Secretion is controlled by the hypothalamus in the base of the brain. Pituitary Gland : Pituitary Gland The pituitary gland is divided into 2 areas, which differ structurally and functionally
each area has separate types of hormone production.
oxytocinthe (natural form of pitocin)
stimulates uterus (contractions)
causes “let down” of milk from the breast.
antidiuretic hormone (ADH) (vasopressin) causes the kidney to retain water. Anterior Pituitary:
thyroid-stimulating hormone (TSH) – stimulates the thyroid gland; raises metabolic rate
growth hormone (GH) – less glucose usage, more fats used as energy
adrenocorticotropin (ACTH) – stimulates the adrenal cortex to release its hormones
follicle-stimulating hormone (FSH); Luteinizing hormone (LH) – stimulate maturation & release of eggs from ovary. Pineal Gland : Pineal Gland Small mass of tissue near the center of the mammalian brain
Secretes the hormone melatonin
Modified amino acid
Affects skin pigmentation
Secreted at night; amount depends on length of night
contains light-sensitive cells or nervous connections from the eyes
Melatonin regulates functions related to light and seasons marked by changes in day length Thyroid Gland : Thyroid Gland The Thyroid Gland
lies in the anterior neck just below the larynx.
Two lobes, located on either side of the trachea, connected by a narrow band of tissue called the isthmus.
Sacs inside the gland contain colloid Within the colloid are the thyroid hormones:
When stimulated (by TSH or cold temp) - released into the circulatory system and raise the metabolic rate.
“C” cells within the thyroid produce the hormone calcitonin.
Calcitonin lowers the calcium levels in the blood as part of calcium homeostasis. Parathyroid Glands : Parathyroid Glands small, pea-shaped glands, located in the neck near the thyroid
usually 4 - number can vary
regulate the level of calcium in the body
Secrete parathyroid hormone (PTH) – raises blood levels of Calcium; opposite to calcitonin
Lack of calcium/PTH – convulsive contractions in skeletal muscle In the kidneys
Stimulates reabsorption of calcium
Activates conversion of vitamine D to its avtive form Pancreas : Pancreas Pancreas
has both endocrine and exocrine functions
1-2% endocrine cells
Rest = exocrine cells
Produces enzymes that are carried to the small intestine via the pancreatic duct Islets of Langerhans
specialized tissues in which the endocrine functions of the pancreas occurs
Each has a population of:
alpha (? )
each secretes an important hormone
Alpha – glucagon
Beta - insulin Pancreas : Pancreas Alpha (?) cells release glucagon, essential for controlling blood glucose levels
When blood glucose levels fall, ? cells raises the amount of glucagon in the blood
stimulates the liver to release glucose stores
stimulates the liver to manufacture glucose Beta Cells (?) release insulin
Insulin raises the rate at which various body cells take up glucose
lowers the blood glucose levels
Insulin is rapidly broken down by the liver and must be secreted constantly. Adrenal Glands : Adrenal Glands Adrenal glands
2 small glands found above the kidneys
Adrenal Medulla –secretes the hormones norepinephrine and epinephrine (catecholamines – class of compounds synthesized from tyrosine
The Adrenal Cortex secretes 3 classes of hormones, all steroid hormones:
androgenic hormones gluticocorticoids:
accounts for 95% of adrenal cortex hormone production
Raises the level of glucose in the blood; ex: cortisol
Released in response to stress, injury, or serious infection
work to regulate the concentration of potassium and sodium in the body. Gonads : Gonads Gonads and Ovaries:
the endocrine glands associated with human reproduction.
Female ovaries produce eggs
Male gonads produce sperm
located in the abdominal cavity adjacent to the uterus.
Under the control of LH and FSH from the anterior pituitary they manufacture estrogen and progesterone
preparation of the uterus for implantation of the egg Testes:
located in the scrotum
produce sperm for reproduction
manufacture testosterone -
promotes male growth and masculinization
Controlled by anterior pituitary hormones FSH and LH. Slide 12: Endocrine System Slide 13: Stress and the Adrenal Glands Hormonal regulation in Insects : Hormonal regulation in Insects 1. neuro secretory cells in the brain produce hormone (BH) which is stored in the corpus cardiacum until release
2. BH signals its main target organ, the prothoracic gland, to produce the hormone ecdysone
3. ecdysone secretion from the prothoracic gland is episodic, with each release stimulating a molt.
Juvenile hormone (JH) determines the result of the molt. JH suppresses the molt. Endocrine and nervous system reactions Disorders : Disorders Diabetes Mellitus
one of the most common diseases in North America.
Decrease in insulin secretion by the Beta (?) cells of the islets of Langerhans in the pancreas.
Hyperthyroidism – thyroid is overactive and grows twice the normal size
Adrenal gland disease – not enough steroid hormones produced
Signs of conditions that often occur together with Addison's: goiter and vitiligo Cushing’s disease
Increased production of cortisol
This can be caused by taking glucocorticoid drugs, or by tumors that produce cortisol or adrenocorticotropic hormone(ACTH).
Use of anabolic steroids
Performance-enhancing drugs usually leads to cancer
Increase in testosterone