Presented by:- Devendra Kumar

(M.Sc. Biotechnology)Suggested by: Dr. Ambika Sharma

Assistant professorDepartment of Veterinary

Biochemistry

•Endocrine glands are ductless, that is they do not have ducts to take their secretions to specific sites. Instead, hormones are secreted directly into capillaries and circulate in the blood throughout the body. •The secretory products of endocrine glands are called hormones.

•Amines-  This  group  includes  thyroxine  from  the  thyroid gland  and  epinephrine  and  norepinephrine  from  the  adrenal medulla.•Proteins-.   Insulin from the pancreas, growth hormone from the  anterior  pituitary  gland,  and  calcitonin  from  the  thyroid gland are all proteins.  Short chains of amino acids are called peptides.   Antidiuretic hormone and oxytocin, synthesized by the hypothalamus, are peptide hormones.•Steroids-  include  cortisol  and  aldosterone  from  the  adrenal cortex,  estrogen  and  progesterone  from  the  ovaries,  and testosterone from the testes.

Endocrine system; Consists of glands, specialized cells clusters and

hormones-chemical transmitter secreted by glands in response to stimulation & CNS.

Regulates and integrates the body’s metabolic activities; maintains homeostasis.

●Hormones & hormone function: chemical substances/messengers synthesized and secreted by a specific organs or tissue- exert action on specific cells called target cells

Hypothalamus: integrative center for endocrine and autonomic nervous systemNegative feedback system

Regulates endocrine system by inhibiting hormone overproduction

Hormone to hormone regulationHypothalamus and pituitary gland

• Endocrine disorders due to

–Hypersecretion or hyposecretion of hormones

–Hyporesponsiveness of hormone receptors

–Inflammation of glands –Gland tumors

Major Glands of the Endocrine systemPituitaryThyroidParathyroidAdrenalPancreasOvariesTestes

Exocrine glands - transport their hormones to target tissues via ducts.

Endocrine ductless

Consists of several glands located in various parts of the body.

Pituitary gland: a small gland located on a stalk hanging from the base of the brain

“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.

-ACTH -thyroid stimulating hormone-Somatotropin- growth hormone -FSH & LH -Prolactin -ICSH- causes testes to secrete testosterone -Melanocyte stimulating hormone -ADH-Oxytocin

The Pituitary Gland is divided into 2 areas, which differstructurally and

functionally each area has

separate types of hormone production.

The two segments are: Posterior Pituitary:

produces oxytocin and antidiuretic hormone (ADH)

Anterior Pituitary:produces thyroid-

stimulating hormone (TSH)

growth hormone (GH)adrenocorticotropin

(ACTH)follicle-stimulating

hormone (FSH)

And even more…luteinizing hormone

(LH)prolactin

Let’s go over these one at a time...

Posterior PituitaryOxytocin (the natural

form of pitocin)stimulates gravid

uteruscauses “let down” of

milk from the udder.ADH (vasopressin)

causes the kidney to retain water.

- TSH stimulates the thyroid gland to release its hormones, thus ↑ metabolic rate

Growth hormone (GH) stimulates growth of tissues and bones

ACTH stimulates the adrenal cortex to release its hormones

FSH & LH stimulates maturation & release of eggs from ovary.

Giantism- oversecretion of somatotropin before puberty

Dwarfism- undersecretion of somatotropin. Cause: tumor, injury, infection, genetics

Diabetes insipidus- decreased ADH

Adrenocorticotropic hormone (ACTH) deficiency leads to adrenal insufficiency, a lack of production of glucocorticoids such as cortisol by the adrenal gland. If the problem is chronic, symptoms consist of fatigue, weight loss, failure to thrive, delayed puberty (in adolescents), hypoglycemia (low blood sugar levels), anemia and hyponatremia (low sodium levels). If the onset is abrupt, collapse, shock and vomiting may occur.ACTH deficiency is highly similar to primary Addison's disease, which is cortisol deficiency as the result of direct damage to the adrenal glands.

Thyroid-stimulating hormone (TSH) deficiency leads to hypothyroidism (lack of production of thyroxine (T4) and triiodothyronine (T3) in the thyroid). Typical symptoms are tiredness, intolerance to cold, constipation, weight gain, hair loss and slowed thinking, as well as a slowed heart rate and low blood pressure. In neonates, hypothyroidism leads to delayed growth and in extreme forms to a syndrome called cretinism

Growth hormone (GH) deficiency leads to a decrease in muscle mass, central obesity (increase in body fat around the waist) and impaired attention and memory. neonates experience growth retardation and short stature

Deficiency of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leads to different symptoms in animals like irregular estrus and infertility.

Antidiuretic hormone (ADH) deficiency leads to the syndrome of diabetes insipidus: inability to concentrate the urine, leading to polyuria polydipsia, as well as hypernatremia (high sodium levels in the blood).Oxytocin deficiency generally causes incomplete let-down of milk.

lies in the anterior neck just below the larynyx.

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: thyroxine (T4) triiodothyronine (T3)

When stimulated (by TSH or by cold), these are released into the circulatory system and ↑ the metabolic rate.

“C” cells within the thyroid produce the hormone calcitonin.

Thyroid gland must have any source of iodine

goiter- not enough iodine

hyperthyroidism hypothyroidism

Increased thyroid hormone release causes hyperthyroidism, commonly called Graves’ disease. Signs and symptoms:

insomnia, fatiguetachycardiahypertensionheat intoleranceweight loss

Long term hyperthyroidism:Exopthalmos

bulging of the eyeballs (picture Barbara Bush)

In severe cases - a medical emergency called thyrotoxicosis can result.

Hypothyroidism is the underproduction of the thyroid hormones T3 and T4.

Typical symptoms are abnormal weight gain, tiredness, baldness, cold intolerance, and bradycardia.

Hypothyroidism is treated with hormone replacement therapy, such as levothyroxine

Hyperthyroidism, or overactive thyroid, is the overproduction of the thyroid hormones T3 and T4, and is most commonly caused by the development of Graves' disease.

It presents with symptoms such as a thyroid goiter, protruding eyes (exopthalmos), palpitations, excess sweating, diarrhea, weight loss, muscle weakness and unusual sensitivity to heat. The appetite is often increased.

small, pea-shaped glands, located in the neck near the thyroid

usually 4 - number can vary

regulate the level of calcium in the body

produce parathyroid hormone - ↑ level of calcium in blood

Hypocalcemia can result if parathyroids are removed or destroyed.

Hypoparathyroidism is decreased function of the parathyroid glands with under production of parathyroid hormone. This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany (involunary muscle contraction), and several other symptoms.

The signs and symptoms of primary hyperparathyroidism are those of hypercalcemia.

The symptoms include kidney stone, bone loss, abdominal disorders like constipation etc

Secondary hyperparathyroidism refers to the excessive secretion of parathyroid hormone (PTH) by the parathyroid glands in response to hypocalcemia (low blood calcium levels) and associated hypertrophy of the glands.

This disorder is especially seen in patients with chronic renal failure.

pancreatic juices into the intestine

secretes insulin, a hormone that transports glucose into cells.

Also secretes glucagon- increases glucose in bloodstream

Pancreas

Pancreasa key gland located in the

folds of the duodenumhas both endocrine and

exocrine functions secretes several key

digestive enzymes

Islets of Langerhans specialized tissues in

which the endocrine functions of the pancreas occurs

include 3 types of cells:alpha (α )beta (β)delta (∂)

each secretes an important hormone.

Alpha (α) cells release glucagon, essential for controlling blood glucose levels.

When blood glucose levels fall, α cells ↑ the amount of glucagon in the blood .

The surge of glucagon stimulates the liver to release glucose stores (from glycogen and additional storage sites).

Also, glucagon stimulates the liver to manufacture glucose -

Beta Cells (β) release insulin (antagonistic to glucagon).

Insulin ↑ the rate at which various body cells take up glucose. Thus, insulin lowers the blood glucose level.

Insulin is rapidly broken down by the liver and must be secreted constantly.

Delta Cells (∂) produce somatostatin, which inhibits both glucagon and insulin.

Type 1 diabetes: results from the body's failure to produce insulin, and presently requires the person to inject insulin. (Also referred to as insulin-dependent diabetes mellitus, IDDM for short, and juvenile diabetes.)

Type 2 diabetes: results from insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with an absolute insulin deficiency. (Formerly referred to as non-insulin-dependent diabetes mellitus, NIDDM for short, and adult-onset diabetes.)

Located just above the kidney

Secretes many hormones

Epinephrine NorepinephrineMany steroid

hormones, including estrogen and androgens.

Adrenal glands

Adrenal Glands2 small glands that sit

atop both kidneys.

Each has 2 divisions, each with different functions.

the Adrenal Medulla secretes the catecholamine hormones norepinephrine and epinephrine (closely related to the sympathetic component of the autonomic nervous system).

The Adrenal Cortex secretes 3 classes of hormones, all steroid hormones:gluticocorticoids

mineralocorticoidsandrogenic hormones

One at a time…gluticocorticoids:accounts for 95% of

adrenal cortex hormone production

↑ the level of glucose in the blood

Released in response to stress, injury, or serious infection - like the hormones from the adrenal medulla.

Mineralocorticoids:work to regulate the

concentration of potassium and sodium in the body.

Prolonged ↑ in adrenal cortex hormone results in Cushing’s Disease.

Signs & Symptoms of Cushing’s Disease: ↑ in blood sugar levelsunusual body fat

distributionrapid mood swings

And - if there is an ↑ in mineralocorticoids as wellA serious electolyte

imbalance will occur due to the ↑ potassium excretion by the kidney, which results in hypokalemia.

Sodium can also be retained by the kidney, resulting in hyponatremia.Causes:

dysrhythmiascomadeath

usually results from a tumor.

Addison's disease and congenital adrenal hyperplasia can manifest as adrenal insufficiency.

Symptoms include: hypoglycemia, dehydration, weight loss, and disorientation. Symptoms may also include weakness, tiredness, dizziness, low blood pressure that falls further when standing (orthostatic hypotension), muscle aches, nausea, vomiting, and diarrhea.

the endocrine glands associated with reproduction.

Female ovaries produce eggs

Male gonads produce sperm

both have endocrine functions.

Ovaries:located in the

abdominal cavity adjacent to the uterus.

Under the control of LH and FSH from the anterior pituitary they manufactureestrogenprotesterone

Estrogen and Progesterone have several functions, including sexual development and preparation of the uterus for implantation of the egg.

Testes:located in the scrotumproduce sperm for

reproductionmanufacture

testosterone -promotes male

growth and masculinization

Controlled by anterior pituitary hormones FSH and LH.

Gonadal disorders lead to abnormal primary and secondary sexual characteristics, both in males and females.

Gonadal disorder also lead to reproductive failure due to inconsistent ovulation, lack of libido and inappropriate spermatogenesis.