endocrine i.ppt
TRANSCRIPT
ENDOCRINE SYSTEM
presented by THARANNI
Learning objectivesDefine hormoneDraw and label the location of anterior and
posterior pituitary lobe, thyroid gland, parathyroid gland, pancreatic islets, adrenal gland, pineal gland, thymus gland, testes and ovary
List the major hormones secreted by anterior pituitary gland, posterior pituitary gland, thyroid gland, pancreatic islets, adrenal gland, pineal gland, thymus gland, testes, ovary including their functions.
• Controls many body functions– exerts control by
releasing special chemical messenger/mediator into the blood called hormones
• Derives its name from the fact that various glands release hormones directly into the blood, which in turn transports the hormones to target tissues via ducts.
The Endocrine System
• 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.
The Endocrine System
• The Pituitary Gland is divided into 2 areas, which differ– structurally and
functionally – each area has
separate types of hormone production.
• The two segments are:– Posterior Pituitary:
• oxytocin and antidiuretic hormone (ADH)
– Anterior Pituitary:• thyroid-stimulating hormone (TSH)• growth hormone (GH)• adrenocorticotropin (ACTH)• follicle-stimulating hormone (FSH • luteinizing hormone (LH)• prolactin
• Posterior Pituitary– Oxytocin (the natural
form of pitocin)• stimulates gravid
uterus• causes “let down” of
milk from the breast.
– ADH (vasopressin) causes the kidney to retain water
• Anterior Pituitary– Primarily regulates
other endocrine glands– rarely a factor in
endocrinological emergencies
– TSH stimulates the thyroid gland to release
• T3,T4• thus metabolic rate
– Growth hormone (GH) glucose usage consumption of fats
as an energy source
– ACTH stimulates the adrenal cortex to release
• aldosterone• Cortisol• androgen– FSH & LH stimulates
maturation & release of eggs from ovary.
• The Thyroid Gland– lies in the anterior neck
just below the larynyx.• 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.
– Calcitonin, when released, lowers the amount of calcium in the blood.
• 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
– produce parathyroid hormone - level of calcium in blood
– Hypocalcemia can result if parathyroids are removed or destroyed.
• Pancreas– a key gland located in
the folds of the duodenum
• Islets of Langerhans– specialized tissues in
which the endocrine functions of the pancreas occurs
– include 2 types of cells:
• alpha ( )• beta ()
• Alpha () cells release glucagon, essential for controlling blood glucose levels.
• When blood glucose levels fall, 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).
• Glucagon also stimulates the liver to manufacture glucose
• Glycogenolysis
• Beta Cells () 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.
• Gluconeogenesis.
• Adrenal Glands– 2 small glands that sit
at top both kidneys.
• the Adrenal Medulla secretes the catecholamine hormones norepinephrine and epinephrine (stimulated by sympathetic nerve & ACTH).
• The Adrenal Cortex secretes 3 classes of hormones, all steroid hormones:– mineralocorticoids– gluticocorticoids – androgen
Gluticocorticoids:(CORTISOL)– 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:• (aldosterone)
– 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
levels– unusual body fat
distribution– rapid mood swings
• And - if there is an in mineralocorticoids as well– A 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:
• dysrhythmias• coma• death
Androgen :• Stimulates the
development and maintenance of male and female 2ndry characteristcs
• Gonads and Ovaries:– the endocrine glands
associated with human 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 manufacture
• estrogen• protesterone
• Estrogen - estrous cycle &
development of 2ndry sex charcteristics.
Male..maturation of sperm
• Progesterone preparation of the uterus for implantation of the egg.
• Testes:– located in the scrotum– produce sperm for
reproduction– manufacture testosterone –
have anabolic and androgenic effect
• promotes male growth and masculinization
– Controlled by anterior pituitary hormones FSH and LH.
Thymus Gland
• Thymosin hormone• Stimulates the
maturation of T-lymphocyte
Pineal gland
• Melatonin• It’s release is stimulated by darkkness• Effects – synchronizer of the circadian rhythm Helps control the timing and release of female
reproductive hormones
• RECALL BACK TIME
REFRENCES
• Anatomy and physiology Tortora eight edition
• Youtube• Wikipidea• Notes