Summarize the following text to main points and sub-points and make detailed explain for them:

  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
 
 
 
 
 
 
Endocrinology 
 
-The medical specialty that studies the anatomy and physiology of the endocrine system 
and uses diagnostic tests, medical and surgical procedures, and drugs to treat 
endocrine system diseases. 
 
 
Endocrine System: Endocrine glands secrete hormones directly into bloodstream 
 
- Hormones regulate body activities 
 
✓ Metabolic rate 
✓ Water and mineral balance 
✓ Immune system reactions 
✓ Sexual functioning 
 
 
 
❖ Organs of the endocrine System 
 
✓ Adrenal glands (two) 
✓ Gonads (Ovaries and Testes) (two of each one) 
✓ Hypothalamus 
✓ Pancreas (islets of Langerhans) 
✓ Parathyroid glands (four) 
✓ Pineal gland 
✓ Pituitary gland 
✓ Thymus gland 
✓ Thyroid gland 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
- Hormones are chemicals that act on target organs to increase or decrease 
target’s 
activity level 
 
- Responsible for homeostasis (maintenance of internal environment stable). 
 
 
 
 
 
 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
 
❖ Types of glands in the body 
Exocrine glands: Release secretions into duct that carries them to outside of body or inside 
body. 
- Example: sweat glands and pancreas 
 
Endocrine glands: Release hormones directly into  
bloodstream. 
 
- Have no ducts, referred to as ductless glands 
 
Example: thyroid gland, pancreas, pituitary and adrenal Gland 
 
 
 
 
 
 
 
 
 
 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
❖ 
Glands located in the brain 
➢ Hypothalamus 
 
- Shaped like a flattened funnel, size of kidney bean 
 
- Forms floor and walls of third ventricle of the brain 
 
- Regulates primitive functions of the body 
from water balance and thermoregulation 
to sex drive and 
childbirth many of its 
functions carried out by pituitary gland 
 
 
▪ Hypothalamic Hormones 
 
- Eight hormones produced in hypothalamus 
 
- Six regulate the anterior pituitary 
 
- Two are released into capillaries in the posterior pituitary  
(oxytocin and antidiuretic hormone) 
 
✓ Six releasing and inhibiting hormones stimulate or inhibit the anterior pituitary 
 
-Thyrotropin releasing hormone (TRH), corticotropin releasing hormone (CRH), 
gonadotropin releasing hormone (GnRH), and growth hormone releasing hormone 
(GHRH) are releasing hormones 
 
- Prolactin inhibiting hormone (PIH) inhibits secretion of prolactin,  
and somatostatin 
inhibits secretion growth hormone & thyroid stimulating hormone 
 by the anterior pituitary. 
 
✓ Two other hypothalamic hormones are oxytocin (OT) and antidiuretic hormone 
(ADH) 
• Both stored and released by posterior pituitary 
• 
Posterior pituitary does not synthesize them 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
➢ Pituitary Gland 
 
- Small marble-shaped gland , Located underneath brain. 
 
Composed of two structures with independent origins 
and 
separate functions 
 
A. Adenohypophysis (anterior pituitary) 
 
B. Neurohypophysis (posterior pituitary) 
 
- Divided into anterior and posterior lobes 
 
- Regulated by hypothalamus 
 
▪ Anterior Pituitary : Referred to as “master gland” 
 
- Secretes hormones that regulate other endocrine glands 
 
- Thyroid-stimulating hormone (TSH): Regulates function of thyroid gland 
 
- Adrenocorticotropin hormone (ACTH): Regulates function of adrenal cortex 
 
- Gonadotropins: Follicle-stimulating hormone (FSH) , Luteinizing hormone (LH) 
 
• FSH: Responsible for development of ova and sperm ,  
                            Also stimulates ovary to  
secrete estrogen 
• LH: Stimulates secretion of sex hormones, Plays a role in releasing ova in 
 
 
 
 
 
 
 
 
 
 
 
 
 
females 
 
- Growth hormone (GH) (somatotropin) : Stimulates cells to grow and divide. 
 
- Prolactin (PRL): Stimulates milk production in breast. 
 
- Melanocyte -stimulating hormone (MSH):  
                                      Stimulates melanocytes to produce more 
melanin. 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
▪ Posterior Pituitary 
 
- Produced in hypothalamus 
 
- Transported to posterior lobe 
 
- Releases hormones when hypothalamic neurons are stimulated 
 
- Antidiuretic hormone (ADH), Called vasopressin :  
                                             Promotes water reabsorption by 
the kidney tubules 
- Oxytocin: Stimulates uterine contractions during labor and delivery,  
                                   After birth 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
stimulates release of milk from breast 
 
 
 
 
 
➢ Pineal Gland 
 
- Small pine cone-shaped gland 
 
- Part of thalamus region of brain 
 
- Secretes melatonin 
 
- Not well understood, but plays a role in 
regulating body’s circadian rhythm 
 
- 24-hour clock that governs periods of 
wakefulness and sleepiness 
 
 
 
 
 
 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
❖ 
Glands located in the neck 
 
➢ Thyroid Gland 
 
- Located on either side of trachea 
 
- Resembles a butterfly in shape 
 
- Divided into right and left lobes 
 
Thyroid hormones 
 
- Thyroxine (T4) - Triiodothyronine (T3) :  
                                                                 Needs iodine to make hormones 
 
- These hormones: 
 
o Regulate energy production 
o Adjust metabolic rate 
 
 
 
 
- Also secretes calcitonin 
 
- Regulates level of calcium in bloodstream 
 
- If calcium levels in blood rise too high: 
 
• Calcitonin levels in blood increase >> Increases deposition of calcium into bone 
 
So Lowers levels of calcium in bloodstream 
 
Its action is opposite of parathyroid hormone 
 
 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
 
➢ Parathyroid Glands 
 
- Four tiny glands 
 
- Located on dorsal surface of thyroid gland 
 
- Secretes parathyroid hormone (PTH) 
 
- Regulates level of calcium in bloodstream 
 
- If calcium levels in blood fall too low: 
 
o Parathyroid hormone levels 
in the blood 
increase 
o Stimulate bone breakdown 
 
- Releasing more calcium into bloodstream 
 
❖ 
Glands located in the chest : 
 
➢ Thymus Gland 
 
- Located in mediastinum 
 
- Part of immune system , Also endocrine gland 
 
- Secretes thymosin which is essential for 
growth and 
development of T cells 
 
- Critical part of body’s immune system 
 
- Present at birth and grows to largest size during puberty 
 
At puberty begins to shrink and eventually is replaced with connective and adipose 
tissue. 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
 
❖ 
Glands located in the abdomen : 
 
➢ Pancreas 
- Located along lower curvature of stomach 
- Only organ that has both endocrine and exocrine functions 
 
- Exocrine portion 
 
- Releases digestive enzymes 
through duct into 
duodenum 
 
- Endocrine sections of the pancreas 
 
- Islets of Langerhans → produce insulin and glucagon 
- Insulin (produced by β-cells) 
✓ Stimulates glucose 
uptake from 
bloodstream by cells 
✓ Lowers blood sugar level 
✓ Occurs after eating a meal and 
absorbing 
carbohydrates 
- Glucagon (produced by α-cells) 
✓ Stimulates liver to release 
stored glucose 
into 
bloodstream 
✓ Raises blood sugar levels 
✓ Occurs when body needs more glucose 
 
- Also, secrets somatostatin 
secreted by delta cells and 
pancreatic polypeptide 
by γ cells 
 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
 
➢ Adrenal Glands 
 
 
- Two glands, one located above each kidney 
- Each gland is composed of two sections: 
- Adrenal cortex 
- Adrenal medulla 
 
▪ Adrenal cortex secrets corticosteroids 
- Three different families of corticosteroids 
- Mineralocorticoids 
- Glucocorticoids 
- Steroid sex hormones 
 
- Mineralocorticoid 
✓ Example: aldosterone: Regulates sodium (Na+) 
and potassium (K+) levels 
- Glucocorticoid 
✓ Example: cortisol :Regulates carbohydrates 
- Steroid sex hormones 
✓ Androgens, estrogen, and 
progesterone: Regulate 
secondary sexual characteristics 
 
▪ Adrenal Medulla secretes 
epinephrine 
(adrenaline) and 
norepinephrine (noradrenaline) 
(stress hormones) 
 
- Critical during emergency situations 
- Increases blood pressure 
- Increases heart rate 
Increases respiration rate 
 
 
 
 
 
 
 
  Presented By :  
  Dr. Tareq Abu-Libdeh 
Endocrine System 
1. ر 
 
 
 
❖ 
Glands located in the pelvis: 
 
➢ Testis 
 
- Two oval glands located in scrotum 
 
- Secrete testosterone 
 
- Testosterone: 
 
• Produces male 
secondary sexual 
characteristics 
• Regulates sperm production 
 
 
 
➢ Ovaries 
 
- Two ovaries located in pelvic cavity of females 
 
- Secrete female sex hormones, estrogen and progesterone 
 
- Estrogen is responsible for: 
 
✓ Female sexual characteristics 
✓ Regulation of menstrual cycle 
 
- Progest

Summary :