Endocrine system

The **endocrine system** includes those organs of the body which produce hormones.
It helps to regulate metabolism, growth and development, tissue function, and plays a part also in mood.
The field of medicine that deals with disorders of endocrine glands is endocrinology.

In physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body.

The endocrine system is in contrast to the exocrine system, which secretes its chemicals using . The endocrine system is an information signal system like the nervous system, yet its effects and mechanism are different.

The endocrine system's effects are slow to start, and long-lasting in their response. The nervous system sends information quickly, and responses are generally short lived. Hormones are complex chemicals released from endocrine tissue into the bloodstream where they travel to target tissues and  a .

Features of endocrine glands are, in general, they have no ducts, they have a good blood supply, and usually they have vacuoles or granules inside their cells, storing their hormones.

s. (Male left, female on the right.) **1.** Pineal gland **2.** Pituitary gland **3.** Thyroid gland **4.** Thymus **5.** Adrenal gland **6.** Pancreas **7.** Ovary **8.** Testes]]

## Endocrine glands and the hormones they secrete 
### Central nervous system 
* **Hypothalamus** produces
** Thyrotropin-releasing hormone (TRH) *Parvocellular neurosecretory neurons*
** Gonadotropin-releasing hormone (GnRH)  *Neuroendocine cells of the Preoptic area*
** Growth hormone-releasing hormone (GHRH)  *Neuroendocrine neurons of the Arcuate nucleus*
** Corticotropin-releasing hormone (CRH)  *Parvocellular neurosecretory neurons*
** Vasopressin* Parvocellular neurosecretory neurons*
** Somatostatin (SS; also GHIH, growth hormone-inhibiting hormone) *Neuroendocrince cells of the Periventricular nucleus*
** Prolactin inhibiting hormone or PIH or Dopamine (DA) *Dopamine neurons of the arcuate nucleus*
** Prolactin releasing hormone
* **Pineal body** produces
** Melatonin (mainly)  *Pinealocytes*
* **Pituitary gland** (hypophysis) produces
** **Anterior pituitary** lobe (adenohypophysis)
*** Growth hormone (GH) *Somatotropes*
*** Prolactin (PRL) *Lactotropes *
*** Adrenocorticotropic hormone (ACTH, corticotropin) *Corticotropes*
*** Lipotropin *Corticotropes*
*** Thyroid-stimulating hormone (TSH, thyrotropin) *Thyrotropes*
*** Follicle-stimulating hormone (FSH) *Gonadotropes*  
*** Luteinizing hormone (LH)  *Gonadotropes*
** **Posterior pituitary** lobe (neurohypophysis)
*** Oxytocin *Magnocellular neurosecretory cells*
*** Vasopressin (AVP; also ADH, antidiuretic hormone) *Magnocellular neurosecretory cells*
** **Intermediate pituitary** lobe (pars intermedia)
*** Melanocyte-stimulating hormone (MSH) *Melanotroph*

### Thyroid 
* **Thyroid** produces 
** Triiodothyronine (T3), the potent form of thyroid hormone *Thyroid epithelial cell*
** Thyroxine (T4), also known as tetraiodothyronine: it is a  less active form of thyroid hormone (mainly) *Thyroid epithelial cell*s
** Calcitonin  *Parafollicular cell*s

### Parathyroid 
*Parathyroid hormone PTH triggers an increase in blood calcium levels.

### Muscles 
* **Striated muscle** produces
** Thrombopoietin  *Myocytes*

### Alimentary system 
* **Stomach** produces
** Gastrin (mainly)  *G cells*
** Ghrelin  *P/D1 cells*
** Neuropeptide Y (NPY)
** Secretin *S cells*
** Somatostatin  *D cells*
** Histamine  *ECL cells*
** Endothelin *X cells*
* **Duodenum** produces
** Cholecystokinin  *I cells*
* **Liver** produces
** Insulin-like growth factor (IGF) (mainly)  *Hepatocytes*
** Angiotensinogen  *Hepatocytes*
** Thrombopoietin *Hepatocytes*
* **Pancreas** produces
** Insulin (mainly)  *β Islet cells*
** Glucagon (also mainly)  *α Islet cells*
** Somatostatin  *δ Islet cells*
** Pancreatic polypeptide  *PP cells*

### Kidney 
* **Kidney** produces
** Renin (Primarily) *Juxtaglomerular cells*
** Erythropoietin (EPO)  *Extraglomerular mesangial cells*
** Calcitriol (the active form of vitamin D3)
** Thrombopoietin

### Adrenal glands 
* **Adrenal glands**
** **Adrenal cortex** produces
*** Glucocorticoids (chiefly cortisol) *Zona fasciculata and Zona reticularis cells*
*** Mineralocorticoids (chiefly aldosterone) *Zona glomerulosa cells*
*** Androgens (including DHEA and testosterone) *Zona fasciculata and Zona reticularis cells*
** **Adrenal medulla** produces
*** Adrenaline (epinephrine) (Primarily) *Chromaffin cells*
*** Noradrenaline (norepinephrine)  *Chromaffin cells*
*** Dopamine  *Chromaffin cells*
*** Enkephalin  *Chromaffin cells*

### Reproductive system 
#### Male 
* **Testes**
** Androgens (chiefly testosterone) *Leydig cells*
** Oestradiol *Sertoli cells*
** Inhibin *Sertoli cells*

#### Female 
***Oestrous cycle**
** **Ovarian follicle/Corpus luteum**
*** Progesterone *Granulosa cells, Theca cells*
*** Androstenedione  *Theca cells*
*** Oestrogens (mainly oestradiol) *Granulosa cells*
*** Inhibin *Granulosa cells*
** **Placenta** (when a woman is pregnant)
*** Progesterone (Primarily)
*** Oestrogens (mainly oestriol) (Also primarily)
*** Human chorionic gonadotropin (HCG)  *Syncytiotrophoblast*
*** Human placental lactogen (HPL)  *Syncytiotrophoblast*
*** Inhibin *Fetal trophoblasts*
** **Uterus** (when a woman is pregnant)
*** Prolactin (PRL) *Decidual cells*
*** Relaxin  *Decidual cells*

### Calcium regulation 
* **Parathyroid** produces
** Parathyroid hormone (PTH) *Parathyroid chief cell*
* **Skin** produces
** Vitamin D3 (calciferol)

### Miscellaneous 
* **Heart** produces
** Atrial-natriuretic peptide (ANP) *Cardiac myocytes*
** Brain natriuretic peptide (BNP)  *Cardiac myocytes*
** Adenosine  *Cardiac myocytes*
* **Adipose tissue**
** Leptin (Primarily) *Adipocytes*
** Oestrogens (mainly oestrone)  *Adipocytes*
* **Bone marrow** produces
** Thrombopoietin

## Related pages 
* Hormones
* Nervous system

## References 
## Other websites 
* Journals Designed for Clinical Endocrinologists
* Islet cell antibody 
* Binding of antibody to pancreas 
* Kidshealth.org