Nervous System

Transmits electrical impulses

Use the neurons to transmit the signal

Signal transmission is fast

Effect is localized

Endocrine System

Transmits chemical biological messengers Impulses

Use the circulatory system to transmit the signal

Signal transmission is slow

Effect is widespread

Nervous System vs Endocrine System

Endocrine glands are called ductless glands. They secrete hormones.Hormones are non-nutrient chemicals act as intercellular messengers. They are produced in trace amounts.

Location - Below the thalamus & just above the brainstem

It synthesizes and secretes certain neurohormones.

These hormones regulate the synthesis and secretion of pituitary hormones.

Two types of hormones are produced by hypothalamus: Releasing Hormones Inhibiting Hormones

Synthesizes & releases hypophysiotropic hormones:

Thyrotropin-releasing hormone (TRH)

Corticotropin-releasing hormone

(CRH)

Gonadotropin-releasing hormone

(GnRH)

Growth hormone-releasing hormone

(GHRH)

Growth hormone-inhibiting hormone

(GHIH)

Prolactin-releasing factor (PRF)

Prolactin-inhibitn hormone (PIH)

A marble-sized gland at the base of the brain

Location - in the bony cavity called sella tursica.

Controlled by the hypothalamus or other neural mechanisms and therefore the middle man.

Divided anatomically into:

(i) Adenohypophysis

(ii) Neurohypophysis

Hormone Target(s)  Function

GH All cells in the body 

Stimulates growth and repair. Hyper-secretion of GH leads to Gigantism and low secretion of GH results stunted growth called Dwarfism.

TSH Thyroid Stimulates the thyroid gland to secrete the hormone thyroxine (T4) and triiodothyronine (T3). It regulates the body's metabolic activities.

ACTH Adrenals Stimulates the adrenal gland to produce glucocorticoids.

PRL Breasts Stimulates the growth of the mammary glands and formation of milk.

LH Testes (men) Ovaries (women)

LH and FSH are called gonadotrophins as stimulate gonadal activity.LH stimulates the synthesis and secretion of hormones called androgens from testis.Stimulates the ovaries to produce oestrogen and progesterone.

FSH Ovaries (women)

Stimulates growth and development of the ovarian follicles in females.

MSH Melanocytes in skin

Stimulate the production and release of melanin which regulates pigmentation of the skin.

Oxytocin UterusBreasts 

Stimulates a vigorous contraction of uterus at the time of child birth, and milk ejection from the mammary gland.

Vasopressin (ADH)

Kidneys 

Stimulates reabsorption of water and electrolytes by the distal tubules and reduces loss of water through urine (Diuresis).

The pineal gland is reddish-gray and about the size of a grain of rice in humans.

Location - on the dorsal side of forebrain.

Hormone – MelatoninFunction - It affects the modulation

of sleep patterns in the circadian rhythms and seasonal functions.

It helps in maintaining the body temperature.

It influences metabolism, pigmentation, the menstrual cycle as well as our defense capability.

Sources: http://www.bibliotecapleyades.net/ciencia/ciencia_brain01.htm

Location - Thyroid is a small, butterfly-shaped gland located at the base of the neck below the thyroid cartilage.

Composition - It is composed of two lobes located on either side of the trachea.

The thyroid gland is composed of follicles and stromal tissues.

Each thyroid follicle is composed of follicular cells, enclosing a cavity.

Thyroid hormones:

Tetraiodothyronine or thyroxine (T4)

Triiodothyronine (T3)

Hypothyroidism is a condition characterized by abnormally low thyroid hormone production.

Hyperthyroidism is a condition in which the thyroid gland produces and secretes excessive amounts of thyroid hormones, triiodothyronine (T3) and/or thyroxine (T4).

Goiter Hyperthyroidism

Hypothyroidism in Man

HypothyroidismIn Child

Location - Two pairs of parathyroid glands located behind the outer wings of the thyroid.

It secrete a peptide hormone called parathyroid hormone (PTH).

The secretion of PTH is regulated by the circulating levels of calcium ions.

Function - PTH regulates the amounts of calcium, phosphorus and magnesium in the bones and blood.

It increases the blood Ca2+ levels and maintain calcium balance in the body.

Location - Dorsal side of the heart and the aorta

Hormone – ThymosinsRole - Plays an important

role in the development of the immune system.

Role of Thymosin : Provide cell-mediated

immunity Promote production of

antibodies to provide humoral immunity

o Thymus is degenerated in old individuals

Location - anterior part of each kidneyComposed of two types of tissues:

Centrally located tissue adrenal medulla

Outside tissue adrenal cortex

Source : http://robbwolf.com/2012/04/09/real-deal-adrenal-fatigue/

ADRENAL MEDULLA Adrenal medulla releases the catecholamines:

i)Adrenaline or Epinephrineii)Noradrenaline or Norepinephrine

These hormones are released in stressful situations, hence called emergency hormones or hormones of Fight or Flight.

These hormones increase the heart beat, alertness, pupilary dilation, piloerection (raising of hairs), sweating etc.

ADRENAL CORTEX Adrenal cortex divided into three layers:

Function of Adrenal Medulla and Cortex

Sources: http://www.austincc.edu/apreview/PhysText/Endocrine.html

The pancreas is a flattened organ lies in the abdomen, posterior and slightly inferior to the stomach.

It is a composite gland and acts as both exocrine and endocrine gland.

Histologically, it consists of islets of Langerhans and acini cells.

Source: https://www.atrainceu.com/course-module/1691107-090_diabetes-type-2-module-04

Location - Present in the scrotal sac (outside abdomen) of male.Testis performs dual functions as a primary sex organ as well as

an endocrine gland.

Composed of seminiferous tubules and interstitial tissue.The Leydig cells or interstitial cells produce a hormones called androgens mainly testosterone.During puberty, testosterone helps to bring about the following physical changes that turn a boy into an adult male: Increase in muscle mass and strength, and increase in

height. Growth of facial and pubic hair, Deepening of the voice, male hair patterns, Sperm production (spermatogenesis)

Location - A pair of ovaries located in the abdomen of female.

It is the primary female sex organ which produces one ovum during each menstrual cycle.

It produces two groups of steroid hormones : Estrogen and Progesterone.

EstrogenEstrogen is synthesised and secreted by ovarian

follicles.It is responsible for development of growing ovarian

follicles, the appearance of female secondary sex characteristics at puberty such as high pitch of voice, development of mammary gland.

ProgesteroneProgesterone is secreted by corpus luteum.It regulates female sexual behaviour.It prepares the uterus for pregnancy, and the

mammary glands for lactation. Progesterone supports pregnancy.

Atrial wall of heart secretes peptide hormone atrial natriuretic factor (ANF), which decreases blood pressure.

Juxtaglomerular cells of kidney produce a peptide hormone erythropoietin which stimulates erythropoiesis (formation of RBC).

Gastro-intestinal tract secrete four major peptide hormones:

Gastrin, Secretin, Cholecystokinin (CCK) Gastric inhibitory peptide (GIP).

Gastrin acts on the gastric glands and stimulates the secretion of hydrochloric acid and pepsinogen.

Secretin acts on the exocrine pancreas and stimulates secretion of water and bicarbonate ions.

Cholecystokinin (CCK) acts on both pancreas and gall bladder and stimulates the secretion of pancreatic enzymes and bile juice, respectively.

Gastric Inhibitory Peptide (GIP) inhibits gastric secretion and motility.