ENDOCRINE SYSTEM

BY:

DR. JAMALUDDIN BIN HJ. MUHAMAD

PAKAR PERUNDING PEDIATRIK

HOSPITAL TUANKU FAUZIAH

KANGAR, PERLIS.

FUNCTION OF THE ENDOCRINE SYSTEM

1. Water balance – controlling the solute concentration of the blood.

2. Uterine contractions and milk release-delivery of the newborn and breast milk flow

3. Growth, metabolism and tissue maturation-many tissues, adult features.

4. Ion regulations-regulates Na+, K+ and Ca2+ in the blood.

5. Heart rate and blood pressure regulation-for physical activity.

6. Blood glucose control7. Immune system regulations8. Reproductive functions control

Hormones

Defination: secreted by the endocrine glands (ductless gland), its effect away from the glands-target tissue.

Intracellular chemical signals transported in the blood.

Receptors-membrane bound. intracellular Hormone bound with the receptor to produce

effect.

ENDOCRINE SYSTEM:

Hormone – peptide / proteins - steroids / lipid Regulation of Hormone secretions some

times regulated by other hormones Other hormones:- Prostaglandins inflamation- Erythroproeitin production- Human chronic gonadotophris (placenta)

Hormones – protein, lipids or peptides Protein / most peptide hormones bind to

receptor on the cell membrane cause (i) Permeability changes(ii) Production of intracellular chemical signals Lipid – soluble hormones eg: steroid and thyroid hormone Effect : enter the cell and bind to receptor

inside the cell effects.

REGULATOR OF HORMON SECRETION

Secretion of hormones is control by negative – feedback mechanism

Secretion of hormones controlled by

(i) Chemical

(ii) Other hormones

(iii) Nervous system

PITUITARY AND HYPOTHALAMUS

Pituitary – infundibulum – brain.

Anterior and posterior pituitary Section of hormones from anterior pituitary

controlled by hormones from hypothalamus Section of hormones from posterior pituitary

control by action potentions caried by axchy from the hypothalamus.

Anterior pituitary : Growth hormone (GH) Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Luteinizing hormone (LH) Follicle stimulating hormone (FSH) Prolactin Melanocyte stimulating hormone (MSH)

POSTERIOR PITUITARY HORMON :

Antidiuretic hormone (ADH) oxytocin

GH :

Increase protein synthesis

Breakdown of lipids

Glucose level

Somatic growth

TSH :

T4, T3 secretions

ACTH :

glucocorticoid secretion eg: cortisol

skin pigmentation

MSH :

melanin production

LH :

Ovulation progesterone production;

testosterone production

FSH :Follicle maturation and estrogen secretion in

ovary ; sperm productionPROLACTIN :Stemulates milk productionADH : water reabsorption (regulation of blood

volume)

OXYTOCIN : urine contraction milk “let-down”THYROID GLAND :Thyroid hormones - thyroxine (T4) and

triiodothyronine (T3)Function : metabolic ratesNormal process of growth and maturation

CALCITONIN :

parafollicular cells

Function :

Ca2+ level (resulate Ca2+ level)

rate of bone breakdown

PARATHYROID GLANDS :

PTH (parathyroid hormone)

Function:

bone breakdown by osteoclasts

vitamin D synthesis

Ca2+ levels

ADRENAL :

i) Medulla - epinephrine, norepinephrine

a. Epinephrine, norepinephrine :

- cardiac output

- blood flow to skeletal muscles, heart,

glucose in the blood,

fatty acids

# prepare body for physical activity

ii) Cortex - Mineralocorticoids (aldosterone), glucocorticoids (cortisol) and androgens

a. Aldosterone:

- Na+ reabsorption & water retention

- H2O Excretion (blood concentration)

PANCREAS

Pancreas: insulin - glucose & amino acids

uptake in tissue (liver)

skeletal muscle,

adipose tissue

Islets of langerhans alpha cell glycogen

B cell insulin

b. Cortisol :

- fat and protein breakdown

- glucose (CHO metabolism)

- maintain blood pressure

- inhibit inflamation and immune response

c. Androgens :

- female sexual drive, pubic hair and axillary hair growth

Glucogen glucogen breakdown glucose level

Renin (pathway) angiotensionogen BP Renin angiotensin I

angiotensin II aldosterone secretion

Vasocontraction BP Na+ retention K+ excretion H2O retention

Reproductive organs

Testes Testosterone - sperm cell production - maintenance of functional reproductive organs, secondary sexual characteritics - male sex behaviorOvaries Estrogen & - Uterine and mammary gland progesterone development & function - external genitalia - secondary sexual characteristic - sexual behavior - menstrual cycle

Thymus gland thymosin - promotes immune

system

development and

function

Pineal body melatonin - regulate the

onsent of puberty

Calcium Metabolism

Calcium level is maintain

If Ca2+ PTH secretion

calcitonin breakdown of bone matrix

secretion by osteoclasts

Ca2+ release

breakdown of Ca2+ reabsorption in the kidneys

bone maxtrix by Ca2+ reabsorption from small intestine

osteoclasts (through Vit. D)

If Ca2+ level stimulate parathyroid

gland

PTH secretions

calcitonin breakdown of bone matrix by osteoclast

secretion Ca2+ release

Ca2+ reabsorption by the kidneys

breakdown Vitamin D synthesis Ca2+

of bone matrix Absorption from the small intestine

Regulation of Blood Glucose Level

glucose pancreatic islets cells

insulin secretions

uptake of glucose by the

tissues

glucose glycogen (skeletal muscle, liver)

glucose adipose tissue

glucose level

glucose pancreatic islets cell

insulin secretions

Insulin is an anabolic hormone