Human Endocrine System Flashcards
Chemical Coordination
The type of control and coordination brought about by hormones in the blood
Hormones
Organic chemical messengers
Target organ
an organ that is affected by a specific hormone
Negative feedback mechanism
Any deviation from the normal levels elicits a response that restores the normal levels
Hormones of Pituitary Gland (7)
- Thyroid stimulating hormone
- Growth hormone
- Follicle-stimulating hormone
- Luteinising hormone
- Prolactin
- Antidiuretic hormone
- Oxytocin
Hormones of Thyroid
Thyroxin
Hormones of Pancreas (2)
- Insulin
- Glucagon
Hormones of Adrenal Glands (2)
- Aldosterone
- Adrenalin
Hormones of Gonads (3)
- Testosterone
- Oestrogen
- Progesterone
Thyroid Stimulating Hormone
Stimulates thyroid to secrete thyroxin
Growth Hormone
Promotes growth of skeleton and muscles by stimulating the synthesis of proteins.
Under-secretion is dwarfism.
Over-secretion is gigantism or acromegaly
FSH
Stimulates the development of primary follicles into mature Graafian follicles
Activates the germinal epithelium that produces sperm cells.
LH
Stimulates the release of the secondary oocyte (ovulation) and the development of the corpus luteum
Stimulates the cells of Leydig to produce testosterone
Prolactin
Stimulates mammary glands to produce milk after the birth of a baby
ADH
Controls the reabsorption of water
Oxytocin
Causes contractions necessary for the birth process
Positive feedback mechanism
Thyroxin
Increases basal metabolic rate
> Increases breathing and heart rate
> Essential for normal growth and development of organs
> Essential for normal functioning of nervous system
Under-secretion is cretinism or myxoedema or exophthalmia
Over-secretion is hyperthyroidism
Insulin
Decreases blood glucose level
Glucagon
Increases blood glucose level
Antagonistic hormones
Hormones that have opposite effects on the body
Aldosterone
A steroid hormone that regulates the ionic balance of the tissue fluid
Adrenalin (7)
> Accelerates and strengthens the heart rate
Increases the blood pressure
Accelerates the conversion of glycogen to glucose
Increases rate and depth of breathing
Increases the muscle tone of the skeletal muscles
Dilates pupil
Increases sweat production
Testosterone (3)
> Responsible for the secondary male sexual characteristics.
Responsible for the development of the male sex organ.
Maturation and quality of sperm
Oestrogen (4)
> Secondary female sexual characteristics
Development of the female sex organs
Thickening of endometrium
Inhibits secretion of FSH
Progesterone (2)
> Thickening and maintenance of the endometrium during pregnancy
Suppresses the release of FSH and LH
Homeostasis
The maintenance of a constant internal environment in the body
Negative feedback mechanism
Is when the detection of a deviation from the normal results in a reaction that counteracts the change and returns to normal. The return to normal is detached and the corrective action is switched off.
