Endocrine System Flashcards
What do hormones do?
Hormones are molecules produced by the endocrine system that send messages to various parts of the body. They help regulate your body’s processes.
How do hormones work?
They attach to receptors on the surface of target cells
What glands/organs make up the endocrine system?
Pituitary gland Thyroid gland Adrenal gland Pancreas Ovaries/testes
Features of the pituitary glaand:
- Master gland
- extensive influence on other organs
- Linked to hypothalamus
- stimulates and inhibits pituitary hormones
- Responsible for making hormones to stimulate organs to act
What hormones are the pituitary gland responsible for?
- Prolactin - breast development and lactation
- LH/FSH (Luteinizing hormone and follicle-stimulating hormone)- stimulate ovaries and testes to produce oestrogen and testosterone
- ACTH (Adrenocorticotropic hormone) - stimulates the adrenal gland to produce cortisol, aldosterone, androgens
- Growth hormone - skeletal system growth
- TSH (thyroid stimulating hormone)- stimulates thyroid gland to produce thyroxine
- ADH (Antidiuretic hormone) - kidney water regulation
- Oxytocin - labour ad lactation
What are three hormone abnormalities?
Deficiency, excess and resistance
What are the 4 stages of growth?
Foetal
Infancy
Childhood
Puberty/adolescence
Features of foetal growth:
- Growth is dependent on mother’s genetics, health and placental nutrition.
- Most rapid growth period
- Peaks at 10cm a month around 13-18 weeks
Features of growth in infancy:
- Linear growth is initially rapid but the growth rate then declines.
- Most important influencing factor is nutrition
Features of growth in childhood:
- Period of relatively steady growth
- Growth rate - 4-7cm/year
How does nutrition affect growth rate?
Nutrition becomes less important the older children get
Define adrenarche:
Onset of androgen dependent changes, eg, pubic and axillary hair, BO, acne
Define thelarche:
Onset of female breast development
Define puberty:
Development of secondary sexual characteristics. Attain reproductive capacity.
Define menarche:
Onset of menstruation
Factors affecting the onset of puberty:
Genetics
Environment
General health
Normal puberty in girls:
Puberty development after the age of 8 years (mean 10 yrs)
Normal puberty in boys:
Puberty development after the age of 9 years (mean 12 yrs)
What is Anti Diuretic Hormone synthesised by?
Synthesised by the hypothalamus and stored in the posterior pituitary gland
Function of Anti Diuretic Hormone?
Stimulates the DCT and collecting ducts of the nephrons to increase water reabsorption when dehydrated to decrease water loss.
What does plasma osmolality measure?
Plasma osmolality measures the concentration of all chemical particles found in the fluid in the blood.
What is a normal plasma osmolality level?
285-295mOsm/L