Anatomy and function of the organs of the endocrine system Flashcards
where does the nervous and endocrine system interact?
Pituitary Gland and Hypothalamus
what does the hypothalamus regulate?
Hypothalamus regulates
secretions of anterior pituitary
what is an extension of the hypothalamus?
Posterior pituitary is an
extension of the
hypothalamus
anterior pituitary produces nine major hormones that…
◦ Regulate body functions
◦ Regulate the secretions
of other endocrine glands
examples of hormones the anterior pituitary produces?
Leptin secreted by adipose tissue (endocrine organ)
Leptin acts to stimulate satiety and inhibit hunger
Leptin binds to receptors on hypothalamus, inhibiting feeding behaviour
anterior pituitary gland: Growth hormone influences what and is secretion is controlled through what?
Influences growth of all
tissues
Secretion controlled through hypothalamus
what are the actions of growth hormone?
Actions:
◦ Increases tissue uptake of amino acids
◦ Synthesises new protein
◦ Stimulates long bone growth
growth hormone spares what and mobilises what?
Spares plasma glucose and mobilises fatty acids
posterior pituitary gland-Antidiuretic Hormone (ADH) does what?
Reduces water loss
Antidiuretic hormone is stimulated through what?
Stimulated through low water concentration (osmoreceptors in hypothalamus) or low plasma volume (stretch receptors in right atria)
Antidiuretic hormone during exercise does what?
During exercise, plasma volume will decrease and
osmolality increases
Antidiuretic hormone during exercise above 60% max will increase ADH to do what?
Exercise above 60 % max will show increased ADH to maintain plasma volume.
Thyroid has what?
◦ T3 and T4 (metabolic rate or presence of themselves, inhibitory to their presence)
◦ Calcitonin (controls calcium level in blood)
Parathyroid releases what?
◦ PTH
what does PTH do? Effects of PTH on Bone
inhibits osteoblasts
stimulates osteoclasts
bone is broken down, releasing calcium ions into bloodstream
what does PTH do? Effects of PTH on kidneys
PTH stimulates kidney tubule cells to recover waste calcium from the urine.
PTH stimulated kidneys tubule cells and releases calcitonin
what does PTH do? Effect of Calcitonin on intestine
stimulates intestines to absorb calcium from digesting food
Calcitonin release does what?
High concentrations of calcium stimulate parafollicular cells in the thyroid to release calcitonin
what are the effects of Calcitonin on bone?
stimulates osteoblasts
inhibits osteoclasts
calcium is removed from blood and used to build bone.
Adrenal Glands-Adrenal Medulla, what are Epinephrine and Norepinephrine used for?
used to be called adrenalin
◦ ↑ metabolic rate ◦ ↑ rate and force of heart contraction ◦ ↑ blood pressure ◦ ↑ muscle blood flow ◦ maintain plasma glucose concentration
what is the Adrenal Medulla?
The adrenal medulla is part of the sympathetic
nervous system so hormones released from it
affect a large number of systems
what is the Adrenal Cortex?
Secretes over 30 different steroid hormones -
corticosteroids such as:
◦ Mineralocorticoids (e.g. aldosterone)
◦ Glucocorticoids (e.g. cortisol)
◦ Gonadocorticoids (e.g. androgens and oestrogens)
what is Cortisol?
- Maintains plasma glucose during fasting and exercise
- Makes amino acids available for tissue repair
- Released in response to hypoglycaemia, exercise and stress
Pancreas-insulin does what?
Stimulates uptake of nutrients and storage of
glycogen, proteins and fats
Facilitates glucose diffusion across membranes
A lack of insulin can cause glucose to be lost in urine
(diabetes mellitus)
Insulin secretion is influenced by blood glucose
concentrations
Pancreas-Glucagon is what?
Stimulates mobilisation of glucose and fatty acids
Increased secretion in response to low plasma
glucose concentration
Testes and Ovaries-Testosterone is what?
Both anabolic (tissue building) and androgenic
(promoter of masculinity)
Key hormone responsible for muscle growth
Primary parameter to assess anabolic status of
the body
what are the effects of testosterone?
Effects of Testosterone:
◦ Influence protein synthesis
◦ Mineralisation of skeleton
◦ Growth plate maturation and function
