Endocrine system Flashcards
(23 cards)
What is the endocrine system
Network of glands that produce and release hormones which act as chemical messengers to regulate bodily functions, including growth, development and reproduction
What do annabolic steroids do
Have receptors in muscles that stimulate muscle protein production
What are the organs of the endocrine system
In the head/neck: Hypothalaums
Pituitary gland
Pineal Gland
Parathyroid glands
In the main body: Thyroid gland
Adrenal glands
Pancreatic islets
What does the hypothalamus do
Produces ADH (antidiuretic hormone), oxyroxin and regulatory hormones
What does the pituitary gland do
Releases hormones that control growth development and reproduction
What does the pineal gland do
Secrete melatonin
What do the parathyroid glands produce
Parathyroid Hormone and calcitonin
What does the thyroid gland produce
thyroxine, triiodothyronine and calcitonin
What does the adrenal gland produce
adrenal medulla = epinephrine and norepinephrine
Adrenal cortex = cortisol
What do the pancreatic islets produce
Insulin and glucagon
What are the organs with a secondary endocrine function (7)
The heart, thymus, adipose tissue, digestive tract, kidneys, gonads, testes/ovaries
How is endocrine communication done
Through the blood stream using hormones, from endocrine glands to target cells in other tissues and organs
How do hormones work
Are the organic chemical messengers produced and secreted by endocrine glands into the blood stream. They:
1- Bind to receptors in target cells
2- And stimulate protein/gene expression, to regulate integrate and control a wide range of physiological features
What are steroid hormones
Hormones that cam easily diffuse through the membrane of a cell, as they derive from cholestrol
Effects of anabolic steroid use (6)
Stunted skeletal growth and sexual maturation in teenagers
Liver damage
Reduced sperm count = infertility
Increase in prostate cancer
Baldness
Facial hair
cessation of menstrual pattern in females
What are the three types of hormones
Amino acid derivatives, small molecules that are similar to amino acids
peptide hormones, consisting of chains of amino acids
Lipid derivatives, steroids and eicosanoids
Explain the two locations of hormone receptors
On the cell = for non lipid soluble hormones. These trigger cascades in the cell
Inside the cell = receptors for all steroid and thyroid hormones
What are involved in cascades inside a cell
G proteins and secondary messengers (like cyclic AMP (cAMP), or cyclic GMP (cGMP))
What hormones can act as trancription factors
Steroid, as they are lipid soluble, and thyroid hormones as they can cross the cell membrane via diffusion or transport mechanisms
This can alter the rate of transcription of DNA, directly effecting metabolic activity
What happens to free hormones (and steroid and thyroid) once secreted
Most hormones remain functional for less than an hour, before they either bind to their receptor protein, or are broken down by the liver, kidney or enzymes in the plasma
Steroid and thyroid = stay in circulation for much longer because they are often bound. 99% attach to special transport proteins, with the blood stream containing a large reserve of these bound horomones
What controls the endocrine system, and whats their function
The hypothalamus = is the connection between the nervous and endocrine system, and regulates the hormones that effect the:
The pituitary = the anterior lobe produces hormones that control other endocrine organs
What is the hypophyseal portal system
Is a specialized network of blood vessels that connects the hypothalamus to the anterior pituitary gland.
The system takes regulatory hormones from the hypothalamus to the pituitary gland to send out to the body
What sort of feedback controls hormone levels
Negative feedback
