Anatomy and physiology Flashcards
Describe the endocrine system
A system that consists of glands that release chemical messengers known as hormones. This enables the organs to communicate
What Is the function of the thyroid gland
regulates the bodies metabolism using the hormones T3 and T4
What is the main role of the parathyroid gland? and why is this important ?
It regulates the bodies calcium levels. This is important because calcium controls many things in our bodies such as muscle contraction, regulating the hearts rhythm and bone growth
What is the role of the adrenal glands and where are they located ?
They are located on top of the kidneys and they have 2 different roles:
- in the cortex: where steroids are made (cortisol and aldosterone)
- Medulla: where it makes adrenaline and noradrenaline
what is the role of the gonads?
They release sex hormones. In males the testes produce testosterone and in females the ovaries produce oestrogen and progesterone
What is the role of the pancreas?
Controls the bodies blood sugar via the hormones insulin and glucagon (glucagon increases glucose and insulin decreases it)
What is the role of the pituitary gland
Known as the master gland. It produces many hormones that control different processes in the body.
- adrenocorticotrophic hormone
- Luteinising hormone and FSH
- Prolactin
- TSH
What is the role of the hypothalamus?
It is the control centre. It releases hormones to the pituitary gland which stimulates it to release hormones to the endocrine organs.
it produces:
- Oxytocin (stimulates contraction of the uterus during child birth)
- Anti- diuretic hormone (causes water reabsorption at the kidneys)
What is the main difference between the anterior and posterior pituitary gland?
The anterior pituitary gland produces and releases hormones whereas the posterior pituitary gland only stores the hormones
Explain the hypothalamus- pituitary- thyroid axis
Plays a major role in regulating the thyroid hormones.
- The hypothalamus synthesises and releases TRH into the pituitary circulation.
- TRH binds to the TRH receptors then encourages the release of TSH from the anterior pituitary and into the circulation
- TSH binds to the receptor on the thyroid gland on the follicular cells
- This initiates the release of T3 and T4
What would abnormal TRH levels indicate?
Something is wrong with the hypothalamus
What is the role of T3 and T4? and how are they made ?
Iodine and thyroglobulin make the thyroid hormones T3 and T4.
T3 (Triiodothyronine)
The active hormone
T4 (Thyroxine)
The inactive form
The hormones work by regulating the body’s metabolism. Too much or too little of these hormones = hypo/hyper thyroidism
What does it mean for TRH and TSH if T3 and T4 are increased ?
It means they are decreased
