The Endocrine System Flashcards
Give 4 differences between the endocrine and nervous systems.
Endocrine system is made up of glands where as the nervous system is made up of neurons
The endocrine system transmits hormones whereas the nervous system transmits neurotransmitter
The endocrine system works by realising chemical impulses whereas the nervous system realises electrical impulses through the synapse
The effects of the endocrine system are generally longer lasting than those of the nervous system
How do hormones secreted by glands in the endocrine system reach target cells?
The endocrine uses the circulatory system as a means of transport. Hormones are therefore transported in the bloodstream.
What is a steroid hormone?
Steroid hormones enter a target cell and bind receptors within the nucleus. These then activate specific genes within the cell.
What is a non steroid hormone?
Non steroid hormones bind receptors in the target cell membrane. The hormone receptor signals a membrane protein to produce secondary messenger molecules. These carry the signal.
What are prostaglandins?
Prostaglandins act upon the cells of the organs which produce them.
Name three ways in which hormonal secretion is controlled.
- In response to hormones realised by the hypothalamus or anterior pituitary gland
- In response to impulses from neurons
- In response to levels of a substance within the blood stream
Describe negative feedback.
A gland senses the concentration of a hormone which it regulates. When the concentration is too high, the realise of the hormone from the gland is inhibited. When the concentration is too low, the gland is stimulated to produce more of the hormone. This maintains a balanced concentration.
Name five hormones realised by the anterior pituitary gland. What are the functions of these hormones?
Prolactin: stimulates and sustains the production of milk.
Growth hormone: stimulates cells to enlarge and divide more frequently.
Thyroid stimulating hormone: stimulates the thyroid to produce its own hormones.
Luteinising hormone and follicle stimulating hormone: These are both gonadotropins associated with the reproductive system.
Name the two hormones secreted by the posterior pituitary gland and describe their function.
Oxytocin: contracts the smooth muscle of the uterine wall and initiates the let down reflex in breastfeeding.
Antidiuretic: reduces the volume of water the kidneys secrete.
Where is the thyroid gland located?
In the neck
What two hormones does the thyroid produce? What are the functions of these hormones?
Thyroxine and Triiodothyronine. They work together to stimulate lipid utilisation, enhance protein synthesis and increase the metabolic rate of cells.
Where are the parathyroid glands located?
On the posterior surface of the thyroid gland in the neck.
What is the main function of the parathyroid hormones?
To increase blood calcium levels
Where are the adrenal glands located?
At the top of the kidneys.
What two structures make up the adrenal glands?
Adrenal cortex and adrenal medulla.
