The endocrine system Flashcards
What is the endocrine system
The endocrine system includes all of the endocrine cells and tissues of the body.
Glandular secretory cells surrounded by an extensive network of capillaries that allows for diffusion of hormones from cells to the blood stream
Where do endocrine secretory cells secrete?
Directly into the blood
What are the two different classes of hormone
Lipid hormones
Water soluble hormones
What hormones are included within the lipid hormone class
The lipid-soluble hormones include steroid and thyroid hormones.
What hormones are included in the water soluble hormone class?
Amine, peptide and protein hormones
What are the 5 changes that a hormone is able to produce?
➢Alters plasma membrane permeability or membrane potential, or both by opening or closing ion channels.
➢Stimulates synthesis of enzymes and other proteins within the cell.
➢Activates or deactivates enzymes.
➢Induces secretory activity.
➢Stimulates mitosis
Where are receptors for water soluble hormones located
The cell membrane
Where are receptors for lipid soluble hormones located?
Inside the cell
What do the hypothalamus and pituitary gland do
They act as a unit, regulating the activity of most of the other endocrine glands.
What does the hypothalamus do?
The hypothalamus is a small part of the brain below the thalamus. It secretes several releasing (stimulatory) and suppressing (inhibitory) hormones that regulate nearly all aspects of growth, development, metabolism and homeostasis
Where is the pituitary gland
The pituitary gland lies in the hypophyseal fossa of the sphenoid bone below the hypothalamus, to which it is attached by a stalk
What are the two parts of pituitary gland?
The anterior pituitary
The posterior pituitary
Where is the anterior pituitary gland
An UP growth of glandular epithelium from the pharynx.
Where is the posterior pituitary gland
A DOWN growth of nervous tissue from the brain.
What is between the hypothalamus and the posterior pituitary gland?
A network of fibres
What does the anterior pituitary gland do
The anterior pituitary is supplied indirectly with arterial blood that has passed through the capillaries of the hypothalamus.
As well as providing oxygen and nutrients, this blood transports releasing and inhibiting hormones secreted by the hypothalamus.
These hormones stimulate the release of several other hormones.
What are the anterior pituitary gland hormones? (Tropic hormones; there are 6)
(Think FSH and LH) (GCSE biology)
- Growth Hormone (Stimulates growth)
- Prolactin (lactating for women)
- Leutanising hormone (LH) (the production of testosterone in testi and secretion of progesterone and oestrogen)
- FSH (formation of sperm and maturation if ovary and oestrogen)
- TSH (Stimulates the secretion of thyroid hormones T3 & T4)
- Adrenocorticotropic hormone (ACTH) (synthesis and secretion of the glucocorticoid and adrenal androgens by the adrenal cortex)
What does the posterior pituitary gland do
The posterior pituitary does not synthesise hormones, but stores and releases hormones produced by the cells of the hypothalamus.
What hormones are released from the posterior pituitary gland?
- Vasopressin or ADH
2.Oxytocin
The posterior pituitary gland does not synthesise hormones, what does it do with them instead?
Stores and releases hormones produced by cells of hypothalamus
What is there a network of between the hypothalamus and posterior pituitary gland
Network of fibres through which the hormones travel through
What is the posterior pituitary gland supplied by
Arterial blood
What is vasopressin or antidiuretic hormone? (released by the posterior pituitary)
a short peptide that is secreted in response to elevated plasma osmolarity (high salt or low water content) or decreased blood volume.
It acts on the kidney tubules to enhance water reabsorption from the tubular fluid and the formation of more concentrated urine (i.e., a water conservation mechanism).