The Endocrine System Flashcards
What are the 3 types of cell to cell communication?
- Neurotransmitters Short-range chemical messengers - Neurohormones Released into blood by neurosecretory neurone - Hormones Long-range messengers
How does the Endocrine System differ from the Nervous System?
It uses hormones interred of nerve signals to effect a site far from release. It targets cells throughout the body and occurs for seconds - days.
What is the purpose of the endocrine glands and how does this occur?
Their purpose is to produce hormones.
Secretion of hormones into fluid that borders the gland, diffusion into the local capillaries and blood transports the hormones to the target cells
What is a hormone?
Lipid/water soluble that is secreted by the glands into the surrounding interstitial fluid, which then diffuses into the blood stream
What are Exocrine Glands?
Glands that secrete their products into ducts and then a channel into an organ’s interior or to the body’s outer surface
What are Endocrine glands?
Glands that secrete hormones into the intestitial fluid that borders the cell, then diffuse into local capillaries and then hormones are transported by blood to target cells
What are the two chemical classes of hormones and the difference between them?
Lipid Soluble Hormones - Hydrophobic hormones that circulate abound to transport proteins
Water Soluble Hormones - Circulate freely in the blood
How do lipid soluble hormones signal cells?
They enter the cell and bind to receptors in the cytoplasm or nucleus
How do water soluble hormones signal cells?
They bind to cell surface receptors as they cannot pass the membrane
What are the two types of hormone structures and what are their effects?
Protein - soluble, binds to cell surface, rapid response
Steroid - Insoluble, diffuses through cell membrane and response is relatively slow
What are the two classes of hypothalamic regulatory hormones?
- Releasing Hormones (RH)
- Inhibiting Hormones (IH)
The rate of secretion is controlled by a negative feedback
What are the 5 types of Anterior Pituitary Cells?
- Somatotroph
- Thyrotrophs
- Gonadtrophs
- Lactotrophs
- Corticotrophs
What are the roles of Oxytocin?
Oxytocin controls milk release from lactating breasts and controls uterine contraction at onset of labour
What does Growth Hormone do via Growth Hormone receptors?
Protects against hypoglycaemia, increases muscle mass and decreases fat deposits in adipose tissue
Where is the Thyroid Gland located?
Inferior to thyroid cartilage of larynx
