Hormones Flashcards
What are endocrine glands, what is an example?
contain cells that produce a hormone and release it straight into the blood
- e.g. pancreatic cells, release insulin directly into the blood
What are exocrine glands, what is an example?
they have a duct that carries the secretion to another place, produce hormones which are not directly released into the blood
-e.g. liver makes bile, used in the small intestine
What are the characteristics of protein/peptide hormones?
They are not soluble - hydrophilic (cannot pass through the cell membrane)
bind to a specific cell receptor
What are the characteristics of steroid hormones?
are lipid soluble, bind to steroid hormone receptors to form complex
the complex formed acts as a transcription factor - inhibits or facilitates the transcription of a specific gene
What are some examples of steroid hormones?
oestrogen
testosterone
What are some examples of protein hormones?
insulin and adrenaline
What are the comparisons of hormonal and neuronal communication?
hormones = not directly released to their target cell, slower and less specific response, not broken down very fast = longer lasting effect
neuronal = transmission very rapid, short lived, effect is temporary and reversible
What is the definition of a target cell?
the target organs/destination of the hormone
Where in the body are adrenal glands located?
on top of each kidney
What is the structure of the adrenal glands from the outside layer going in?
outside = capsule
middle = adrenal cortex
inside = medulla
What is the adrenal cortex?
produces steroid hormones that are vital to life, helps control metabolism
What is the adrenal medulla?
produces non essential hormones, such as adrenaline
What type of gland is the adrenal gland?
endocrine gland, releases hormones directly into the blood
What are the three types of hormones produced by the adrenal cortex?
glucocorticoids = cortisol, helps control metabolism of carbohydrates and proteins in the liver
mineralocortoids = e.g. aldosterone controls the ion conc. in the blood
androgens = small volumes of male and female sex hormones released
When are hormones in the adrenal medulla released?
when the sympathetic nervous system is stimulated e.g. when the body is stressed
Which 2 hormones does the adrenal medulla release?
adrenaline = increases H.R, B,R and blood glucose conc.
noradrenaline = neurotransmitter which widens the air passage to the lungs, pupil dilation and shutting down of non essential organs e.g. digestive system
How does adrenaline effect cells?
- adrenaline (the primary messenger), which binds to the receptor site of the cell surface membrane
- this forms an adrenaline - receptor complex, which activates the Adenyl cyclase
- the Adenyl cyclase converts ATP to cAMP, which can activate other enzymes inside the cell
- the cAMP works inside the cell as a secondary messenger
How does the pancreas act as a exocrine gland?
to produce enzymes and release them via a duct into the duodenum
How does the pancreas act as a endocrine gland?
to produce hormones and release them into the blood
What does the exocrine glandular tissue release and why?
produces digestive enzymes and an alkaline fluid known as pancreatic juice
How do hormones and enzymes get transported to the cells that need it?
enzyme producing cells arranged around tubules which join up to form the pancreatic duct
What are the three important types of digestive enzyme produced by the pancreatic cells?
- Amylase - carbohydrase (breaks down starch into simple sugars)
- Proteases - break down proteins into amino acids
- Lipases - break down lipids into three fatty acids and a glycerol molecule
What is the role of the endocrine gland in the pancreas?
hormone secretion (insulin and glucagon)
there is only a small region of endocrine tissue known as the islet of Langerhans
What are the two types of cells located in the islet of Langerhans, and which hormones do they produce?
Alpha cells produce glucagon
Beta cells produce insulin
secreted directly into the bloodstream
