BP: The endocrine system Flashcards
(24 cards)
What are endocrine glands?
- Special groups of cells within the endocrine system, whose function is to produce & secrete hormones, (chemical substances that regulate the activity of cells or organs in the body.)
- Each gland in the endocrine system produces different hormones, which regulate the activity of organs and tissues in the body.
What is the endocrine system?
A network of glands throughout the body that manuacture and secrete chemical messengers known as hormones.
What are hormones?
The body’s chemical messengers. They travel through the bloodstream, influencing many different processes including mood, the stress response and bonding between mother and newborn baby.
What is the Pituitary Gland?
The ‘master gland’ whose primary function is to influence the release of hormones from other glands.
How does the endocrine system transmit information around the body and how is this different to the nervous system?
Endocrine system- information travels via blood vessels to deliver hormones to their target sites in the body.
Nervous system- Uses nerves to transmit information.
What are the different glands/ parts in the Endocrine System & what does each part do?
Hypothalamus- (brain region controlling the pituitary gland.)
Pituitary gland- (secretes many different hormones, some of which affect other glands.)
Adrenal glands- (help trigger the fight-or-flight response)
Ovary- (secretes female sex hormones)
Testis- (secretes male sex hormones.)
How is the endocrine system regulated?
(And examle if you can of the process)
Regulated by feedback that is similar to how a thermostat regulates temperature in a room.
e.g.
- A signal is sent from the hypothalamus to the pituitary gland in the form of a ‘releasing hormone’.
- This causes the pituitary to secrete a ‘stimulating hormone’ into the bloodstream.
- This hormone then signals the ‘target gland’ (e.g. adrenal gland) to secrete its hormone.
- As levels of this hormone rises into the bloodstream, the hypothalamus shuts down secretion of the ‘releasing hormone’ and the pituitary gland shuts down secretion of the stimulating hormone.
- This slows down the secretion of the target glands hormone, resulting in stable concentrations of hormones circulating in the bloodstream.
Although hormones come into contact with most cells in the body- what does a given hormone usually only affect?
Affects only a limited number of cells, known as target cells.
What do target cells do?
- Target cells respond to a particular hormone because they have receptors for that hormone.
- Cells that do not have such a receptor cannot be influenced directly by that hormone.
- When enough receptor sites are stimulated by hormones, this results in a physiological reaction in the target cell.
Why is timing of the release of hormones and the amount of hormones released critical for normal functioning?
Too much or too little at the wrong time can result in dysfunction of bodily systems.
(e.g. too high a level of cortisol can lead to Cushings syndrome, characterised by high blood pressure and depression. The most common cause of excess cortisol is a tumour in the pituitary gland which makes too much of a hormone called adrenocorticotrophic ACTH which stimulates the adrenal glands to make too much cortisol.)
Where are the two adrenal glands located?
They sit on top of the kidneys.
What is each adrenal gland made up of?
- Made up of two distinct parts.
- The outer part of each gland is called the adrenal cortex and the inner region is known as the adrenal medulla.
What are the differences between the adrenal cortex and the adrenal medulla?
One of the main distinctions is that the hormones released by the adrenal cortex are necessary for life; those released by the adrenal medulla are not.
What does the adrenal cortex produce and what does this do?
Adrenal cortex produces cortisol, which regulates or supports a variety of important bodily including cardiovascular and anti-inflammatory.
When is cortisol production increased ?
It is increased in response to stress.
What happens if your cortisol level is low?
The individual has low blood pressure, poor immune function and an iability to deal with stress.
What does the adrenal cortex also produce other than cortisol?
What does this do?
Produces aldosterone, which is responsible for maintaining blood volume and blood pressure.
What does the adrenal medulla release?
Releases adrenaline and noradrenaline, hormones that prepare the body for fight or flight.
What does adrenaline do?
What does noradrenaline do?
Adrenaline: Helps the body respond to a stressful situation, e.g. by increasing heart rate and blood flow to the muscles and brain and helping with the conversion of glycogen to glucose to provide energy.
Noradrenaline: Constricts the blood vessels, causing blood pressure to increase.
What are ovaries responsible for?
Responsible for the production of eggs and for the hormones oestrogen and progesterone.
What has progesterone found to be associated with?
Progesterone (more important in the post-ovulation phase of the menstrual cycle) has been found to be associated with heightened sensitivity to social cues that indicate the presence of social opportunity (e.g. recruiting allies) or threat (from outsiders) that would be significant in the case of pregnancy (Maner & Miller, 2014).
What are the testes?
What does testosterone do?
- Testes- the male reproductive glands that produce the hormone testosterone.
- Testosterone causes the development of male characteristics such as growth of facial hair, deepening of the voice and the growth spurt that takes place during puberty.
What is testosterone production controlled by?
Controlled by the hypothalamus and the pituitary gland. The hypothalamus instructs the pituitary gland on how much testosterone to produce and the pituitary gland passes this message to the testes.
What does testosterone play a role in?
- Plays a role in sex drive, sperm production and maintenence of muscle strength and is assoicated with overall health and well being in men.
- Testosterone is not exclusively a male hormone. Women also have tesosterone but in smaller amounts.
