Endocrine System

What makes up the endocrine system?

• comprised of various glands which work together with various tissues and organs to regulate how the body operates

What is the function of glands in general?

• to release chemical messengers called hormones into the bloodstream

How do hormones do their job?

• they bind to specific receptors on target tissues to produce an effect

What monomers are hormones based on?

• amino acids

• lipids

How are hormones based on amino acids?

• water soluble, therefore cannot diffuse through the cell membrane

• receptors are on the cell’s surface

• create reactions inside of the cell

How are hormones based on lipids?

• fat soluble, therefore cannot diffuse through the cell membrane

• receptors are inside of the cell

• activate genes to build certain proteins

How are hormones regulated?

• via negative feedback

How does negative feedback work with hormones?

• a stimulus triggers a hormone’s release

• effect of the hormone decreases the stimulus, and decreases the output of the hormone

What is the function of tropic hormones?

• target other glands to stimulate the release of hormones

Where is the pituitary gland located?

• the brain

What is the pituitary gland known as and why?

• “master control gland”

• releases a number of tropic hormones

What is the pituitary gland controlled by?

• hypothalamus

What is the function of the pituitary gland?

• regulates metabolism, growth, development, reproduction

What are the divisions of the pituitary gland?

• posterior pituitary

• anterior pituitary

What hormones does the posterior pituitary store and release?

• antidiuretic hormone (ADH)

• oxytocin

What hormones does the anterior posterior produce?

• human growth hormone (hGH)

• thyroid stimulating hormone (TSH)

• adrenocorticotropic hormone (ACTH)

• prolactin

• follicle-stimulating hormone (FSH)

• luteinizing hormone

What does human growth hormone stimulate?

• the liver to release growth factors

What do human growth hormone and growth factors promote?

• protein synthesis

• fat utilization

• cell division & growth (especially of cartilage, bone, and muscle)

What occurs if you have too much hGH?

• gigantism

What occurs if you have too little hGH?

• dwarfism

Where is the thyroid gland located?

• below the larynx

What is the function of the thyroid gland?

• regulates metabolism

What hormones does the thyroid gland release?

• thyroxine (T4)

• calcitonin

What is the function of thyroxine?

• increases metabolic rate by increasing cellular respiration in the heart, muscles, kidneys, and liver

What stimulates the release of thyroxine (T4)?

• thyroid simulating hormone (TSH)

What is the function of calcitonin?

• brings down blood calcium levels

• decreases reabsorption of calcium in kidneys

• decreases the action of osteoclasts

What are osteoclasts?

• cells that recycle bone

Where are the parathyroid glands located?

• four small glands attached to the back of the thyroid

What hormones do the parathyroid glands release?

• parathyroid hormone (PTH)

What is the function of parathyroid hormone (PTH)?

• increases blood calcium

• increases reabsorption of calcium in kidneys

• increases action of osteoclasts

Where are the adrenal glands located?

• a pair of glands that sit on the kidneys

What is the function of the adrenal glands?

• regulate the stress response

What are the sections of the adrenal glands?

• adrenal medulla

• adrenal cortex

Is adrenal medulla inner or outer?

• inner

What is the function of the adrenal medulla?

• regulates short-term stress response (fight/flight/freeze)

What regulates the adrenal medulla?

• the sympathetic nervous system for speed

What hormone does the adrenal medulla release?

• epinephrine (Adrenalin) + norepinephrine (noradrenalin)

What is epinephrine also known as?

• adrenaline

What is norepinephrine also known as?

• noradrenaline

What is the function of epinephrine and norepinephrine?

• increases breathing, heart rate, blood pressure, dilate eyes, send blood to muscles, converts glycogen to glucose

Is the adrenal cortex inner or outer?

• outer

What is the function of the adrenal cortex?

• regulates long-term stress response

What is the adrenal cortex stimulated by?

• adrenocorticotropic hormone

What hormones does the adrenal cortex release?

• glucocorticoids

• mineralocorticoids

What is the function of glucocorticoids?

• increase blood sugar

What is an example of a glucocorticoid?

• cortisol

What is the function of cortisol?

• breaks down fats and proteins into glucose

What happens if you have chronic cortisol?

• increased levels causes weight gain, frequent infections, and memory loss

What is the function of mineralocorticoids?

• increases blood sugar

What is an example of a mineralcorticoid?

• aldosterone

What does the pancreas contain?

• specialized cells called islets

What is the function of islets?

• release hormones that regulate blood sugar

What hormones are released by the pancreas?

• insulin

• glucagon

What is the function of insulin?

• decreases blood sugar

• targets muscle cells and tells them to become more permeable to glucose for cellular respiration

What happens once insulin is released?

• liver becomes more permeable to glucose for conversion into glycogen and fat

What is the function of glucagon?

• increases blood sugar

What happens once glucagon is released?

• fat and glycogen are converted into glucose

Where is the pineal gland located?

• in brain

What hormone is released by the pineal gland?

• melatonin

What is the function of melatonin?

• regulates our circadian rhythm including our sleep-wake cycle

What is circadian rhythm?

• changes in the body over a 24 hr period

When do we have an increase of melatonin?

• when it’s dark

• can be affected by screens

What hormone is released by the brainstem?

• serotonin

What is the function of serotonin?

• regulates our mood and sexual desire

What are the glands in the body?

• pituitary gland

• thyroid gland

• parathyroid glands

• adrenal glands

• pancreas

• pineal gland

• brainstem