Endocrine Sytem - Bio Exam 3

Endocrine system

Network of glands and organs that create and release hormones directly into the bloodstream. Has slower speed of communication, but long-lasting effects

Water soluble hormone

Hormones that act on membrane receptors. Has rapid effects. Ex. Peptides and Amines

Lipid soluble hormones

Hormones that act on intracellular receptors. Has slow but long-lasting effects. Must travel with transport proteins. Ex. Steroids

Pituitary gland

“Master” endocrine gland. Under the hypothalamus, it regulates vital bodily functions and controls the activity of many other hormone-producing glands in the endocrine system.

Posterior pituitary gland

Pituitary gland which is directly connected to the brain. Neurosecretory cells secrete posterior pituitary hormones that go directly to the bloodstream, such as ADH and Oxytocin.

Anterior pituitary gland

Pituitary gland which is connected to the brain by vessels. Neurosecretory cells do not leave the hypothalamus or extend to the pituitary gland. They instead have releasing hormones which go to vessels, which then trigger the release of anterior pituitary hormones, such as TSH and ACTH.

Oxytocin

Regulates maternal activities such as contractions at birth, and stimulating milk ejection. When acting as a neurotransmitter, promotes relationship bonding.

ADH (Antidiuretic hormone)

Conserves water by reducing water loss in urine. When system is too salty, is released and the kidney pulls water back in.

Releasing (or inhibiting) hormones

Released by the anterior pituitary gland neurosecretory cells in the hypothalamus. Released into portal vessels, which bind to anterior pituitary receptors.

Anterior pituitary hormones

Releasing hormones bind to anterior pituitary receptors, which release these

Adrenal gland

On top of the kidney, consists of and outer layer: the adrenal cortex and the inner core: the adrenal medulla

Adrenal cortex

Releases steroid hormones like glucocorticoids, impacting blood glucose. These have slow, long lasting effects

Adrenal medulla

Releases amine hormones like epinephrine and norepinephrine. These have rapid effects, such as for fight or flight

Components of Adrenal Cortex

Releasing hormone creates CRH, which binds to the anterior pituitary, secreting ACTH. ACTH receptors then cause Glucocorticoids to be released - cortisol in humans.

Glucocorticoids

Cortisol in humans, causes the breakdown of proteins and fats to glucose, suppresses the immune system, inhibits reproduction and growth

Components of Adrenal Medulla

Does not involve the pituitary gland. Nerve signals go to spinal cord, then adrenal gland. Epinephrine and norepinephrine (adrenaline) is then released

Epinephrine and norepinephrine

Adrenaline, causes increased blood glucose, blood pressure, breathing rate, blood flow to the brain, heart, and muscles, and decreased digestive processes.

Thyroid

A small, butterfly-shaped endocrine gland located at the front of the neck

Thyroid hormone pathway

Neurosecretory cells release TRH, which goes to anterior pituitary gland and creates TSH, which goes to thyroid gland, which creates T3 and T4

T3 and T4

Thyroid hormones which target cells increase cellular metabolism

Hyperthyroidism

Too much thyroid hormone. Causes feeling too hot, lost weight, and irritability

Hypothyroidism

Not enough thyroid hormone. Causes feeling too cold, weight gain, and tiredness. Caused by not enough iodine in the diet, as the thyroid gland needs iodine to product T3 and T4