Endocrinology

Question 1

hormones vs neurotransmitters

Answer 1

hormones are produced in the endocrine glands and released into the blood to find target cells, slow (minutes - day)

neurotransmitters are released into the synaptic cleft by a terminal of a stimulated pre-synaptic neuron, extremely fast (milliseconds)

Question 2

hormones vs neurohormones

Answer 2

hormones are produced in the endocrine glands and released into the blood cell to find target cells

neurohormones are produced and released into the bloodstream to find target cells by specialized neurons called neuroendocrine cells

some neurohormones act like neurotransmitters to signal another neuron

Question 3

hormone

Answer 3

a chemical signal secreted into the blood to act on a distant tissue

Question 4

steroid hormones

Answer 4

ex) testoterone, estrogen, coritsol

building block: cholesterol

hydrophobic that are bound to plasma proteins to move within blood and diffuse through the plasma membrane into the target cell to bind to the receptor (intracellular)

Question 5

protein or peptide (shorter) hormones

Answer 5

ex) hypothalamic and pituitary hormones

building blocks: amino acids

hydrophilic and dissolve into the blood to bind the receptors on the plasma membrane

Question 6

amine hormones

Answer 6

ex) thyroid hormones (T₃, T₄) (hydrophobic), epinephrine (hydrophilic)

building block: tyrosine (most)

can be hydrophobic and hydrophilic so some can dissolve into the blood (hydrophilic) and bind to receptors on the plasma membrane

some have to be bound to a plasma protein (hydrophobic) and bind to receptors intracellularly by diffusing through the plasma membrane

Question 7

peptide hormone and membrane receptor

Answer 7

if a hormone bind membrane receptors, it signals intracellular events

• events tend to alter pre-existing proteins
• protein hormones have faster responses than hormones that bind to intracellular receptors
  ex) opening ion channel, changing activity of protein

Question 8

steriod hormone and intracellular receptors

Answer 8

if a hormone binds intracellular receptors, it signals intracellular events

• event tend to affect production of new proteins
• steroid hormones give a slower response than hormones that trigger membrane receptors
  ex) activates the DNA to make proteins which is slow

Question 9

posterior pituitary and hormones

Answer 9

posterior pituitary is made of neurons

hormones released: neurohormones

oxytocin

antidiuretic hormone (ADH)

Question 10

oxytocin

Answer 10

oxytocin: a peptide neurohormone
- promotes uterine contractions during labour
- promotes milk excretion during breastfeeding

Question 11

antidiuretic hormone

Answer 11

antidiuretic hormone (ADH): a peptide neurohormone

• also called vasopressin
• promotes water absorption in kidneys
• conserves water and regulate blood volume

Question 12

anterior pituitary

Answer 12

• anterior pituitary made of endocrine cells (to make peptide hormones)
• hypothalamus releases hormones to signal the anterior pituitary to release hormones
• through the hypothalamic-hypophyseal portal system

Question 13

what local bloodstream connects the hypothalamus to stimulate hormone release from the anterior pituitary?

Answer 13

hypothalamic-hypophyseal portal system