BIO Ch. 5 Endocrine System

Question 1

How do peptide hormones operate?

Answer 1

peptide hormones bind to membrane-bound receptors to initiate a signaling cascade, using second messengers like cyclic adenosine monophosphate (cAMP), inositol triphosphate (IP3), and calcium

Question 2

What is the diff b/w peptide and steroid hormones?

Answer 2

peptide hormones are made up of amino acids derived from polypeptides, water-soluble, short-lived, charged, and travel through the bloodstream.
steroid hormones are derived from cholesterol produced by gonads and adrenal cortex, nonpolar, and can easily cross the cell membrane

Question 3

How do steroid hormones work?

Answer 3

they bind to intracellular receptors in the cytosol or nucleus and function by binding to DNA to alter gene expression altering the amount of mRNA and protein present in a cell

Question 3

How are steroid hormones activated?

Answer 3

while attached to carrier proteins, steroid hormones are inactive and must disassociate to carry out function, thus the levels of carrier proteins change the level of active hormones

Question 4

What are some examples of amino-acid-derived hormones?

Answer 4

epinephrine, norepinephrine, triiodothyronine, thyroxine

Question 5

What are some examples of peptide-derived hormones?

Answer 5

insulin, vasopressin, thyroxine, triidyronine

Question 6

What are some examples of steroid-derived hormones?

Answer 6

testosterone, estrogen, cortisol, glucocorticoids, cholesterol

Question 7

What is the diff b/w the activation of catecholamines and thyroid hormones?

Answer 7

catecholamines (norepinephrine and epinephrine) bind to G-protein-couple receptors while thyroid hormones bind intracellularly

Question 8

How does the hypothalamus regulate?

Answer 8

via negative feedback which occurs when a hormone later in the pathway inhibits its hormones earlier in the pathway

Question 8

What is the diff b/w direct and tropic hormones?

Answer 8

direct hormones are secret directly on the target tissues such as insulin secreted by the pancreas causing the increase of uptake of glucose by muscles
tropic hormones require an intermediary to act such as gonadotropin-releasing hormone (GnRH) from the hypothalamus to stimulate the release of LH and FSH which can then act to stimulate testosterone and estrogen

Question 9

Where does the hypothalamus secrete its products?

Answer 9

it secretes compounds into the hypophyseal portal system (blood vessel system that directly connects the hypothalamus to the anterior pituitary) that travel down the pituitary stalk to bind to receptors on the anterior pituitary

Question 10

Which hormones are released by the pituitary when GnRH hormone is secreted by the hypothalamus?

Answer 10

FSH and LH

Question 11

Which hormones are released by the pituitary when GHRH hormone is secreted by the hypothalamus?

Answer 11

Growth hormone

Question 12

Which hormones are released by the pituitary when TRH hormone is secreted by the hypothalamus?

Answer 12

TSH

Question 13

Which hormones are released by the pituitary when CRF hormone is secreted by the hypothalamus?

Answer 13

ACTH

Question 14

Which 2 hormones are received by the posterior pituitary?

Answer 14

oxytocin and antidiuretic hormone (ADH) are synthesized by the thpothalmus and reasles in the posterior pituitary

Question 15

What is the exception hormone of the hypothalamus?

Answer 15

prolactin-inhibiting factor (PIF), which is actually dopamine, is released by the hypothalamus and causes a decrease in prolactin secretion

Question 16

What is the role of oxytocin?

Answer 16

stimulation contractions of uterine smooth muscles during labor through a positive feedback mechanism, and milk letdown during lactation

Question 17

What is the role of ADH?

Answer 17

Increase of water reabsorption in the collecting ducts of the nephrons in the kidneys in response to increased plasma osmolarity or increased concentration of solutes within the blood

Question 18

What Are the 4 tropic hormones released by the anterior pituitary gland?

Answer 18

FSH, LH, ACTH, TSH

Question 19

What Are the 4 Direct hormones released by the anterior pituitary gland?

Answer 19

prolactin, endorphins, and GH

Question 20

What is the role of growth hormone?

Answer 20

promotes the growth of bone and muscle, prevents glucose uptake in certain tissues (those not growing), and stimulates the breakdown of FA

Question 20

What is the role of prolactin?

Answer 20

stimulation of milk production in the mammary glands

Question 21

What is the diff b/w gigantism, dwarfism, and acromegaly?

Answer 21

bone growth originates in the epiphyseal plates which seals during puberty. An excess of GH release in childhood before the closure of the plates can cause gigantism and a deficit results in dwarfism. Acromegaly affects the smaller bones like the hands, feet, and head

Question 22

What is the role of triiodothyronine and thyroxine?

Answer 22

increased amounts of T3 and T4 will lead to increased cellular respiration, leading to a greater amount of protein and FA turnover by speeding up both the synthesis and degradation of these compounds

Question 23

Where are triiodothyronine and thyroxine produced?

Answer 23

both are produced by the iodination of the amino acid tyrosine. the numbers 3 and 4 refer to the number of iodine atoms attached to the tyrosine

Question 24

What is the diff b/w hyper and hypothyroidism?

Answer 24

hypo - insufficient or no secretion of thyroid hormones characterized by lethargy, decreased body temp, slower respiratory and heart rate, cold intolerance, and weight gain.
hyper - excessive secretion of thyroid hormone

Question 25

What is cretinism?

Answer 25

a deficient of thyroid hormone in children that results in mental retardation and developmental delay

Question 26

What are the 2 hormones produced by the thyroid?

Answer 26

parafollicular cells/C-cells produce calcitonin, follicular cells produce T3 and T4

Question 27

What is the role of Calcitonin?

Answer 27

acts to decrease plasma calcium levels by decreasing calcium excretion from the kidneys, decreasing calcium absorption from the gut, and increasing storage of calcium in the bone

Question 28

What is the role of calcium?

Answer 28

bone structure and strength, the release of neurotransmitters from neurons, regulation of muscle contraction, clotting of blood (calcium cofactors), cell movement, and exocytosis of cellular materials

Question 29

What is the role of Parathyroid hormone (PTH)?

Answer 29

an antagonist to calcitonin and affects the phosphorous homeostasis by reabsorbing phosphate from bone and reducing reabsorption and excretion of phosphate in the kidney as urine

Question 30

How does PTH antagonist calcium?

Answer 30

PTH raises blood calcium levels, decreases excretion of calcium by the kidneys, increases absorption of calcium in the gut via vit.D, and increases bone resorption, freeing up calcium

Question 31

What are glucocorticoids?

Answer 31

steroid hormones that regulate glucose levels released y the adrenal cortex

Question 32

What are 2 glucocorticoid hormones?

Answer 32

cortisone and cortisol

Question 33

What are the roles of cortisone and cortisol?

Answer 33

raise blood glucose levels by increasing gluconeogenesis and decreasing protein synthesis, and they also decrease inflammation and immunological response

Question 34

How are glucocorticoid hormones released?

Answer 34

corticotropin-release factors (CRF) from the hypothalamus promote the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary, which promotes the release of glucocorticoids from the adrenal cortex

Question 35

What is the diff b/w aldosterone and ADH?

Answer 35

Aldosterone does not change the osmolarity as with ADH

Question 36

What are mineralocorticoid?

Answer 36

hormones that balance water and salt via effecting the kidneys

Question 37

How does aldosterone work?

Answer 37

it increases sodium reabsorption in the distal convoluted tubule and collecting duct of the nephron. water follows the sodium cations into the bloodstream, increasing blood volume and pressure. Aldosterone also decreases the reabsorption of potassium and hydrogen ions in the distal convoluted tubule and collecting ducts of the nephrons, promoting their excretion through urination

Question 38

How is aldosterone secreted?

Answer 38

decreased blood pressure causes the juxtaglomerular cells of the kidneys to secrete renin, which cleaves an inactive plasma protein angiotensin, to its active form, angiotensin I. Angiotensin I is then converted to angiotensin II by the angiotensin-converting enzyme (ACE) in the lungs. angiotensin II stimulates the adrenals to secrete aldosterone