Final 2 Lec For MT3

Question 1

Hydrophilic hormones (water loving)

Answer 1

• Highly water soluble : Low lipid solubility
Cells can make ahead of time and CAN CONTAIN until they are needed
Quicker response, available almost immediately bc they were just being stored
Ready to go

Question 2

Lipophilic hormones (lipid-loving)

Answer 2

Highly lipid soluble: Low water solubility
Don’t travel well on own in blood
Cells that make them CANT contain them- they diffuse out and you prob have to make them on demand - have to wait to make them

Question 3

Chemical properties of a hormone impact

Answer 3

a. If it can be stored in cells before release into bloodstream
b.How the hormone is carried throughout the bloodstream
c. Its metabolism and excretion
d. Its mode of action at target cells

Question 4

Secretion vs storage

Answer 4

• Hydrophilic hormones can be stored in secretion vesicles after synthesis, secretion can be regulated separately from synthesis
• Lipophilic hormones diffuse out of cells as soon as synthesized
• Secretion rate can be pulsatile and/or follow a circadian rhythm

Question 5

Transport

Answer 5

• Hydrophilic hormones are soluble in plasma
• Lipophilic hormones bound to both general and specific proteins in plasma

Question 6

Secreted hormones can be modified to become less-active:

Answer 6

1) Hydrophilic: cleaved by circulating proteases (DPP-IV on GLP1)
2) Lipophilic: modified to be more water soluble and more easily lost in urine

Question 7

Secreted hormones can be modified to become MORE ACTIVE:

Answer 7

1) Hydrophilic: cleaved by specific proteolytic enzymes

Angiotensinogen ——-Angiotensin I —— Angiotensin II (from liver)

2) Lipophilic: enzymes in target cells can modify structure to produce more active hormone

Question 8

Hormone receptors are expressed in target tissues and upon hormone binding…

Answer 8

Initiate biochemical chain of events that alters cell function
Always signal transduction cascade

Question 9

Hydrophilic hormones act via

Answer 9

receptors in target cell membrane (i.e., membrane receptors) and activate receptor-enzyme complexes, or recruit second-messenger systems to produce their physiological response

Question 10

Lipophilic hormones act via

Answer 10

intracellular receptors that act in the cell nucleus (i.e. nuclear receptors) to induce gene transcription, producing their physiological response.

Question 11

Hydrophilic hormones can use MEMBRANE RECEPTORS

Answer 11

that activate downstream “second messengers” pathways, e.g. cAMP
Huge amplification possible

Question 12

Effect time of Lipophilic hormones

Answer 12

Effects are generally slower onset, longer lasting than effects via membrane receptors (hydro)

Lipophilic hormones use intracellular (nuclear) receptors to regulate specific gene transcription

Question 13

Hypothalamus

Answer 13

site in our CNS that collects and integrates
information from different inputs

Question 14

Pituitary

Answer 14

‘master’ endocrine gland that controls many of the endocrine systems in our body

Question 15

Glandular portion of pituitary gland

Answer 15

hormones of the ANTERIOR pituitary are produced in the pituitary, in response to hypothalamic releasing and inhibiting hormones.

Question 16

Posterior pituitary

Answer 16

neural portion– hormones of the posterior pituitary are synthesized in the hypothalamus and stored in vesicles in the pituitary where they are released into circulation

Question 17

Hormones of posterior pituitary released in response to

Answer 17

neural input from the hypothalamus

Travel down axons
Release vasopressin and oxytocin into systemic blood

Question 18

Oxytocin and pair bonding

Answer 18

Oxytocin influences pair-bonding and parent-offspring bonding
• Giving a female prairie vole oxytocin causes her to stay with her mate, and to bond with her offspring.

Question 19

Tropic hormones of anterior pituitary controlled by

Answer 19

hypothalamic releasing or inhibiting hormones
Neurosecretory neurons in hypothalamus secrete releasing and inhibiting hormones into portal system
Endocrine cells of anterior pituitary secrete anterior pituitary hormones into systemic blood

Question 20

Variations in neuro hormone release

Answer 20

Release of neurosecretory hormones from the hypothalamus in the median eminence (anterior pituitary) or directly in the systemic circulation (posterior pituitary)

Release of anterior pituitary hormones (most are trophic) directly in the systemic circulation

Question 21

Tropic hormones

Answer 21

-Regulate hormone secretion by another endocrine gland
-Stimulate and maintain their endocrine gland target tissues

Question 22

Is prolactin a trophic hormone

Answer 22

NOT trophic
No downstream signaling

Question 23

Growth hormone (GH)

Answer 23

Regulator of somatic cell growth and metabolism

Question 24

Metabolic effects of growth hormone

Answer 24

Adaptation to fasting during sleep
Incr Glucose production by liver
Incr Fatty acid breakdown (Adipocyte)
Incr Amino acid uptake, protein synthesis (Skeletal muscle)
Decr Protein turnover (Skeletal muscle)

Question 25

IGF-1 influence

Answer 25

Inhibits GH from anterior pituitary and GHRH secretion from hypothalamic gland
Inhibit higher 2 layers

Question 26

Hypothalamus is just an

Answer 26

Integration center
Integrates info from across the body

Question 27

Growth hormone excess

Answer 27

Maybe a pituitary tumor ; excess GH; huge

Question 28

Dwarfism

Answer 28

Too little GH or GH receptor defect

Question 29

IGF-1 stimulates

Answer 29

chondrocyte growth and osteoclast differentiation

Question 30

Stop growing

Answer 30

Once growth plate is sealed

Question 31

ACTH: adrenocorticotropic hormone

Answer 31

Stimulate adrenal cortex

Question 32

What type of hormones are released from the adrenal cortex

Answer 32

Lipophilic (steroid ) hormones

Question 33

What releases aldosterone

Answer 33

adrenal cortex releases aldosterone primarily in response to the renin-angiotensin system

1. Aldosterone acts via mineralocorticoid receptor(MR) on the distal and collecting tubules of the kidney, resulting in expansion of plasma volume, which should increase blood pressure.
2. Adrenocorticotropic hormone(ACTH) does not significantly promote aldosterone secretion. Therefore regulation of aldosterone is independent of anterior pituitary control.

Question 34

DHEA released by

Answer 34

Adrenal cortex in response to ACTH

Only adrenal sex hormone of importance
• Feeds back to inhibit GnRH rather than CRH
• Physiologically negligible in men, but accounts for ~50% of circulating androgens in women
– Growth of pubic and axillary hair
– Enhancement of pubertal growth spurt
– Development and maintenance of female sex drive

Question 35

Steroid hormones of the adrenal cortex

Answer 35

Aldosterone, cortisol, sex steroids

Question 36

Cortisol effects

Question 37

Adrenal medulla releases ______ hormones

Answer 37

Hydrophilic (catecholamine)
Epinephrine (~80%)
Norepinephrine (~20%)

Question 38

Adrenal medulla releases catecholamines…

Answer 38

primarily in response to sympathetic signals arising in the hypothalamus and brainstem

1. Adrenal secretion of norepinephrine (noradrenaline) and epinephrine (adrenaline) generally reinforces sympathetic output.
   • Recall, this is your “Fight or flight response.”
2. Epinephrine also has specific effects by acting via b2 adrenergic receptors (which have no affinity for norepinephrine).
   • relaxes smooth muscle of blood vessels supplying skeletal muscles
   • dilation of airways in lungs
   • induces liver to release glucose via glycogenolysis (major) and/or gluconeogenesis (minor)
   • Induces fat cells to release fatty acids (lipolysis) for fuel
   • Stimulates glucagon release (b1) and inhibits insulin release (a2)

Question 39

Integrated response to stress