Endocrine Physiology

Question 1

Hormone

Answer 1

• chemical messenger
• secreted from ductless gland
• emptied directly into circulation
• transported by blood to alter target organ
• present in small concentrations

Question 2

Endocrine system

Answer 2

Glands that release hormones into circulation

- helps establish systemic homeostasis

Question 3

What 3 things does the endocrine system regulate?

Answer 3

• metabolism
• growth and development
• mood

Question 4

Endocrine glands

Answer 4

• hypothalamus
• pituitary
• thyroid
• parathyroid
• adrenal
• pancreas
• repro (ovary, testicle, placenta, mammary)
• kidneys
• GIT

Question 5

Hormone structure affects

Answer 5

• function
• transport
• interaction with target cell

Question 6

Protein hormones

Answer 6

Mostly go to the brain

• dissolved in blood: hydrophilic, no carrier needed
• receptors on plasma membrane

Question 7

Hypothalamic protein hormones

Answer 7

• TRH

- CRH

Question 8

Pituitary protein hormones

Answer 8

• TSH, ACTH
• growth hormone
• vasopressin
• oxytocin

Question 9

Amine hormones

Answer 9

Derived from tyrosine

• thyroid hormones
• transported bound to proteins (99%) –> lipophilic
• only free form is active
• bound protein isn’t excreted
• receptors: intracellular

Question 10

Steroid hormones

Answer 10

Derived from cholesterol

• transported bound to proteins –> lipophilic
• only free form is active
• receptors: cytosolic, nuclear
• cortisol
• sex hormones

Question 11

Feedback control

Answer 11

Regulation of hormonal secretion from an endocrine gland by an effect of the circulating hormone that the gland itself produces

Question 12

Negative feedback

Answer 12

Increased hormone concentrations result in less production of the hormone, usually through an interaction with the hypothalamus or pituitary gland

Question 13

Negative feedback example (thyroid)

Answer 13

Higher thyroid hormone concentrations decrease release of stimulatory and releasing hormones (TSH, TRH)
- decreased release of stimulatory and releasing hormones results in decreased synthesis of T4

Question 14

_____ of hormone production results in increased release of ______

Answer 14

Lack; sitmulatory hormones

Question 15

The hypothalamus is part of the _______

Answer 15

Diencephalon

- forms floor of 3rd ventricle

Question 16

Anterior versus posterior pituitary

Answer 16

Anterior: adenohypophysis
- glandular
- pars distalis/tuberalis/intermedia
Posterior: neurohypophysis
- neural tissue

Question 17

AP embryology

Answer 17

• Rathke’s pouch
• invagination of pharyngeal epithelium
• epithelioid cells

Question 18

PP embryology

Answer 18

• neural outgrowth from hypothalamus

- neural tissue

Question 19

Hypothalamic/pituitary relationship

Answer 19

• hypothalamus controls release of pituitary hormones
• AP: releases hormones/inhibitory hormones
• PP: neuronal control

Question 20

How does the hypothalamus receive signals from the brain?

Answer 20

• break in BBB

- fenestrated capillaries allow sampling of chemicals in the blood

Question 21

Median eminence

Answer 21

Lower-most portion of HT

• connects with pituitary stalk
• arteries penetrate ME
• HT blood flows thru ME directly to AP
• HT hormones released into ME

Question 22

Magnocellular

Answer 22

“Large neurons”

• cell bodies of PP in HT
• supraoptic nuclei (ADH)
• paraventricular nuclei (oxytocin)
• axons terminate in PP

Question 23

Hormones secreted from PP neurons

Answer 23

Transported down nerve fibers

- released into surrounding capillaries

Question 24

Anterior pituitary hormones

Answer 24

• corticotropes (20%): ACTH
• thyrotropes (4%): TSH
• somatotropes (30-40%): growth hormones –> acidophils
• lactotropes (4%): prolactin
• gonadotropes (4%): FSH, LH

Question 25

Antidiuretic hormone

Answer 25

Aka: vasopressin

• regulates free water excretion from kidneys
• blood pressure

Question 26

Oxytocin

Answer 26

• milk expression
• birth
• orgasm