Endocrine Physiology MBR 2022

Endocrine Physiology

tips​

Elaine C. Cunanan, MD, MHPEd

Assistant Professor

Department of Physiology, UST-FMS​

Multiple Choice

Steroid hormones are derived from which parent compound?

• inositol triphosphate

• polyunsaturated fatty acids

• prohormones

• cholesterol

Multiple Choice

Which is secreted by the hypothalamus?

• Oxytocin

• Dopamine

• TSH

• Testosterone

Multiple Choice

Which is produced by the hypothalamus?

• Oxytocin

• Prolactin

• TSH

• Testosterone

​Synthesized/Produced in the Hypothalamus

(Magnocellular neurons)​

• Vasopressin (supraoptic nuclei)

• ​Oxytocin (paraventricular nuclei)​

​

*Stored and secreted/released by the posterior pituitary (neurohypophysis)

Multiple Choice

Which causes increased secretion of oxytocin?

• Milk ejection

• Dilatation of the cervix

• Increased prolactin

• Increased serum osmolarity

​Oxytocin Secretion

Stimuli:

1. Suckling

2. Dilation of the cervix​

​

Actions of oxytocin

1. Contraction of myoepithelial cells in the breast

Milk ejection / letdown

2. Contraction of the uterus

​

Multiple Choice

Which causes increased secretion of vasopressin?

• hyperkalemia

• hyponatremia

• hypotension

• decreased plasma osmolarity

​ADH (Vasopressin) Secretion

q Main stimulus: increased extracellular fluid osmolarity​

q Secondary stimuli: low blood volume, low blood pressure

​

​

​​

​ q Functions/effects:​

V1 receptors of blood vessels à vasoconstriction

V2 receptors of Distal Tubules and Cortical Collecting Ducts 

à insertion of water channels (aquaporin-2)

à water reabsorption

​

Multiple Choice

Pituitary stalk compression by a tumor will usually lead to an increase in

• FSH

• TSH

• Prolactin

• ACTH

F SH

L H

A CTH

G H

T SH

--

P​rolactin

Multiple Choice

Which is not part of the actions of prolactin?

• inhibits spermatogenesis

• stimulates breast development

• stimulates ovulation

• stimulates milk production

Multiple Choice

Which of the following inhibits the secretion of growth hormone by the

anterior pituitary?

• sleep

• somatomedin

• starv

• stress

Multiple Choice

Proopiomelanocortin (POMC) is a precursor of which substance?

• Thyroid-releasing hormone

• Luteinizing hormone

• Adreno-corticotropic hormone

• Follicle-stimulating

  hormone

Multiple Choice

Which of the following would be expected in a patient with Graves

disease?

• increased TSH

• atrophy of the thyroid gland

• increased thyroid peroxidase activity

• decreased 5' deiodinase activity

Multiple Choice

Which is secreted by the apha cells of the pancreas?

• glucose insulinotropic hormone

• insulin

• dipeptidyl peptidase

• glucagon

Multiple Choice

Insulin stimulates glucose uptake by the following cells EXCEPT:

• adipose

• hepatic

• neuron

• skeletal muscle

Multiple Choice

Insulin stimulates

• glycogenolysis

• gluconeogenesis

• ketogenesis

• glucose uptake in fats

Multiple Choice

Characteristic of Glucagon-like peptide 1

• inhibits glucagon

• inhibits insulin

• increases postprandial glucose

• secreted during fasting

Multiple Choice

What type of volume contraction is seen in adrenocortical insufficiency?

• Hyperosmotic contraction

• Hypoosmotic volume contraction

• Hyperosmotic expansion

• Hypoosmotic volume expansion

Multiple Choice

A 46-year-old woman has hirsutism, hyperglycemia, obesity, muscle

wasting, and increased circulating levels of adrenocorticotropic hormone

(ACTH). The most likely cause of her symptoms is

• primary adrenocortical insufficiency (Addison disease)

• primary overproduction of ACTH (Cushing disease)

• treatment with exogenous glucocorticoids

• cortisol-producing adrenal tumor

Multiple Choice

Which of the following results from the action of parathyroid hormone

(PTH) on the renal tubule?

• inhibition of 1-alpha hydroxylase

• Stimulation of Ca2+ reabsorption in the distal tubule

• Stimulation of phosphate reabsorption in the proximal tubule

• Interaction with receptors on the luminal membrane of the proximal tubular

  cells

Multiple Choice

About 60% of testosterone is bound to which of the following?

• Plasma globulin

• testicular tissue

• plasma albumin

• sex-hormone binding globulin

​Peripheral testosterone (or estrogen):

60% bound to sex hormone-binding globulin (SHBG)

38% bound to plasma albumin

2% - "free" hormone

Multiple Choice

Which step of spermatogenesis do all the 46 chromosomes replicate?

• last phase of spermatogenesis

• first meiotic division

• first stage of spermatogenesis

• second meiotic division

Diploid (2N) 46 chromosomes = 23 pairs (male 46XY)

Haploid (N) 23 chromosomes

Multiple Choice

Which area in the ovum does the anterior membrane of the sperm bind specifically with a receptor protein?

• cytoplasm

• perivitelline space

• nucleus

• zona pellucida

Multiple Choice

Which hormone increases endometrial gland secretion?

• human 17B-estradiol

• estrogen

• progesterone

• Human chorionic gonadotropins

Multiple Choice

Approximately which day does the final involution of the corpus luteum occur in the menstrual cycle?

• 14th

• 18th

• 26th

• 28th

Multiple Choice

A patient consulted for heavier menses lasting more than her usual 7 days. What type of menstrual disorder does she have?

• polymenorrhea

• menorrhagia

• menometrorrhagia

• metrorrhagia

​Menorrhagia - menstruation at regular cycle intervals but with excessive flow and duration (total blood loss exceeding 80 mL per cycle or menses lasting longer than 7 days)

​

​Metrorrhagia - flow at irregular intervals

​

Menometrorrhagia - frequent, excessive flow

​

Polymenorrhea - bleeding at intervals < 21 days