Endocrinology Final Exam

Question 1

Pars distalis

Answer 1

Region of the adenohypophysis that has 5 cell types that secrete 6 different polypeptide structured-tropic hormones (LH, FSH, PRL, TSH, ACTH, GH)

Question 2

Gonadal Recrudescence

Answer 2

Period of increased gonadal activity (Ex: active gametogenesis)

Question 3

Oogenesis

Answer 3

Female egg formation/production (Oogenesis + Spermatogenesis = Gametogenesis)

Question 4

Viviparous

Answer 4

Live birth (Ex: humans and most mammals)

Question 5

Seasonal Reproduction

Answer 5

Occurs usually once a year and is on a yearly cycle (cyclical in that sense) (Ex: crocodiles and Alligator mississippiensis show seasonal reproduction)

Question 6

Neurohormone

Answer 6

Bioregulators secreted from a neuron into the blood (Ex: oxytocin)

Question 7

Intracrine

Answer 7

Type of cytocrine that affects the intracellular matrix (2nd messenger) (Ex: cAMP)

Question 8

Agonist/Antagonist

Answer 8

Agonists mimic bioregulators, interacting/binding to the receptor and causes it to activate. Antagonists also mimic bioregulators and interact/bind to the receptor but DO NOT activate it.

Question 9

Gluconeogenesis

Answer 9

Process of producing glucose from non-carbohydrate sources

Question 10

Paracrine

Answer 10

A type of cytocrine that affect cells that are not of the same cytocrine cell type

Question 11

Natural Selection

Answer 11

The differential success in the reproduction of a phenotype out of an organism’s interaction with the environment.
- Variation exists among individuals in regard to trait
- Variation is heritable
- Difference is fitness exists among individuals in a population; There is a correlation between the trait and ability to reproduce
If all of these are in place, then the phenotype in subsequent generations will be predictably different than those of previous generations

Question 12

Endocrine Disruptors

Answer 12

Chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and/or immune effects in both humans and wildlife

Question 13

Possible Effects of Endocrine Disruption

Answer 13

Systemic abnormalities, cancer, developmental disorders, impaired neurological function

Question 14

Stress

Answer 14

A physiological response to any factor, environmental condition, or demand that impairs homeostasis, regulatory function, reproduction, growth, and/or Darwinian fitness

Question 15

Testosterone Mechanism

Answer 15

Free testosterone is transported into the target tissue cell cytoplasm. It is reduced by 5-alpha-reductase to 5-alpha-di-hydro-testosterone (DHT). DHT will bind to an androgen receptor-heat shock protein complex. When DHT binds to the AR, the HSP is kicked off the AR. The DHT-AR complex then enters the nucleus through the nuclear pore complex via a 2nd messenger system. After it is in the nucleus, the DHT-AR complex will bind to a specific nucleotide sequence on the DNA. The DHT-AR complex will act as the transcription factor and mRNA transcription will be activated. The mRNA will promote the reduction of cholesterol to pregnenolone. STAR protein regulates steroid biosynthesis by controlling the transport of cholesterol from outer to inner mitochondria. Once cholesterol enters the mitochondria, CYP11A1 (a cholesterol side chain cleavage enzyme) will catalyze the conversion of cholesterol to pregnenolone. HSD3B1(hydroxy-delta-5-steroid dehydrogenase- 3 beta- and steroid delta-isomerase 1) is an oxidative reducer and converts pregnenolone to progesterone. CYP17A1 in the smooth endoplasmic reticulum is a hydroxylase that converts progesterone to androstenedione. CYP17A1 is important in steroid synthesis. The outcome of this entire mechanism is the production of androstenedione, a steroid hormone (and precursor of testosterone) used in the synthesis of testosterone. Sometimes the mRNA can travel directly to the smooth endoplasmic reticulum and bypass the mitochondria steps.

Question 16

Stress Triad

Answer 16

Defined by Hans Selye
Adrenal and corticoid hypertrophy, atrophy of the thymus and lymphoid tissue, ulceration of the digestive tract

Question 17

General Adaptation Syndrome Step

Answer 17

Alarm, Resistance, Exhaustion

Question 18

Alarm Stage

Answer 18

Recognition of the stressor and preparation to respond to the stressor (adrenaline and activation of the HPA and SNS)

Question 19

Resistance Stage

Answer 19

Homeostatic mechanisms attempt to resolve stress

Question 20

Exhaustion Stage

Answer 20

Continuation of the stressor leads to maladaptation (Adrenal fatigue)

Question 21

Distress

Answer 21

Gets to exhaustion stage and never resolves

Question 22

Eustress

Answer 22

Does not go past the resistance stage

Question 23

Corticosteroid

Answer 23

Bioregulators involved in stress and in some cases they can aid in metabolic pathways (2 subcategories)

Question 24

Subcategories of Corticosteroids

Answer 24

Glucocorticoids and Mineralocorticoids

Question 25

Glucocorticoids

Answer 25

Cortisol and Corticosterone

Question 26

Mineralocorticoids

Answer 26

Aldosterone

Question 27

Cortisol and Corticosterone

Answer 27

In humans the main corticosteroid bioregulator is cortisol, while most other mammals use corticosterone

Question 28

Physiological Effects of Glucocorticoids

Answer 28

Promotes gluconeogenesis Acute: Increase in glucose substrates Chronic: Catabolism of skeletal muscles

Question 29

Behavioral Effects of Glucocorticoid

Answer 29

Increased locomotor activity, increased feed rate, redirection of energy away from reproductive activity

Question 30

Example Endocrine Disruptors

Answer 30

Can be both natural and man-made Pharmaceuticals, Pesticides (DDT), Herbicide (Atrazine), Foods, Detergents, Plastic bottles, Metal cans

Question 31

DDT

Answer 31

Dichlorodiphenyltrichloroethane, an organic pesticide for mosquitos carrying malaria

Question 32

Effects of DDT

Answer 32

Caused a decrease in eagle population due to endocrine disruption; Saw highest effects in eagles due to biomagnification

Question 33

DDT Persistence

Answer 33

Persistence in the environment due to strong covalent carbon bonds

Question 34

Endocrine Disruption and Frogs

Answer 34

Amphibian malformations; Frogs were seen to have skeletal and eye abnormalities

Question 35

Dr. Lou Gillette

Answer 35

Studied the reproductive system and cycles of alligators

Question 36

Endocrine Disruption and Alligators

Answer 36

Males had lower levels of testosterone and smaller penis sizes

Question 37

Tyrone Hayes

Answer 37

Studied atrazine and X. laevis

Question 38

Atrazine

Answer 38

Widely used herbicide (weed killer)

Question 39

Endocrine Disruption and X. laevis

Answer 39

Atrazine caused inhibited growth of larynx in males (lack of mating calls/songs), caused both testis and ovary formation, caused low fertility in males (not enough testosterone to maintain male behavior and sperm count), induced aromatase activity by atrazine causes increase in estrogen by promoting the conversion of testosterone and other plasma androgens to estrogen (leading to increased feminization of male X. laevis)