The smart way to learn. The smart way to teach.

MRCOG PART 1 - CLINICAL MX & DATA

Course PAID
notes170
SBA669
Do you realy want to delete this discussion?
Forum >>

MRCOG I Single best answers: Endocrinology II

MRCOG I Single best answers: Endocrinology II Posted by Farrukh G.

 

1) At birth, the normal ovary contains

 

A) 500 primordial follicles

B) 500,000 primordial follicles

C) 2 million primordial follicles  

D) 500,000 Graafian follicles

E) 2 million Graafian follicles

 

2) At puberty, the ovary contains

A) 2 million primordial follicles

B) 2 million Graafian follicles

C) 400,000 primordial follicles  

D) 400,000 Graafian follicles

E) 40,000 Graafian follicles

 

 

3) The oocyte is separated from the granulosa cells by

 

A) The theca interna

B) The theca externa

C) The zona pellucida  

D) The lamina propria

E) The follicular antrum

 

4) The zona pellucida is produced by

 

A) The oocyte  

B) The granulosa cells

C) The theca cells

D) Ovarian stromal cells

E) The lutein cells

 

5) Between the 2nd and the 5th day of the menstrual cycle

 

A) FSH levels are high

B) LH levels are low  

C) Oestradiol levels are high

D) Progesterone levels are high

E) Granulosa cells begin conversion into lutein cells

 

Questions 6-7

 

A) Theca interna

B) Theca externa

C) Zona pellucida

D) Zona granulosa

E) Lamina propria

 

6) Layer of glycoprotein surrounding the oocyte

 

7) The capsule of the developing Graafian follicle

 

 

8) Ovulation

A) Typically occurs 7 days after the LMP

B) Typically occurs 7 days before the onset of menstruation

C) Typically occurs 14 days before the onset of menstruation  

D) Typically occurs 7 days after the LH surge

E) Typically occurs 18 hours after the FSH surge

 

9) The size of the ovarian follicle just before ovulation

A) 2.5 mm

B) 4.5 mm

C) 25 mm  

D) 45 mm

E) 55 mm

 

10) At ovulation, the granulosa cells surrounding the oocyte form

 

A) The zona pellucida

B) The theca externa

C) The theca interna

D) The cumulus oophorus  

E) The zona granulosa

 

 

11) The corpus luteum

A) Is formed 7 days after the LMP in a woman with a 28 day cycle

B) Degenerates 14 days after the LMP in a woman with a 28 day cycle

C) Is formed from the corpus albicans

D) Has a maximum diameter of 15-30 mm which is attained 7 days after the LMP

E) Secretes oestrogens, progesterone and androgens  

 

 

12) The proliferative phase of the endometrial cycle

 

A) Is characterized by coiling of the spiral arteries

B) Is characterized glycogen accumulation within endometrial epithelial cells

C) Is associated with copious watery cervical mucus  

D) Occurs from day 1 to day 7 of a 28 day cycle

E) Occurs under the influence of progesterone from the corpus luteum

 

13) The secretory phase of the endometrial cycle

 

A) Is under the influence of oestrogen and progesterone from the Graafian follicle

B) Occurs from days 7 to 14 of a 28 day cycle

C) Is associated with the accumulation of glycogen and lipids in endometrial epithelial cells  

D) Is prolonged if fertilization occurs

E) Is prolonged in anovulatory cycles

 

 

14) During the menstrual phase of the endometrial cycle

 

A) The entire epithelial layer of the endometrium is shed

B) The entire stromal layer of the endometrium is shed

C) Cell death occurs mainly by apoptosis

D) There is vasospasm of the spiral arterioles  

E) Levels of progesterone fall while levels of oestrogen rise

 

15) The menstrual phase of the endometrial cycle is characterized by

 

A) Rising levels of oestrogens

B) Rising levels of progesterone

C) Rising levels of follicle stimulating hormone  

D) Blood loss of about 35 ml per day

E) Dilatation of the spiral arterioles

 

16) The mean blood loss during the menstrual cycle is

 

A) 4 ml per day

B) 35 ml  

C) 35 ml per day

D) 80 ml

E) 80 ml per day

 

17) Menstrual blood does not usually clot because

 

A) It does not contain platelets

B) It contains fibrinolysin  

C) It contains tissue thromboplastin

D) It contains activated factor X

E) It does not contain prothrombin

 

Questions 18-20

A) Oestradiol

B) Oestrone

C) Oestriol

D) Ethinyl-oestradiol

E) Oestradiol glucuronate

 

18) The major oestrogen secreted by the ovary

 

19) The oestrogen that is predominantly formed from androgens

 

20) The most potent oestrogen produced in vivo

 

21) In a woman with a regular 28 day cycle, peak oestrogen concentrations occur on

 

A) Days 2-5

B) Day 7

C) Day 14  

D) Day 21

E) Day 28

 

 

22) Oestrogens are excreted by

A) Metabolism by plasma aromatases

B) Conjugation in the liver and excretion in urine  

C) Conjugation in the liver and excretion in bile

D) Conjugation in the liver

E) Direct excretion in urine

 

 

23) Oestradiol

 

A) Circulates in plasma bound mainly to albumin

B) Acts via a receptor located in the cytoplasm  

C) Stimulates pituitary FSH secretion during the secretory phase of the menstrual cycle

D) Inhibits pituitary FSH secretion during the menstrual phase of the menstrual cycle

E) Is a less potent oestrogen than oestriol

 

 

24) Which one is not a recognized effect of oestrogen?

 

A) Stimulates proliferation of endometrial glands

B) Increased ciliary activity in the epithelium of the fallopian tube

C) Decreases sensitivity of the myometrium to oxytocin  

D) Increased uterine blood flow

E) Induces ferning of cervical mucus

 

25) Which one is not a recognized effect of oestrogen?

A) Inhibits fusion of the epiphyses of long bones  

B) Stimulates osteoblastic activity

C) Increases production of cervical mucus

D) Inhibits milk secretion

E) Stimulates growth of the stroma and ducts of the breasts

 

26) Which one is not a recognized effect of oestrogen?

A) Stimulates fat deposition in the breasts

B) Stimulates development of the alveoli of the breasts  

C) Increases blood supply to the skin

D) Increases deposition of sub-cutaneous fat

E) Stimulates sodium and water retention by the kidneys

 

27) Which one is a recognized physiological effect of oestrogen?

A) Decreased concentration of sex hormone binding globulin

B) Decreased concentration of thyroxine binding globulin

C) Decreased concentration of cortisol binding globulin

D) Increased insulin resistance  

E) Increased concentration of free cortisol

F) Increased concentration of free thyroxine

 

 

28) With respect to the effect of oestrogens on the coagulation system

 

A) Levels of factor II are decreased

B) Levels of factor VII are unchanged

C) Levels of factor X are increased  

D) Levels of anti-thrombin III are increased

E) The risk of thrombosis is decreased

 

29) Oestrogen therapy is associated with

 

A) Increased serum folate concentration

B) Decreased HDL cholesterol concentration

C) Decreased LDL cholesterol concentration  

D) Decreased total cholesterol concentration

E) Decreased triglyceride concentration

 

30) Progesterone

A) Is a C24 steroid

B) Acts via receptors located in the cytoplasm and nucleus  

C) Is mainly metabolized by serum proteases

D) Is mainly metabolized into androstendione

E) Is not produced in significant amounts by the placenta

 

31) The following hormones are correctly paired with their recognized physiological effect(s)

 

 

A) Oestrogen – catabolic hormone

B) Progesterone – anabolic hormone

C) Progesterone – ferning of cervical mucus

D) Oestrogen – increased ventilation

E) Progesterone – 0.5C rise in basal body temperature  

 

32) The following hormones are correctly paired with their recognized physiological effect(s)

A) Progesterone – proliferation of the stroma and ducts of the breasts

B) Progesterone – stimulates milk secretion

C) Progesterone – inhibits uterine contractions  

D) Progesterone – increased diuresis

E) Progesterone – proliferative changes in endometrial glands

 

 

 

Answers Posted by Farrukh G.

 

  1. = C
  2. = C

 

FOLLICULAR DEVELOPMENT AND OVULATION

At birth, the 2 million ova are surrounded by a layer of granulosa cells forming the primordial follicle. These degenerate and by puberty, only 400,000 are left.

 

3 = C

4 = A

5 = B

6 = C

7 = B

 

 

PRIMORDIAL TO ANTRAL STAGES

The ovum increases in size from < 0.5mm to 10-20mm and the layer of granulosa cells thickens to form the primary follicle - this may occur without gonadotropin stimulation

The oocyte secretes glycoproteins which condense around it to form the zona pellucida which separates the oocyte from the granulosa cells

During the first few days after the onset of menstruation, the FSH and later LH concentrations begin to rise. FSH stimulates the proliferation of granulosa cells in 6-12 primary follicles. Stromal proliferation also occurs to form the theca interna and externa

The theca externa forms the capsule of the developing follicle while the theca interna forms an inner glandular and highly vascular layer

Granulosa cells secrete follicular fluid causing an antrum to appear within the mass of granulosa cells - this marks the beginning of the antral phase of development.

The follicular antrum increases in size and the oocyte becomes surrounded by a dense mass of granulosa cells- the cumulus oophorus

The antral follicle secretes increasing amounts of steroids - mainly 17-beta oestradiol and oestrone (granulosa cells - produced de novo or by aromatization of androgens from thecal cells). The main androgens produced are testosterone and androstendione (thecal cells)

Activin suppresses androgen secretion but stimulates aromatizing capacity of granulosa cells. Inhibin stimulates androgen secretion but reduces aromatizing capacity of granulosa cells

LH has a synergistic effect with FSH in stimulating the growth of granulosa cells.

Granulosa cells secrete oestrogen which stimulated the expression of FSH receptors thereby increasing sensitivity to FSH.

 

8 = C

 

9 = C

10 = D


OVULATION

A single dominant follicle is selected within 7 days of the onset of menstruation.

The remainder undergo atresia and apoptosis

An LH surge is essential for ovulation and occurs about 18h before ovulation which typically occurs on day 14 of a 28 day cycle

The follicle grows to a diameter of up to 25mm before ovulation

Within 2h of the LH surge, there is a transient increase in oestrogen and androgen out-put from the follicle followed by a decline. The outer granulosa cells begin secretion of progesterone

Proteolytic enzymes such as plasminogen activator and renin play a role in ovulation

The released oocyte is surrounded by a layer of granulosa cells which form the cumulus oophorus. Meiosis I is completed at ovulation and the secondary oocyte is released

The oocyte enters meiosis II which arrests at metaphase

 

 

11 = E

CORPUS LUTEUM

Formed mainly from granulosa cells after ovulation

The granulosa cells enlarge, develop an extensive smooth endoplasmic reticulum and become filled with lipid inclusions giving them a yellowish appearance (lutenisation) and secrete increasing amounts of progesterone

Thecal cells form smaller lutein cells which produce progesterone and androgens

About 15 - 30mm in diameter by 8 days after ovulation and is functional for 14 days after which it involutes (luteolysis) into the corpus albicans. If fertilization occurs, the corpus luteum persists under stimulation of HCG produced by the placenta

Secretes oestrogens, 17-alpha-hydroxyprogesterone and progesterone in addition to androgens, inhibin, relaxin and oxytocin

Percentages of the total cell number are as follows: large luteal cells - 4.2%; small luteal cells - 18.5%; fibroblasts - 16.8%; endothelial cells and pericytes - 52.6%. The remaining 7.9% comprised other miscellaneous cell types including macrophages

The corpus luteum survives for ~14 days in a woman with a regular 28 day cycle

12 = C

 

13 = C

14 = D

 15 = C

16 = B

 17 = B

 

ENDOMETRIAL CYCLE
PROLIFERATIVE PHASE

Under influence of oestrogen

Rapid proliferation of stromal and epithelial cells with mitotic figures.

Endometrium is re-epithelialised within 3-7 days of the onset of menstruation

Elongation of spiral arteries. Endometrium is 3-4mm thick at ovulation

Cervical mucus becomes copious, watery and more elastic with ferning when dried.

Easily penetrated by sperm

Vaginal epithelial cells accumulate glycogen, become large and cornified and their nuclei shrink

SECRETORY PHASE

Under influence of oestrogen and progesterone from the corpus luteum

Endometrial glands become tortuous and accumulate glycogen and lipid vacuoles which migrate towards the lumen of the glands. Spiral arteries become elongated and coiled

Stroma becomes oedematous

Endometrium is 5-6mm thick at the end of the secretory phase

Percentage of cornified cells in the vaginal epithelium falls

Cervical mucus becomes thick, viscous and less penetrable to sperm

MENSTRUAL PHASE

Initiated by a sudden fall in oestrogen and progesterone concentrations

There is involution followed by vasospasm in the spiral arterioles 24h before the onset of menstruation

There is necrosis and shedding of the superficial layers of the endometrium.

On average, 35ml of blood are lost per menstrual cycle.

Menstrual blood does not clot because of the presence of fibrinolysin.

Clotting indicates excessive bleeding.

Following menstruation, only a thin layer of stroma and epithelial cells in the crypts are left.

 

 

18 = A

 19 = B

 20 = A

 

OESTROGENS

Steroid hormones synthesised from cholesterol and secreted mainly by the ovary but also by the adrenal cortex and in large quantities by the placenta

Three forms - Oestradiol, Oestrone and Oestriol. Oestradiol is the major oestrogen secreted by the ovary. Oestrone is mainly formed from androgens while Oestriol is an oxidative product of oestradiol and oestrone

Oestradiol has 12 times the oestrogenic potency of oestrone and 80 times that of oestriol

Serum oestradiol concentrations are maximal just before ovulation on day 14 of a regular 28 day cycle

Circulate bound loosely to plasma proteins (mainly SHBG and albumin)

Conjugated by the liver into glucuronides and sulphates. 20% of these are excreted in bile and 80% in urine. The liver also converts oestradiol to oestrio

Inhibits FSH secretion by the anterior pituitary. Positive feed-back effect results in pre-ovulatory LH surge

Has two known receptors located within the cytoplasm / nucleus - ER - alpha and beta

 

 

 

 

21 = C

 22 = B

 23 = B

 

 

OESTROGENS

Steroid hormones synthesised from cholesterol and secreted mainly by the ovary but also by the adrenal cortex and in large quantities by the placenta

Three forms - Oestradiol, Oestrone and Oestriol. Oestradiol is the major oestrogen secreted by the ovary. Oestrone is mainly formed from androgens while Oestriol is an oxidative product of oestradiol and oestrone

Oestradiol has 12 times the oestrogenic potency of oestrone and 80 times that of oestriol

Serum oestradiol concentrations are maximal just before ovulation on day 14 of a regular 28 day cycle

Circulate bound loosely to plasma proteins (mainly SHBG and albumin)

Conjugated by the liver into glucuronides and sulphates. 20% of these are excreted in bile and 80% in urine. The liver also converts oestradiol to oestrio

Inhibits FSH secretion by the anterior pituitary. Positive feed-back effect results in pre-ovulatory LH surge

Has two known receptors located within the cytoplasm / nucleus - ER - alpha and beta

 

24 = C

 

25 = A

 26 = B

 27 = D

28 = C

29 = C

 

 

OESTROGEN - EFFECTS

Development of secondary sexual characteristics. Pubertal hair growth is under androgenic control

VAGINA: Increase in size, conversion of cuboidal to stratified squamous epithelium at puberty. Vaginal epithelial cells accumulate glycogen, their nuclei shrink and they become cornified

ENDOMETRIUM - stimulates proliferation of glandular and stromal elements. Stimulates the development of progesterone receptors in endometrial cells

MYOMETRIUM - increases sensitivity to oxytocin

Increases uterine blood flow - vasodilates uterine artery

FALLOPIAN TUBES - proliferation of glandular tissue; increased number of ciliated cells and increased ciliary activity

CERVIX - increased mucus production- thin, watery and clear with a ferning pattern if dried on a slide. Mucus shows increased elasticity and a drop may be stretched to 10-12cm and is easily penetrable by sperm

BREASTS - stimulates fat deposition and growth of stroma and ducts. Development of lobules and alveoli are mainly under influence of progesterone and prolactin. Inhibits milk secretion

SKELETON - stimulates osteoblastic activity; stimulates fusion of the epiphyses of long bones

METABOLISM

Anabolic effect; stimulates protein deposition in specific organs.

Increases sub-cutaneous fat and blood supply to skin.

Stimulates sodium and water retention by the kidneys

Increases hepatic globulin synthesis: sex hormone binding globulin, thyroxine and cortisol binding globulins

Free thyroxine and free cortisol unchanged

Increased transferring concentrations

Serum albumin levels are usually decreased (along with the associated calcium levels).

Reduced serum folate concentration

Increase insulin resistance

Increase HDL cholesterol

Decrease LDL cholesterol

Increase total cholesterol

Increase triglycerides

Clotting factors - increase in factors II, V, VII, IX, X, XII and especially VII; decrease of Antithrombin III. Therombogenic

 

 

 

30 = B

31 = E

32 = C

 

PROGESTERONE

C21 steroid Synthesised from cholesterol by the corpus luteum

Acts via receptor located in the cytoplasm / nucleus

Also secreted in large quantities by the placenta

Metabolised by the liver into pregnanediol, 10% of which is excreted in urine

 

PROGESTERONE - EFFECTS

UTERUS - secretory changes in the endometrial glands. Inhibits uterine contractions. Cervical mucus is thick, viscous and non-ferning

FALLOPIAN TUBES - secretory changes in epithelium

CERVIX - production of small quantity of viscous mucus which is less penetrable to sperm

BREASTS - proliferation of lobules and alveoli. Secretory changes in alveoli. Does not stimulate milk secretion (Prolactin).

RESPIRATION - increased ventilation

METABOLISM - catabolic hormone; thermogenic with a rise of ~0.5C in basal body temperature; induces sodium and water retention by the kidneys. Promotes development of the lobules and alveoli of the breast