Case 1 Questions

Question 1

What hormone peaks on around the 13th day of the Menstrual Cycle?

Answer 1

Oestrogen

Question 2

What type of cells does GnRH target?

Answer 2

Gonadotropes

Question 3

Which Hormone alters from negative to positive feedback in the menstrual cycle?

Answer 3

Oestrogen. Oestrogen at low concentrations has a negative feedback where as at high concentrations it has a positive feedback.

Question 4

Which type of receptor do Granulosa cells have on their cell membrane?

Answer 4

Follicle Stimulating Hormone Receptors

Question 5

What type of hormone is Follicle Stimulating Hormone?

Answer 5

Peptide Hormone

Question 6

What type of receptor is the FSH receptor?

Answer 6

G-Protein coupled receptor

Question 7

What type of Hormone is Luiteinizing Hormone?

Answer 7

Peptide Hormone

Question 8

What type of receptor is the LH receptor?

Answer 8

G-Protein coupled receptor

Question 9

Which type of receptor do Thecal cells have on their cell membrane?

Answer 9

Luiteinizing Hormone Receptors

Question 10

What reaction occurs within theca interna cells?

Answer 10

cholesterol into pregnenolone, pregnenolone into 17 a-hydropregnenolone and hydroxypregnenolone into DHEA, DHEA into adrostenedione

Question 11

What reaction occurs in granulosa cells?

Answer 11

androstenedione is converted into testosterone. Testosterone is converted into estrone and 17-b-estradiol

Question 12

Which enzyme catalyses the conversion of testosterone into 17-b-estradiol?

Answer 12

aromatase

Question 13

Which enzyme is prevalent in theca interna cells? (turning cholesterol into pregnenolone and pregnenolone into 17-a-hydroxypregnenolone)

Answer 13

desmolase

Question 14

What function does desmolase have?

Answer 14

destruction of c-c bonds

Question 15

What is the function of Luiteinizing Hormone in women?(5)

Answer 15

Stimulates theca interna cells, triggers ovulation, sustains the corpus luteum, completion of meiosis 1, proliferation of theca interna cells

Question 16

What are theca externa cells responsible for?(2)

Answer 16

Theca externa cells are highly vascular connective tissue that eventually becomes the capsule, theca externa cells release proelytic enzymes (lysozomes) to dissolve the follicular capsular wall and weaken the wall of the ovary.

Question 17

In which area of the pituitary gland are FSH and LH produced?

Answer 17

gonadotrope cells in the anterior pituitary gland

Question 18

Which cells produce oestrogen in the ovary?

Answer 18

granulosa cells

Question 19

What type of hormone is oestrogen?

Answer 19

Steroid hormone

Question 20

What is the function of FSH in women?(2)

Answer 20

FSH stimulates the maturation of follicles in the ovary causing proliferation of granulosa and theca cells. Binds to granulosa cells allowing the production of oestrogen

Question 21

What is the difference between a primordial follicle and a primary follicle?

Answer 21

A primordial follicle is a smaller, dormant follicle with a single layer of granulosa cells. The primary follicle is larger and has multiple layers of cuboidal granulosa cells which are mitotic. Primordial follicles are arrested in prophase dictyotene (late diplotene). The primary follicle has a zona pellucida which is a thick glycoprotein layer.

Question 22

What is the difference between a primary and secondary follicle?

Answer 22

A secondary follicle has more layers of follicular cells as well as more intercellular spaces filled with follicular fluid which is nutrition for the oocyte. While in the secondary follicle stage. There is differentiation of theca into two layers: Theca interna and theca externa

Question 23

At which stage to theca cells differentiate into theca interna and theca externa cells?

Answer 23

As a secondary follicle

Question 24

What are the 5 stages of prophase? (in order)

Answer 24

Leptonene, Zygotene, Pachytene, Diplotene(Dictyotene), Diakinesis

Question 25

What occurs during Leptotene?

Answer 25

Chromosomes become visible as they condense

Question 26

What occurs during Zygotene?

Answer 26

Homologous chromosomes align directly opposite each-other in a process called synapsis and are held together at several points along their length

Question 27

What occurs during Pachytene?

Answer 27

Each pair of homologous chromosomes known as the bivalent. Become tightly coiled. Crossing over occurs during which homologous regions of DNA are exchanged between chromatids

Question 28

What occurs during Diplotene?

Answer 28

The homologous recombinant chromosomes begin to separate but are still attached at some points where crossing over has occurred. These are called chiasmata

Question 29

In what stage are primordial follicles arrested in?

Answer 29

Diplotene - Dictyotene (LATE PROPHASE OF MEIOSIS 1)

Question 30

What occurs during Diakinesis?

Answer 30

Separation of homologous chromosomes occur and chromosomes become maximally condense

Question 31

What occurs during Metaphase 1?

Answer 31

Homologous chromosomes line up against each-other along the equator of the cell and spindle fibres attach to their centromeres. The nuclear membrane disappears.

Question 32

What occurs during Anaphase 1?

Answer 32

Chromosomes are pulled to opposite poles of the cell towards the centrioles as the spindle contracts

Question 33

What occurs during telophase 1?

Answer 33

Each set of haploid chromosomes have separated cleaving two new daughter gametes

Question 34

If non-disjunction occurred during meiosis 1 of oogenesis, which cell would be effected?

Answer 34

Secondary oocytes

Question 35

If non-disjunction occurred during meiosis 2 of oogenesis, which cell would be effected?

Answer 35

The Graafian follicle

Question 36

What is non-disjunction?

Answer 36

Non-disjunction is the failure of a homologous pair of chromosomes to separate during anaphase.

Question 37

What is anaphase lag?

Answer 37

The delayed movement of chromosomes after separation at anaphase

Question 38

What are the main causes of Aneuploidy?

Answer 38

Anaphase lag and non-disjunction

Question 39

How can triploidy arise?

Answer 39

The fertilization of an ovum by two sperm. or The fertilization of an haploid egg by a diploid sperm/Fertilisation of a diploid egg by a haploid sperm.

Question 40

Explain the process of luitenization of the remaining follicle after ovulation.

Answer 40

The cells will become filled with lipids which are yellow this giving a yellow colour which is characteristic of the lutein cells formed

Question 41

What is a polar body formed during meiosis of oocytes?

Answer 41

A polar body is a daughter cell which does not gain enough cytoplasm so degenerates leaving one secondary oocyte/ovum

Question 42

What process triggers meiosis 2 in oogenesis?

Answer 42

Fertilization by sperm.

Question 43

Which cells produce progesterone in a corpus luteum?

Answer 43

Granulosa lutein cells as well as theca cells! (large and small lutein cells)

Question 44

What is the role of progesterone during the menstrual cycle?

Answer 44

Progesterone inhibits the secretion of LH, progesterone also maintains the endometrium promoting angiogenesis making it highly glandular and vascular. Progesterone keeps spiral arteries dilated

Question 45

What are some general roles of progesterone?

Answer 45

Bone Growth, Maintenance of endometrium, secondary sex characteristics, Increases core temperature during ovulation, reduces myometrial contractility, Thickens cervical mucus, inhibits lactation

Question 46

Why is the Menstrual Phase marked by bleeding?

Answer 46

Without the influence of progesterone, arteries constrict within the endometrium, this causes a lack of oxygen and nutrients supplying the endometrium and causing the shedding of the stratum functionalis due to it becoming necrotic

Question 47

What type of hormone is Progesterone?

Answer 47

Steroid Hormone

Question 48

What hormone is detected in a home pregnancy test?

Answer 48

Human Chorionic Gonadotropin

Question 49

Where is hCG produced?

Answer 49

By the corpus luteum in the ovary