BIOM3020 (2022) Exam MCQs Flashcards
What is typically associated with hypothyroidism
(in the blood)
low levels of thyroid stimulating hormone (TSH) in the blood.
Where is the first capillary bed of the hypothalamic portal vein system
It is found in the median eminence
Where is the hypothalamus located
The hypothalamus is posterior to (i.e., behind) the lamina terminalis and anterior
commissure
What is The primary target of the release-promoting and -inhibiting hormones of the hypothalamus
The anterior pituitary
What four hormones are associated with increased insulin resistance
resistin, glucagon-like peptide 1 (GLP-1), placental lactogen and cortisol
The mammalian circadian rhythm is synchronised to geophysical time by photic input from the eyes via what tract
the retinohypothalamic tract
What is the mammalian circadian rhythm largely dependent on
the hypothalamic suprachiasmatic nucleus for normal function
The establishment of diploidy in the newly formed zygote requires what
Completion of meiosis
What is the status of the oocyte in a primordial follicle?
Diploid, primary oocyte arrested in prophase I
In puberty what is the primary event underlying gonadal activation
Activation of pulsatile GnRH secretion
Using an Endometrial Receptivity Assay, doctors at an IVF clinic determine that a female patient’s window of implantation is delayed. The likely therapeutic approach to this problem
would be
A personalized embryo transfer of frozen embryos in the next cycle.
What are some (five) actions of the secretory phase progesterone on the female reproductive tract
Reduces fluid secretion, causes the cervix to become firmer, Promotes uterine spiral artery thickening and enlargement, lifts body temperature up by 0.6-1.0 degree and Drives an increase in the complexity of endometrial glands
Can asthma worsen in pregnancy and why
Yes, due to viral infection
What is erythropoietin (Epo) produced in response to
low tissue oxygenation, which acts on the Epo-R in red blood cell progenitors and
precursors in the bone marrow and promotes cell differentiation
What does aldosterone bind to
the mineralocorticoid receptor
Increased blood pressure (hypertension) over sustained periods of time is a primary risk factor for cardiovascular disease.
A series of compounds (such as phenoxbenzamine, guanethidine, resperine and hydralazine) were developed in the middle of the 20th century to lower blood pressure but they did not gain wide acceptance primarily because
they commonly lead to unpleasant side-effects
Eric Olson’s group from Texas reported that cardiac cells express a microRNA derived from the alpha myosin heavy chain gene, which regulates the MED13 complex in the heart to control which of the following processes?
The rate and strength of contraction of cardiomyocytes.
What are the two standard therapies to treat primary aldosteronism
Adrenalectomy and mineralocorticoid receptor antagonists
How is primary aldosterone diagnosed, and how can medication effect the results
A high aldosterone to renin ratio (ARR) measurement can indicate primary
aldosteronism, but antihypertensive medications can lead to false positives and false
negatives
The year is 2027 and you are working for a large biotech company and your role is to make a mouse model of COVID-19 infectivity. To do this, you design and produce a transgenic mouse where the endogenous mouse ACE2 gene is replaced by the human ACE2 sequence. Although you successfully produce the mouse line, you discover that the expression of the human ACE2 is 10-fold higher than expected. In characterising this transgenic mouse, which one of the following outcomes is most likely?
A dramatic reduction in COVID-19 infectivity
What are the functional units of the ovary?
The functional units of the ovary are called follicles
How are follicle growth and recruitment regulated?
Follicle growth and recruitment are regulated by hormones, primarily follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
What is the process of oogenesis?
Oogenesis is the process of egg cell development. It involves meiosis, where a diploid oogonium undergoes two divisions to produce a single haploid egg cell (ovum) and polar bodies.
What is the Hypothalamic-Pituitary-Gonadal (HPG) axis?
The HPG axis is a complex hormonal pathway involving the hypothalamus, pituitary gland, and gonads (ovaries in females). It regulates the production and release of reproductive hormones such as FSH and LH
What is the 2-cell 2-gonadotropin hypothesis in the ovarian cycle?
The 2-cell 2-gonadotropin hypothesis explains the interactions between the ovarian follicles, FSH, LH, and the production of estrogen and progesterone during the ovarian cycle.
What is the menstrual cycle?
The menstrual cycle is the monthly cycle in females, characterized by changes in the uterus and ovaries, regulated by hormonal fluctuations. It involves the shedding of the endometrium (menstruation) and the development and release of an egg (ovulation).
Describe the hypothalamic-pituitary-gonadal (HPG) axis.
The HPG axis is a complex hormonal pathway that regulates reproductive functions. It involves interactions between the hypothalamus, pituitary gland, and gonads (ovaries in females). The hypothalamus produces gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones, in turn, act on the gonads (ovaries) to regulate the production of sex hormones (estrogen and progesterone) and support follicle development and ovulation
What hormone is produced by ‘H’ in the HPG axis?
The hormone produced by the hypothalamus (‘H’) is gonadotropin-releasing hormone (GnRH).
What two hormones are produced by ‘P’ in the HPG axis?
The two hormones produced by the pituitary gland (‘P’) are follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
What two hormones are produced by ‘G’ in females in the HPG axis?
In females, the two hormones produced by the gonads (ovaries) (‘G’) are estrogen and progesterone.
What is the relationship between GnRH and FSH/LH production?
GnRH released by the hypothalamus stimulates the pituitary gland to produce and release FSH and LH. GnRH acts as a releasing factor for FSH and LH.
Describe the 2-cell 2-gonadotropin hypothesis of steroid hormone production
The 2-cell 2-gonadotropin hypothesis explains how FSH and LH regulate steroid hormone production. The two cells involved are the granulosa cells and the theca cells. FSH stimulates the granulosa cells to convert androgens from the theca cells into estrogen. LH acts on the theca cells to promote the production of androgens, which are then converted into estrogen by the granulosa cells.
What are the two cells involved in the 2-cell 2-gonadotropin hypothesis? What are the two gonadotropins involved?
The two cells involved are the granulosa cells and the theca cells. The two gonadotropins involved are follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
List the two major ovarian hormones that regulate female reproduction. Where are they produced in the ovary? What are their primary functions in the menstrual cycle?
The two major ovarian hormones that regulate female reproduction are estrogen and progesterone. Estrogen is primarily produced in the granulosa cells of the developing follicles, while progesterone is produced by the corpus luteum. Estrogen is responsible for the growth and development of the uterine lining (endometrium) during the follicular phase of the menstrual cycle. Progesterone prepares the uterus for implantation and supports pregnancy during the luteal phase.
Describe the hormonal profile during the menstrual cycle. When and why does ovulation occur? When and why does menstruation occur?
During the menstrual cycle, the levels of estrogen and progesterone fluctuate. In the follicular phase, estrogen levels rise, leading to the development of the uterine lining. Ovulation occurs around the mid-cycle when there is a surge in luteinizing hormone (LH), triggering the release of an egg from the ovary. In the luteal phase, progesterone levels increase, preparing the uterus for implantation. If fertilization does not occur, estrogen and progesterone levels decline, leading to menstruation, which is the shedding of the uterine lining.
Which hormone is dominant in the follicular phase, and which hormone is dominant in the luteal phase of the menstrual cycle?
Estrogen is dominant in the follicular phase of the menstrual cycle, while progesterone is dominant in the luteal phase.
What is the preovulatory follicle?
The preovulatory follicle is a mature follicle in the ovary that is ready to release an egg (oocyte) during ovulation
What are the structural and molecular changes that occur during ovulation?
During ovulation, the preovulatory follicle undergoes structural changes, such as enlargement and thinning of the follicular wall. It also undergoes molecular changes, including an increase in proteolytic enzymes that help weaken the follicle wall for rupture
What is the role of the oocyte and oocyte-secreted factors (OSFs) in ovulation?
The oocyte plays a critical role in ovulation. It secretes factors known as oocyte-secreted factors (OSFs), which stimulate changes in the surrounding cumulus cells and promote follicle rupture and cumulus-oocyte complex release during ovulation.
What is the role of cumulus cells/cumulus expansion in oocyte maturation?
Cumulus cells are a specialized group of cells that surround the oocyte within the follicle. They play a crucial role in oocyte maturation. During ovulation, the cumulus cells undergo expansion, forming a protective matrix around the oocyte, allowing it to be released from the ovary. Cumulus expansion also helps facilitate the interaction between the oocyte and sperm during fertilization.
What are the structural and molecular changes that are induced in the preovulatory follicle by the LH surge?
The LH surge induces several structural and molecular changes in the preovulatory follicle. Structurally, the follicle undergoes enlargement and swelling. The follicular wall becomes thinner, and there is an increased blood flow to the follicle. Molecularly, the LH surge stimulates the production of proteolytic enzymes, such as matrix metalloproteinases, which help weaken and degrade the follicular wall, leading to follicle rupture and ovulation
What role does PGR play in ovulation?
PGR (progesterone receptor) plays a critical role in ovulation. It is expressed in the granulosa and cumulus cells of the preovulatory follicle. Progesterone, acting through PGR, promotes the expression of genes that are involved in follicle rupture and ovulation, including the production of proteolytic enzymes that weaken the follicular wall.
What is the main factor produced by cumulus cells and supplied to the oocyte via gap junctions that maintains meiotic arrest?
The main factor produced by cumulus cells and supplied to the oocyte via gap junctions to maintain meiotic arrest is cyclic adenosine monophosphate (cAMP). Cumulus cells produce high levels of cAMP, which diffuses through gap junctions and enters the oocyte. Elevated cAMP levels in the oocyte prevent resumption of meiosis, thereby maintaining the oocyte in a prophase I arrest until ovulation.
What is the main factor supplied by the granulosa cells to cumulus cells that results in cumulus expansion following the LH surge?
The main factor supplied by the granulosa cells to cumulus cells for cumulus expansion following the LH surge is hyaluronic acid. Granulosa cells produce and secrete hyaluronic acid, which accumulates in the extracellular matrix of the cumulus cell mass. Hyaluronic acid acts as a hygroscopic gel and absorbs water, leading to the expansion and dispersion of cumulus cells, creating a protective matrix around the oocyte.
