Reproductive physiology Flashcards
What is the main function of the Pineal gland?
The main function of the Pineal gland is the regulation of diurnal cycles (sleep and wake cycles) by producing melatonin.
What are the components of the Diencephalon?
The Diencephalon consists of the Thalamus, Hypothalamus, and Epithalamus, including the Pineal gland and Habenula (habenular commissure).
Why is the Pineal gland sometimes referred to as the third eye?
The Pineal gland is sometimes called the third eye due to its association with regulating diurnal cycles and producing melatonin in response to light and darkness.
Which nucleus is known as the biological clock?
The Suprachiasmatic Nucleus (SCN) is known as the biological clock.
How does the Retinohypothalamic Tract (RHT) contribute to the regulation of sleep-wake cycles?
The RHT carries action potentials from light receptors in the retina to the SCN, contributing to the regulation of sleeping and waking.
What chemicals are released by the SCN to stimulate different organs?
The SCN releases specific chemicals, usually glutamate, to stimulate different organs in the body.
What is the role of the Paraventricular Nucleus (PVN) in the regulation of the sleep-wake cycle?
The PVN is stimulated and sends signals down the spinal cord to the Superior Cervical Ganglion (SCG), contributing to the regulation of the sleep-wake cycle.
Which neurotransmitter is secreted by postganglionic motor neurons to signal the Pineal gland?
Postganglionic motor neurons secrete norepinephrine (NE) to signal the Pineal gland.
What type of receptors do Pinealocytes have for NE?
Pinealocytes have specific adrenergic receptors for NE.
Describe the intracellular pathway stimulated by adrenergic receptors in Pinealocytes.
Adrenergic receptors in Pinealocytes stimulate the intracellular pathway: Tryptophan → 5-hydroxytryptamine → Serotonin → Melatonin.
How does light influence the SCN and Pineal gland activity?
Light inhibits the SCN, leading to Pineal gland inhibition and decreased melatonin secretion, promoting staying awake.
What happens in response to darkness regarding the SCN and Pineal gland activity?
Darkness stimulates the SCN, leading to Pineal gland stimulation and increased melatonin secretion, promoting sleep.
Where are the receptors for melatonin located, and what effect does increased melatonin have on the SCN?
Receptors for melatonin are located in the SCN, and increased melatonin levels rest the biological clock of the SCN.
What is the general timeframe for a normal menstrual cycle?
A normal menstrual cycle typically lasts around 28 days, with a normal timeframe ranging from 21 to 39 days.
Define ovulation in the context of the menstrual cycle.
Ovulation is the process where a mature female sex cell (ovum) is released by a Graafian Follicle, traveling to the fallopian tube in preparation for fertilization.
What are the two special nuclei in the hypothalamus responsible for releasing Gonadotropin-Releasing Hormone (GnRH)?
The two special nuclei in the hypothalamus responsible for releasing GnRH are the Arcuate Nucleus and the Pre-Optic Nucleus.
What hormones are synthesized and released by the anterior pituitary in the context of the menstrual cycle?
The anterior pituitary controls the synthesis and release of gonadotrophins, specifically Follicular Stimulating Hormone (FSH) and Luteinizing Hormone (LH).
In the ovary, what do gonadotropins (FSH and LH) work on?
Gonadotropins (FSH and LH) work in the ovary.
What hormones are released by the ovary, and what are they converted into?
The ovary releases androgens, which are converted to estrogen, followed by the later release of progesterone.
What is the role of primordial follicles in the context of ovarian follicle growth?
Primordial follicles, which arise from oogoniums, are diploid cells that become necessary stem cells during a female’s reproductive years.
How many chromosomes do oogoniums have, and what do they develop into before puberty?
Oogoniums have 46 chromosomes (diploid), and before puberty, they develop into primordial cells.
What is the status of the first oocyte in a primordial cell, and in which phase is it stationary?
The first oocyte in a primordial cell continues to be diploid and is stationary in Prophase I.
What are the potential variations in menstruation, and what conditions do they indicate?
Menstruation can vary, with conditions like amenorrhea (non-existent menstruation) or menorrhagia (longer and heavier bleeding events) indicating variations in the menstrual cycle.
What stimulates primordial follicles to develop into a primary follicle in females after reaching puberty?
Local androgens stimulate primordial follicles into developing into a primary follicle.