Lecture 20: Reproductive Physiology I Flashcards by Isobel Speiran

What are some differences between somatic and reproductive cell division?

Somatic = mitosis, creates 2 identical daughter cells.
Repro = meiosis, produces 4 gametes with half the genetic material

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When do primordial germ cells develop? Where do they migrate from, and where do they go?

Develop around 4th-5th week. Migrate from the yolk sac –> dorsal mesentery of hindgut –> gonadal ridges.

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How long does spermatogenesis take in humans? What is a spermatogonium cell?

65-75 days. Undifferentiated male germ cells.

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Where does spermatogenesis occur?

Seminiferous tubules of the testes

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Where do testes extend from? What does each lobule of the testes contain?

Tunica albuginea. Each lobule contains seminiferous tubules.

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What are the three types of cells in the testes, what do they produce?

Spermatogenic: sperm
Sertoli: supporting cells
Leydig: produce testosterone

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Spermatogonium cells are _____ cells containing the full ________ _________. What process do they undergo?

Stem, genetic complement. Mitosis.

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Some daughter spermatogonium cells move away from the ________ ________ to differentiate into what?

Basement membrane, primary spermatocytes

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Each chromosome is made of 2 _________ attached by a _________.

Chromatid, centromere.

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After meiosis I, which cells are present (how many chromosome)?

Secondary spermatocytes, 23 chromosomes.

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After meiosis II, which cells are present? How many chromosomes?

4 haploid cells (2 chromatids separate). Therefore, 1 primary spermatocyte yields 4 spermatids (haploid cell).

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What is spermiogenesis? How do sertoli cells support this process?

Final stage of spermatogenesis where haploid spermatids develop into sperm cells. Sertoli cells dispose of excess cytoplasm.

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What occurs during spermiation?

Sperms are released from sertoli cells

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How do sperm cells get to the epididymis? What occurs there?

Lumen of seminiferous tubule. “Swimming lessons.”

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What is the role of the acrosome and where is it found in the sperm cell?

Found in the head, is a vesicle filled with enzymes that facilitate fertilization.

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Where is the mitochondria found in sperm cells? Centrioles?

Mitochondria = tail, arranged in a spiral, provides energy for locomotion.
Centrioles = neck, forms microtubules that form the tail

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At puberty, _______ neurosecretory cells increase production of ___________-________ hormone.

Hypothalmic, gonadotropin-releasing

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Gonadotrophs in the ________ _______ increase secretion of which two gonadotropins?

Anterior pituitary. Luteinizing hormone, follicle-stimulating hormone.

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How does LH act? FSH?

LH: stimulates Leydig cells to secrete testosterone
FSH: stimulate secretion of androgen-binding protein from sustentacular cells into seminiferous tubules

How does ABP act?

ABP finds to testosterone to keep concentration around spermatogenic cells high

What do sustentacular cells do, generally?

Provide structural and metabolic support to sertoli cells.

What do sustentacular cells release when sperm is made? What does this substance do?

Release inhibin. Inhibin will inhibit FSH secretion. If sperm needs to increase, less inhibin is released.

Oocytes are surrounded by cells called _________ and develop in the __________ of the ovary.

Follicles, cortex.

What are differences in functions between the ovarian cortex and medulla?

Cortex: gametes develop
Medulla: circulation, lymphatics, nerves

What are primary oocytes surrounded by? What do gonadotropins stimulate every month?

Supportive matrix of collagen fibers and stromal cells. Stimulate development of several primordial follicles.

What is the female equivalent of spermatogonium cells? What is atresia?

Oogonia. Atresia is the process of degeneration and reabsorption of immature or non-dominant follicles in the ovaries before they reach ovulation.

What are the five layers of a primary follicle deep to superficial?

1. primary oocyte 2. zona pellucida 3. granulosa cells 4. basement membrane 5. theca folliculi

When secondary follicles mature, the theca become 2 separate layers. Differentiate these 2 layers.

1. theca interna: highly vascularized, secretes estrogens 2. theca externa: stromal cells, collagen fibers

What is the antrum of a secondary follicle? What is the corona radiata?

Collection of fluid secreted by granulosa cells. Corona radiata: innermost layer of granulosa cells.

What does meiosis I produce in females?

Polar body: packet of discarded genetic material (smaller) Secondary oocyte: released during ovulation (larger)

Which layer of the uterine call do embryos implant?

Endometrium

In the endometrium, there is ________-responsive _______ that lines the ______ cavity. Numerous glands, a supportive _________, and highly ___________.

Hormone, mucosa, uterine, stroma, regenerative.

What are the two sub-layers of the endometrium and their functions?

1. functional zone: endometrial glands, shed each month 2. basilar zone: regenerative layer, creates functional zone

Estrogen is synthesized from ________ in the _______. It stimulates what?

Cholesterol, ovaries. Stimulates proliferation of endometrial cells.

What secretes progesterone? Which two structures does it prepare?

Cells of corpus luteum. 1. prepares endometrium for implantation 2. prepares mammary glands for milk secretion

What produces relaxin and what does it do?

Relaxin is produced by the corpus luteum, inhibits contracts/'quiets' uterus.

What occurs during menstrual phase?

Declining levels of progesterone and estrogen stimulate release of progesterone. Necrosis of stratum functionalis.

During the preovulatory phase, what do estrogens cause? What is this phase also called?

Stimulate mitosis in stratum basale, produce new stratum functionalis. Also called proliferative phase.

What is the dominant follicle? What occurs during the follicular phase?

Secondary follicle that has outgrown the others. Estrogens and inhibin decrease secretion of FSH, other follicles undergo atresia.

What occurs during ovulatory phase?

Rupture of mature follicles to release secondary oocyte. High levels of estrogens, more GnRH, surge of LH, oocyte released into abdominal cavity.

What happens to the endometrium during the secretory phase?

Growth of endometrial glands, thickening of endometrium.

How and when is the corpus luteum formed?

Formed during post-ovulatory/secretory phase. Remaining theca/granulosa combine under influence of LH --> corpus luteum. (luteal phase).

What are the two functions of nitric oxide in the penis?

1. endo smooth muscle cell relax 2. vasodilation/widening of sinuses

Ejaculation is a _________ reflex involving which three muscles?

Levator ani, ischiocavernosus, bulbiospongiosus.

What does SEVEN UP stand for?

Ejaculatory pathway. 1. seminiferous tubules of testes 2. epididymis 3. vas deferens 4. ejaculatory duct 5. nut 6. urethra (internal close) 7. penis