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What is the primary function of the uterus?
What structure partially surrounds the ovary?
How long is the vagina typically?
Which region of the uterus is located superior to the entrance of the uterine tubes?
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Which of the following accurately describes the cervix?
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What is a key role of the vagina?
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What is the infundibulum of the uterine tube shaped like?
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Which structure is located between the bladder and rectum?
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What is the primary hormone produced during the follicular phase of the ovarian cycle?
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What triggers ovulation in the ovarian cycle?
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During which phase does the endometrial lining undergo regeneration and thickening?
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What event marks the end of the follicular phase in a typical menstrual cycle?
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What role does follicle-stimulating hormone (FSH) play in the ovarian cycle?
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Which gland is responsible for releasing gonadotropin-releasing hormone (GnRH)?
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What occurs as progesterone and estrogen levels drop at the end of the menstrual cycle?
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What is the significance of the hypothalamic-pituitary-ovarian axis in hormonal regulation?
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What initiates the spermatogenesis process in the seminiferous tubules?
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Which component of the male duct system serves as a temporary storage site for immature sperm?
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Which structure protects the testis and provides a division into lobules?
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What is the primary function of the ductus deferens?
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During spermatogenesis, what do secondary spermatocytes mature into?
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What connective tissue sheath encloses blood vessels, nerves, and the ductus deferens?
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What is the final part of the male duct system where sperm exits the body?
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Which cells in the seminiferous tubules are directly involved in the production of testosterone?
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What is the main function of the penis in the male reproductive system?
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Which structure is NOT part of the male external genitalia?
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What is the correct term for the conceptus during the embryonic period?
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What is viviparity?
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How is the penis structurally prepared for sexual excitement?
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What defines the term 'gestation'?
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Oviparity is characterized by which of the following?
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What is meant by fertility in the context of reproduction?
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Which vertebrate groups do not have paired testes?
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What is the role of spermatogonia in sperm formation?
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In which type of animals does sperm production occur in separate tubular compartments?
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What structure in male sharks and rays is specialized for sperm transfer?
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Which feature is commonly shared between mammals and reptiles regarding reproduction?
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In amphibians, what method of fertilization is most commonly associated?
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What role does the baculum play in some mammals?
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What distinguishes the duct systems of amphibians from those of fishes?
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Study Notes
Female Reproductive System
- The distal end of each uterine tube expands as the funnel-shaped infundibulum, which has fingerlike projections called fimbriae that partially surround the ovary.
- The uterus is located in the pelvis between the urinary bladder and rectum.
- The uterus functions to receive, retain, and nourish a fertilized egg.
- The major portion of the uterus is referred to as the body.
- The rounded region superior to the entrance of the uterine tubes is the fundus.
- The narrow outlet of the uterus, which protrudes inferiorly into the vagina, is the cervix.
- The vagina is a thin-walled tube 8 to 10 cm long.
- The vagina lies between the bladder and rectum and extends from the cervix to the body exterior.
- The vagina provides a passageway for the delivery of an infant and for the menstrual flow to leave the body.
Hormonal Regulation of the Ovarian Cycle
- Estrogen is crucial for the development and regulation of the female reproductive system and secondary sexual characteristics.
- The production of ovarian hormones is tightly regulated by the hypothalamic-pituitary-ovarian axis.
- Hypothalamus: Releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland.
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Pituitary Gland: Releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in response to GnRH.
- FSH stimulates the growth of ovarian follicles and the production of estrogen.
- LH triggers ovulation and supports the corpus luteum’s production of progesterone.
- Ovaries: Respond to FSH and LH by producing estrogen and progesterone in varying amounts throughout the menstrual cycle.
Uterine Cycle
- The uterine cycle is a series of cyclic changes that the endometrium (mucosa of the uterus) goes through each month.
- The uterine cycle is driven by changing blood levels of ovarian hormones.
- The cycle begins with primitive stem cells called spermatogonia found in the outer edge of each tubule.
- Spermatogonia undergo mitotic divisions producing two stem cells.
- One stem cell continues the cycle, while the other becomes a primary spermatocyte.
- The primary spermatocyte matures into a secondary spermatocyte.
- Secondary spermatocytes undergo further changes until it reaches spermiogenesis.
- Menstrual Phase (Days 1-5): This is the shedding of the endometrial lining, accompanied by bleeding.
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Proliferative Phase (Days 6-14): This phase follows menstruation and involves the regeneration and thickening of the endometrial lining.
- As the follicular phase of the ovarian cycle progresses, rising levels of estrogen stimulate the endometrium to rebuild and grow.
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Secretory Phase (Days 15-28): This phase is marked by the development of progesterone-secreting glands under the influence of progesterone.
- The endometrial lining further thickens and becomes more vascular.
- If fertilization occurs, the fertilized egg implants into the prepared endometrium.
- If fertilization does not occur, the corpus luteum degenerates, leading to a decline in progesterone and estrogen levels.
- Menstruation and the New Cycle: The decrease in progesterone and estrogen from the degenerated corpus luteum triggers the endometrial lining to shed, initiating a new menstrual cycle.
Male Primary Divisions
- In the cross-section of the Testis, the spermatic cord, which is a connective tissue sheath that encloses blood vessels, nerves and ductus deferens, is found.
- The tunica albuginea protects the testis and extensions of these capsules divide into lobules.
- The lobules contain seminiferous tubules which are crucial in forming sperm cells.
- Seminiferous tubules are found in the lobules called rete testis which is a network of channels that connects the seminiferous tubules to the efferent ductules.
- Under the seminiferous tubules are the other soft connective tissue called interstitial cells which is relevant for androgen and testosterone production.
Duct System
- The duct system is composed of three primary parts: the epididymis, ductus deferens and the urethra.
- Epididymis: The epididymis is the first part of the male duct system and provides a temporary storage site for the immature sperm.
- Ductus deferens (vas deferens): Propels live sperm from their storage sites—the epididymis and distal part of the ductus deferens—into the urethra.
- Urethra: Extends from the base of the urinary bladder to the tip of the penis and serves as the passage for the sperm cells to ejaculate.
External Genitalia
- The male external genitalia include the scrotum and the penis.
- The scrotum is a divided sac of skin with sparse hairs that hangs outside the abdominal cavity, between the legs at the root of the penis.
- The penis functions to deliver sperm into the female reproductive tract.
- The skin-covered penis consists of a shaft, which ends in an enlarged tip, the glans penis.
- Internally, the spongy urethra is surrounded by three elongated areas of erectile tissue.
- Erectile tissue fills with blood during sexual excitement, causing the penis to enlarge and become rigid (erection/tumescence) which is vital for copulation.
FUNCTION AND EVOLUTION
- Fertility: Refers to the ability of the female to produce fertilizable eggs or of the male to produce sperm in sufficient numbers to achieve fertilization.
- Internal fertilization: The union of an egg and sperm cell during sexual reproduction inside the female body.
Embryonic & Fetal Development
- From fertilization through week 8, the conceptus is called an embryo.
- From week 9 through birth, the conceptus is called a fetus.
Modes of Reproduction
- Viviparity: Development of the embryo inside the body of the mother with the maternal circulation providing for the metabolic needs of the embryo's development until the mother gives birth to a fully or partially developed juvenile.
- Oviparity: Animals reproduce by depositing fertilized zygotes outside the body in metabolically independent incubation organs known as eggs.
Gestation
- Gestation lasts from conception to hatching or birth.
- Gestation includes fertilization, implantation (in some species), and development.
The Testes of Various Animals
- In vertebrates, testes are paired. They are suspended from the dorsal wall of the coelom by a mesentary, which was the mesorchium.
- Exceptions to the paired testes include cyclostomes (jawless fishes), elasmobranch (sharks) and some teleosts (ray-finned fishes).
- In Amniotes (egg-laying animals), sperm form within the luminal wall of the seminiferous tubules which lack subcompartments.
- Primordial germ cells, called spermatogonia, divide by mitosis in Amniotes.
- In Anamniotes (egg-laying aquatic animals), sperm are produced in clones, each located within a cyst or follicle.
- These clones are housed in separate tubular compartments within the testes.
- The testes of the frog is an ovoid body which lies close to the fore end of the kidney.
Similarities in Reproductive Systems
- Rabbits and humans share the same features in duct system.
- Sperm cells pass through a series of ducts to reach the outside of the body in both species.
- Fishes and frogs have an intact mesonephric duct system.
- In male sharks, rays, chimaeras, and some placoderms, the pelvic fins are specialized as claspers.
- In amphibians, most of the time their fertilization is external, however some species such as male salamander species produce a spermatophore, which consists of a cap of sperm on top of a gelatinous pedestal.
- Mammals and reptiles share the same external genitalia used in reproduction which are the penis.
- In addition, insectivores, bats, rodents, carnivores, and most primates except humans have a baculum (os penis).
- The baculum is a permanent bone located within the connective tissue of the penis to stiffen it.
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Description
Test your knowledge on the female reproductive system and its functions. This quiz covers the anatomy of the uterus, ovaries, and vagina, as well as hormonal regulation. It's essential for understanding female physiology and reproductive health.
