MCAT Biology Reproductive System Flashcards
What are the three glands in the reproductive system that produce semen?
- Seminal vesicles
- Prostate gland
- Bulbourethral glands
A region at the head of a sperm cell that contains digestive enzymes which, when released during the ___reaction, can facilitate penetration of the corona radiata of the oocyte and fertilization
Acrosome
A sac filled with fluid that surrounds and protects a developing embryo
Amnion
Male sex hormones, testosterone is the primary__
Androgen
A function in the reproductive system, controlled by the parasympathetic nervous system, that includes erection (via dilation of erectile arteries) and lubrication
Arousal
A fluid-filled sphere formed about five days after fertilization of an ovum that is made up of an outer ring of cells and an inner cell mass. This is the structure that implants in the endometrium of the uterus
Blastocyst
Small, paired glands found inferior to the prostate in males and at the posterior end of the penile urethra. They secrete an alkaline mucus on sexual arousal that lubricates the urethra and helps to neutralize any traces of acidic urine in the urethra that might be harmful to sperm
Bulbourethral glands
An increase in the fragility of the membranes of sperm cells when exposed to the female reproductive tract.
Capacitation
__ is required so that the acrosomal enzymes can be released to facilitate fertilization
Capacitation
The opening to the uterus.
Cervix
The __ is typically plugged with a sticky acidic mucus during non-fertile times (to form a barrier against the entry of pathogens), however during ovulation the mucus becomes more watery and alkaline to facilitate sperm entry
Cervix
The portion of the placenta derived from the zygote.
Chorion
The ____ secrete hCG to hlp maintain the endometrium during the first trimester of a pregnancy
Chorion
The rapid mitotic divisions of a zygote that begin within 24-36 hours after fertilization
Cleavage
The layer of granulosa cells that surround an oocyte after it has been ovulated
Corona radiata
“Yellow body”. The remnants of an ovarian follicle after ovulation has occurred. The cells enlarge and begin secreting progesterone, the dominant female hormone during the second half of the menstrual cycle. Some estrogen is also secreted
Corpus luteum
The point during cellular development at which a cell becomes committed to a particular fate.
Determination
A thick, muscular tube that connects the epididymis of the testes to the urethra. Muscular contractions of this during ejaculation help propel the sperm outward. Severing of this results in sterility of a male
Ductus deferens
One of the three primary (embryonic) germ layers formed during gastrulation. This layer ultimately forms external structures such as the skin, hair, nails, and inner linings of the mouth and anus, as well as the entire nervous system
Ectoderm
A subphase of male orgasm, a reflex reaction triggered by the presence of semen in the urethra. __ is a series of rhythmic contractions of muscles near the base of the penis that increase pressure in the urethra, forcing semen out
Ejaculation
The period of human development from implantation through eight weeks of gestation
Embryonic stage
Gastrulation, neurulation, and organogenesis occur during this time period.
Embryonic stage
A subphase of male orgasm. __ is the movement of sperm (via the ductus deferens) and semen into the urethra in preparation for ejaculation
Emission
One of the three primary (embryonic) germ layers formed during gastrulation. This layer ultimately forms internal structures:
- inner lining of the GI tract
- some glandular organs
Endoderm
A long, coiled duct on the outside of the testis in which sperm mature.
Epididymis
Specialized tissue with a lot of space that can fill with blood upon proper stimulation, causing the tissue to become firm. __tissue is found in the penis, clitoris, labia, and nipples
Erectile tissue
__ stimulates the development of female secondary sex characteristics during puberty, maintains those characteristics during adulthood, stimulates the development of a new uterine lining after menstruation, and stimulates mammary gland development during pregnancy
Estrogen
The depolarization of the egg plasma membrane upon fertilization, designed to prevent the entry of more than one sperm into the egg
Fast block to polyspermy
The fusion of a sperm with an ovum during sexual reproduction. In humans__ typically occurs in the uterine tubes and requries capacitation of the sperm and release of the acrosomal enzymes
Fertilization
The period of human development beginning at 8 weeks of gestation and lasting until birth (38-42 weeks of gestation). During this stage organs formed in the embryonic stage grow and mature.
Fetal stage
Fingerlike projections of the uterine (fallopian) tubes that drape over the ovary
Fimbriae
A developing oocyte and all of its surrounding (supporting) cells
Follicle
A tropic hormone produced by the anterior pituitary gland that targets the gonads. In females this hormone stimulates the ovaries to develop follicles (oogenesis) and secrete estrogen; in males this stimulates spermatogenesis
Follicle stimulating hormone (FSH)
The first phase of the ovarian cycle during which a follicle (an oocyte and its surrounding cells) enlarges and matures. This phase is under control of FSH from the anterior pituitary, and typically lasts from day 1 to day 14 of the menstrual cycle. The follicle secretes estrogen during this time period
Follicular phase
The formation of haploid gametes (sperm or ova) via meiosis
Gametogenesis
The division of the inner cell mass of a blastocyt (developing embryo) into the three primary germ layers. This occurs during weeks 2-4 of gestation
Gastrulation
A hormone released from the hypothalamus that triggers the anterior pituitary to secrete FSH and LH
Gonadotropin releasing hormone (GnRH)
Anterior pituitary tropic hormones FSH (follicle stimulating hormone) and LH (luteinizing hormone) that stimulate the gonads (testes and ovaries) to produce gametes and to secret sex steroids
Gonadotropins
A large, mature, ovarian follicle with a well-developed antrum and a secondary oocyte. Ovulation of the oocyte from this type of follicle
Graafian follicle
The majority of the cells surrounding an oocyte in a follicle.
Granulosa cells
___ secrete estrogen during the follicular phase of the ovarian cycle
Granulosa Cells
__ is a hormone secreted by the trophoblast cells of a blastocyst (developing embryo) that prolongs the life of the corpus luteum, and thus increases the duration and amount of secrete progesterone.
Human chorionic gonadotropin
___ helps to maintain the uterine lining so that menstruation does not occur. The presence of __ in the blood or urine of a woman is used as a positive indicator of pregnancy
hCG
The burrowing of a blastocyst (a developing embryo) into the endometrium of the uterus, typically occurring about a week after fertilization
Implantation
A protein hormone secreted by the sustenacular cells of the testes of the granulosa cells of the ovaria that acts to inhibit the release of FSH from the anterior pituitary
Inhibin
The mass of cells in the blastocyst that ultimately give rise to the embryo and other embryonic structures (the amnion, the umbilical vessels)
Inner cell mass
Called the Leydig cells, these are cells within the testes that produce and secrete testosterone. They are stimulated by luteinizing hormone (LH)
Interstitial cells
The folds of skin that enclose the vaginal and urethral openings in females
Labia
Strong contractions of the uterus (Stimulated by oxytocin) that force a baby out of the mother’s body during childbirth.
Labor contractions
___ are part of a positive feedback cycle, during which the baby’s head stretches the cervix, that stimulates stretch receptors that activate the hypothalamus, that stimulates the posterior pituitary to release oxytocin, that stimulates strong uterine contractions (labor contractions) that cause the baby’s head to stretch the cervix. The cycle is broken once the baby is delivered
Labor contractions
The third phase of the ovarian cycle, during which the corpus luteum is formed from the remnants of the follicle that has ovulated its oocyte. The corpus luteum secretes progesterone and estrogen during this time period, which typically lasts from day 15 to day 28 of the menstrual cycle.
Luteal phase
Formation of the corpus luteum during this phase of menstruation is triggered by the same LH surge that triggers ovulation, however in the absence of LH, the corpus luteum begins to degenerate
Luteal phase
A tropic hormone produced by the anterior pituitary gland that targets the gonads. In females it triggers ovulation and the development of the corpus luteum during the menstrual cycle
Luteum
In males __ strimulates the production and release of testosterone
Luteinizing hormone (LH)
In females __ triggers ovulation and the development of a corpus luteum
Luteinizing hormone (LH)
The first phase of the uterine (endometrial) cycle, during which the unused endometrium from the previous cycle is shed off. Estrogen and progesterone levels are low during this time period
Menstruation
This phase is the first phase of the uterine cycle and typically lasts from day 1 to day 5 of the cycle
Menstruation cycle
One of the three primary (embryonic) germ layers formed during gastrulation. __ is ultimately forms “middle” structures such as :
- bones
- muscles
- blood vessels
- heart
- kidneys
Mesoderm
A solid clump of cells resulting from the cleavage in the early embryo. Because thee is very little growth of these cells during cleavage, the _ is about as large as the original zygote
Morula
Early embryonic ducts that can develop into female internal genitalia in the absence of testosterone
Mullerian ducts
A substance secreted by embryonic testes that casues the regression of the Mullerian ducts
Mullerian inhibiting factor (MIF)
The muscular layer of the uterus
Myometrium
The __ is made of smooth muscle that retains its ability to divide in order to accommodate the massive size increases that occur during pregnancy. Th __ is stimulated to contract during labor by the hormone oxyctocin
Myometrium
Cells that separate from the neural tube during neurulation and migrate to different parts of the embryo.
Neural crest
__ cells differntiate into a variety of cell types including”
- melanocytes
- glial cells
- adrenal medulla
- some peripheral neurons
- some facial ocnnective tissue
Neural crest cells
The formation of the nervous system during weeks 5-8 of gestation. ___ begins when a section of the ectoderm invaginates and pinches off to form the neural groove, which ultimately forms the neural tube, from which the brain and spinal cord develop
Neurulation
A precursor cell that undergoes mitotis during fetal development to produce more of itself. These cells are then activated to produce primary oocytes, which remain dormant until stimulate to undergo meiosis 1 during some future menstrual cycle
Oogonium
The stage of human development when organs form. It begins after gastrulation and is completed by the 8th week of gestation
Organogenesis
A function of the reproductive system controlled by the sympathetic nervous system. In males it includes the emission and ejaculation; in females it is mainly a series of rhythmic contractions of the pelvic floor muscles and the uterus
Orgasm
The 28 days of the menstrual cycle as they apply to events in the ovary. There are three subphases of it
- follicular phase
- ovulation
- luteal phase
Ovarian cycle
The female primary sex organ. The __ produces female gametes OVA and secretes estrogen and progesterone
Ovary
The release of a secondary oocyte (along with some granulosa cells) from the ovary at the approximate midpoint of the menstrual cycle (typically around day 14). ___ is triggered by a surge in LH
Ovulation
A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding
Oxytocin
An organ that develops during pregnancy, derived in part from the mother and in part from the zygote. The __ is the site of exchange of nutrients and gases between the mother’s blood and the fetus’s blood. The __ is formed during the first three months of pregnancy
Placent
Zygote-derived projection that extend into the endometrium of the uterus during pregnancy. Fetal capillaries grow into the __, which are surrounded by a pool of maternal blood. This facilitates nutrient and gas exchange between the mother and the fetus, without actually allowing the bloods to mix
Placental villi
A small cell with extremely little cytoplasm that results from the unequal cytoplasmic division of the primary and secondary oocytes during meiosis (oogenesis). The __ degenerate
Polar body
The fertilization of an oocyte by more than one sperm. This occurs in some animals but in humans, blocks to prevent it exist so that only a single sperm can penetrate the oocyte
Polyspermy
Diploid cells resulting from the activation of an oognoium; ___ are ready to enter meiosis 1
Primary oocytes
Diploid cells resulting from the activation of a spermatogonium; __ are ready to enter meiosis 1
Primary spermatocytes
A steroid hormone produced by the corpus luteum in the ovary during the second half of the menstrual cycle
Progesterone
A hormone secreted by the anterior pituitary that targets the mammary glands, stimulating breast milk
Prolactin
The second phase of the uterine (endometrial) cycle during which the endometrium (shed off during menstruation) is rebuilt. This phase of the cycle is under control of estrogen, secreted from the follicle developing in the ovary during this time period. The __ typically lasts from day 6 to day 14 of the menstrual cycle
Proliferative phase
A small gland encircling the male urethra just inferior to the bladder. Its secretions contain nutrients and enzymes and account for approximately 35 percent of the ejaculate volume
Prostate
A function of the reproductive system (controlled by the sympathetic nervous system) that returns the body to its normal resting state after sexual arousal and orgasm
Resolution
A haploid cell resulting from the first meiotic division of oogenesis. Note that the cytoplasmic division in this case is unequal, producing one large cell with almost all of the cytoplasm the ___ and one smaller cell with virtually no cytoplasm (the first polar body). The __, along with some follicular cells, is released from the ovary during ovulation
Secondary oocyte
The set of adult characteristics that develop during puberty under the control of sex steroids. In males the __ include enlargment and maturation of the genitalia, growth of facial, body, and pubic hair, increased muscle mass, and lowering of the voice. In females it includes onset of menstruation and the menstrual cycle, enlargement of the breasts, widening of the pelvis, and growth of pubic hair
Secondary sex characteristics
Haploid cells resulting from the first meiotic division of spermatogenesis. __ are ready to enter meiosis 2
Secondary spermatocytes
The third phase of the uterine (endometrial) cycle, during which the rebuilt endometrium is enhanced with glycogen and lipid stores. The __ is primarily under the control of progesterone and estrogen (secreted from the corpus luteum during this time period), and typically lasts from day 15 to day 28 of the menstrual cycle
Secretory phase
An alkaline, fructose-rich fluid produced by three different glands in the male reproductive tract and released during ejaculation. __ is very nourishing for the sperm
Semen
Paired glands found on the posterior external wall of the bladder in males. Their secretions contain an alkaline mucus and fructose, among other things, and make up approximately 60 percent of the ejaculate volume
Seminal vesicles
Small convoluted tubules in the testes where spermatogenesis takes place
Seminiferous tubules
The __ occurs after a sperm penetrates an oocyte (fertilization). It involves an increase in intracellular (Ca2+) in the egg, which causes the release of cortical granules near the egg plasma membrane. This results in the hardening of the zona pellucida and its seperation from the surface of the egg, preventing the further entry of more sperm into the egg
Slow block to polyspermy
A haploid but immature cell resulting from the second meiotic division of spermatogenesis. __ undergo significant physical changes to become mature sperm (spermatozoa)
Spermatid
__ results in the production of four mature gametes from a single precursor cell (spermatogonium). For maximum sperm viability, __ requires cooler temperatures and adequate testosterone
Spermatogenesis
A diploid cell that undergo mitosis to form more spermatogonium, and can also be triggered to undergo meiosis to form sperm
Spermatogonium
Cells that form the walls of the seminiferous tubules and help in spermatogenesis. __ are also called Sertoli cells and respond to Follicule stimulating hormones
Sustenacular cells (sertoli cells)
What are the two functions of the testes:
- produce sperm
2. Secrete tesotsterone
