Reproductive System Flashcards
is an essential characteristic of living organisms, and functional male and female reproductive systems are necessary for
humans to reproduce.
Reproduction
The reproductive system performs the following functions:
Production of gametes
Fertilization
Development and nourishment of a new individual
Production of reproductive hormones
Specialized organs of the reproductive system produce gametes:
Sperm cells in males
Oocyte (egg) in females
The reproductive system enables _______ of the oocyte by the sperm.
Fertilization
The female reproductive system nurtures the developing fetus in the ______ until birth and provides nourishment (milk) after birth.
Uterus
produced by the reproductive system control its development and the development of the gender-specific body form.
Hormones
is a type of cell division specialized for sexual
reproduction.
Meiosis
During meiosis, one cell undergoes two consecutive divisions to produce four genetically different
Daughter cells
In humans, meiosis occurs only in the
____________ and produces sperm cells in males and oocytes in females.
Testes and ovaries
In humans, the ___________ normally have 46 chromosomes, called the diploid number (2n).
Somatic cells
Chromosomes exist in 23 homologous pairs—22 autosomal pairs and 1 pair of
Sex chromosomes
The sex chromosome pair is composed of an X and a Y chromosome in males and two X chromosomes in females.
XX Males
XY Females
One chromosome of each __________
is inherited from the male parent, and the other chromosome of each pair is inherited from the female parent.
Homologous pair
The chromosomes of each homologous pair are alike in size and shape and contain
_____ for the same traits.
Genes
Sperm cells and oocytes contain the _______ number (n) of chromosomes, which is half the diploid number, or 23.
Haploid
Each ______ contains one chromosome from each of the homologous pairs.
Gamete
Upon fertilization, the sex of the baby is determined by the
Sperm cell
The two divisions of meiosis are called
Meiosis I
Meiosis II
The stages of meiosis have the same names as the stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
Before meiosis begins, all the chromosomes are
Duplicated
At the beginning of meiosis, each of the 46 chromosomes consists of _____________ connected by a centromere
Two sister chromatids
In prophase I, the chromosomes become visible, and the homologous pairs come together in a process called
Synapsis
Because each chromosome consists of two chromatids, the pairing of the homologous
chromosomes brings two chromatids of each chromosome close together, an arrangement called a
Tetrad
The exchange of genetic material between maternal and paternal chromosomes is called
__________ and may result in new gene combinations on the chromosomes.
Crossing over
During _________, homologous pairs of chromosomes line up near the center of the cell.
Metaphase I
During _________, the homologous pairs are separated to each side of the cell
Anaphase I
During __________, new nuclei form, and the cell completes division of the cytoplasm to form two cells
Telophase I
Since the chromosome number is reduced
from a 2n number to an n number during meiosis I, this division is often called a
Reduction division
At the end of meiosis I, each of the 23 chromosomes in the daughter cells still consists of
Two chromatids
The separation of the chromatids of the duplicated chromosomes occurs in
Meiosis II
The second meiotic division is similar to
Mitosis
When the centromere separates, each of the chromatids is called a
Chromosome
Each of the four daughter cells produced by meiosis contains
23 chromosomes
The male reproductive system consists of the
Testes
A series of ducts
Accessory glands
Supporting structures
The ducts include the
Epididymides
Ducta Deferentia
Urethra
Accessory glands include the
Seminal Vesicles
Prostate Gland
Bulbourethral Glands
Supporting structures include the
Scrotum
Penis
in which the sperm cells develop, are located outside the body cavity in the scrotum.
Testes and epididymides
lead from the testes into the pelvis, where
they join the ducts of the seminal vesicles to form the ampullae.
Ducta Deferentia
Extensions of the ampullae, called the __________, pass into the prostate and empty into the urethra within the prostate.
Ejaculatory ducts
is a saclike structure that contains the testes.
Scrotum
Scrotum is divided into ____ internal compartments by an incomplete connective tissue septum.
Two
Externally, the compartments of the scrotum are marked by a midline irregular ridge called the
Raphe
The ______ extends posteriorly to the anus and
anteriorly onto the inferior surface of the penis.
Raphe
The wall of the scrotum includes the skin, a layer of superficial fascia consisting of loose connective tissue, and a layer of smooth
muscle called the
Dartos Muscle
In ____ temperatures, the dartos muscle contracts, causing the skin of the scrotum to
become firm and wrinkled and reducing its overall size.
Cold
which are extensions of abdominal skeletal muscles into the scrotum, contract and help pull the testes nearer the body.
Cremaster Muscles
These changes in size and position of the scrotum help keep the testes
Warm
The perineum is divided into two triangles by the
Superficial Transverse Muscles
Deep Transverse Perineal Muscles
is the area between the thighs that is bounded by the symphysis pubis anteriorly, the coccyx posteriorly, and the ischial tuberosities laterally.
Perineum
These muscles run transversely
between the two ischial tuberosities
Superficial Transverse Muscles
Deep Transverse Perineal Muscles
The two triangles are the
Urogenital Triangle
Anal Triangle
In males, the __________ triangle, or anterior triangle, contains the base of the penis and the scrotum
Urogenital
In males, the smaller ____ triangle, or posterior triangle, contains the anal opening
Anal
are small, oval-shaped organs, each about
4–5 cm long, within the scrotum
Testes
The testes function as both
Exocrine and Endocrine Glands
Major exocrine secretion is
Sperm Cells
Major endocrine secretion is the
Hormone Testosterone
The outer part of each testis is a thick, white capsule consisting mostly of fibrous connective tissue called the
Tunica Albuginea
Extensions of the tunica albuginea extend into the testis and form
Incomplete Septa
The septa divide each testis into about _____ cone-shaped lobules.
300-400
The lobules contain _____________,
in which sperm cells develop.
Seminiferous tubules
Loose connective tissue surrounding the seminiferous tubules contains clusters of endocrine cells called
Interstitial Cells or Leydig cells
The interstitial cells secrete
Testosterone
The seminiferous tubules empty into a set of short, straight tubules called the
Tubuli Recti
These in turn empty into a tubular network called the
Rete Testis
The rete testis empties into 15–20 tubules
called ___________ that pass through the tunica
albuginea to exit the testis.
Efferent ductules
The efferent ductules have a ciliated
_______________________, which helps move sperm cells out of the testis.
Pseudostratified columnar epithelium
By approximately 8 weeks following fertilization, the testes have
developed as
Retroperitoneal organs
The testes are located high in the ____________ near the developing kidneys.
Abdominopelvic Cavity
Each testis is connected to a labioscrotal swelling by a ___________, a fibromuscular cord.
Gubernaculum
The labioscrotal swelling becomes the
Scrotum
The testes descend toward the area where the
_________ will form.
inguinal canals
The _________ extends through the inguinal canal, enlarging the canal.
Gubernaculum
Between ___________ of development, the testes move through the inguinal canals into the scrotum
7 and 9 months
As it moves into the scrotum, each testis is preceded by an out-pocketing of the peritoneum called the
Process vaginalis
The superior part of each process vaginalis usually degenerates, and the inferior part remains as a small, closed sac called the
Tunica Vaginalis
Tunica Vaginalis is a serous membrane consisting of a layer of simple squamous epithelium resting on a
Basement membrane
The tunica vaginalis surrounds most of the ____ in much the same way that the pericardium surrounds the heart.
Testis
The testes have descended into the scrotum in approximately __________ delivered prior to 28 weeks of development.
79% of male infants
The inguinal canals are bilateral, oblique passageways in the
Anterior Abdominal Wall
Inguinal canals originate at the __________, which open through the aponeuroses of the transversus abdominis muscles.
Deep inguinal rings
The canals extend inferiorly and obliquely and end at the ____________, openings in the aponeuroses of the external abdominal oblique muscles.
Superficial inguinal rings
is the failure of one or both of the testes to descend into the scrotum.
Cryptorchidism
At ________ years of age, the interstitial cells increase in number and size, a lumen develops in each seminiferous tubule, and sperm cell production begins.
12-14
It takes approximately ____ for sperm cells to be produced.
74 days
For about 50 of those days, the sperm cells are in the
Seminiferous Tubules
is an abnormal opening in the abdominal wall in the inguinal region through which a
structure, such as a portion of the small intestine, can protrude.
Inguinal Hernia
Inguinal hernias can be of two types
Indirect
Direct
If the deep inguinal ring remains open, or if it is weak and enlarges later in life, a loop of intestine can protrude into or even pass through the inguinal canal, resulting in an
Indirect Inguinal Hernia
results from a tear, or rupture, in a weakened area of the anterior abdominal wall near the inguinal canal, but not through the inguinal canal.
Direct Inguinal Hernia
sperm cell development, occurs in the seminiferous tubules
Spermatogenesis
The seminiferous tubules contain two types of cells
Germ cells
Sustentacular Cells or Sertoli cells (also sometimes referred to as nurse cells)
are the ones that divide and differentiate during spermatogenesis to form sperm cells.
Germ cells
are large cells that extend from the periphery to the lumen of the seminiferous tubule.
Sustentacular cells
The sustentacular cells nourish the germ cells and probably produce, together with the
interstitial cells, a number of hormones, such as
Androgens
Estrogens
Inhibins
In addition, tight junctions between the sustentacular cells form a _____________ between germ cells and sperm cells.
Blood-testis barrier
isolates the sperm cells from the immune system
Blood-testis barrier
Interstitial cells secrete testosterone, which passes into the sustentacular cells and binds to
Intracellular Receptors
Testosterone in the sustentacular cells is converted to two other steroids: ________________, a specific type of estrogen
Dihydrotestosterone and estradiol
The sustentacular cells also secrete a protein
called _________ into the seminiferous tubules.
Androgen-binding protein
Testosterone and dihydrotestosterone bind to androgen-binding protein and are carried along with other secretions of the seminiferous tubules to the
Epididymis
Estradiol and dihydrotestosterone may be the _____________ that promote sperm cell
formation.
Active Hormones
are partially embedded in the sustentacular cells
Germ cells
The most peripheral cells, those adjacent to the basement membrane of the seminiferous tubules, are __________, which divide by mitosis
Spermatogonia
Other daughter cells differentiate to form
___________, which divide by meiosis
Primary spermatocytes
begins when the primary spermatocytes
divide.
Spermatogenesis
Each primary spermatocyte passes through the first meiotic division to become two
Secondary spermatocytes
Each secondary spermatocyte undergoes a second meiotic division to produce two even smaller cells called
Spermatids
Each spermatid contains one of each of the __________ of chromosomes.
Homologous pairs
Each sperm cell contains 22 __________ and either an X or a Y chromosome.
Autosomes
Each spermatid undergoes the last phase of spermatogenesis, called _____________, to form a mature sperm cell, or spermatozoon
Spermiogenesis
During spermiogenesis, each spermatid develops
a head, a midpiece, and a tail, or flagellum.
The nucleus of the sperm is located in the
Head
Just anterior to the nucleus is a vesicle called the __________, which contains enzymes necessary for the sperm cell to penetrate the female oocyte
Acrosome
The flagellum is similar to a _________, and microtubules within the flagellum move,
propelling the sperm cell forward.
Cilium
Sperm cells in the seminiferous tubules move through the
tubuli recti to the rete testis.
From the rete testis, they pass through the ___________, which leave the testis and enter the epididymis.
Efferent ductules
The sperm cells then leave the epididymis, passing through the ductus deferens, ejaculatory duct, and urethra to the _________ of the body.
Exterior
The efferent ductules from each testis become extremely convoluted and form a comma-shaped structure on the posterior side of the testis called the
Epididymis
The head contains the ______________, which empty into the duct of the epididymis, a single convoluted tube located primarily within the body of the epididymis
Convoluted Efferent Ductules
Each epididymis consists of a
Head
Body
Tail
The duct of the epididymis has a pseudostratified columnar epithelium with elongated microvilli called
Stereocilia
The final maturation of the sperm cells occurs within the
Epididymis
It takes _____ days for sperm to travel through the epididymis and appear in the ejaculate.
12–16
The penis is composed of three erectile tissues:
Two corpora cavernosa
One corpus spongiosum, which surrounds the urethra
During sexual arousal, the blood flow increases
to the __________, leading to an erection
Corpora cavernosa
prevents the urethra from being compressed
during erection, ensuring that sperm can be expelled during ejaculation.
Corpus Spongiosum
is a muscular tube that transports sperm
from the epididymis to the urethra for ejaculation.
Vas Deferens
sperm mixes with secretions from accessory glands, including the seminal vesicles, prostate gland, and bulbourethral glands, to form
Semen
controls the process of ejaculation, which involves the contraction of smooth muscles in the reproductive ducts, leading to the expulsion of semen from the penis.
Sympathetic Nervous System
which is responsible for initiating an erection by dilating blood vessels in the penis.
Parasympathetic Nervous System
are the female gonads responsible for producing oocytes (eggs) and hormones such as estrogen and progesterone.
Ovaries
The process of __________ begins in fetal life, but eggs do not complete their maturation until puberty.
Oogenesis
At puberty, the eggs undergo periodic
development during the
Menstrual Cycle
containing oocytes are present at birth, and some of these will mature into primary follicles.
Primordial follicles
During each menstrual cycle, a dominant follicle matures into a __________, and upon ovulation, an oocyte is released.
Graafian follicle
After ovulation, the oocyte is captured by the _________ at the end of the fallopian tube.
Fimbriae
The fallopian tube is lined with_____, which help
move the oocyte towards the uterus.
Cilia
This is where fertilization usually occurs if sperm are present.
Fallopian Tube
The uterus consists of three layers:
Endometrium
Myometrium
Perimetrium
the innermost layer, undergoes cyclic changes in response to hormones like estrogen and progesterone.
Endometrium
Endometrium thickens during the ___________ to prepare for implantation of a fertilized egg.
Menstrual Cycle
If implantation does not occur, the
endometrium is ______ during menstruation.
Shed
is the muscular layer responsible for uterine contractions during menstruation and childbirth.
Myometrium
is the outer serous layer.
Perimetrium
in the endometrium supply blood to the thickened lining.
Spiral Arteries
If pregnancy does not occur, these spiral arteries _________, leading to the shedding of the endometrial lining.
Constrict
The menstrual cycle is divided into several phases:
Follicular phase
Ovulatory Phase
Luteal Phase
Follicular phase is characterized by the maturation of follicles in the ovaries, leading to an increase in _________ production.
Estrogen
is marked by the release of the oocyte (ovulation), triggered by a surge in luteinizing hormone (LH).
Ovulatory Phase
The luteal phase occurs after ovulation, during
which the ruptured follicle transforms into the
corpus luteum, which secretes ____________ to
prepare the uterus for pregnancy.
Progesterone
If fertilization does not occur, the corpus luteum degenerates, and estrogen and progesterone levels drop, leading to the onset of
Menstruation
are responsible for milk production.
Mammary glands
Mammary glands consist of ___________ organized into lobes that contain alveoli,
where milk is produced.
Glandular tissue
stimulates milk production
Prolactin
is responsible for the milk ejection reflex.
Oxytocin
is the principal male sex hormone, produced
primarily by Leydig cells in the testes.
Testosterone
Testosterone plays a vital role in:
- The development of male secondary sexual
characteristics, such as deeper voice, facial hair,
and muscle growth
2.Stimulating spermatogenesis in the seminiferous tubules. - Regulating libido and maintaining overall
reproductive health.
In females, estrogen is produced primarily by the ovaries and is involved in:
- The development of female secondary sexual
characteristics, such as breast development and wider hips. - Regulating the menstrual cycle and preparing the endometrium for implantation.
If pregnancy occurs, progesterone levels remain _______, but if fertilization does
not occur, levels drop, leading to menstruation.
Elevated
are released by the anterior pituitary gland
and play crucial roles in the menstrual cycle:
Luteinizing Hormone (LH)
Follicle-Stimulating Hormone (FSH)
stimulates the growth of ovarian follicles
Follicle-stimulating hormone
triggers ovulation
Luteinizing hormone
In males, ________ supports spermatogenesis
Follicle-stimulating hormone
In males, ________ stimulates testosterone production from Leydig cells.
Luteinizing hormone
undergoes significant cyclic changes, responding to fluctuating estrogen and progesterone levels. These changes prepare the uterus for possible implantation and support early pregnancy if fertilization occurs.
Endometrium
are responsible for the bulk of the penile erection
Corpora cavernosa
The structure of the mammary glands includes ___________ where milk production occurs.
Lobes
Lobules
Alveoli
The alveoli are surrounded by __________ that contract to expel milk during lactation.
Smooth muscle cells
