module 1 Flashcards
(191 cards)
1
Q
Gametes
A
Are the mature, specialized sex cells which are capable of fusing with the sex of the opposite sex to form a zygote
2
Q
Haploid cells:
A
cell that contain a single set of chromosomes, carries only one member of the sex chromomere pair
3
Q
Gonads
A
Are the primary sex organs
4
Q
what do gonads produce
A
gametes and sex hormones that regulate the reproductive process
5
Q
Reproductive Ducts
A
Designed to transport and/or store the gametes after they have been produced
6
Q
External Sex Organs
A
Make possible the delivery of gametes to facilitate their fusion (fertilization)
7
Q
basic components of the reproductive system
A
- gametes
- gonads
- reproductive ducts
- external sex organs
8
Q
gametes, Female
A
Ova or eggs
9
Q
gametes, male
A
Sperm
10
Q
Reproductive ducts Female
A
- Fallopian tubes
- vagina
11
Q
Reproductive ducts males
A
- Epididymis
- Vas deferens
- Ejaculatory ducts
- Urethra
12
Q
Gonads females
A
Ovaries
13
Q
Gonads Male
A
Testes
14
Q
External sex organs female
A
vulva
15
Q
External sex organs male
A
- Penis
- Scrotum
16
Q
Diploid cells : formation of gametes
A
Formation of gametes, termed gametogenesis, includes the meiotic division of precursor diploid cells
17
Q
after gametogenesis,
A
the result haploid gametes will contain only one sex chromosome
18
Q
what chromsome do ova carry
A
x chromosomr
19
Q
what chromosome do males carry
A
x or y
20
Q
At the moment of fertilization
A
the sex chromosome carried by the sperm ultimately determines the genetic sex of the zygote and directs the path of development for the resulting embryo
21
Q
Meiotic division:
A
meiosis is a special type of cell division that reduces the chromosome number by half, creating haploid cells
22
Q
Embryo:
A
the developmental stage between the moment of fertilization and until 8 weeks of development
23
Q
what is the SRY gene
A
This gene is found on the Y chromosome and is called the SRY gene Sex-determining Region of the Y chromosome
24
Q
Indifferent gonads
A
the stage of the undifferentiated mammalian gonads when neither male or female characteristics have been acquired
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Male Gonad development:
To be a male, individual must be exposed to a cascade of factors initiated by the SRY gene
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what does the SRY gene encode
a protein, activating the gene required for the development of the testes at week 7 of development
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what does the SRY suppress
genes that are important for female development
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Spermatogonia
the undifferentiated male germ cells from which mature sperm develop
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Female Gonad development:
Females don’t have a Y chromosome so they DON’T have a SRY gene
- therefore other gene expressed that lead to development of oogonia and ovaries
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what has happened to some males with no working SRY gene
seen to develop female reproductive systems instead of male supporting the role of SRY gene
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Intersex disorders:
- Cause physiological variations in sexual characteristics that do not fit the typical definition of either male or female
- Problems with the normal development of reproductive organs and can also involve metabolic abnormalities with wide health implications
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examples of intersex disorders
turner syndrome
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turner syndrome
- Female is partially or completely missing one of her X chromosomes
- Non-functioning ovaries, heart defects, hormonal imbalances, and impaired skeletal development, among many other health issues due to the loss of important functional gene
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Sex-linked disorders
- Caused by genetic abnormalities inherited through sex chromosomes only
- Do not always effect the sexual characteristics of an person
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example of a sex-linked disorder
- As males only have a single X chromosome, any mutations carried in the maternal X chromosome will be expressed in an autosomal dominant fashion
- Females have 2 X chromosomes, so are much more resilient to X-linked sex disorders
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is there differnece between male and female embryos during first stages of development?
no.
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Indifferent stage
the period preceding sexual differentiation, when no differences can be observed between genetic male and female embryos
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when does the indifferent stage occurs
week 0-6 of ferilization
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Blastocyst Formation:
- The embryo starts as a simple bundle of cells
- After fertilization it will begin to divide and grow so it can start developing more complex structures
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what does the growing of blastocyst develop into
tissues, organs, finally organ systems
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Early blastocyst:
- an inner and outer layer form
- Trophoblast layer anchors the blastocyst to the uterus
- Inner cell mass can go on to for, the embryo proper
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Late blastocyst:
- Outer cells are busy anchoring the embryo to the uterus
- Inner cells go on to form a flattened plate with 2 distinct tissue
Layers epiblast, hypoblast
- Only the epiblast will participate in embryo development
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what is gastrulation
Landmark stage
- Embryo establishes 3 germ layers that provide the source tissue of all organ systems
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what/where is the embryo at the start of gastrulation
week 2 of development the embryo is already securely attached at its permanent location for the rest of pregnancy**
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what happens during gastrulation
- The epiblast folds inward forming the primitive streak through process known as invagination
- As they migrate inwards, they differentiate and form the 3 germ layers
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what are 3 germ layers
- Ectoderm
- Mesoderm
- Endoderm
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Primitive streak
a structure that forms in the early embryo stages, which indicates the start of gastrulation
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what happens once the 3 germ layers are formed
each germ layer will give rise to the tissues from which specific structures and organ system will form
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Embryonic folding: what does it establish
- bodily axes, dorsoventral and cranial-caudal axes
- future position and location of all organ systems
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when does embryonic folding occur
between week 3 and 4 of feralization
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Gonadal development:
- Tissues begin to differentiate and grow, embryo will begin the process of sexual differentiation, along with the development of other organs
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what are the first component of the reproductive system
gonads
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where do gonads begin developing from
mesoderm layer (source of all tissues from the reproductive system)
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when does gonadal development occur
Week 4 of development
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Tissues ridges
known as genital or gondal ridges
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what is the earliest cells associated with emergence of gonads
Primordial germ cells
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PGCs:
migrating towards the gonadal ridges around week 4 of development, arriving and invading area around week 6
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before arrival of primodial germ cells
the gonadal ridges will form finger-like tissue projections known as primary sex cords
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after arrival of PGCs
interact with this tissue and, depending on the genetic sex of the embryo, will go to form the structures of either male gonad (testis) or female gonad (ovaries)
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what happens if primordial germ cells don't arrive at the gonad ridges
no gonads will develop
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Male gonadal development:
- The SRY gene found on the Y chromosome prompts the development of the testes
- Primary sex cords develop to form the primitive testes, which begin to produce testosterone, the major androgen in males
- Testosterone will direct the development of the male reproductive ducts
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when does male gondal development occur
week 7 and 8
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what does Dihydrotestoerone (DHT) do
is synthesized from testosterone will direct the development of external male genitalia
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what do testes produce
Testes produce anti-mullerian hormone (AMH)
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what happens in the 3rd month 10-13 weeks of male development and the testes
need to migrate outside the body into scrotal sac
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testi migration
- is vital for the proper function of testes, and is commonly referred to as the descent of the testes
-
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what is testes migration influenced by
Influenced by a combination of growth processes and hormones
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descent of the testes: second month
- Is facilitated by the gubernaculum testis (a structure that arises in the course of week 7 development)
- Forms at the caudal end of the gonads and attaches in the region of the scrotal swelling the future scrotum
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descent of testes : 3rd month
- Between the 7th and 12th week
- Gubernaculum begins to shorten, puling the testes towards their future location in the labioscrotal swelling, pulling the layers of the abdominal wall with it creating the ingunal canal
These layers will become the layers surrounding the testes
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descented of testes: final month of pregnancy
Testes reach the scrotum at roughly the time of birth under the influence of specific hormones
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Female Gonad development
Absence of SRY, the primary sex cords degenerate, and cortical sex cords begin to develop as the gonads take the path towards ovarian development
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what do the coritcal sex cords for females develop
form the ovarian follicles
○ Site of oocyte production
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gubernculum female gonad developement
- causes the ovaries to change their position slightly
- goes on to form the ovarian ligament and further down the round ligament of the uterus that reaches the labia majora through the inguinal canal
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Migration anomalies
Can cause pathology of the inguinal canal, such as inguinal hernia or undescended testes
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Migration anomalies - Males
- More prone to inguinal hernias than females
- Due to the migration process during the descent of the testes
-
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what happens as testicles descend down the inguinal canal
they create a gap in the abdominal muscle after birth- which makes them more likely developing inguinal hernia
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Migration anomalies - female
Inguinal canal is much smaller
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what is undescended testes called
Cryptorchidism
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how/when do undescended testes occur
- when one or both testicles fail to complete their migration toward the scrotum
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what can undescended testes lead to
- impaired sperm production as the testis need to be at a slightly lower temperature than body temperature for sperm production to proceed normally
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Male and female genital duct development- when does it start
week 4 all embryos develop 2 pairs of ducts which become the origin of the entire genitourianry duct system
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what are the 2 ducts both females and males develop in week 4
- wolffian (mesonephric) ducts
- mullerian (pharmacophoric ducts)
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where do to common week 4 ducts originate from
common region in the mesodermal layer called the intermediate mesoderm and end at the clocac at the caudal end of the primitive gut
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female developing ducts/how- mulleruan ducts
The absence of testosterone causes the mullerian ducts to go on to form the fallopian/uterine tubes, the uterus, and the upper portion of the vagina
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male developing duct/how: mullerian ducts
Developing testes produce testoerone and antimullerian hormone- causing the mullerian ducts to regress around week 8 of development
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female developing ducts - wolffian duct turn into what?
go on to differentiate and form the epididymis
87
male developing ducts - wolffian duct turn into what?
go on to differentiate and form the epididymis, vas/ductus deferens, the seminal vesicles, and ejaculatory ducts, a process which is completed by week 12 of development
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female when do the wolffian ducts regress
approx. week 10
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when does external genitalia development occur
Begins around week 3 no difference can be detected between male and female embryos until around week 9
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external genitalia: Undifferentiated: stage end of week 5
cloacal fold form on both sides of the urogenital sinus and are joined by the genital tubercle at the anterior end
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external genitalia: Undifferentiated: stage by 7th week
he cloacal folds have differentiated into the urogenital fold and the anal fold
- Genital swellings develop from the lateral part of the genital tubercle
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external genitalia: week 10 in male
exposure to dihydrotestosterone (DHT) results in growth of the genital tubercle and an increase in size of the genital swellings
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external genitalia: week 10 in female
there is minimal growth of the genital tubercle and genital swellings
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newborn: extenral genitalia male
the genital tubercle continues to grow to form a phallus, and the urogential folds fuse to form a scrotum
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newborn: extenral genitalia female
the genital tubercle develops into the clitoris, and the urogenital fold do not fuse but give rise to the labia majora and labia minora
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Three primary functions: males
1. To produce and maintain sperm cells
2. to transport and deliver sperm cells into the female reproductive tract
3. To produce and secrete sex hormone
97
male external organs
Penis
Scrotum
Epididymis
Testes
98
function of penis
Serves as both a reproductive and urinal duct
- Passage of both urine and semen
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what are the 3 columns of tissue in males
- corpora cavernose
- Corpus spongiosum
- tunica albuginea
100
layout of the 3 penis tissue
- 2 corpora cavernose that lie next to each other on the dorsal side
- Corpus spongiosum that lies between the corpora cavernosa on the ventral side
- Surrounding the corpora cavernose is a tough of connective tissue called the tunica albuginea
101
The glans penis what is functin and how is it formed
- Is the bulbous end of the penis formed by the corpus spongiosum
Supports the foreskin (prepuce) that retract to expose the glands
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Penile Fracture
- Can "break"
- Involves a rupture in the tunica albuginea (layer coving the corpora cavernosa)
- Is a medical emergency due to the injury to urethra, nerves, and blood vessel of the penis, requiring surgical intervention
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what is the scrotum
Dual chambered suspended sack of skin and smooth muscle that contains the testes
104
what casues the colour and hair on scrotum
Increased testosterone secretion during puberty causes the darkening of the skin and development of pubic hai
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function of scrotum
- the temp of the testes slightly lower than that of the rest of the body
- left testis is usually lower than the right, which may function to avoid compression in the event of impact and to allow more effective cooling
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what is the degrees drop it should be for optimal sperm production
2 degrees below body temp
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testes function
male gonads
- production of sperm
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layers of scrotal sac
1. scrotal skin
2. dartos fascia and muscle
3. external spermatic fascia
4. cremaster muscle
5. internal spermatic fascia
6. tunica vaginalis
7. tunica albuginea
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Scrotal skin
the external most later
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Dartos fascia and muscle
a layer of fascia and smooth muscle that carriers the blood supply to the skin, helping regulate the testes temp
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External spermatic fascia:
a thin layer of fascia
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Cremaster muscle:
a layer of smooth muscle that carriers blood and nerve supply to the testes, and is responsible for the cremasteric reflex of the scrotum
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Internal spermatic fascia:
thin layer of fascia
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Tunica albuginea
the final and inner most layer covering the teste
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Tunica Vaginalis:
a serous membrane that covers the testis. It is continuous with the surface of testis and the internal surface of the scrotum, creating a pouch or cavity in between
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what are under the tunica albuginea of males
seminiferous tubules
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what happens in the Seminiferous tubules
site of spermatogenesis
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Spermatogenesis
production or development of mature spermatozoa
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Cells of the seminiferous tubules
1. Spermatogonial stem cells
2. Sertoli cells
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Spermatogonial stem cells
Become mature sperm
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Sertoli cells
Facilitate the process of sperm maturation
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what Located between seminiferous tubule
Leydig cells
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Leydig cells
Produce and secrete testosterone and other androgens required to sustain spermatogenesis, sexual development, and puberty
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types of Seminiferous Tubules
1. Convoluted
2. Straight
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Seminiferous Tubules: Convoluted
Located toward the lateral side
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Seminiferous Tubules: Straight
As the tubule comes medially to form ducts allowing sperm to exit the testis
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Rete Testis:
► Follow the seminiferous tubules
► Network of tubes where the sperm are mixed and some fluids are reabsorbed
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where do Rete Testis: exit
into efferent ducts
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Efferent ducts:
► Sperm are further concentrated via reabsorption of fluids
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what do the efferent ducts connect with
the initial section of the epididymis
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Epididymis:
- Where newly created sperm cells mature
- Single tightly coiled tube
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what are the sperm like in the epididymis
Sperm cells are not motile at this point, the peristaltic movement of the epididymis push the sperm forward
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where do sperm go after epididymis
Vas Deferens:
134
Vas Deferens:
► After epididymis sperm moves into the vas deferens
► Transported to the ejaculatory ducts
► Empty into the urethra for expulsion
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Vasectomy :
- Deferentectomy
- Method of contraception in which the vas derens are permanently cut
- Modern procedure: injecting an obstructive material into the ducts to block the sperm going out (not cutting required)
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Genital (accessory) glands function
- Produce seminal fluid
- They lubricate and clean the urethra
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what are the genital accessory glands
Seminal vesicles:
Prostate gland:
Bulbourethral glands:
138
Seminal vesicles:
- Are sac-like pouches that attach to the vas derends near the base of the bladder
- Produce molecules such as fructose that serve as energy sources for sperm
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what makes up 50-70% of mans ejaculation
Seminal fluid
140
Prostate gland:
- Walnut sized
- Below urinary bladder, infront of rectum
- Contributes additional fluid to the ejaculate that serves as nourishment for sperm and contributes to sperm motility
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what is the prostate gland composed of
muscular tissue that ensures seminal fluid is forcefully expelled into the urethra and outwards during ejaculation
142
Bulbourethral glands
- Are pea-sized structures located on the sides of the urethra just below the prostate gland
- Produce clear, slippery fluid that empties directly into the urethra
- Fluid produced lubricates the urethra and neutralizes acidity associated with residual urine
143
Functions of the female reproductive system
- Production and transport of female gametes, the oocytes
-The reception and transport of male gametes, the sperm
- Maintenance of the developing fetus
Birthing and post-natal nourishment of the baby
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The ovaries:
Are the ovum-producing organs (gonads)
144
Paired ovaries: attached by
fibrous cord called the OVARIAN LIGAMENT
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The ovaries: ethered to the body wall by
the suspensory ligament of the ovary and located within the peritoneal cavity
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Structure of the ovaries:
1. Germinal epithelium
2. Tunica albuginea:
3. Ovarian cortex
4. Ovarian medulla
147
Germinal epithelium
The outermost layer covering the ovary
148
Tunica albuginea:
A fibrous layer of connective tissue that protects the inner structures of the ovary
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Ovarian cortex
Contains supporting connective tissue and the ovarian follicles, and therefore is the site of oocyte production
150
Ovarian medulla
Contains the majority of the vascular tissue that supports the ovary
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Ovarian follicles and ovulation:
Site of oocyte production
152
Each follicle contain
single, immature oocyte that periodically and cyclically matures and develops under the influence of sex hormones
153
Ovarian follicles, Cellular composition
- Changes according to their maturation stage
- Can be determined by their size
- When oocyte maturation is completed, the follicle ruptures and the oocyte is release
154
When one ovary is absent or dysfunctional,
,the other will continue to release eggs each month
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Ovarian hormones:
Estrogen
Progesterone
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Estrogen
Responsible for the appearance of secondary sex characteristics in females at puberty and for the maturation and maintenance for the reproductive organs in their mature functional state
157
Progesterone
Functions with estrogen by promoting menstrual cycle changes in the uterus and by helping sustain pregnancy
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The uterus
- Largest and major organ of the female reproductive system
- Is hollow muscular organ about the size of a pear
- Located in the pelvic cavity, between the rectum and the bladder
- Body uterus opens into the vagina via the cervix with the other end, the fundus is connected to the fallopian tubes
159
Layers of the uterus
Endometrium
Myometrium:
Perimetrium
160
Endometrium:
innermost layer, site for implantation of the embryo. Responsible for the changes observed during the menstrual cycle
161
Myometrium
middle layer consisting of smooth muscle. Contains 3 layers going in different directions, which provide support during the distension caused by pregnancy, and faciliate the contraction during birthing
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Perimetrium
is the serous outer covering of the uterus
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Functions of uterus: During intercourse,
it directs blood flow to the pelvis and to the external genitalia, including ovaries, vagina, labia, clit
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Functions of uterus
- Receive a fertilized ovum which passes through the utero-tubal junction form the fallopian tube
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Functions of uterus - After implantation
into the endometrium, the embryo derives nourishment from blood vessels
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Female genital ducts: the fallopian tubes
- oviducts or uterine tubes, are 2 very fine tubes lined with ciliated epithelia that connect the ovaries to the uterus
167
Female genital ducts: the fallopian tubes function
Allow passage of the egg from ovary to uterus
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Different segments: of the fallopian tubes
Infundibulum:
Ampulla
Isthmus
169
Infundibulum
associated with fimbriae near the ovary
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Ampulla:
the major portion of the lateral tube and where fertilization normally takes place
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Isthmus:
the narrower part of the tube that links to the uterus
172
Epithelium of the fallopian tubes:
Ciliated cells
]Peg cells
173
Ciliated cells
- Predominate throughout
- Are most numerous in the infundibulum and ampulla
- Estrogen increases the production of cilia on these cells
- Interspersed between these cells are peg cells
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Peg cells
- Contain apical granules and produce the tubular fluid
- Fluid contains nutrients for spermatozoa, oocytes, zygotes
- Secretions also promote maturation of the sperm by removing glycoproteins and other molecules from the plasma membrane of the sperm
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Female genital ducts: the Vagina
- Is a fibromuscular tubular tract that leads from the opening of the vulva to the cervix, the opening of the uterus
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the Vagina 2 primary functions
1. Sexual intercourse
2. Childbirth
177
Vagina during arousal
produces secretion to facilitate the entrance of the penis
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A series of ridges produced by the folding of the wall of the outer third of the vagina is called the
vaginal rugae
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Transverse epithelial ridges provide the vagina
increased surface area for extension and stretching
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external organs: the vulva
Mons pubis:
Labia
Urinary orifice:
Clitoris:
Vaginal orifice:
181
Mons pubis
pubic region directly in front of the pubic bone
182
Labia:
majora and minora are the folds of skin tissue that cover and protect the more delicate structures of the clit, urinary orifice, and vaginal orifice
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Urinary orifice
vulva also contains the opening of the female urethra, and thus serves the vital function of passing urine. Is the external opening of the urethra
184
Clitoris
small projection of highly innervated, erectile tissue, structurally homologous to the penis, except it plays no role in urination
185
Vaginal orifice:
is the external opening to the vagina, which functions as receptacle for the penis during intercourse
186
Bartholin's:
- Are a pair of secretory glands located to the left and right of the vaginal opening
- Secrete mucus to lubricate the vagina and are homologous to bulbourethral glands in males
187
Skenes glands:
- pair of secretory glands which open to the left and right side of the urethral orifice during
- During sexual arousal, they secrete fluid, although it is unclear how much they contribute to lubrication and whether they have additional functions
188
Mammary glands
- In females that produces milk to feed young offspring
- Are located within the female breast
- 15 to 20 irregularly shaped lobes, each which includes alveolar glands, and lactiferous duct that leads to the nipple and opens to the outside
189
lobes are separated by?
dense CT that support the glands and attach them to the tissues on the underlying pectoral muscles
190
Lactiferous duct:
- Development occurs in females in
response to circulating hormones
- Development begins during the pre- and postnatal stages, and resumes in puberty
- Estrogen promotes branching differentiation, which is inhibited by testosterone in males
