Reproductive System Flashcards
1
Q
Gonads (Testes/Ovaries)
A
Produce gametes and hormones
2
Q
Ducts
A
Transport and store gametes
3
Q
Accessory Glands
A
Produce secretions that support the gametes
4
Q
Structure of the Testicular Reproductive System
A
- Gonads = testes
- Ducts
- Penis
- Accessory Glands
5
Q
Gonads = testes
A
- Located within the scrotum (skin and connective tissue)
- Surrounded by 2 layers (tunics):
- Tunica vaginalis
- Tunica albuginea
6
Q
Tunica vaginalis
A
- Outer (superficial) layer
- Serous membrane derived from peritoneum
7
Q
Tunica albuginea
A
- Inner fibrous connective tissue capsule
- Extends inward to divided testis into lobules (small lobes)
8
Q
What does each lobule contain?
A
- Seminiferous tubules
- Interstitial endocrine (Leydig) cells
9
Q
Seminiferous tubules
A
- Produce sperm (spermatogenesis)
- Tubules unite to form rete testis on posterior side of each testis (rete = network)
- Walls of the tubules are composed of:
- Spermatogenic cells
- Sustentocytes (nurse) cells
10
Q
Spermatogenic cells
A
Germ cells in various stages of development that
will become sperm
11
Q
Sustentocytes (nurse) cells
A
- Surround, nourish and protect developing gametes
- Extend from basement membrane to lumen
- Are connected to one another by tight junctions that form the blood-testis barrier
- Protects developing sperm from immune system, toxins and drugs
- Produce testicular fluid
- For sperm transport in tubule lumen during
12
Q
Interstitial endocrine (Leydig) cells
A
- In connective tissue between seminiferous tubules
- Secrete testosterone (hormone)
13
Q
Ducts
A
- Sperm formed in the seminiferous tubules enter the rete testis, and then move into a series of
ducts:- Epididymis
- Vas (ductus) deferens
c) Ejaculatory Duct
formed by union of vas deferens and duct from seminal vesicle
d) Urethra
transports urine and semen out of the body
3 regions:
i. prostatic urethra – runs through prostate gland
ii. intermediate (membranous) urethra – runs through the urogenital
diaphragm (muscular floor of pelvis)
iii. spongy (penile) urethra – runs through the corpus spongiosum of the
penis and ends at an opening at the tip of the glans penis called the
external urethral orifice
14
Q
Epididymis
A
- Posterior border of testis
- Site of sperm storage and maturation (develop ability to swim)
15
Q
Vas (ductus) deferens
A
- Transports sperm from the epididymis during ejaculation
- Part of the spermatic cord which carries the vas deferens, nerves, blood supply, lymphatic vessels through the body wall
- Enters anterior pelvic cavity and loops over posterior wall of bladder
16
Q
Ejaculatory Duct
A
Formed by union of vas deferens and duct from seminal vesicle
17
Q
Urethra
A
- Transports urine and semen out of the body
- 3 regions:
- Prostatic urethra
- Runs through prostate gland
- Intermediate (membranous) urethra
- Runs through the urogenital diaphragm (muscular floor of pelvis)
- Spongy (penile) urethra
- Runs through the corpus spongiosum of the
penis and ends at an opening at the tip of the glans penis called the external urethral orifice
- Runs through the corpus spongiosum of the
- Prostatic urethra
18
Q
Penis
A
- Urinary and copulatory organ
- Parts:
- Root
- Body (shaft)
- Glans penis (enlarged tip)
- Has three cylindrical bodies of erectile tissue (blood sinuses bound by connective tissue):
- 2 corpora cavernosa
- Dorsal/posterior (in the erect position)
- Form most of the root and shaft - 1 corpus spongiosum
- Midventral/anterior (in the erect position)
- Surrounds urethra and forms the glans penis
- 2 corpora cavernosa
19
Q
Accessory Glands
A
- Contribute secretions during sexual arousal
- ~95% of semen comes from the following glands, listed in order of highest to lowest
contribution:- Seminal vesicles (2)
- Prostate gland (1)
- Bulbourethral glands (2)
20
Q
Seminal vesicles (2)
A
- Posterior to bladder
- Secrete a fluid that provides sperm with a source of nutrients
21
Q
Prostate gland (1)
A
- Inferior to bladder and encircles prostatic urethra
- Secretes a fluid that nourishes and activates sperm motility
22
Q
Bulbourethral glands (2)
A
- Below prostate in urogenital diaphragm (in contact with external urethral sphincter)
- Secretes thick mucus that helps lubricate the urethra and the glans penis
23
Q
Spermatogenesis
A
Spermatogenesis refers to sperm production within the seminiferous tubules
24
Q
Spermatogenesis Flow
A
Type A Spermatogonia (2n)
↓ (Mitosis)
Type B Spermatogonia (2n)
↓ (Mitosis + growth)
2 Primary Spermatocytes (2n)
↓ (Meiosis I)
4 Secondary Spermatocytes (n)
↓ (Meiosis II)
8 Spermatids (n)
↓ (Spermiogenesis)
8 Spermatozoa (n)
25
Spermiogenesis
- A part of spermatogenesis
- Is the differentiation of the spermatids into sperm:
- Develop flagella and acrosomes
- Lose most cytoplasm
26
Structure of Spermatozoa
1. Head
2. Body
3. Tail = flagellum
27
Head (Spermatozoa)
- Nucleus (23 chromosomes (n))
- Top of nucleus is covered by the acrosome
- A modified lysosome
- Contains enzymes required to penetrate secondary oocyte
28
Body (Spermatozoa)
Contains a large number of mitochondria that produce the ATP required for movement
29
Tail = Flagellum (Spermatozoa)
- Propel sperm
- Made of microtubules
30
Semen
- Sperm and testicular fluid (5%), and accessory gland secretions (95%)
- 2-5mL released during ejaculation
- Contains 20-150 million sperm/ml
- pH is slightly alkaline = 7.2 – 7.6
- Provides sperm with transportation medium, nutrients, and protection
31
Structures of the Ovarian Reproductive System
1. Gonads = ovaries
2. Uterine (Fallopian) Tubes
3. Uterus (“womb”)
4. Vagina (birth canal)
5. Vulva
32
Gonads = Ovaries
Located in pelvic cavity on lateral sides of uterus and connected to body wall by ligaments that are continuous with the peritoneum
33
Histology (Gonads = Ovaries)
- 4 layers (from superficial to deep):
1. Surface (germinal) epithelium
- Layer of cuboidal epithelial cells (modified
visceral peritoneum lacking connective tissue)
2. Tunica albuginea
- Dense connective tissue
3. Ovarian cortex
- Contains ovarian follicles and connective tissue
- follicle = layer(s) of cells surrounding each developing oocyte that supports and protects it through its development
4. Ovarian medulla
- Contains blood and lymph vessels, nerves, and connective tissue
34
Uterine (Fallopian) Tubes
- 3 sections:
1. Infundibulum
2. Ampulla = middle
3. Isthmus
35
Infundibulum
- Suspended over each ovary
- Opening of uterine tube into peritoneal cavity
- Has finger-like projections called fimbriae that cover the ovary during ovulation. They help capture and move the oocyte into the uterine tube.
36
Ampulla = Middle
Site where fertilization usually occurs
37
Isthmus
Connects to uterus
38
Histology (Uterine (Fallopian) Tubes)
1. Mucosa
2. Muscularis externa
3. Serosa
39
Mucosa
- Simple columnar epithelium
1. Ciliated cells
- Help move oocyte/zygote/morula along the tube
2. Non-ciliated secretory cells with microvilli
- Secretes fluid that provides nutrients to oocyte/cell mass
40
Muscularis externa
Smooth muscle
- Contraction helps move oocyte/cell mass along the tube
41
Serosa
Visceral peritoneum
42
Uterus (“womb”)
- Hollow, muscular organ located superior to bladder
- 3 parts:
1. Fundus
2. Body
3. Cervix
43
Fundus
Superior to isthmus of uterine tubes
44
Body
- Main portion
- Space within
- Uterine cavity
- Site where most embryo implantation and growth occur
45
Cervix
Inferior, narrow passageway that opens into vagina
46
Histology (Uterus ("womb"))
- 3 layers
1. Endometrium
2. Myometrium
3. Perimetrium
47
Endometrium
- Mucous membrane composed of a simple columnar epithelium that
lines the inner surface of the uterus and a specialized lamina propria that consists of 2 highly vascularized layers:
1. Functional layer (stratum functionalis)
2. Basal layer (stratum basalis)
48
Functional layer (stratum functionalis)
- Superficial layer
- Develops at puberty and is shed monthly (menstruation) along with the simple columnar epithelium
- Contains endometrial glands (epithelial tissue) that
secrete a nutritive fluid for the embryo prior to formation of the umbilical cord
49
Basal layer (stratum basalis)
- Permanent layer attached to myometrium
- Undergoes mitosis to replace the stratum functionalis and the simple columnar epithelium
50
Myometrium (muscularis externa)
Smooth muscle
51
Perimetrium (serosa)
- Outer layer
- Visceral peritoneum
52
Vagina (birth canal)
- Connects uterus to external genitalia
- Female organ of copulation
53
Histology (Vagina (Birth canal))
1. Mucosa
- Thick stratified Squamous Epithelium
- Has Rugae
2. Muscularis externa
- Smooth muscle
3. Adventitia
- Fibroelastic connective tissue
54
Vulva
- Reproductive structures that lie external to the vagina
1. Mons pubis
2. Labia majora/minora
3. Vestibule, containing:
4. Greater vestibular glands
5. Clitoris
55
Mons pubis
Adipose tissue that overlies and cushions pubic symphysis
56
Labia majora/minora
- The labia majora are two large skin folds that surround the labia minora
- The labia minora are small inner folds of skin that surround the vestibule
57
Vestibule, containing:
1. Vaginal opening
2. External urethral orifice
- Anterior to vaginal opening in anatomical position
58
Greater vestibular glands
Secrete mucus to lubricate the vestibule
59
Clitoris
- Mainly internal, with small external portion at anterior junction of labia minora
- Contains erectile tissue
- Derived from the same embryonic tissue as the penis
60
Oogenesis (Before Birth)
oogonia (2n)
↓ (Mitosis)
Many oogonia
↓ (Cells differentiate)
1 oocyte (2n)
↓ (Meiosis I)
2 oocyte or 1 polar body (n)
61
Oogenesis (After Puberty)
2 Oocyte (n)
↓ (Meiosis II)
Ovum (n) or 2 polar body (n)
62
Oogenesis
- 1 primary (1° ) oocyte forms 1 ovum and 2 or 3 polar bodies
- Polar bodies are discarded nuclear materia
63
Oogonia
- Diploid stem cells that multiply by mitosis during fetal development.
- Differentiate into primary oocytes
64
primary oocytes (2n)
- ~ 1 million in ovaries at birth
- Enter meiosis I before birth, but arrested in prophase I
- At puberty less than half of oocytes remain
65
secondary (2°) oocyte (n)
- Begins meiosis II and arrests in metaphase II
- This is ovulated (usually 1/month)
- ~ 500 ovulated from puberty to menopause
66
Ovarian Follicles & Follicular Development
1. Late Embryonic and Fetal period (before birth)
2. Childhood – ovary is mostly inactive
3. At puberty – ovarian cycles and reproductive hormone secretion begins
67
Late Embryonic and Fetal period (before birth)
- Germ cells migrate to the developing gonads where they differentiate into oogonia
- Oogonia begin to proliferate in the embryonic period until several million are formed, at which point proliferation ends
- Oogonia begin to differentiate into primary oocytes during the early fetal period
- Meiosis I begins, but stops in prophase I
- Meiotic arrest continues until puberty
68
Primordial follicle forms
- Primary oocytes become surrounded by a single layer of flat pre-granulosa (follicular) cells
- Most primordial follicles with primary oocytes begin to degenerate over time, such that there are
fewer at birth.
69
Childhood – ovary is mostly inactive
- Some of the primordial follicles develop into primary follicles:
- The single layer of flat pre-granulosa cells becomes cuboidal – now called granulosa cells
- However, in the absence of reproductive hormones, primordial and primary follicles also continue to degenerate such that there is less than half a million primary oocytes are left at
puberty
70
At puberty – ovarian cycles and reproductive hormone secretion begins
Each month, primary follicles continue to form and reproductive hormones selectively stimulate some of these follicles to continue their development in the ovarian cortex. They pass through one or more of the following stages:
1. Secondary follicle
2. Vesicular (antral) follicle
3. Preovulatory (Graafian) follicle – mature vesicular follicle
4. Corpus luteum
5. Corpus albicans
71
Secondary follicle
- During the transition from primary to secondary follicle, hormone secreting theca cells form from surrounding connective tissue cells
- Granulosa cells proliferate (become stratified) and start to secrete fluid and estrogen
- Fluid-filled spaces between granulosa cells start to develop as fluid accumulates
72
Vesicular (antral) follicle
- The fluid filled spaces unite into a single large antrum
- Granulosa cells that still surround oocyte = corona radiata
- Usually, only one dominant vesicular follicle will continue development from this point per ovarian cycle
73
Preovulatory (Graafian) follicle – mature vesicular follicle
- The follicle grows significantly in size and protrudes from the surface of ovary
- Rising hormone levels cause:
1. Formation of a secondary oocyte
2. ovulation
74
Formation of a Secondary Oocyte
Completion of Meiosis I; enters Meiosis II and arrests in Metaphase II
75
ovulation
- Release of secondary oocyte (surrounded by corona radiata) from follicle into peritoneal cavity (follicle remains in ovary)
- If fertilization occurs, the acrosome of a single sperm will penetrate the corona radiata
76
Corpus luteum
- Follicle that remains after ovulation
- Produces high levels of hormones that support fetal development
- If there is no pregnancy, it degenerates into the corpus albicans
77
Corpus albicans
- Scar-like structure on surface of ovary
- Does not release any hormones
78
Reproductive System Related Medical Conditions/Procedures
1. Tubal Ligation/Vasectomy – methods of birth control
2. Ectopic Pregnancy
79
Tubal Ligation/Vasectomy – methods of birth control
- Tubal ligation
- Surgical procedure on the uterine tube that prevents passage of gametes through
the uterine tube (does not affect ovarian/menstrual cycles)
- Vasectomy
- Relatively minor procedure that prevents sperm passage through the vas deferens (ejaculation still occurs, but the semen does not contain sperm or testicular fluid)
80
Ectopic pregnancy
- Complication of pregnancy in which the embryo implants outside of the body of the uterus (mostly in the uterine tube, and to a lesser extent in the peritoneal cavity, cervix, ovarian surface)
- In most cases the developing fetus is unable to survive
- Can lead to rupture of uterine tube (which can be life-threatening) and impaired fertility in future
