Physiology - Exam 3, Deck #1 - Reproduction Flashcards
1
Q
What are the Male Genital Organs?
A
- Testes
- Epididymis
- Vas deferens
- Urethra
- Penis
- Accessory glands
— Seminal vesicles
— Prostate gland
— Cowpers = bulbourethral glands
2
Q
What are the Testes?
A
- 2 small, oval shaped glands situated in a pouch called the SCROTUM and suspended by the spermatic chords;
- DO NOT develop in the scrotal sac
3
Q
What is the Inguinal Canal?
A
- Narrow canal connecting the peritoneal cavity with the scrotal sac;
- Tests decend through canal at 7-9 months fetal life and enter the sac
4
Q
What is Cryptochidism?
A
- Condition in which the testes fail to descend into the scrotum ;
- Male will NOT produce viable sperm
5
Q
What causes Subsequent Inguinal Hernia Formation>
A
Incomplete closure of the inguinal canal at birth
6
Q
How do the testes mature?
A
- Grow little during the first 10 years of life;
- Puberty - 11-12th years and acquire adult proportions
7
Q
What is the main structure of the Testes?
A
- Outer fibrous coat = TUNICA ALBUGINEA;
- Inside glands = number of pyramid shaped LOBULES that face toward the surface
8
Q
What makes up the weight of the Testes?
A
-90% = Seminiferous Tubules;
-10% = Interstitial cells of Leydig + other tissues
= Each lobule is made of of several seminiferous tubules with the interstitial cells of Leydig in between
9
Q
What are Seminiferous Tubules?
A
- More than 800 seminiferous tubules/testes;
- Tubules unite and form a plexus of canals called the RETE TESTIS
10
Q
What is the Rete Testis?
A
A plexus of canals formed from the seminiferous tubules;
-Ends in the upper part of the testes in a series of called the VAS EFFERENS
11
Q
What is the Vas Efferens?
A
The vas efferent penetrate the tunica albuginea (outer coat) and form a convoluted tubular mass lying ON TOP of the testis called the EPIDIDYMIS
12
Q
What is the the Epididymis>
A
-Convoluted tubular mass lying on top of the testes that came form the vas efferent;
13
Q
What is the flow from the Epididymis?
A
-Epididymis — Single Duct (vas deferens) — Urethara
14
Q
What is the function of the Interstitial Cells of Leydig?
A
Site of the male sex hormone production = Testosterone
15
Q
What is Spermatogenesis?
A
The process of sperm formation;
- A type of meiosis that beings with the onset of puberty ;
- Takes place in the germinal epithelium of seminiferous tubules
16
Q
What are Sertoli Cells?
A
Nurse cell located in the germinal epithelium;
- Sertoli cells are the target of FSH and function to causes changes in the spermatid to spermatozoa;
- Provide nutrients, hormones, and enzymes that are needed for transforming the spermatids
17
Q
Where is sperm carried on the chromosomes?
A
- Half is carried on X chromosomes;
- Half is carried on Y chromosomes
18
Q
What is Spermiation or Spermiogenesis?
A
- When spermatids are first formed they possess the characteristics of epitheliod cells, but by attaching to SERTOLI CELLS, the excess cytoplasm is removed and spermatids become spermatozoa;
- Each spermatid elongates into a spermatozoan
19
Q
What makes up a Spermatazoan?
A
- Acrosome head;
- Midpiece;
- Tail
20
Q
Where did the Acrosome head come from?
A
- The acrosome head is formed from the golgi apparatus;
- Contains enzymes HYALURONIDASE and PROTEASES that play roles in entry of the sperm into the ovum
21
Q
What are the stages of Spermatogenesis and Spermiogenesis?
A
START: Spermatogonia — Primary Spermatocytes;
1. Meiosis (first division) — Secondary Spermatocytes;
2. Meiosis (second division) — Spermatids = Testosterone required at Puberty;
3. Spermiogenesis = FSH required at puberty; Testosterone maintains after puberty
END: Spermatozoa
22
Q
Where do sperm go once they are produced?
A
Sperm move from the seminiferous tubules, where they are NONMOTILE and can NOT fertilize an ovum;
23
Q
What is Maturation of Sperm?
A
- After 18 hours to 10 days, they develop the capability of motility even though some inhibiting factors still prevent motility until ejaculation;
- Also develop the ability to fertilize an ovum
24
Q
How do sperm enter the Ejaculatory Duct?
A
Sperm;
- Vas Efferens;
- Inguinal Canal;
- Over Pubic Arch;
- Posteriorly to the point where the vas deferens join the seminal vesicles and forms the EJACULATORY DUCT
25
How does the Vas Deferens meet the Ejaculatory Duct?
Vas deferens receives the duct of the seminal vesicles and enters the tissues of the PROSTATE GLAND as the Ejaculatory Duct
26
Where the the Ejaculatory Ducts go?
The right and left ejaculatory ducts open in the URETHRA within the prostate gland
27
Where is Spermatozoan stored?
A small quantity of sperm is stored in the EPIDIDYMIS, but most are stored in the VAS DEFERENS and in the AMPULLA of the vas deferens;
- They can remain stored in a fertile state for up to several months;
- With frequent sexual activity storage may be no longer than a few days
28
What are the Seminal Vesicles?
-Lobulated sacs located at the posterior surface of the bladder;
29
What fluid is secreted from the Seminal Vesicles?
- Secrete a fluid that forms a part of the semen;
- Fluid of the ejaculatory duct and forms 60% (range 45-80%) the bulk of semen;
- Last fluid to be ejaculated and washes sperm out of the ejaculatory duct and urethra
30
What are components of the Seminal Vesicle FLUID?
1. Fructose = energy source for spermatozoa;
2. Phosphorylchoine = function unknown; legal test for presence of semen;
3. Specific genes in the DNA of the spermatozoa;
4. Prostaglandins = aid fertilization
31
How can a sperm donor be identified?
Through the use of nucleotide sequence analysis of RFLP analysis of specific genes in the DNA of spermatozoa
32
How do Prostaglandins aid fertilization?
1. Reacting with cervical mucous to made it more receptive to sperm;
2. Possible causing reverse peristaltic contractions int eh uterus and fallopian tubes to move sperm to the ovaries
33
What is the Prostate Gland?
- Prostate gland is a muscular, glandular organ located below the bladder and anterior (in front) of the rectum;
- Produces a secretion 15-30% of semen
34
What are the components of the Prostatic Secretion (fluid)?
- Alkaline, somewhat milky, and contributes to the odor of semen;
- 15-30% of semen volume;
- Leaves the prostate gland and enters the URETHRA
35
Why is the Prostatic Secretion ALKALINE ?
Alkalinity (basic) neutralizes the ACIDIC environment of the male and female reproductive tracts so that the sperm won’t be inactivated
36
How the Prostate Gland change with age?
1. Prostate gland tends to ENLARGE in older men and often constricts the urethra making it difficult to empty the bladder — Gland is often removed surgically;
2. Prostate cancer occurs in older men
* *Seminal vesicles and prostate gland are NOT essential for fertility, just enhance the probability
37
What is the test for Prostate Cancer?
1. Includes a digital rectal exam for hard lumps and
2. A blood born prostate specific protein antigen test which has the potential of detaching earlier stages of prostate cancer
38
What are the Bulbourethral (Cowper’s) Glands?
2 small yellow glands, about the size of peas lacerated in the bulb region at the base of the penis;
-These glands empty into the urethra from below
39
What is secreted from the Bulbourethral (Cowper’s) Glands?
- Clear, mucoid fluid discharged during sexual stimulation;
- Most of the secretion precess seminal emission;
- Meant to lubricate the urethra and penis as well neutralizing the acidic condition of the urethra for sperm enter
40
What is the Penis?
- The copulatory (sexual intercourse) organ of the male;
| - Penis become erect during sex due to the Corpora Cavernosa and the Corpus Spongiosum (spongy, bloody sinuses)
41
What is the Glans Penis?
- End of the penis;
| - Covered by loose skin called FORESKIN or PREPUCE (removed by circumcism)
42
What is the Corpora Cavernosa
- Spongy, bloody sinus involved in erection of the penis;
| - Two longitudinal columns of the corpora cavernosa run the length of the penis on the dorsolateral aspect
43
What sit eh Corpus Spongiosum?
- Spongy, bloody sinus involved in erection of the penis;
| - A single column that runs mid-centrically on the penis
44
How is an erection achieved?
By parasympathetic nerve-induced VASODILATATION of the of arterioles that allow blood to flow into the corpora cavernosa and the corpus spongiosum of the penis
45
What is the Neurotransmitter that mediates an erection?
-Nitric Oxide = activates the enzyme guanylate cyclase which catalyzes a reaction that produces increase levels of cyclic monophosphate (cGMP)
46
What is the function of cGMP in causing an erection?
- cGMP causes relaxation of the smooth muscle arterioles by closing Ca2+ channels and decreasing cytoplasmic Ca2+;
- As the erectile tissue becomes engorged with blood and the penis becomes turgid, venous outflow of blood is partially occluded = causing erection
47
What is Erectile Dysfunction?
Failure to obtain or maintain an erection;
-The drug Viagra, Sildenafil Citrate works by selectively inhibiting the enzyme that destroys cGMP = Type 5 Phosphodiesterase;
— Erection is maintained longer due to longer activity of cGMP as it is not degraded
48
What is the volume of sperm released upon ejaculation?
- Avg. 400 million sperm;
- Avg. fluid volume in a seminal emission is 3.5mls;
- Avg. sperm count = 120 million/ml (rage 35-200 million/ml)
49
What defines a below avg. fertility?
-A sperm count of below 60 million/ml
50
What defines infertility?
-A sperm count below 20 million/ml
51
How is Seminal Emission achieved?
* Orgasm;
- By stimulating the vas deferens, seminal vesicles, and prostate gland to pour their accumulated contents into the base of the urethra through the ejaculatory ducts;
- A variety of sensation from ejaculation make up an orgasm;
- Spermatozoa become motile upon ejection
52
How long are ejaculated sperm motile?
- Some sperm can reach the upper uterine tubes in 5 minutes after entering the cervix near the uterus;
- May maintain motility for 24-48 hours;
- the Fertilizable life of the OVUM is only about 6-12 hours — female fertility is highly dependent on time of ovulation
53
What are the components of the Female Reproductive System?
1. Ovaries -2
2. Oviducts = fallopian tubes = 2
3. Utereus
4. Vagina
5. External genitalia
6. Mammary glands
54
What are the Ovaries?
- Paired (2);
- Lie on either side of the uterus and bellow the fallopian tubes;
- Made up of a connective tissue framework, which supports the developing germ cell, muscle cells, blood cells, and nerves
55
What is within the Cortex of the germinal epithelium of the ovaries?
Contains numerous germ cells and follicles in various stages of development
56
Where does the ovum develop from?
- The ovum develops from the OVARIAN FOLLICLE;
| - Various stages of OOGENESIS are passed there, and developing ovum in one of the mature follicles is a Primary Oocyte
57
What hormones influence Follicle development in the ovary?
- 2 hormones from the anterior pituitary;
1. Follicle Stimulating Hormone (FSH);
2. Luteinizing Hormone (LH)
58
What is Ovulation?
- Occurs from puberty to menopause;
- Mature follicles approach the surface of the ovary and rupture mature ova through the surface at regular monthly intervals;
- Occurs about the middle of the 28 day menstrual cycle, but follicle cells persist and transform in the CORPUS LUTEUM
59
What takes place in the Corpus Luteum?
- After ovulation, follicular cells enlarge and increase in numbers by increasing number of cell layers = a thick walled body produced in the corpus luteum;
- Secretes 2 hormones between ovulation and menstruation = estrogen/progesterone
60
What is the role of Progesterone and Estrogen from the corpus luteum?
- They sustain influence over the ENDOMETRIUM = the lining of the uterus;
- Changes in the levels of these hormones depends on if pregnancy occurred or not
61
What are the Fallopian Tubes?
- Tubes that conduct the ova from the ovaries to the uterus;
- Lie in a horizontal plane above the ovaries and possess a funnel-like distal end;
- NOT passive during ovulation by moves closer to the ovary to receive the ovum
62
What lines the Fallopian Tubes?
1. A ciliated epithelium lines the tubes = Beating of the cilia move the ovum along towards the uterus;
2. Smooth muscles in the tubular walls aid in propelling the ovum by peristalsis
63
What is the Uterus?
A thick-walled organ located in the upper pelvic region;
- Receives the blastocyst and provides protection and nourishment to the developing embryo and fetus after implantation;
- Will become slightly larger after first pregnancy;
- Capable of great enlargement during pregnancy and can extend high into the abdominal cavity
64
What is the Endometrium?
Soft lining of the uterus
65
What is the Cervix?
- The lower part of the uterus that is more cylindrical in shape;
- Its external orifice opens into the vagina
66
What is the Vagina?
- The canal leading from the vestibule of the external genitalia to there cervix of the uterus;
- 7-9cm long;
- Becomes part of the birth canal during childbirth (runs from the uterus through the cervix to the exterior)
67
What are the External Female Genitalia?
1. Labia majora
2. Labia minora
3. Clitoris
4. Vestibule
5. Vestibular = Bartholin’s glands
68
What is the Labia Majora?
2 outer fleshy folds covered with pubic hair
69
What is the Labia Minora?
- 2 membranous folds underneath and medial to the labia major;
- Pink or red in color;
- At their upper extremity they extend around the clitoris
70
What is the Clitoris?
- Structure homologous to the penis;
- 2.-2.5cm long, but largely embedded in tissue;
- Only the tip (GLANS CLITORIS) protrudes and it it ordinarily covered with membranes - Erogenous Zone
71
What is the Vestibule?
The space bound by the labia minora and clitoris
72
What is the Vestibular Glands or Bartholin Glands?
Empty into the vestibular region;
| -Their secretion is a lubricant during sexual activity
73
What are the Mammary Glands?
- Modified skin glands in a woman’s breast;
- Breast remain undeveloped until puberty, when the accumulation of fat adds to their size;
- Glandular portion of the glands does not mature and become secretory until the TERMINATION of pregnancy
74
What hormones cause maturation of the mammary glands?
1. Prolactin;
2. Estrogen;
3. Progesterone
75
What does Prolactin influence?
Stimulates and maintains LACTATION
76
What is Colostrum?
- First secretion of the mammary glands that is a thin-yellowish substance;
- Source of ANTIBODIES for babies = provides Passive Immunity
77
Days 1-4 Menstrual Cycle
-Mestruation (MENSES) = avg. blood loss is 35 mls.
78
Day 5-13 Menstrual Cycle
- Preovulatory Period = Proliferative Period;
- Development of the ovarian follicle and growth of the endometrium;
- Rise of estrogen = estradiol level
79
Days 13-15 Menstrual Cycle
- Rapid rise in blood LH concentration triggers ovulation;
| - Ovulation - slight fall in estradiol level
80
Days 15-26 Menstrual Cycle
- Migration and breakdown of unfertilized ovum;
- Development of Corpus Luteum;
- High progesterone levels
81
Days 27-28 Menstrual Cycle
- Premenstrual Period;
- Regression of the corpus luteum;
- Progesterone levels fall;
- Deterioration of endometrium
82
What major changes take place during the menstrual cycle?
1. Changes the the ENDOMETRIUM;
2. Changes in the OVARY;
3. Changes in HORMONE SECRETION
- by the OVARY:
— Estrogen = estriol
— Progesterone
- by the ANTERIOR PITUITARY:
— Follicle stimulating hormone
— Luteinizing hormone
83
Endometrium Changes of Days 1-4 (Menstruation)
Endometrium deteriorates completely;
- Soft mucous lining;
- Removed during menstrual cycle
84
Endometrium Changes of Days 5-13 (Proliferative/Estrogen Phase)
- Controlled by Estrogen;
- Epithelial cells on surface and deep layers of endometrium proliferate (thicken 3x);
- Becomes glandular;
- Present a soft, highly vascular bed at the time of ovulation (Day 14) for implantation of ovum if fertilized
85
Endometrium Changes of Days 15-26 (Secretory/Progestational Phase)
- ~14th day s of cycle, corpus luteum secretes progesterone with estrogen and results in…
1. Endometrial glands secreting nutrient fluid that can be used by a fertilized ovum before implantation;
2. Large quantities of fatty substances and glycogen deposited in deeper endometrial cells;
3. Blood flow to endometrium increases
86
Endometrium Changes of Days 27-28 (Premenstrual Flow)
- At the end of the cycle when NO implantation has occurred, corpus luteum dies and production of estrogen and progesterone STOP;
- Lack of the 2 hormones causes endometrial blood vessels to become spastic = blood supply stops, tissues die, and are lost in menstruation
87
Ovary Changes of Days 1-4 (Menstruation)
Little happens in the ovary
88
Ovary Changes of Days 5-12 (Preovulatory Period)
- Graffian (ovary) follicle grows and ovum reaches maturity;
| - Estrogen production of the Graffian follicle is highest at days 12-13
89
Ovary Changes of Days 13-15 (Ovulation)
- One sign of ovulation is a half a degree C increase in retail or oral temp;
- Cervical mucous changes prior to ovulation;
- Follicle RUPTURES releasing the ovum
90
Ovary Changes of Days 15-25 (Breakdown of Ovum)
- Migration and breakdown of UNFERTILIZED ovum;
| - Corpus luteum becomes very active and reaches max output of both estrogen and progesterone by day 21-25
91
Ovary Changes of Days 25-28 (Premenstrual Period)
-The corpus luteum REGRESSES and the output of estrogen and progesterone falls off rapidly between 26-28 reaching a low day 28
92
Where are the female sex hormones produced?
1. Ovary = estrogen and progesteron;
| 2. Adenopophysis (Anterior pituitary) = FSH and LH
93
What is the role of FSH?
-Follicle stimulation hormone =
| Influences the development of ovarian follicles (the pill)
94
What is the role of LH?
-Lutenizing hormone = aids in stimulating ovulation and is concerned with the development of the corpus luteum
95
How do FSH and Estrogen regulate the female sexual cycle?
* Regulated by ALTERNATING secretion of FSH and estrogen;
1. First part of the month = FSH causes ovary to secrete ESTROGEN and increased estrogen level later causes the ant. pit. to stop FSH;
2. Estrogen level falls off just before menstruation;
3. FSH is secreted again allowing the graffian follicle to mature
96
What changes take place when pregnancy occurs?
- Implantation of the blastocyst (embryo) in the endometrium effects the ovary and uterus in several ways =
1. Chorionic villi embedded in the endometrium secrete human chorionic gonadotropin (HCG) which stimulates the corpus luteum to continue secreting estrogen and progesterone throughout pregnancy
97
What the the role of estrogen/progesterone during pregnancy?
- The ovaries supply of estrogen and progesterone is essential for the development of the embryo during the first 3 months of the gestation;
- From the 3rd month on, placenta produces estrogen and progesterone to help develop the child
98
What is an Ovariectomy?
Results in spontaneous abortion or miscarriage if occurs during the first 3 months of the gestation period
99
Why is there no ovulation during pregnancy?
High levels of estrogen INHIBITS FSH release so there will be NO development of another graffin follicle
100
How does the fetus develop?
1. Ovum becomes fertilized soon after it enter upper end of the fallopian tubes;
2. Zygote continues to develop for 3-5 days as it travels down the oviduct;
3. Developing blastocyst remains in uterus for 205 more days before embedding into endometrium;
* *Total elapsed time from fertilization to implantation = 5-10 days (avg. 7-8 days)
101
How does the placenta develop?
1. Outgrowth of the blastocysts = TROPHOBLASTIC Cells produce the chorionic villi;
2. Small arteries of the endometrium break down and form follicles (blood spaces) and are connected with CHORIONIC VILLI
102
What are the 4 extra-embryonic membranes produced?
1. Chorion
2. Amnion
3. Allantosis
4. Yolk Sac
103
What is the Gestation Period?
- 275-280 days = 38 weeks;
| - 40 weeks from the last menstrual cycle
104
What difference occur between male and female development?
1. Genetic
2. Gonadal
3. Phenotypic (anatomical);
* *For the first MONTH AND A HALF of gestation, all embryos can differentiate to male or female because developing reproductive tissues are identical and indifferent
105
What is Genetic Sex?
Depends on the combination of sex chromosomes at the time of conception and in turn determines GONAL SEX
106
What is Gonadal Sex?
- Whether testes or ovaries develop;
| - Presence of a Y chromosome determines gonadal differentiation
107
When does Gonadal Specificity develop?
Gonadal specificity occurs during the 7th WEEK of intrauterine life;
-This is when the indifferent gonadal tissue of a genetic MALE begins to differentiate into testes under the influence of TESTIS DETERMINING FACTOR (TDF)
108
What is Testis Determining Factor (TDF)?
- Produced by the sex-determingin regions of the Y-chromosome (SRY) = the single gene for determining sex differentiation;
- TDF triggers reactions that lead to physical male development
109
How does SRY determine sexual difference?
- Females LACK SRY and so do not produce TDF;
- Their gonadal cells never signal for testicular formation, so the undifferentiated gonadal tissue starts developing during the 9th WEEK into ovaries instead
110
What is Phenotypic Sex?
-The apparent anatomic sex of an individual depends on the genetics of their gonadal sex
111
What is Sexual Differentiation?
- Sexual differentiation refers to the embryonic development of EXTERNAL genitalia as either male or female;
- Embryos has the the potential to develop either male or female reproductive tracts and external genitalia
112
What causes MALE differentiation?
-Male-type reproductive systems are induced by ANDROGENS (testosterone), which re masculinizing hormones from the developing testes
113
What causes FEMALE differentiation?
-The LACK of testicular hormones in female fetus results in female-type reproductive development
114
When can the sexes easily be distinguished?
-By 10-12 weeks gestation can easily be distinguished by anatomical appearance of EXTERNAL GENITALIA
115
What makes up UNDIFFERENTIATED external genitalia?
1. Genital Tubercle,
2. Paired urethral (urogenetal) folds surrounding a urethral groove;
3. Lateral Genital swellings
116
What comes form the Genital Tubercle?
Gives rise to the exquisitely sensitive erotic tissue =
- Males = the GLANS PENIS (end of the penis)
- Females = the GLANS CLITORIS
117
What are the major differences of the Glans Penis and Glans Clitoris?
1. Smaller size of the Clitoris;
| 2. Penetration of the Glans Penis by the urethral opening
118
What is the Urethra?
Tube through which urine is transported from the bladder to the outside;
-Also serves in males as a passageway for the emission of semen
119
What do the MALE urethral fold (urogenital folds) form?
- they fuse around the urethral groove to form the PENIS;
| - Penis encircles the urethra
120
What do the FEMALE urethral fold (urogenital folds) form?
Urethral folds form the LABIA MINORA
121
What do the MALE genital swellings form?
Genital swellings (labiscrotal folds) similarly fuse to form the scrotum and prepuce = a fold of skin that extends over the penis and covers the glans penis
122
What do the FEMALE genital swellings form?
Genital swellings (labiscrotal folds) form the LABIA MAJORA
123
How do the FEMALE urethral folds and genital swellings develop differently from males?
They DO NOT fuse at midline, but develop instead into the labia minor and labia major respectively;
-Urethral groove remains OPEN, providing access to the interior through the urethral opening and vaginal orifice
124
What do the reproductive tracts develop from?
- Males = Wollfian Ducts (mesonephric) ;
- Females = Mullerian Ducts (paramesonephric)
* *Both duct systems develops in ALL embryos — one will develop and one will degenerate depending on sexual differentiation
125
What determines differentiation of the reproductive tracts?
Male or female reproductive tract development is determines by the presence or absence of 2 hormones of the fetal TESTES =
1. Testosterone
2. Mullerian-inhibiting factor
* *hCG from the placenta stimulates early testicular secretion
126
What is the role of Testosterone in male reproductive tract development?
- Induces development of the Wolffian ducts into the MALE tract;
- Testosterone is then converted to Dihydrotestosterone (DHT) and differentiates external genitalia into penis and scrotum
127
What is the role of Mullerian-Inhibiting Factor in male reproductive tract development?
-Causes regression of the Mullerian Ducts
128
Without Testosterone and Mullerian-Inhibitng Factor….
- Wolffian ducts regress, and the Mullerian ducts develop into the female reproductive tract (oviducts and uterus);
- External genitalia become clitoris and labia
129
What causes female reproductive tract development?
- Indifferent embryonic reproductive tissue passively developed into females structure unless acted on my masculinizing factors;
- W/O male testicular hormones, females reproductive tract and genitalia develop no matter the genetic sex;
- Ovaries do NOT need to be present for feminization
* *Present the high female hormones of gestation from determine sex — all would be feminized
130
What results when the testes fail to properly differentiate and secrete hormones?
-Development of an ANATOMICAL FEMALE, in a genetic male who is sterile
131
What results from a deficiency in the enzyme that converts testosterone to DHT?
- Develops a GENETIC MALE with testes and a male reproductive tract, but FEMALE external genitalia;
- This happens because testosterone acts on the Wolffian ducts to develop the male reproductive tract, but DHT is responsible for the masculinization of the external genitalia
132
What results from excess dehyroepiandrosterone from the anterior pituitary?
This weak androgen is normally secreted in insufficient amounts in females;
-Excess produces a GENETIC FEMALE with a MALE reproductive tract and genitalia
133
Why is it important to diagnose sexual differentiation problems very early in life?
- To avoid a traumatic gender identity crisis
- So that a sex can be assigned and therefore reinforced;
- Might require surgical and hormonal treatments so that psychosexual development can proceed as normal as possible;
- Less dramatic cases of inappropriate sex differentiation occurs as sterility problems
134
What determines chromosomal gender?
- Determined by fertilizing SPERM.;
- Each zygote inherits 23 chromosomes from the mother and 23 from the father = Produce 23 pairs of homologous chromosomes.;
- 22 pairs = autosomal;
- 23rd pair = sex;
- Diploid cell undergoes meiotic division, its daughter cells receive only 1 chromosome from each homologous pair;
- The gametes are HAPLOID.
135
How does sexual differentiation begin?
- 40 days after conception gonads of male/female are similar in appearance;
- Cells that will give rise to spermatogonia and oogonia migrate from yolk sac to developing embryonic gonads
136
How do the Testes form?
1. Testis-determining factor (TDF) promotes the conversion to testes:;
2. Seminiferous tubules appear within 43-50 days following conception and produce:
— Germinal cells = sperm.
— Nongerminal cells = Sertoli cells.
3. Leydig cells = Appear about day 65.
137
When do the Leydig cell start the production of testosterone?
- Leydig cells secrete testosterone at the 8th week and peaks at 12-14th week;
- Masculinizes embryonic structures.;
- Testosterone then declines to very low levels until puberty.;
- Testes descend into scrotum shortly before birth.
138
How do the ovaries form?
- Absence of Y chromosome and TDF, female develop ovaries.;
| - Ovarian follicles DO NOT appear until 2nd trimester, about day 105.
139
What is Hermaphroditism?
- Disorder of embryonic sexual development;
| - Both ovarian and testicular tissue is present in the body
140
What is a Pseudohermaphrodite?
- Disorder of embryonic sexual development;
- Individual with either testes or ovaries but NOT BOTH;
- Have accessory sex organs and external genitalia that are incompletely developed or inappropriate.;
- Most common cause of female pseudohemaphroditism is CONGENITAL ADRENAL HYPERPLASIA.;
- In the male, one cause is TESTICULAR FEMINIZING SYNDROME = Normal functioning testes, but lack receptors for testosterone.
141
What brings the onset of puberty?
- FSH and LH secretion is high in newborn, but falls to low levels in few weeks;
- Gonadotropin remains low until puberty;
- When FHS rises followed by LH, puberty has begun
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What is caused by the rise in Gonadotropin?
1. Maturational changes in the brain that results in increased GnRH secretion by the hypothalamus;
2. Decreased sensitivity of gonadotropin to negative feedback of sex steroid hormones at the time puberty is programmed
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What leads to increased GnRH secretion?
- Maturation of the hypothalamus and other regions of the brain;
- Children WITHOUT gonads show increased FSH at a normal time
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What happens in late puberty?
- During late puberty, pulsatile secretion of LH and FSH increase during sleep and decreased during wakefulness;
- Pulses of increase gonadotropin stimulate a rise in sex steroid secretion
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What sex steroid hormones increase at puberty?
- Stimulates rise in testosterone (testes) and estradiol-17b (ovary);
- Produce secondary sexual characteristics;
- These changes come with a growth spurt, which begins younger for GIRS than in boys
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What determines the age of onset of puberty?
- Age of onset related to the % of body fat and physical activity in the female;
- Leptin secretion from adipocytes may be required for puberty
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How does physical activity affect female puberty?
Girls who are very physically active reach MENARCHE ( first menstrual cycle) at around age 15 — later than the average 12.6 yrs;
- Seems to be due to the minimum % body fast for menstruation;
- Possibly a mechanism of natural selection for the ability to complete a pregnancy and nurse a baby
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How does physical acidity affect women later in life?
- Later lean and physically active women may have irregular cycle and AMENORRHEA (cessation of menstruation);
- May also be related to % body fat;
- Physical exercise may act to inhibit GnRH and gonadotropin secretion by endorphin transmission
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What is Parturition?
LABOR = the process by which a viable fetus is expelled from the uterus through the vagina to the outside
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How many babies born in the US are premature?
1 out of 8;
-Asymptomatic uterine infections, detected by the presence of microorganisms in the amniotic fluid = 1/3 to 1/2 premature births
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What controls the “pregnancy clock”?
Stress hormones that may be affected by diet, emotional stress, and genetic factors
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How does Inflammation affect labor?
* Very big factor!;
- Infections, allergic reactions, stretching of uterine muscles, and manufacture of a hormone from the fetal lung (SP-A) can initiate labor through inflammatory processes
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What initiates labor?
- Shifts in the estrogen and progesterone;
- Most of pregnancy = progesterone relaxes smooth muscles in the uterus and keep the cervix tight with collagen fibers;
* *Blocking the B-Receptor for progesterone INDUCES LABOR
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Role of Progesterone in Labor
- Most of pregnancy = progesterone relaxes smooth muscles in the uterus and keep the cervix tight with collagen fibers;
- Progesterone BLOCKS the genetic factors that trigger labor;
- When progesterone binds its receptor, complex then binds DNA and promotes gene transcription
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Role of Estrogen in Labor
Increasing estrogen excites the uterine muscle and prompt the fetal membranes on the cervix to produce PROSTAGLANDINS;
-Prostaglandins soften the cervix and enzymes digest collagen fibers
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What is Corticotropin-Releasing Hormone (CRH)?
- Placental hormones that stimulates all events leading to labor;
- Blood levels of CRH rise during pregnancy;
- Levels t 4-5 months can be used to determine due date;
- Early increase in CRH due to stress, genetics and dieting can lead to a premature birth
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What stimulate uterine contractions?
1. Oxytocin;
| 2. Prostaglandins — cyclic fatty acids with paracine functions produced within the uterus = PGF2alpha and PGF2
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How does the FETAL adrenal cortex stimulate labor?
- it supplies androgen dehydroepiandrosterone sulfate (DHEAS) to the placenta which becomes estriol;
- Estriol stimulates..
1. Production of oxytocin and prostaglandin receptors;
2. Gap junctions between myometrial cells of uterus;
3. Myometrium becomes more sensitive to oxytocin and prostaglandins with more receptors;
4. Gap junctions coordinate uterine contractions
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What is an Abortion?
Miscarriage;
| -Expulsion of the fetus before the stage of development when the fetus is abele to continue an extrauterine existence
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What is Premature?
Birth after a child is viable but before full term
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What 3 factors are involved in labor?
1. Birth passages = birth canal, cervix, true pelvis, soft parts that line the pelvis and through the vagina;
2. Fetus and membranes;
3. Muscular contractions for delivery
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What is Fetal Universal Flexion?
Head and limbs flexed on trunk
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What is Fetal Presentation?
1. Cephalic presentation = fetal head lowest in birth canal (96%);
2. Transverse presentation = hard every, shoulder, etc;
3. Breech presentation = butt or feet first (4%)
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What are the stages of labor?
1. Dilation = Onset of labor to the complete dilation of cervix (8-24 hours in 1st pregnancy)
2. Expulsion = cervical dilation to birth;
3. Placental stage = birth — expulsion of placenta and membranes (10-45 minutes)
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Human Chorionic Gonadotropin during Pregnancy
- Placental Hormone;
- Begin weeks after onset of pregnancy and peaks ~8wks;
- Similar to LH;
- Maintain corpus lutem for the first 5.5wks;
- May suppress immunological rejection of the embryo;
- Exhibits TSH-like activity
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Estrogens during Pregnancy
- Placental hormone;
- Helps to maintain endometrium;
- Suppresses gonadotropin secretion;
- Stimulates mammary gland development;
- Inhibits prolactin;
- Promotes uterine sensitivity to oxytocin;
- Stimulates mammary duct development
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Progesterone during Pregnancy
- Placental Hormone;
- Helps maintain endometrium;
- Suppresses gonadotropin secretion;
- Stimulates development of the alveolar tissue of the mammary glands
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Human Chorionic Somatomammatripin during Pregnancy
- Placental hormone;
- Similar to prolactin and growth hormone;
- Promotes increased fat breakdown and fatty acid release form adipose and sparing glucose for the fetus (“diabetic-like” effects)
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What stress is the baby under during vaginal delivery?
- Hypoxia and pressure on the baby’s head release stress hormones epinephrine and norepinephrine into the bloodstream;
- Levels equal that of a woman giving birth or someone having a heart attack;
- Surge of these cathecholamines prepare the baby for survival
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What adaptive advantages come from a vaginal delivery?
* From surge of epinephrine and norepinephrine =
1. Clear lungs of fluid, secreting surfactant and change physiology for normal breathing;
2. Mobilize brown fat on babies back to nourish cells;
3. Ensure a rich blood supply to heart and brain;
4. Promote bonding between mother and child
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What are phase of Human Sexual Response?
1. Excitation
2. Plateau
3. Orgasm
4. Resolution
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Excitation Phase of Human Sexual Response
- Myotonia and vasocongestion. ;
- Engorgement of a sexual organ with blood.;
- Erection of the nipples in both genders.
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Plateau Phase of Human Sexual Response
- Clitoris becomes partially hidden.;
| - Erected nipples become partially hidden by swelling of areolae
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Orgasm Phase of Human Sexual Response
- Uterus and orgasmic platform of vagina contract.;
| - Contractions accompanying ejaculation.
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Resolution Phase of Human Sexual Response
- Body returns to preexcitation conditions.;
| - Men enter refractory period.
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What is Male Sterilization?
- Vasectomy;
- Cauterizing or cutting the VAS DEFERENS;
- Performed in a dr office;
- Clinical success in reversing — 80-90%
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What is Female Sterilization?
- Tubal Ligation;
- Fallopian tubes are banded, cauterized, and cut;
- Women who have surgery before age 28 have 5% chance of pregnancy;
- Half done as outpatient;
- Clinical success in reversing — 70%
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What are the Steroidal Contraceptives?
- Oral
- RU-486
- Injections
- Birth control patch
- Vaginal ring
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How do Oral Contraceptives prevent pregnancy?
- Used by more than 10 million in the US;
- Alter normal hormonal rhythms of menstrual cycle;
- Estrogen and progesterone doses prevent FSH and LH and inhibit ovum release;
- Progesterone also immobilizes and kills sperm by thickening cervical mucous;
- 30 different types of estrogen/progesterone pills and some minimills with only progesterone
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How does RU-486 prevent pregnancy?
- Promotes abortion by blocking the actions of progesterone (required for endometrium to maintain pregnancy);
- Competes with progesterone for cytoplasmic receptor proteins in the endometrium;
- RU-486 binds receptors and thus progesterone cannot activate the nuclear genes ;
- Result = endometrium breaks and loss of embryo
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What injection prevent pregnancy?
1. Lunelle = monthly;
2. Depo-provera = 4 times a year; active ingredient is is medroxyprogesterone acetate — synthetic similar to progesterone
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How do Birth Control Patches prevent pregnancy?
- Patch contains PROGESTIN and ESTROGEN;
- Replaces weekly for 3 weeks of each cycle;
- More than 95% effective
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How do Vaginal Rings prevent pregnancy?
- Contains ETONOGESTREL and ESTRADIOL that prevent ovulation;
- Inserted and remains fro 3 weeks;
- Removed at 4th week fro period to occur;
- More than 98% effective
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How do Intrauterine Devices (IUDs) prevent pregnancy?
- Inserted through the cervix into the uterus;
- Prevent implantation of the blastocyst in the endometrium;
- Used to be plastic, now copper-bearing is more effective;
- Some release progesterone = Preogestasert-T (replaced yearly)
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What are the barrier methods of birth control?
1. Condoms — also protect against STDs;
2. Diaphragm — dome-shaped rubber device that covers the cervix;
3. Sponge — polyurethatne sponge with spermicide nonoxynol-9; fits over cervix;
4. Cervical cap — Fem cap/Lea’s shield; rubber and investigational device, NOT over the counter; works like a diaphragm but can remain for 3 days and no spermicide needed
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How do Spermicides prevent pregnancy?
- All spermicides contain the active ingredient NONOXYNOL-9;
- After insertion, a woman must wait 10-15 minutes for it to be effective;
- Less than an hour later it is NOT effective;
- Used by 3 million women as OTC contraception
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What are the fertility awareness methods?
- Rhythm method = religious/cultural group — relies on knowing ovulation;
- Methods of knowing ovulation =
1. Cervical Mucus Method: LUNA methods — pH changes of cervical fluid;
2. Temp. Method — body temp rises following ovulation;
3. Estimation based on past ovulation dates
* *Avoid sex 5 days prior and 2 days after ovulation — sperm and live 5 days in cervical mucus and ovum only 12 hrs after ovulation
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What is Abortion?
The induced terminate of pregnancy before 38 weeks gestation
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First Trimester Abortion
- First 12.67 weeks;
1. Menstrual abortion = evacuate uterine contents by a mild vacuum up to 6 wks after missed period;
2. Dilatation and Curettage — standard surgical method;
3. Vacuum aspiration — 6-12 wks after missed period; more complex apparatus
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Second Trimester Abortion
- Second 12.67 weeks;
1. Hypertonic injections = urea or glucose either intra or extraammniotically ; followed by labor in 24-48hrs and fetus expelled cleanly;
2. Prostaglandins = potent IN VIVO stimulants; either in tra- or extraammionitacally
3. Hysterectomy = remove part of the reproductive tract — ovaries, oviducts, and uterus; High mortality rate
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Third Trimester Abortion
Partial birth abortion
