Week 5: Reproduction Flashcards
Where does spermatogenesis occur (1) and what is the result (2)?
- occurs in the seminiferous tubules
2. results in the formation of mature sperm or spermatozoa
How are seminiferous tubules formed (1) and what are they surrounded by (2)?
- formed by sertoli cells
2. surrounded by leydig cells
What is the role of sertoli cells in spermatogenesis?
secrete a fluid with nutrients that nourish immature germ cells and provide digestive enzymes that play a role in converting spermatocytes to sperm
What are the basic events of spermatogenesis (3)?
- germinal cells (diploid cells) undergo rapid mitotic division and divide into primary spermatocytes
- primary spermatocytes divide by meiosis I to form secondary spermatocytes
- secondary spermatocytes divide by meiosis II to form two spermatids (haploid cell)
What is the role of leydig cells?
produce testosterone in the presence of LH
What is the maturation process of a sperm cell (4)?
- Elongation of the cell
- Formation of acrosome
- Mitochondria for ATP production
- Flagellum develops for motility
What are the major roles of testosterone (3)?
- Stimulates erythropoiesis
- acts on vocal chords
- stimulates behavioral characteristics (sex drive)
Describe feedback regulation and the role of the Sertoli and Leydig cells in this process.
- Hypothalamus releases gonadotropin-releasing hormone (GnRH)
- GnRH stimulates the anterior pituitary to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
- FSH and LH act on the testes - both Sertoli & Leydig activation necessary for sperm maturation
i. FSH stimulates Sertoli cells to stimulate
gametogenesis
ii. Sertoli cells release an androgen-binding
protein for concentrating testosterone and inhibin
that acts in feedback inhibition
iii. LH stimulates Leydig cells to produce
testosterone
What are the major events required for erection to occur?
- Parasympathetic stimulation comes from sensory inputs such as touching or central input such as sexually stimulating images
- Dilation of vascular beds which fill with blood and become engorged
How do agents that increase nitric oxide release help with ED?
Agents that increase nitric oxide release assists with parasympathetic stimulation
How does ejaculation occur (1) and why do urine and sperm never transit the urethra at the same time (2)?
- Involves a spinal reflex stimulated by the SNS that stimulates smooth muscle contraction
- During ejaculation the bladder sphincter is closed so urine cannot pass
Define prostatitis
inflammation of the prostate d/t bacterial infection, most common cause is frequent UTIs
Define benign prostatic hyperplasia (BPH)
prostate enlargement which can lead to urethral compression and cause urinary obstruction
Define prostate cancer
etiology unknown but considered a disease of aging; often an adenocarcinoma in posterior lobe of the prostate gland
What are the three tumor types that typically lead to testicular cancer?
- Seminomas tend to retain the features of the spermatozoa
- Nonseminomas contain multiple cell types and are less differentiated
- Nongerminal cell tumors arise from seminiferous epithelium
Which tumor cell markers are most commonly released in testicular cancer?
human chorionic gonadotropin, lactate dehydrogenase, alpha fetal protein
Define cryptochidism. What is the prevalence?
congenital disorder where one or both testes fail to descend into the scrotum
= occurs in 30% of premature neonates
Define hydrocele
most common cause of scrotal swelling; collection of fluid between visceral and parietal layers in the tunica vaginalis of the testicle or along the spermatic cord
Define testicular torsion
abnormal twisting of spermatic cord due to rotation of testis or the mesorchium, causes strangulation and if untreated infarction of the testis
Define variocele
What is the prevalence in men diagnosed with infertility?
What is the prevalence in males between ages 13 and 18?
mass of dilated and tortuous varicose veins in the spermatic cord
- Between 20 and 40% of men diagnosed with infertility have a variocele
- Occurs in 10-15% of males between ages 13 and 18
Define perimetrium, myometrium and endometrium
Perimetrium = outermost serous layer Myometrium = smooth muscle layer stimulated to contract during parturition Endometrium = mucosal lining of the uterine cavity with two layers: statum functionalis and stratum basalis
What are the major phases of oocyte transit (3)?
- Uterine tubes = fallopian tubes and oviducts - receive ovulated oocyte
○ Curves around the ovary, bent region = ampulla which is the usual site of fertilization - Oocyte is swept into the uterine tube by fimbriae
- Uterine tube empties into the uterus to deliver the possibly fertilized egg or zygote for implantation
3 major facts regarding oogenesis
Takes years to complete
Meiosis I concludes only after ovulation
Meiosis II finishes only after fertilization
What are the oogonia undergoing in utero?
Oogonia develop through mitosis
Oogonia are suspended in meiosis I as primary oocytes
It is estimated that a female baby has __________ at birth that are suspended until ________
- 2 million primary oocytes
2. puberty
Post-puberty how many primordial follicles develop each month?
10-15
When does the follicular phase take place and what are the major events (2)?
Days 1-14
- Proliferation of the follicular/granulosa cells is followed by formation of the theca and zona pelucida
- Selection of the dominant follicle occurs around day 7 in which the antrum expands and the corona radiata forms
When does the ovulation phase take place and what are the major events (3)?
Day 14
- Only the dominant or graafian follicle undergoes ovulation
- Meiosis I is completed and a polar body is formed
- Rupture of the ovary wall releases the oocyte surrounded by corona radiata
When does the luteal phase take place and what are the major events (4)?
Days 15-28
- After ovulation the ruptured follicle forms a new gland called the corpus luteum
- The corpus luteum secretes progesterone and estrogen
- Corpus luteum remains for about 10 days unless fertilization has taken place
- If fertilization has occurred the release of human chorionic gonadotropin (HCG) retains the corpus luteum until the placenta can develop
When does the menstruation phase take place and what is the major event?
Days 1-5
shedding of the functional layer of endometrium
When does the proliferative phase take place and what are the major events (4)?
Days 6-14
- Estrogen levels increasing
- Regeneration of the endometrium
- Synthesis of progesterone receptors
- Thin, streaming mucous produced
When does the secretory phase take place and what are the major events (3)?
Days 15-28
- Thick and sticky mucous released from endometrium
- Inhibition of new follicle development
- As progesterone levels fall, hormonal support is removed
3 phases of estrogen activity and their relation to feedback regulation
- During follicular phase if there are low levels of estrogen it inhibits LH/FSH
- During follicular phase if there are high levels of estrogen it stimulates LH/FSH
- During luteal phase, high levels of estrogen + progesterone, they both inhibit LH/FSH
What are the major roles of estrogen? (3)
- promotes oogenesis & follicle development
- Has an anabolic effect on female reproductive tract - as structures increase in size
- Stimulates growth in bone, breast tissue, fat deposition, widening/lengthening of pelvis
What is the major role of progesterone?
works with estrogen to inhibit muscle contraction of the uterus
Define vaginitis, sx and what are the common causes?
definition: inflammation of the vagina
Sx: Vaginal discharge, itching, swelling, pain from urination or intercourse
Causes: Candida albicans(yeast infection),Trichomonas vaginalis, or bacterial vaginosis
Define cervicitis and what are the common causes?
inflammation of the cervix
Common causes: infection withC. albicans,T. vaginalis,Neisseria gonorrhea,Gardnerella vaginalis,Chlamydia trachomatis, and herpes simplex; may be primary or secondary
Define pelvic inflammatory disease (PID), common causes and complications
acute inflammatory response to upper reproductive tract
Common causes: associated with STIs (Neisseria gonorrhea,C. trachomatis,Haemophilus influenzae, orStreptococcus) and endogenous organisms
Complications: infertility, ectopic pregnancy, abscess formation, chronic pain
Cervical cancer: cause, which screening can be used, prevention
Main cause is infection with HPV (over 100 types - 16 & 18 most closely associated)
Screening with pap smear has reduced incidence
Vaccine available for HPV 16 & 18, 6 & 11
Endometrial cancer: which ages is it more likely to occur in, what 2 physiological changes are associated with it and how does it usually present?
Usually affects women ages 55 to 65
Strongly associated with excessive estrogen stimulation and endometrial hyperplasia
Presents as bleeding
Risk factors for ovarian cancer
family history and mutations in TS genes BRCA 1 and BRCA 2
Tumor marker associated with ovarian cancer
CA-125
Why is ovarian cancer often difficult to diagnose?
d/t diffuse sx: bloating, pelvic pain, difficulty eating, frequent urination
75% of women dx when it reaches advance stage
Define amenorrhea, primary and secondary
lack of menstruation d/t hormone dysfunction
Primary: failure to menstruate initially
Secondary: cessation of menstruation caused by low fat stores, as in athletes
Define dysmenorrhea
painful menstruation often caused by increased prostaglandins (stimulate smooth muscle contraction, often under progesterone control)
Define menopause
final episode of menstrual bleeding - a process rather than a single event
Define premenstrual syndrome, causes, s/s
condition with onset 7 to 14 days before menses and that subsides with menses
Causes: unclear, stress can exacerbate
S/S: changes in behavior or personality, breast/abdominal tenderness or swelling, headache, heart palpitations, dizziness, diarrhea or constipation, skin problems
Define premenstrual dysphoric disorder
severe form of PMS with cyclical occurrence of psychiatric symptoms (anger, irritability, severe mood swings) that interfere with everyday life
Define fibroids
uterine leiomyomas = benign tumors in myometrium of the uterus
Define ovarian cysts
Can form as follicular cysts: follicles undergoing development during the monthly cycle that become filled with fluid
Can form as luteal cysts from corpus luteum
What are the risk factors for breast cancer?
increasing age and family history of breast cancer (5-10% are hereditary)
Mutations in BRCA1 and BRCA 2 TS genes increase susceptibility
Screening and treatment options for breast cancer
Screening: mammogram + clinical breast evaluation
Treatment: surgery, chemo, radiation, hormonal manipulation
How does PCOS occur?
Excessive LH combined with hyperinsulinemia that sensitizes ovaries in an individual with underlying genetic susceptibility
Excessive androgens released
What are the symptoms of PCOS?
anovulation, amenorrhea, ovulation-related infertility resulting in polycystic ovaries, hirsutism, acne
What are the major goals for treatment of PCOS?
Aim to lower insulin, restore fertility, reduce hirsutism/acne, restore normal menstruation
Prevention of endometrial hyperplasia and endometrial cancer
Define endometriosis
endometrial tissue found in ectopic sites outside of the uterus
S/S of endometriosis
painful periods, abdominal or pelvic cramps, pain during or following sexual intercourse, pain with defecation bleeding, premenstrual spotting, possible infertility
Treatment for endometriosis
Induce pseudopregnancy to stop menstruation
Hormone use to suppress estrogen production
Surgery to open fallopian tubes or remove uterus
Steps in the process of fertilization (7)
- Oocyte released by ovary (viable for 24 hours)
- Capacitation: flagellum and membranes of postejaculatory sperm made more permeable (viable for 48-72 hours)
- Acrosomal reaction: contents of acrosome released
- Block to polyspermy: enzymes released to prevent additional sperm from binding
- Completion of meiosis II by oocyte
- Fusion of pronuclei of ovum and spermatozoa
- Zygote formed
Define blastocyst
= hollow ball of cells formed after the division of cells take place; implants in the uterus on day 6
Define trophoblast, cytotrophoblast & syncytiotrophoblast
= lining of the blastocyst, supplies nutrients and secretes HCG
- cytotrophoblast = inner layer, protects the blastocyst
- syncytiotrophoblast: outer layer which embeds in the endometrium
What is HCG, which cells release it? What’s it’s main role?
What: human chorionic gonadotropin
Secreted by trophoblast
Role: maintains corpus luteum, stimulates hormone secretion
Which hormone is detected in early pregnancy testing?
HCG
Hormonal changes during pregnancy (3)
- Estrogen and progesterone remain high
- GnRH (LH and FSH) inhibited by negative feedback loops - high estrogen and progesterone combo suppress LH & FSH
- HCG relased by blastocyst and stimulates hormone secretion, declines at 12 weeks and results in degeneration of CL
Common physical changes during pregnancy (8)
Increased vascularization Enlargement of breast tissue Heartburn Constipation Stress incontinence Dyspnea Increased cardiac output Varicose veins
What are the functional roles of the placenta?
Prevents mixing of maternal and embryonic blood
Secretes progesterone, estrogens, human placental lactogen, human chorionic thyrotropin and relaxin
Maintains hormones for the duration of pregnancy
What are the functions of human placental lactogen, human chorionic thyrotropin and relaxin?
Human placental lactogen: prepares breast tissue for lactation
Human chorionic thyrotropin: increases maternal metabolism during pregnancy
Relaxin: relaxes and increases flexibility of pelvic ligaments and pubic symphysis
What are the basic events of development during the pre embryonic, embryonic, and fetal stages?
Pre-embryonic (zygote to week 2): Cleavage reactions and implantation of blastocyst
Embryonic (week 2-8): Formation of organs and trilaminar embryo
Fetal (8 weeks to birth): Complete formation of all major systems and external features
What are the general structures derived from each layer of the trigeminal embryo?
Ectoderm: skin epidermis and nervous system
Mesoderm: everything else
Endoderm: epithelial linings of digestive, respiratory and urogenital systems and glands
What are the basic events of parturition (4)?
- Placenta releases prostaglandins
- Maternal release of oxytocin from posterior pituitary occurs
- Oxytocin and prostaglandins stimulate smooth muscle contraction
- After delivery of infant, placenta is delivered
What are the basic events of lactation (4)?
- Prolactin and estrogen develop breast tissue during pregnancy
- Estrogen levels decrease at birth, prolactin stimulates milk production
- Nutrient-rich colostrum secreted along with milk
- Oxytocin stimulates milk letdown by contracting smooth muscle cells that are part of the alveoli in mammary tissue
Gonorrhea: infectious agent, effects and treatment
neisseria gonorrheoae
PID and sterility
antibiotics
Syphilis: infectious agent, effects and treatment
treponema pallidum
skin rash, fever, joint pain, anemia, neuro disorder
antibiotics
Chlamydia: infectious agent, effects and treatment
chlamydia trachomatis
sterility
antibiotics
Genital warts: infectious agent, effects and treatment
HPV
cervical cancer
topical treatment of warts
Genital herpes: infectious agent, effects and treatment
herpes simplex, epstein-barr virus
lesions, congenital malformations
antiviral drugs
What are common causes of male infertility (3)?
- impaired production or function of sperm
- Low sperm concentration
- Impaired delivery of sperm
What are common causes of female infertility (8)?
- Fallopian tube damage or blockage
- Endometriosis
- Ovulation disorders
- Hyperprolactinemia
- PCOS
- Early menopause
- Uterine fibroids
- Pelvic adhesions
What is the definition of infertility?
failure to become pregnant after 1 year of unprotected intercourse
