Reproductive system Flashcards
(110 cards)
1
Q
Where are gametes produced?
A
Gonads
- Male = testes
- Female = ovaries
2
Q
Pelvis location & structure
- Where is the pelvis located?
- What makes up the pelvis?
- What are the bones of the pelvis?
- What are the joints of the pelvis?
A
- Bony basin b/w lower limb & the trunk
- Hip bones + sacrum + coccyx
- ilium
- ischium
- sacrum
- coccyx
- pubis
- Sacroiliac joint
- Pubic symphysis (can widen)
3
Q
Pelvic Inlet & outlet (holes)
- Which is open and which is closed by muscles?
- Which is bigger?
A
- Inlet is open, outlet is closed by muscles
- Inlet always bigger than outlet
4
Q
What are the pelvic subdivisions?
A
- False/greater pelvis
- True/lesser pelvis
5
Q
Features of the pelvic subdivisions
- Which is superior region?
- Which is inferior region
- Where is the false/greater pelvis located?
- Where is the true/lesser pelvis located?
- Which contains the GI tract?
- Which contains the reproductive organs?
A
True/lesser
- inferior region
- b/w inlet & outlet
- contains reproductive organs
False/greater
- superior region
- situated above pelvic inlet
- contains GI tract
6
Q
Female vs Male pelvis
- Subpubic angle?
- Inlet shape?
- Coccyx shape?
A
Female
- Broader subpubic angle
- Oval inlet
- Straighter coccyx
Male
- Narrower subpubic angle
- Heart-shaped inlet
- Curved coccyx
7
Q
- What closes over the pelvic outlet?
- What are the muscles involved?
- What are the openings in the pelvic floor?
A
- Pelvic floor
- Levator ani & cocygeus
- Urethra
- Anal canal
- Vagina (females)
8
Q
Perineum
- What does it contain?
- What are the two triangle divisions?
A
- External genitalia & anus
- Anterior: urogenital triangle
- Posterior: anal canal & fat
9
Q
Male reproductive tract
- What path is it?
- What does it include?
A
- Path that sperm travel along
- Testes
- Epididymis
- Ductus (vas) deferens
- Ejaculatory duct
- Urethra
10
Q
What is makes up the scrotum?
A
- 2 testes
- 2 spermatic cord
11
Q
Testes
- What do the produce?
- What are they surrounded by?
A
- Sperm
- Testosterone
- Inhibin
- Dense fibrous capsule - tunica albginea
12
Q
Seminiferous tubules
- Where are they found?
- What do they join to form?
A
- Contained in the lobules of the testes
- Join to form rete testes; which
- Join to form ductules leading to epididymis
13
Q
What are the cells of the seminiferous tubules?
A
- Leydig cells: testosterone
- Sertoli cells: inhibin
- Spermatogenic cells: spermatozoa
14
Q
Epididymis
- What is it made up of?
- Whare does the sperm enter & leave?
A
- Head, body & tail
- Enters from seminiferous tubules
- Exits via ductus deferens
15
Q
Ductus Deferens (‘vas deferens’)
- What is it in?
- What is covered by?
- What does run behind?
- What does it dilate to form?
A
- In spermatic cord
- Covered by smooth muscle
- Runs behind bladder
- Dilates to form the ampulla
16
Q
The spermatic cord
- How many?
- Where does it run?
- What does it contain?
A
- One on each side
- Runs b/w abdomen & testes
Contains
- Ductus deferens
- Blood vessels (testicular arteries & veins)
- Nerves
- Lymphatics
17
Q
Ejaculatory ducts
- What are they formed by?
- Where does i t open?
A
- Formed by the union of the duct from the seminal vesicle & the ampulla
- Opens in the prostatic urethra
18
Q
Urinary/ urethral sphincters
- External
- Internal
A
External
- Skeletal muscle, voluntary control of urination
Internal
- Detrusor muscle - closes bladder thus ensures sperm ejaculated through the urethra; retrograde ejaculation - sphincter doesn’t close, therefore ends up in bladder
19
Q
What is the path of sperm?
A
Testes (manufactured) → epididymis → ductus deferens → ejaculatory duct → urethra
20
Q
The Penis
- What is the Dual function?
- What makes up the cylindrical organ?
- What are the 3 cylindrical erectile tissues?
- What are their features?
A
- Urination
- Copulation
- Root (bulb)
- Body
- Glans, covered by prepuce/foreskin
→ 2 corpora cavernosa - main erectile tissue - dorsal aspect → 1 corpus spongiosum - contains urethra - forms bulb & glans - ventral aspect
21
Q
The scrotum
- Where does it house the testes? And why?
- Which muscle is it lined by?
- Which muscle contracts? And why?
A
- Houses testes away from the body to maintain temp @ ~34 °C
- Lined by dartos muscle
- Cremator muscle - contracts for heat conservation (thermoregulation)
22
Q
Accessory glands
- What do they produce?
- What are the 3 glands associated w/ male RS
A
- Produce most seminal fluid (composition, volume)
- Seminal vesicles
- Prostate gland
- Bulbourethral glands
23
Q
Seminal vesicles
- How many?
- Location?
- What does it merge with and become?
- What does it produce?
- What does it contain?
- What does alkaline pH protect?
A
- 2
- Posterior to bladder, lateral to ampulla of ductus deferens
- Merges w/ ampulla to form ejaculatory duct
→ Produce viscous secretion
- 60% of semen
- Contain fructose & other nutrients to nourish sperm
- Alkaline pH protects sperm against acidic environment in urethra & vagina
24
Q
Prostate gland
- Location?
- What does it produce?
- pH? Why?
- What does it contain
- What is contribute to?
A
- Inferior to bladder, wraps around prostatic urethra
→ Produces secretion
- 30% of semen
- Slightly acidic, milky fluid containing enzymes & PSA (prostate specific antigen)
- Contains citrate to nourish sperm
- Contributes to sperm activation, viability & motility
25
Bulbourethral glands
- How many?
- Location?
- What does it open into?
- How much does it contribute to semen vol.
- What do the secretions do?
- 2 glands
- Located in the urogenital diaphragm
- Open into spongy/penile urethra
- Contributes to 5% of semen vol.
- Secretions lubricate & neutralise acidity in urethra prior to ejaculation
26
Vasectomy
- What is it?
- Contraception; cut/tie ductus deferens
| - Doesnt change seminal fluid vol.; bc accessory glands still functioning
27
- What is Gametogenesis?
- Males?
- Females?
- What type of control is it?
- How does it occur?
- Formation of the sex cells
- Males: spermatogenesis
- Females: oogenesis
- Under hormonal control
- Occurs via meiosis
28
- What is spermatogenesis?
- What type of cell division occurs?
- What are the 3 main stages of this cell division?
- Cell type
- Number of chromosomes
- Spermatogonia → mature spermatozoa (sperm)
- Occurs via meiosis
- Process:
1. Primary spermatocyte (diploid: 2n = 46)
Meiosis I
2. Secondary spermatocyte (n = 23)
Meiosis II
3. Spermatid/spermatozoa (haploid: n = 23)
29
Spermatogenesis during development
Spermatogonia migrate from yolk sac to testes & remain dormant until puberty
30
Spermatogenesis during puberty
- What does spermatogonia divide by?
- What does type B spermatogonia differentiate into?
What does it undergo to do this?
- What is formed after this step?
- What do these undergo next?
- What do spermatids differentiate into?
- Where are spermatozoa released?
- How many spermatozoa are formed from 1 type B spermatogium?
- Spermatogonia divide by mitosis into type A&B spermatogonia (diploid - 46 chrom.)
- Type B spermatogonia differentiate into 1* sex cell/ 1* spermatocyte (diploid) which undergoes meiosis I
- Forms 2* spermatocytes (haploid)
- These undergo meiosis II to form spermatids (haploid)
- Spermatids differentiate into spermatozoa w/ a head, body & tail via spermiogenesis
- Spermatozoa released into lumen
- 1 type B spermatogium forms 4 spermatozoa
31
- How often does spermatogenesis take place?
- Where does sperm develop mobility?
- Where does sperm mature?
- Spermatogenesis takes place continuously daily after puberty
- Sperm develop mobility in epididymis
- Sperm mature in the epididymis
32
What is spermiogenesis?
Spermatid → Spermatozoon (change shape)
33
What is the spermiogenesis process?
1) Appearance of acromosomal vesicle & flagellum in spermatid
2) Growth of acrosome & flagellum
3) Shedding of excess cytoplasm (more streamline)
4) Mature sperm
34
- What hormone acts on the gonads?
- What is GnRH & where is it released from?
- What is LH & where is it released from?
- What is FSH & where is it released from?
- gonadotropin
- GnRH - gonadotropin releasing hormone
- released from hypothalamus (released in pulsatile fashion)
- LH - Luteinising hormone (a gonadotropin)
- from anterior pituitary
- FSH - Follicle stimulating hormone (a gonadotropin)
- from anterior pituitary
35
What are the reproductive hormones?
1) GnRH - gonadotropin releasing hormone
2) LH - Luteinising hormone (a gonadotropin)
3) FSH - Follicle stimulating hormone (a gonadotropin)
36
- What are the hormones in males?
| - Where are they from?
Inhibin
- from sertoli cells
Testosterone
- from leydig cells
- Androgen
37
What is androgen?
- Hormones which develop male characteristics (eg gonads → testes; spermatogenesis, aggression & libido)
- Synthetic androgens (steroids) - therapeutic purposes
38
Endocrine controls of the testes
- What does LH stimulate the production of?
- What controls spermatogenesis?
- What does inhibin inhibit?
- What does the negative feedback of testosterine suppress?
- LH stimulates the production of testosterone
- FSH & testosterone control spermatogenesis
- Inhibin inhibits FSH
- Negative feedback of testosterone suppresses LH & GnRH
39
Oogenesis
- What is it the formation of?
- What does it require?
- When is it initiated? and when does it continue?
- Where do oocytes develop?
- Formation & development of the oocyte from oogonia
- Requires mitosis & meiosis
- Initiated before birth, continues b/w puberty & menopause
- Oocytes develop w/in ovarian follicles (one per follicle)
40
Generating the ovum - before birth
1) Oogonium (diploid) migrate to developing gonad
2) Population of oogonia ↑ by mitosis
3) Oogonia differentiate to form 1* oocytes (diploid)
- Encased in primordial follicle
- Many 1* oocytes undergo cell death (atresia)
4) 1* oocytes start meiosis
- Halts at prophase 1 until puberty begins
41
Generating the ovum - from menarche till menopause
1) Under GnRH influence, small number of follicles recruited each ovarian/mestrual cycle
2) Only one oocyte will complete development & ovulate
3) 1* oocyte completes meiosis I
- forms a 2* oocyte & first polar body (both haploid)
4) 2* oocyte starts meiosis II
- Halts at metaphase II until fertilisation
5) Meiosis II resumes when the sperm penetrates plasma membrane of the ovum at fertilisation
- If not fertilised, will die (atresia)
42
Oogenesis w/in developing follicle
- What develops in the developing follicle?
- Are follicles multilayered?
- What are the cells of the developing follicle?
- During ovulation what is released into the peritoneal cavity?
- Oocyte develops w/in developing follicle
- Follicles are multilayered
- Granulosa cells - produce estradiol
- Theca cells
- Ovulation: oocyte & corona radiata released into peritoneal cavity
43
Hypothalamus Hormones
- What is found and released in the hypothalamus?
- What does this stimulate?
- GnRH (gonadotropin releasing hormone)
| - Release of FSH & LH
44
What are the Anterior Pituitary Hormones?
- FSH (follicle stimulating hormone)
- LH (luteinising hormone)
- Prolactin
45
FSH (follicle stimulating hormone)
- What does it signal
- What does it stimulate? And initiate?
- Signals to ovary
| - Stimulates the growth of ovarian follicles & initiates estradiol production
46
LH (luteinising hormone)
- What 2 things does it stimulate?
- What does it cause?
- Stimulates completion of follicle & oocyte growth → estrogen secretion by follicle
- Stimulates ovulation (by causing ovum expulsion from follicle)
- Causes formation of corpus luteum from ruptured follicle → progesterone & estrogen secretion by corpus luteum
47
Prolactin
- What does prolactin stimulate?
- Stimulates production of milk in the mammary glands
48
What are the hormones produced in the Ovary (follicles)?
- Estradiol (developing follicles)
- Inhibin (granulosa cells)
- Progesterone (corpus leum
49
Estradiol (developing follicles)
- What does it assist with?
- What type of characteristics?
- What feedback?
- Assist follicle growth (w/ FSH), bone & muscle growth, endometrial growth
- Secondary sex characteristics
- Feedback to anterior pituitary (to alter circulating levels of FSH/LH)
50
Inhibin (granulso cells)
- What type of feedback?
- -ve feedback to anterior pituitary to suppress FSH
51
Progesterone (corpus luteum)
- What type of feedback?
- How does it maintain pregnant state?
- -ve feedback to supress GnRG (thus LH & FSH)
| - Endometrial maturation, maintains pregnant state
52
Ovarian cycle
| Follicular (preovulatory) phase
- day 1-14 (av. 14 days)
- ↓ FSH from the anterior pituitary
- Stimulates follicular growth growth
- Growing follicles secrete estradid & inhibin
- ↓ FSH from anterior pit. (-ve feedback)
- Growing follicles undergo astresia (except dominant one)
- Dominant follicle secretes large amounts of estradiol
- High estradiol stimulates surge of LH (+ve feedback)
- Follicle ruptures & ovulation occurs
- Oocyte enters peritoneal space & collected by uterine tube
53
Ovarian cycle
| Lucteal (post-ovulatory) phase
- day 15-28 (av. 14 days)
- Ovulated follicle collapses & forms corpus luteum
- secretes progesterone, estradiole @ inhibin
- These ↓ FSH & LH secretion
- -ve feedback on hypothalamus
- Progesterone stimulates maturation of the endometrium
- glands become secretory
- If pregnancy doesn't occur, the corpus luteum involutes (luteolysis)
- ↓ in progesterone & estradiol
- Endometrium breaks down & bleeds (menstruation)
- Removes -ve feedback on FSH & LH; cycle starts again
54
Menstrual/Endometrial cycle
| Proliferative (& menstrual) phase
- Day 1-14
- Estradiol stimulates endometrial growth from ~ days 6-14
- Rapid tissue growth, incl. growth of glands & vasculature
55
Menstrual/Endometrial cycle
| Secretory (& pre-menstrual) phase
- Day 15-28
- After ovulation (day14) - corpus luteum secretes progesterone
- Progesterone promotes endometrial maturation
- Glands become secretory
- Spiral arterioles grow & coil
- If pregnancy doesnt occur
- Corpus luteum atrophies (degenerates)
- Progesterone levels ↓
- Spiral arteries contract
- Endometrial tissue breaks down & bleeding occurs
- Shed tissue & blood removed via cervix & vagina (menstruation)
56
Interlinking of cycles
- Ovarian cycle: produces ovum each month to regulate the menstrual cycle
- Menstrual/endometrial cycle: ensures lining of uterus suitable for implantation
57
Breast (Mammary glands)
- Function?
- Location?
- What stimulates development of breast tissues?
- Structure?
- Function: nourish infants
- Lie on pectoralis major muscles
- Estradiol & progesterone stimulate development of breast tissue
- Lobes → lobules → alveoli → lactiferous ducts → lactiferous sinuses
58
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Breast feeding
Milk production (lactation)
```
- Rapid ↓ in circulating estradiol & progesterone after birth allows breast to respond to prolactin
- Prolactin stimulates milk prodution/secretion/synthesis
- Suckling stimulates continued production of prolactin
- Amount of prolactin determined by strength/duration of nipple stimulation during suckling
59
Breast feeding
| Milk let-down/milk ejection reflex
- Suckling also stimulates oxytocin secretion
- Oxytocin stimulates contraction of smooth muscle around alveoli
- Milk goes into lactiferous ducts, allowing infant to feed
60
Posterior pituitary
- What is released?
- What does it act on?
- Oxytocin
| - Acts on breast to cause milk let-down
61
Female perineum
- How many divisions?
- What is the Anterior division?
- What is the posterior division?
- 2 triangular division
- Anterior: urogenital triangle
- Urethral & vaginal opening: external genitalia (vulva)
- Poster: anal canal
- Anal canal & fat
62
External genitalia (vulva)
- Where is the Mons pubis?
- What is the labia structures?
- What is the space b/w labia?
- Vestibular gland location? Function?
- What does the clitoris consist of?
- In front of the pubic symphysis
- Major (labia majora) - larger & more lateral
- Minor (labia minora) - smaller & more medial; spreads around the urethral opening
- Space b/w = vestibule
- Deep to the labia
- Lubricate the vaginal orifice
Consist of: glans (singular), body, crura (x2), bulbs (x2)
63
Reproductive tract
- What does it allow
- What does it provide?
- What is it delivery of?
- What are the structures w/in?
- Allows transport of sperm & ova to the site of fertilization
- Provides a site for the developing embryo & fetus to grow - protection & nourishment
- Delivery of fetus
- Ovary
- Uterine tubes
- Uterus
- Cervix
- Vagina
egg → Ovary → uterine tube → uterus → cervix → vagina
64
Uterine tube (3 parts)
- What part is the most lateral portion?
- What is it shaped like?
- What does the fimbriae help with?
- What is the mid-portion part?
- What area?
- What occurs here?
- What part is the most medial portion?
1) Infundibulum (most lateral portion)
- Funnel shaped
- Fibriae (finger-like projections)
- Fimbriae hover over the ovary to help collect/guide the ovulated ovum to the opening in the infudundibulum
2) Ampulla (mid-portion)
- Dilated area
- Fertilisation normally occurs here
3) Isthmus (most medial portion)
- means "narrow passage"
65
Uterus
- Function?
- 3 major components
- Wall: 3 layers
- Position?
- Movement of sperm
- Implantation of blastocyst
- Retain & nourish embryo & fetus through pregnancy
- Allow parturition (childbirth)
- Fundus
- Body
- Cervix
1) Perimetrium - outer layer; connective tissue
2) Myometrium - middle layer; smooth muscle
3) Endometrium - inner layer; columnar epithelium (uterine glands & arteries)
- Position: anterior inclination (anteverted)
66
Cervix
- 3 sections?
- External os
- Cervical canal
- Internal os
67
Vagina
-Fibromuscular, distensible copulatory organ
68
Uterus
- Function?
- 3 major components
- Wall: 3 layers
- Position?
- Movement of sperm
- Implantation of blastocyst
- Retain & nourish embryo & fetus through pregnancy
- Allow parturition (childbirth)
- Fundus
- Body
- Cervix
1) Perimetrium - outer layer; connective tissue
2) Myometrium - middle layer; smooth muscle
3) Endometrium - inner layer; columnar epithelium (uterine glands & arteries)
- Position: anterior inclination (anteverted)
69
Cervix
- 3 sections?
- External os
- Cervical canal
- Internal os
70
Vagina
- Fibromuscular, distensible copulatory organ
- Also functions as part of the birth canal
- Lies b/w the bladder & rectum
- Extends from the perineum to the cervix
71
Blood supply
- Branches off?
- Uterus
- Vagina
- Ovary
- Branches off abdominal aorta & internal iliac arteries
- uterus: from uterine artery, which branches off internal iliac arter
- Vagina: From vaginal artery, branches off internal iliac
- Ovary: Ovarian arteries, which branches off abdominal aorta
72
Blood supply in myometrium & endometrium
Where?
- Where are spiral arteries?
- Uterine artery → arcuate arteries → radial arteries → spiral & straight arteries
- Spiral arteries move deeper into endometrium (closer to lumen): join venous supply
73
Ovaries
- Bilateral structures: lateral & posterior side of the uterus in the lateral portion of the true pelvic cavity
Consist of:
- Outer cortex (follicles)
- Inner medulla (connective tissue, blood vessel, nerves & lymphatics)
- Site of oogenesis & hormone production
74
Ligaments
What are the ligaments?
- Folds & presses over structures to create other ligaments
1) Broad ligament
- Mesometrium ("of the wobm")
- Mesosalpinx ("of the tube")
- Mesovarium ("of the ovary")
2) Ovarian ligament
3) Suspensory ligament
4) round ligament
75
Pouches
- What do they allow?
1) Vesicouterine pouch: location
2) Rectouterin pouch: location
- Allow uterus to expand/enlarge during pregnancy
- Vesicouterine pouch: continuous fold of broad ligament anteriorly located over bladder
- Rectouterin pouch: continuous fold of broad ligament posteriorly located over rectum
76
What are the functions of ligaments & peritoneal sheaths?
- Anchor & support
- Have vasculature & nerves running thr' them
- From important anatomical boundaries (i.e pouches)
77
What are the 3 cylindrical erectile tissues?
- 2 Corpora cavernosa
| - 1 corpus spongiosum
78
Facia
- What are the different types of fascia surrounding the erectile tissues?
- Tunica albuginea - innermost
- Deep (Bucks) fascia - Middle
- Superficial fascia - outer
79
What is erectile tissue made up of?
- Trabeculae = smooth muscle fibres
| - Lacunae = cavernous space
80
Vascular & nerve supply - penis
- What is the path of blood supply
- What does the internal pudendal artery supply?
- What are the arteries that branch to the penis?
→ Abdominal aorta → common iliac artery → internal iliac artery → internal pudendal artery
Pudendal artery supplies perineum & external genitalia
- Artery to the bulb
- Urethral artery
- Dorsal artery
- Deep (cavernosal) artery
81
Blood supply to penis ↑ during erections
- What swells? Why?
- What is compressed?
- Cavernous spaces swell due to blood
| - Veins compressed as lacunae fill
82
Nerve supply to the penis
- What is the penis innervated by?
- What does this include?
- What does the pudendal nerve supply?
- Where does the pudendal nerve supply?
- Where is the autonomic innervation to the penis derived from?
- What does parasympathetic nerves stimulate?
- What do the deep arteries do?
- What does the sympathetic nerves stimulate?
- What does it include?
- What does the somatic motor stimulate
- Penis richly innervated by sensory & motor nerves
- Includes sensory fibres responsive to touch, pressure & temperature
- Pudendal nerve supplies sensory & somatic motor innervation to perineum & external genitalia
- Dorsal nerve of penis
- Autonomic innervation to penis derived from pelvic plexus - (parasympathetic & sympathetic)
- Parasympathetic (erection)- Stimulates production of NO (vasodilator) by deep arteries of penis
- Deep arteries dilate & fill lacunae in corpora cavernosum
- Sympathetic (ejaculation)- Stimulates contraction of smooth muscle (moves sperm - peristaltic contractions)
- Reproductive ducts
- Accessory glands
- Somatic motor (ejaculation) - Stimulates contraction of skeletal muscles around bulb of penis
83
Erection: Parasympathetic response to stimuli
- Afferent
- Where?
- What stimulations from the brain?
- Efferent
- What signals does it cause to the penis & bulbourethral gland?
- Afferent to spine
1) Visual, mental & other stimuli (from brain)
2) Stimulation of genital region, particularly glans (from pudendal nerve)
- Efferent
1) Penis: deep artery dilation, erectile tissues fill w/ blood, penis becomes erect
2) Bulbourethral gland: secretes bulbourethral fluid
84
Emission: Sympathetic response
- Efferent signals to?
1) Ductus deferens (peristalsis, sperm → ampulla, ampulla contracts, sperm → urethra)
2) Seminal vesicles (Secretes components of seminal fluid)
3) Prostate gland (Secretes components of seminal fluid)
85
Expulsion: somatic & sympathetic reflexes
- Afferent signals to?
- Efferent?
- Accessory glands
- Additional secretions from?
- Contraction of what?
- What type of signals?
- What muscle contracts?
- What does it do to the penis?
- Afferent signals to spinal cord from semen in urethra
- Efferent sympathetic signals
- Additional secretions from prostate gland & seminal vesicles; contraction of internal urethral sphincter (urine stays in bladder)
- Efferent somatic signals
- Bulbocavemous muscle: contracts & rhythmically compresses bulb/root of penis, which compresses urethra; semen is expelled
86
Resolution: sympathetic reflex
- What happens to the penis?
- What type of signals?
- What constricts, ↓ blood flow to penis?
- What muscle contracts & what does it do to the blood?
- What does the penis become?
- Blood flow to penis ↓, becomes flaccid
- Efferent sympathetic signals
1 - Internal pudenal artery: constricts, ↓ blood flow to penis
2 - Trabecular muscle: contract, squeeze blood from erectile tissues
3 - penis becomes flaccid
87
Female sexual response
- What is it a similar sequence of compared to the men?
- Engorgement of what? in response to autonomic stimulation
- What is secreted?
- What happens to the vagina in response to tactile stimulation?
- What is there rhythmic contraction of in response to pudenal nerve?
- Similar sequence of reflex responses as in the male
- Engorgement of corpora of clitoris, bulbs of vestibule, labia & vagina in response to autonomic stimulation
- Lubricating fluid secreted through vaginal wall; secretion of mucus in vestibule (greater vestibular glands)
- ↑ width & length of vagina in response to tactile stimulation, uterus elevates upwards
- Rhythmic contraction of vaginal, uterine & perineal (pelvic floor) muscles in response to stimuli from pudenal nerve
88
Contraception - Natural methods
- What do they rely on?
- High or low failure rate?
What type of methods are there
- Rely on timing of coitus (1,3) or behaviour during coitus (2)
- High failure rate
1) Rhythm method (periodic abstinence)
2) Withdrawal method (coitus interruptus)
3) Lactational infertility
89
artificial Mechanical/physical barriers
1) Caps, diaphragms
- Used in what & with what?
- How long doe sit have to remain in for after intercourse?
- Why is it rarely used nowadays?
2) Condoms
- Price
- Availability?
- Difficulty to use?
- ↓ chances of what?
1) Caps, diaphragms
- Imperfect barrier; used in conjunction w/ spermicidal creams, sponges, etc
- Needs to remain > 6 hours after intercourse
- Rarely used nowadays; replaced by safer, more convenient methods
2) Condoms
- Cheap
- Readily available
- Easy to use
- ↓ risk of STIs & STDs
90
- Steroidal contraceptives
Combined oral contraceptives ('the pill')
- What does it contain
- What does it suppress?
- What does it affect
- Contain oestrogen AND progestin
- Suppress ovulation (affect feedback loops to the hypothalamus & pituitary)
- Affects mucus produced by cervix (prevents sperm penetration)
91
Steroidal contraceptives
Progestin-only pill -
1) Progesterone-only pill
- Low doses of what?
- Effects what?
2) Subdermal implant/injectable progestins
- Long or short acting?
- What doe sit act on?
Intrauterine device (IUD)
3a) Copper IUD
- Causes low what?
- ↓ what?
- toxic to?
- Impairs what?
3b) Hormonal IUD (eg mirena)
- What does it contain?
- What does it affect?
- What type of effects are there?
- What does it prevent?
1) - Low doses of progestin
- Effects on cervical mucus
2) - Long acting (over years)
- Act primarily by disrupting follicular growth & ovulation
3a) - Causes low grade inflammation
- ↓ sperm transport
- toxic to oocyte & zygote
- impais implantation
3b) - Contains progestins
- Affects cervical mucus, ↓ sperm transport
- Local effects on endometrium
- May prevent ovulation
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Artificial - surgical contraception
- What are they?
- Tubal ligation
- Vasectomy
- Hysterectomy
93
Artificial - surgical contraception
- What do you cut in the tubal ligation?
- What do you cut in a vasectomy?
- What do you remove in a hysterectomy?
- What doesn't this alter?
- What does it ensure?
- Tubal ligation - cut uterine tubes
- Vasectomy - Cut ductus (vas) deferens
- Hysterectomy - remove entire uterus
- Doesn't alter sperm/oocyte production or ovulation
- Ensures sperm & egg cannot meet
94
Fertilisation
- How long does the ovum survive for?
- Where is the oocyte swept into? Where is it fertilised?
- What is fertilisation?
- Ovum survives ~24h
- Oocyte & surrounding cells swept into uterine tube; fertilised in the ampulla
- Fertilisation; when a male & female gamete fuse to form a diploid cell
95
Fertilisation process
1 - Capacitation
- Where does the sperm undergo changes?
- What happens to the sperm?
- How long does capacitation take?
2 - Fertilisation (3 Phases)
- Penetration of?
- Penetration of?
- Penetration of?
3 - Oocyte changes (after)
- What happens to the zona pellucida
- What is completed?
- What forms?
- What moves closer to the female pronucleus?
- What degeneragtes
4 - Pronuclei fuse
- What forms?
- What occurs?
- What is there initiation of?
- Sperm undergoes changes in female tract:
- ↑ motility & acrosome membrane becomes fragile
- 6-8h
- Penetration of corona radiata
- penetration of Zona pellucida
- Penetration of the oocyte cell membrane
- Zona pellucida becomes immpenetrable (blocks polyspermy)
- Meiosis II completes → ovum produced
- Female pronucleus forms
- Spermatozoon nucleus moves close to female pronucleus
- Spermatozoon tail degenerates
- Forms a single nucleus (n=46)
- Sex determination occurs
- Initiation of cleavage
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Cleavage
- For 2 cells?
- For 4 cells?
- For 16 cells (morula)
- 2 cells ~ 30h
- 4 cells ~40h
- 16 cells (morula) ~3 days
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Cleavage process
1) - What happens to the fertilised cell?
2) - What is formed & what are they called?
3) What happens by day 16?
4) What happens to the cell?
5) What happens in days 4-5?
1) Mitotic cell division of fertilised cell
2) 2 daughter cells each called a blastomere
3) By day 3; 16 cell morula
4) cells of morula rearrange:
- Inner mass = epiblast
- Outer mass = trophoblast
5) Days 4-5; fluid filled blastocyst
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The blastocyst
- What are the 2 layers?
- What is the blastocyst inside of? & for how long?
1) - Inner cell mass = embryo/amnion
2) - trophoblast = embryonic placenta
- Blastocyst is inside zona pellucida until plantation
99
Implantation
1) - What does the blastocyst break out of?
2) - What happens in days 6-7?
3) - What happens on day 10?
4) - What 2 layers does the trophoblast form?
5) What invades the endometrium?
6) What does the trophoblast secrete?
7) What does this maintain?
1) blastocyst breaks out of zona pellucida
2) Days 6-7: moves to endometrium, implantation begins
3) Day 10: blastocyst completely implanted
4) Trophoblast forms 2 layers
- Inner - cytotrophoblast
- Outer - synctiotrophoblast
5) Outer cells invade endometrium; which envelops blastocyst
6) trophoblast secretes human chorionic gonadotropin (hCG)
7) Maintains the corpus luteum (ie corpus luteum doesnt die down into corpus albicans)
100
Ectopic pregnancy
- Where is the implantation?
- What is the visibility?
- Internal?
- Implantation outside of uterine cavity
- Rarely visible
- Internal haemorrhage
101
development week 2
- What are the 2 layers of embryoblast or inner cell mass?
- What are the 2 cavities that are formed?
- What is their function?
2 layers of embryoblast or inner cell mass
- Epiblast
- Hypoblast
2 cavities form
- Amniotic cavity: surrounds & protects developing cavity
- Yolk sac: primordial germ cells arise near here; first site of blood cell formation: used for early nutrition transfer
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Placenta
- What does it allow & by what week does it allow this?
- Where does the embryo grow?
- What is the embryo connected to? What does this contain?
- What is the placenta made up of?
- Where does the exchange occur?
- What bathes in maternal blood?
- Allows diffusion of maternal fetal blood by week 4
- Embryo grows out from uterus wall
- Embryo connected to placenta via umbilical cord (contains fetal blood vessels - carry oxygenated to & deoxygenated away)
- Made up of both maternal tissue AND fetal (chirion = trophoblast) components
- Exchange (gas, nutrients, waste) occurs across chorionic villi (which contain blood vessels carrying fetal blood)
- Chorionic villi bathe in maternal blood → exchange
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Parturition
- What happens to the cervix?
- What happens to the fetal membrane?
- What causes the birth of a baby?
- What happens to the placenta?
- What do contractions close?
1) Cervix dilates to allow fetal head through; Contractions; rupture of the fetal membranes
2) contractions (short); birth of baby
3) Placenta detaches; contractions close the maternal arteries that supplied the placenta
104
Development potency
- What are cells initially?
- What can they develop in to?
- What happens 5 days after fertilisation?
- What do these cells form?
- Initially; cells (morula) are totipotent; can develop into any cell in the body or placenta
- By 5 days after fertilisation blastocyst has 2 types of cells: trophoblast cells (will form placenta) & inner cell mass cells (form embryo)
- Cells are pluripotent: can form almost any cell type (not placenta cells)
105
- What is gastrulation?
| - What forms in the epiblast during the 3rd week of gastrulation? What does this form? How?
- Formation of 3 germ cell layers from the 2-layered bilaminar disc
- Primitive streak forms; cells of the epiblast move into the primitive streak and form 2 new layers: the mesoderm and endoderm
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What are the germ cell layer & what do they form?
Ectoderm (outer layer of skin)
- Brain & spinal cord
- Nerve cells
Mesoderm
- Muscle
- Connective tissue
- Kidneys
- Gonads
Endoderm
- Lining of the GI tract
- Respiratory system - lining of lungs & bronchi
107
- What is neurulation?
| - Process?
- Process of forming a tube from a piece of ectoderm (neural tube)
1) Rises up at the edges to form the neural folds
2) Neural folds converge together
3) Neural folds fuse to form the neural tube
108
- What does intermediate mesoderm form?
- What does the paraxial mesoderm form?
- What does the lateral mesoderm form?
- Kidney/gonads
- Bone
- Skeletal muscle
- Endothelial cells
- Dermis
- Tendons
- Circulatory system
- Body Wall
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What happens if the process of gastrulation goes wrong?
- To the fetal?
- What causes it?
- Fetal abnormalities & usually death
| - Gene mutations or environmental effects (smoking, alcohol, etc)
110
Sensitivity to environmental chemicals
1) - 0-2 weeks (fertilised egg → embryonic disc)
2) - Embryo (3-8 weeks)
3) Fetus (9-38 weeks)
1) - Not sensitive
- High rate of lethality may occur
2) - Period of greatest sensitivity
- Development of organ systems
3) - ↓ sensitivity
- Period of functional maturation
