8 Flashcards
What is the SRY gene?
The sex-determining part of the Y chromosomes.
Acts during early development; signals to produce testis.
How are can individuals with the gametes XY possess primary and secondary female characteristics?
They have a missing/mutated SRY gene
How many autosomes do oocytes and spermatozoons contain?
22
Where do embryonic gonads develop from?
Bipotential primordia – called genital ridge primordia
What type of tissue forms the structure of the gonads but doesn’t contain the germ cells?
Mesenchymal tissue
Where do gametes originate?
Embryonic yolk sac
What do gametes originate as?
PGC – primordial germ cells
Where to germ cells migrate from and to?
From hindgut.
To gonad rudiment.
In normal males, what do the primordial germ cells (PGC) colonise?
The medulla
In normal females, what do the PGCs colonise?
The cortex
What do PGCs expand by?
Mitosis
Do PGCs differ in both sexes?
No
What are coelomic epithelia?
Epithelium lining surface of body and abdominal organsIt constitutes the outermost layer of the male and female gonads, thus forming the germinal epithelium of the female / male.
In males, what does the coelomic epithelia form?
A network of cords which surround and envelop the PGCs
Why doesn’t coelomic epithelium not form cords in females?
Because they lack SRY
What does PGCs in the cortex form?
Most tissues of ovaries
What does PGCs in the medulla form?
Most tissues of testis
In females, what happens to the medulla?
Degenerates
What does the sex cords lack in females?
Structure, they condense and cluster around PGCs (forming primary oogonia)
Once SOX9 is present what happens?
SRY is no longer needed as SOX9 is self-sustaining.
SOX9 initiates expression of PGD2
What does PGD2 drive production of and what does that do?
FGF9;
Drives migration of mesonephric cells
What do sertoli cells produce?
AMH (Anti-Mullerian hormone).
Which prevents Mullerian duct development (they differentiate to form the fallopian tubes, uterus, the uterine cervix, and the superior aspect of the vagina)
Name 2 hormones essential for male development
AMH and androgen
Which cells maintain the Wolffian duct?
Leydig cells
What does lack of androgen lead to in male development?
Wolffian duct regression
What do mesonephric primordia make in males and females?
Males – myoid cells, vascular tissue, Leydig cells.
Females – theca cells, vascular tissues
How do reproductive tracts of females and males differ?
Females – vagina, uterus, oviduct.
Males – vas deferens, seminal vesicles
What does androgen exposure after birth lead to?
Defeminisation; no change in internal or external genitalia
What does castration after birth lead to?
Demasculisation; no change in genitalia
What does removal of foetal ovaries lead to?
WD degenerate and MD develop
What role does the hypothalamus play in sex?
Role in secondary sexual characteristics
What is Turner’s syndrome?
X unpaired,
Infertile
Female
Describe Klinefelter’s syndrome
XXY.
Essentially maleInfertile
Underdeveloped testes
What is AIS?
Androgen insensitivity syndrome.
Androgen secreted by testes but target issues doesn’t respond
What determines the male phenotype (external appearance and secondary sexual characteristics)?
Testosterone levels and testosterone receptors.
Testis produce testosterone
What is congenital adrenal hyperplasia?
XX.
Foetal adrenal hyperactivity to overcome low production of corticosteroids which leads to WD and MD being retainedE.
xternal male genitalia
If Y chromosome is not present, what does the gonad become?
Ovaries
Which disease is the most common cause of erectile dysfunction?
Vascular – atherosclerosis
In the male reproductive system which embryological ducts remain in place and which degrade?
- Mesonephric (Wolffian) ducts remain
* Paramesonephric (Mullerian) ducts degrade
What is the embryological origin of the prostate?
Urethra
What are the muscles of the pelvic diaphragm?
Levator ani
• Ileococcygeus
• Pubococcygeus
• Puborectalis(Ischio)coccygeus
Nerve supply to levator ani (pelvic floor muscles)?
S3, S4
Describe the histology of the male urethra
Prostatic urethra
• Transitional epithelium
Membranous urethra
• Pseudostratified columnar epithelium
Penile urethra
• Pseudostratified columnar epithelium
What is found in the superficial perineal pouch?
Erectile tissue
• Corpus cavernosum
• Corpus spongiosum
Muscles
• Ischiocavernosus
• Bulbospongiosum
• Superficial transverse perineal muscle
What muscles are in the deep perineal pouch?
- External urethral sphincter
- Deep transverse perineal muscle
- Sphincter urethrovaginalis (Only in women)
- Compressor urethrae (Only in women)
What structure travels through the opening in the perineal membrane?
Urethra
What are the characteristics of Turner’s syndrome (X)?
- Ovaries present but infertile
- Poor breast development
- No menstruation
- Low hairline
- Short stature
What do the medulla and cortex of the gonads develop into in males?
Males
- Medulla develops into testis
- Cortex degenerates
What do the medulla and cortex of the gonads develop into in females?
Females
- Cortex develops into ovary
- Medulla degenerates
What do primary follicles consist of?
Oocyte surrounded by granulosa cells
What is the allantois?
Small sausage-shaped outpouching from the caudal wall of the yolk sac of the early embryo
Which 3 pairs of tubes drain into the bladder in the embryo?
Pronephros, mesonephros, metanephros
Which embryological tubes that drain into the bladder are the ones we keep in the adult urinary system?
Metanephros
Via which ducts does the gonads drain into the bladder?
Mesonephric (Wolffian) duct
What drains the kidneys into the bladder?
Ureters
What duct system is left behind for the gonads (testes)?
Epididymis (collecting tubules within testicles)
What is the mesonephric duct now called in adult males?
Ductus deferens (runs from epididymis into bladder)
What runs from the epididymis into the bladder?
Ductus deferens
Where are the testes located?
Between posterior abdominal wall and peritoneum
What do the testes descend through and into?
Inguinal canal into scrotal sac
What does the vas deferens loop over?
Ureter
Where do the ductus deferens from R and L testes come together?
Ejaculator duct
What does the ejaculatory duct pass into?
Prostate gland (at base of bladder)
Which 2 accessory glands open into the prostate?
Seminal vesicles
What are the 2 regions of the prostate gland?
Central zone – inner part; where ducts are located.
Peripheral zone – cortex layer on outside
Which part of the prostate tends to enlarge in benign prostatic hypertrophy?
The central zone of the prostate gland
What type of epithelium is found in the glans penis?
Stratified squamous
What is the perineum?
A diamond shaped region at the pelvic outlet
What is the perineal diamond subdivided into?
2 triangles:
- anterior urogenital triangle
- posterior anal triangle
What forms the roof of the perineum?
The pelvic diaphragm muscles
What is the deep perineal pouch?
A space enclosed by the perineal membrane and pelvic diaphragm
What are the major hormones involved in regulating female reproductive cycle?
LH, FSH, GnRH
What is the precursor of cholesterol?
Acetate
Name the structural unit in which oocytes develop.
Follicle
At what state in development are oocytes at birth?
Arrested in prophase 1, termed primary oocytes, residing in primordial follicles
What is the pattern of GnRH release in the prepubertal female and post-pubertal females?
Pre- Irregular.
Post - Regular pulses at approx. hourly intervals
At what stage of follicle development does ovulation occur?
Tertiary, preovulatory stage
What triggers follicle growth?
LH and FSH
What does oestrogen stimulate?
The secretion of LH by the anterior pituitary
What does progesterone promote?
Thickening of the endometrium
What does progesterone inhibit?
Secretion of FSH and LH by the anterior pituitary
What gonadotropins act at the ovary?
FSH and LH
What does inhibin do?
Inhibits FSH secretion from the anterior pituitary
What do sertoli cells secrete?
ABP – stimulates spermatogenesis
Define primordial follicle
Single layer of squamous granulosa cells; oocyte non-growing
Which gonadotrophin acts on granulosa cells?
FSH
What is the main hormone produced by the corpus luteum?
Progesterone
Function of progesterone.
Maintains pregnancy and supports luteal phase of the cycle
What are the main functions of the ovary?
Oogenesis
Folliculogenesis .
Corpus luteum formation
What is the effect of LH action at theca cells?
Androgen production
What is the effect of FSH at granulosa cells?
Oestrogen production
What cells does LH act on?
Theca cells
During what phase of meiosis is an oocyte released?
Metaphase II
How long does the corpus luteum last?
10 days
What do luteal cells produce?
Progesterone primarily and bits of oestrogen
After ovulation, what do the granulosa cells become?
Luteal cells
From day 1-14 of the menstrual cycle what phase occurs?
Follicular phase
What is the stimulus for the retention of the corpus luteum?
Beta HCG (pregnancy)
What are therapies for hot flashes in menopause?
HRT, SSRIs
What is the cell that implants in the uterine wall?
Blastocyst
When is premature menopause?
Below age 40
What do sertoli cells secrete?
ABP – stimulates spermatogenesis
If a woman has a uterus, what do you give her for HRT? What about if she doesn’t have a uterus?
Uterus: oestrogen and progesterone Hysterectomy: oestrogen
What are negative complications of HRT?
Increased MI, blood clots, breast cancer, stroke risk
In males, when is the initiation of spermatogenesis?
Puberty
What does ovulation normally occur?
14 days before the onset of menses
What is the source of HCG in the body?
Trophoblast
What is done in a male sterilisation?
Ligation/cauterisation of the vas deferens
What are some risks of vasectomy?
Soreness/bruising.
Not immediately effective
What techniques are used for female sterilisation?
Laparoscopic rings, clips or cautery.
Mini-laparotomy.
Tubal ligation at the time of the C-section.
Essentially mechanical blockage of the tubes
What is a copper IUD used for?
EC and normal contraceptive
How long is a copper IUD used for?
10 years
What is the mechanism of a copper IUD?
Copper ions inhibit the motility of sperm
What are the risks of using the levonorgestrel system?
Perforation, expulsion, infection
What are the non-contraceptive benefits of the IUS?
Decreased risk of PID, amenorrhea
What are the disadvantages of the implant?
Irregular bleeding
What are contraindications for a copper IUD?
Pelvic infection, uterine anomalies
How long is the implant used for?
3 years
What are contraindications for the implant?
Hepatic tumour, liver disease, breast cancer, allergies
What are contraindications of the progesterone only oral contraceptives?
Breast cancers
What are the non-contraceptive benefits of depo?
Decreases risk of seizuresAmenorrhea
How many times per month do you place a vaginal ring?
Once
How many times per month do you use the patch?
3 times (once a week and none for 1 week)
What type of lubricant can you use w/ latex condoms and why?
Water-based or silicone-based because oil-based lube will degrade the condom
How soon after unprotected coitus do you have to take levonorgestrel?
Within 72 hours
What is the mechanism of spermicides?
Destroys the sperm cell membrane
To have effectiveness w/ fertility awareness, what is a requirement?
- Abstaining on fertile days
2. Regular menses to predict fertile days
What are the advantages of the barrier methods?
STI protection
What is the axis that Is involved w/ the production of testosterone?
HPT axis:
- Hypothalamus
- Pituitary
- Testis
What is the axis that Is involved w/ the production of oestrogen?
HPO axis:
- Hypothalamus
- Pituitary
- Ovaries
Where does LH act at the testis?
Leydig cells
Which cells produce testosterone?
Leydig cells (stimulated by LH)
Where does FSH act in the testis?
Sertoli cells
What is the function of FSH?
Regulate spermatogenesis
What is the function of the sertoli cells?
Spermatogenesis regulation
How is testosterone transported from the testes to circulation?
Through diffusion
What is the effect of testosterone and its metabolites on the: kidney, bone marrow, bone, skin and liver?
Kidney – stimulation of EPO
Marrow – stimulation of stem cells
Bone – accelerated linear growth and closure of epiphyses
Skin – hair growth, balding, sebum
Liver – synthesis of serum proteins
What is the action of testosterone in the male sexual organs?
Penile growth, spermatogenesis, prostate growth and function
What are the metabolites of testosterone?
DHT: dihydrotestosterone oestradiol
When is the 1st meiotic division completed?
Upon ovulation
When is the 2nd meiotic division completed?
Upon fertilisation
What does the corpus luteum become is there is no fertilisation?
Corpus albicans
What are the functions of oestradiol?
Breast tissue and bone formation
What enzyme is responsible for the production of DHT?
5 alpha reductase
What is the effect of testosterone on bone density and what mediates this effect?
Increases bone density Oestradiol mediates this
Where is the adrenal glands in the body?
Small, conical organs on top of kidneys
What do adrenal glands produce?
Variety of hormones including adrenaline, aldosterone, cortisol
What is the functional unit of the ovary?
Single ovarian follicle
What are the developmental steps that occur in the transformation of primordial germ cells to primary oocytes?
Primordial germ cell
- mitosis
- oogonia
- enter prophase of meiosis I
- primary oocyte
What are the stages in the development of the primordial ovarian follicles to mature follicle?
Primordial ovarian follicle
- primary follicle (remains until puberty)
- secondary follicle
- graafian follicle
- ovulation
Why can’t theca cells produce oestradiol?
Contain cholesterol desmolase (stimulated by LH) thus can produce testosterone, but not androgen aromatase
How is oestradiol produced in the ovaries?
LH stimulates theca cells to produce androgens.
Androgens diffuses to granulosa cells and is converted to 17 beta-oestradiol using androgen aromatase (stim by FSH).
What cells produce inhibin B and what affect does this have on the anterior pituitary?
Granulosa cell; -ve feedback on FSH production in anterior pituitary
What does low and high oestrogen conc. do?
Granulosa cell; -ve feedback on FSH production in anterior pituitary
What does low and high oestrogen conc. do?
Low – inhibits LH secretion.
High – stimulates LH secretion from anterior pituitary this triggers ovulation and granulosa cells to produce progesterone
How does oestrogen conc. increase in the follicular phase of the menstrual cycle?
Androgen acts on granulosa cells to cause proliferation.
As granulosa cell numbers increase they produce more oestrogen collectively
What increases granulosa cell numbers?
Androgen
What does the LH spike stimulate?
Ovulation of the most mature follicle in the ovary
What enzyme does granulosa cells express?
Androgen aromatase in response to FSH
What are abdominal cramps caused by?
The contraction of the uterine and abdominal muscles to expel the menstrual fluid
After ovulation levels of what drops?
LH drops
FSH and GnRH will also decrease
What does corpus luteum secrete?
Oestrogen, inhibin, progesterone
What does an increase in progesterone do?
Negative feedback on hypothalamus which inhibits GnRH secretion
What happens once the corpus luteum has fully degenerated?
Progesterone decreases so GnRH levels increases then new menstrual cycle can occur
What happens to the endometrial lining in decreased levels of progesterone and oestrogen?
Lining not maintained and sheds
Which hormone prepares the endometrium lining of the uterus for implantation?
Progesterone
What are the stages of the uterine cycle?
Proliferative and secretory
What are the 2 types of HRT?
E2 (oestrogen) only and Combined E2/P4 (progesterone)
What causes menopause?
Falling E2 levels due to follicle depletion
What are the major hormones regulating the female reproductive cycle?
GnRH, FSH, LH, E2, P4, Inhibin, AMH
What are the phases of the ovarian cycle?
Follicular and luteal stages
What is the hormone profile of the ovarian cycle?
Rising levels of LH and FSH lead to E2 surge causing LH surge which induces ovulation then LH levels falling again and P4 levels rise
What is the purpose of menstruation?
Shed the lining of the endometrium in the absence of pregnancy
What is oocyte maturation?
Progression from PI to MII, resulting in haploid gamete
How does DEPO (progesterone only injection) work?
Inhibits ovulation
What happens in the follicular phase?
Maturation of follicles in ovary due to FSH being released from pituitary gland
What should you warn patients about if they are using the coitus interruptus method?
Pre-ejaculate contains sperm
What is the MoA of the combined oral contraceptive?
Inhibits ovulation via action on hypothalamo-pituitary-ovarian axis to decrease LH and FSH; alters cervical mucus and endometrium
What is migraine w/ aura a contraindication of?
Oestrogen containing contraceptive
What is thelarche?
Breast development as part of puberty
Define pubarche
Pubic hair development as part of puberty
Define adrenarche
Adrenal development towards puberty
What is menopause defined as?
The last menstrual bleed (12 months ago)
How does menopause affect FSH and LH hormone levels and why?
They increase; because there is no negative feedback from the ovaries
What is the critical weight for onset of menarche?
46 kg
How has age of menarche change and why?
Decreased due to health and nutrition improvement
Where is oestradiol produced?
Granulosa cells around each oocyte
List 5 menopausal symptoms
Hot flushes, menstrual irregularity, mood swings, forgetfulness, dry skin and vagina
How does blindness affect menarche?
Lack of sunlight leads to later menarche
What is precocious puberty?
Menarche <9 yrs
What is delayed puberty?
Menarche >16 yrs
Why can puberty be delayed?
Low body weight
E.g. athletes, congenital, chromosomal abnormalities
Where is oestradiol produced?
Granulosa cells around each oocyte
List 5 menopausal symptoms
Hot flushes, menstrual irregularity, mood swings, forgetfulness, dry skin and vagina
What can unopposed oestrogen(s) stimulate?
Endometrial hyperplasia and carcinoma
How does smoking affect fertility?
Negatively; reduces number of oocytes
What happens to the pronephros in embryo?
Degenerates; only leaves behind mesonephros (males)
Which ducts are lost in males?
Paramesonephric ducts
Which ducts are lost in females?
Mesonephric ducts
What are the collecting tubules within each testicle called?
Epididymis
What does the mesonephric duct become eventually in men?
Ductus deferens
What slips down between the abdominal wall and peritoneum to the floor of the pelvis and emerge from the anterior abdominal wall?
The testes
What does the kidneys use to drain into the bladder?
Ureters (metanephros in embryo)
Name the 2 histological zones of the prostate gland
Central zone (inner part where all ducts are located).
Peripheral zone (cortex layer on the outside)
Where is the prostate relative to the bladder?
Inferior
Where does the superficial perineal pouch lie?
Between perineal membrane and (superficial fascia and skin)
Which nerve provides most of the somatic motor and sensory innervation of the dorsal penis and scrotum?
Pudendal nerve
Where does autonomic fibres for vasodilation and stimulation of erection come from?
Parasympathetic fibres; inferior hypogastric plexus; from S2,3,4
Where does sympathetic fibres for smooth muscle contraction, internal urethral sphincter, reproductive tract, glands and muscle come from?
T10-L2
Which spinal levels does the pudendal nerve come from?
S2,3,4
Where does autonomic fibres for vasodilation and stimulation of erection come from?
Parasympathetic fibres; inferior hypogastric plexus; from S2,3,4
Where does sympathetic fibres for smooth muscle contraction, internal urethral sphincter, reproductive tract, glands and muscle come from?
T10 - L2
What does the internal pudendal artery supply?
Everything except the testes
Where does the testes get their blood supply?
Anterior division of internal iliac A (abdo vessels) because they developed from posterior abdominal wall
Where to the testes drain to and via what?
Testicular/spermatic vein from testis to IVC via pampiniform plexus
What is the pampiniform plexus?
A network of small veins found in human male spermatic cord and female ovaries
Where does the right ovary drain blood to?
From pampiniform plexus to ovarian vein to IVC
What does the left ovary drain blood to?
From pampiniform plexus to ovarian to L renal vein to IVC
What hormone raises uterine threshold to contractile stimuli during pregnancy?
Progesterone – until foetus is ready to be delivered
What hormone affects body temperature during what part of the menstrual cycle?
Progesterone raises body temp during the luteal phase
Where is the pancreas located?
Across the back of the abdomen, behind the stomach
What is the pancreas connected to?
Duodenum and spleen
What regions is the pancreas divided into?
Exocrine – 98%
Endocrine – 2% (arranged in Islets of Langerhans)
What does the exocrine pancreas secrete?
Bicarbonate – pH buffering
Zymogens – inactive precursor of enzyme
Enzymes – food digestion
Describe the structure of the exocrine pancreas?
Acinus – clusters of cells that resembles lobed berries Intercalated ducts – lead directly from acinus to striated duct, lined by ductal cells
Striated duct – gland duct which connects intercalated duct w/ intralobular duct
What do ductal cells secrete?
Bicarbonate
Where is secretin produced?
Small intestines
Describe the secretion of bicarbonate?
Secretin from SI changes levels of ATP produced in duct cells.
This increased ATP acts in ATP sensitive CFTR ion channels and changes potential of the cell which induces a movement of ions
Which hormones control secretions of the exocrine pancreas and how?
Secretin – released from s cell of duodenum; binds to ductal cells leading to secretion of HCO3-CCK – digestion of fat and protein, binds to acinus cells, triggers enzyme release
What does the endocrine pancreas secrete?
Insulin, glucagon, somatostatin – regulate blood glucose.
Pancreatic polypeptide, ghrelin – increases appetite
Describe beta cell
Secrete insulin which decreases blood glucose.
Found in the centre of the islets
Describe alpha Islets of Langerhans cells
Secrete glucagon which increases blood glucose.
Found on outer ridges of the islets; less numerous than beta cells
Describe delta cells?
Less common than alpha and beta cells.
Secrete somatostatin which inhibits insulin and glucagon secretion; dotted around islets
Describe epsilon cells
Uncommon; secrete ghrelin which increases appetite
Describe PP cells
Secrete pancreatic polypeptide which promotes satiety and inhibits pancreatic secretions
What is the pituitary gland attached to?
Base of brain (hypothalamus) by infundibulum
How many lobes does the pituitary gland have?
2 – anterior and posterior
What is the main function of the pituitary gland?
Master endocrine gland, secretes several hormones that control other endocrine glands
Describe the histology of the anterior pituitary lobe
Cell types based on staining:
- Chromophobes (unstained)
- Chromophils (stained) - subdivisions: acidophils and basophils
List the 5 basic secretory cells in the anterior pituitary lobe
Somatotrophs, mammotrophs, corticotrophs, thyrotrophs, gonadotrophs
List the acidophils in the anterior pituitary lobe
Somatotrophs and mammotrophs
List the basophils in the anterior pituitary lobe
Corticotrophs, thyrotrophs, gonadotrophs
What do corticotrophs secrete?
ACTH – which stimulates secretion of glucocorticoids from the adrenal cortex via the HPA axis
What does thyrotrophs secrete?
Thyroid stimulating hormone (TSH)
What does gonadotrophs secrete?
FSH and LH
What does mammotrophs secrete?
Prolactin which initiates lactation in mammary glands
Describe the histology of the posterior pituitary lobe
Essentially neural tissue, mainly non-myelinated axons, pituicytes – glial cells of posterior pituitary lobe
What is the arterial supply of the thyroid gland?
Superior and inferior thyroid artery (from common carotid)
What is the venous drainage of the thyroid gland?
Superior, middle, inferior thyroid vein
What is the importance of the venous drainage of the thyroid gland?
It’s how secretory products are put into the body
Describe the histology of the thyroid gland
Composed of many follicles, stores part of the secretory product.
Follicular cells are a single layer of epithelium around follicles.
Parafollicular cells secrete calcitonin
What do parafollicular cells of the thyroid gland secrete?
Calcitonin
What do follicular cells in thyroid produce and secrete?
Thyroid hormones thyroxine (T4) and triiodothyronine (T3)
Where are the parathyroid glands located?
On the posterior surface of the thyroid gland
What are parathyroid glands contained within?
Connective tissue capsule
How many parathyroid glands are there?
42 superior and 2 inferior
What do the ovaries produce?
Gametes and hormones (progesterone, oestrogen, inhibin, relaxin)
What ligaments are associated w/ the ovaries?
Broad ligament, suspensory ligament, ovarian ligament, round ligament, transverse cervical ligament
When do testes begin to descend into scrotum?
7th month of foetal development
What do the testes produce?
Sperm and testosterone
What does the tunica albuginea surround?
Layer of connective tissue covering the testicles and ovaries
What are seminiferous tubules lined w/?
Sertoli cells (columnar type cell)
What does the scrotum contain?
A pouch that contains 1 testis
What does the spermatic cord connect?
Testis to abdominal cavity
Where is the epididymis found?
Posterior border of each testis
Where is the site for sperm maturation?
Epididymis
What is the histology of the epididymis?
Pseudostratified columnar epithelium
What does the ductus deferens loop over?
The ureter and passes down the posterior side of the urinary bladder
What do the seminal vesicles store and produce?
Some of the liquid portion of semen
What do the seminal vesicles secrete?
Alkaline fluid, fructose, prostaglandins, clotting proteins
What is the function of fructose secreted by seminal vesicles?
ATP production
What is the function of prostaglandins secreted by seminal vesicles?
Contribute to sperm motility and viability
What is the function of alkaline secreted by seminal vesicles?
Help sperm survive acidic environment of the vagina
What is the function of clotting proteins secreted by seminal vesicles?
Help semen coagulate after ejaculation
What are the 2 main muscles of the scrotum?
Dartos – smooth muscle Cremaster – skeletal muscle
What do the muscles of the scrotum do?
Act to regulate temperature of the testes
What does the ductus deferens loop over?
The ureter and passes down the posterior side of the urinary bladder
What do the seminal vesicles store and produce?
Some of the liquid portion of semen
What is the ejaculatory ducts formed from?
Union of the seminal vesicles and ampulla of the ductus deferens
Where does the ejaculatory ducts pass through?
Inferiorly through prostate
What is the blood supply to the reproductive system?
Testes/ovaries – gonadal arteries from abdominal vessels.
Rest – internal pudendal artery from internal iliac artery
What is the corpus spongiosum?
Contains and spongy urethra and keeps it open during ejaculation
What are the corpus cavernosa?
Erectile tissue which contains most of the blood in the penis during an erection
What does the perineum contain?
Anal canalDistal urethra.
External genitaliaSpaces between
What is the bulb?
Posterior continuation of the base of the corpus spongiosum
What encloses the bulb?
Bulbospongiosus muscle
Describe the venous drainage of the male repro system.
Internal pudendal vein (except deep dorsal vein drains into prostate plexus)
What are the 2 pouches in the peritoneal cavity?
Recto-uterine pouch.
Vesico-uterine pouch
What is the endometrium made up of?
Stratum basale – provides base.
Stratum functionale – changes depending on phase
What is myometrium?
The smooth muscle layer of uterus
Describe the arterial supply to the uterus
Aorta – Supplies ovarian branch for ovariesInternal iliac – Gives off uterine, vaginal, and internal pudendal arteries for vagina/uterus
Describe the histology of the cervix
Epithelial transformation zone
- Lower part of cervix – stratified squamous epithelium.
- Upper part – simple columnar epithelium.
In females, what does the internal iliac artery give off?
Uterine, vaginal and internal pudendal arteries
Which artery supplies the ovaries?
Ovarian branch from aorta
Via which nerve is most somatic, motor and sensory info of the uterus transmitted?
Pudendal nerve
Describe the autonomic innervation of the uterus
Parasympathetic – S2-4
Sympathetic – T10-L2
What does the mesonephric duct become?
Ductus deferens
In females, what does the paramesonephric ducts become?
Uterine tubes and uterus
What is the hymen?
A thin membranous covering at distal end of vaginal canal;
Remnant of connection between vaginal canal and urogenital sinus
What is the broad ligament?
2 layers of peritoneum that drapes over the uterus and underneath uterine tubes
What is the significance of the gap between the ovary and infundibulum?
The zygote (after fertilisation) can fall between these cracks and attach to the abdominal cavity rather than the uterus.
Ectopic!
What sits inside the infundibulum?
Ovary
Where does the round ligament attach?
Ovary It runs along rim of the pelvic and passes through inguinal canal, ending up in the labia majora
What does the words ‘anteflexed’ and ‘retroflexed’ mean in relation to the uterus?
Anteflexed – uterus flopped forward to the cervix.
Retroflexed – uterus flopped backwards towards rectum
What is the fornix?
Little gully that goes around edge of cervix
What does the external iliac artery supply?
Lower limbs
Name the 2 openings in the perineal membrane in females
Vaginal opening and urethral opening
How is BMI calculated?
kg/m2
What is obesity linked to?
Poor socio-economic class; deprivation; men; ‘thrifty’ gene
What health conditions is obesity associated w/?
High BP, high glucose, high insulin (insulin resistance), low HDL, high plasma triacylglycerol, high LDL
What is leptin associated w/?
Reducing appetite
Where is leptin secreted from?
Adipose tissue
What is associated w/ increased appetite?
Ghrelin
What is a satiety hormone?
Hormone which is released once you’re fed; reduce appetite
Which structure releases satiety hormones after a meal?
GIT; it reduces appetite
Name 2 satiety hormones
PYY and GLP-1
What does direct calorimetry measure?
Heat output from the body
What does indirect calorimetry measure?
Oxygen consumption
What is type 1 diabetes caused by?
Damage of beta pancreatic cells leads to no insulin production
What is type 2 diabetes?
Insulin resistance.
Efficacy of insulin is reduced and glucose not taken up by muscles and organs leading to hyperglycaemia
What is the benefit of the genes related to type 2 diabetes?
Enabled people in famine environments to survive
Name 2 factors which are key factors for the basis of type 2 diabetes
Foetal and early nutrition – greater extent
Genetic (Mt16189 gene associated w/ insulin resistance) – smaller extent
What forms in the hypophyseal diverticulum?
The pituitary gland
What is the embryonic origin of the anterior pituitary lobe?
Oral ectoderm from roof of mouth
What is the embryonic origin of the posterior pituitary lobe?
Neuro-ectoderm from diencephalon
What is the isthmus?
Where the R and L lobe of the thyroid gland joins
How does the posterior and anterior pituitary gland differ in the way they release products into the bloodstream?
Anterior – neurohormones from hypothalamus enter arterial supply of the lobe, endocrine cells within the anterior lobe secretes products from endocrine cells into venous drainage, e g GH, PR, ACTH, MSH, TSH, FSH, LH.
Posterior – made of neural tissue not endocrine tissue; serves as a site for the secretion of neuro-hypophysial hormones directly into venous blood to body, e g oxytocin, ADH
What do chief cells of parathyroid glands secrete?
PTH – parathyroid hormone
What are parafollicular cells aka and what do they secrete?
Calcitonin, C cells
How does the parathyroid glands differ from the thyroid?
Structurally – para doesn’t have follicles, 4 glands rather 1 bi-lobed glandVasculature usually same
What does the follicular cells of the thyroid secrete?
T4 93%
T3 7%
What are the physiological effects of thyroid hormones on the CV system?
Increased HR, contraction force, CO, peripheral vasodilation
What are the physiological effects of thyroid hormones on the CN system?
Needed for normal brain development (cerebellar growth and nerve myelination), normal intellectual development in infants, emotional stability in adults
What is the effects of thyroid hormone on RR?
Increases RR and depth of respirations
How do thyroid hormones effect growth?
Indirectly promotes growth formation by actions on the pituitary gland; acts synergistically w/ growth hormone and other growth factors that promote bone formation
What effects do thyroid hormones have on the GI?
Increases appetite, secretion of digestive juices, gastric motility
What effect does PTH have on the intestine, kidney and bone?
Intestine – increases calcium absorption from food Kidney – promotes activation of vitamin D and ↑ Ca reabsorptionBone – activates osteoclasts; Ca2+ and K+ released into blood
What hormone is released in response to hypocalcaemia?
Parathyroid hormone (PTH)
Where are parathyroid glands located relative to thyroid gland?
Posterior, 2 on each side
Where is the thyroid gland located?
Anterior to the trachea, below and lateral to thyroid cartilage, wraps around the cricoid cartilage
What is the arterial supply of the thyroid gland?
Superior thyroid artery – a branch of external carotid artery.
Inferior thyroid artery – a branch of thyrocervical trunk
What is the venous drainage of the thyroid gland?
Superior and middle thyroid vein – into internal jugular vein.
Inferior thyroid vein – drains into L and R brachiocephalic veins
How does PTH act on the renal system?
Promotes renal Ca2+ and PO43- reabsorption
How are thyroid hormones synthesised?
In follicles, iodine added into tyrosine residues at thyroglobulin (where synthesis of TH takes place)
What is thyroid peroxidase?
Catalyses ionisation of tyrosine residues (production of TH)
What would happen is thyroid peroxidase is inhibited?
Autoimmune hypothyroidism
List the signs of hypothyroidism
Dry and scaly skin, dry and thin hair, puffy eyes, anaemia
What is the thyroid gland composed of?
Follicles (main secretory cells) – functional units of thyroid; secrete thyroid hormones and store TH in colloid within follicles.
C cells – less numerous and larger (secrete calcitonin)
What hormone inhibits osteoclast activity in bone?
Calcitonin – from follicular cells of thyroid gland
How does calcitonin act on the renal system?
Inhibits renal Ca2+ and PO43- reabsorption
What is diabetes insipidus?
Low levels of vasopression leading to polyuria.
Treat with desmopressin (vasopressin analogue)
Which 2 hormones control growth hormone secretion?
GHRH – increases GH from anterior pituitary.
Somatostatin – inhibits GHRH-mediated GH release
What is Addison’s disease?
Autoimmune primary adrenal insufficiency leading to.
Hypocortisolism
What is Cushing’s disease?
Secondary hypercortisolism (due to pituitary tumour)
What is Cushing’s syndrome?
Primary excess cortisol (hypercortisolism)
What is primary hyperparathyroidism?
Overactive parathyroid glands –> hypercalcaemia
How does carbimazole (treats hyperthyroidism) work?
Reduces TH synthesis by inhibiting thyroperoxidase which normally iodinates tyrosine residues in thyroglobulin to give the precursors of T3 and T4
What is the epidemiology of hypothyroidism and hyperthyroidism?
More prevalent in. women
How is hyperthyroidism treated?
Medication – carbimazole (thionamides) interfere w/ thyroid hormone production
Radioactive iodine – Destroys part of the gland by emitting X rays and beta radiation that is cytotoxic to local thyroid cells.
Surgery – reduces amount of functioning thyroid tissue
What controls the regulation of thyroid hormone secretion?
HPT – axis controls thyroid hormone releaseH - secretes TSH.
Anterior pit - secretes THT - secretes T3 and T4; inhibits hypothalamus and anterior pit secretions
How does hyperthyroidism affect TSH, T4 and T3 levels?
TSH – decrease and T4 and T3 – increase
What usually causes primary hyperparathyroidism?
Single benign parathyroid adenoma
What is the tail of the pancreas also known as?
Splenic end
What is the head of the pancreas also known as?
Duodenal end
What happens when pancreas is removed from the body?
It digests itself within 30 seconds
What causes insulin dependent diabetes mellitus?
Destruction of beta pancreatic cells
What is the endocrine pancreas surrounded by?
Exocrine pancreas
Which type of pancreas has large nuclei?
Endocrine
What does exocrine pancreas secrete?
Bicarbonate (pH buffer).
Zymogens – inactive precursor to enzymes
E.g. pepsinogen, trypsinogen Enzymes – food digestion
What does endocrine pancreas secrete?
Insulin, glucagon, somatostatin – regulate blood glucose levels.
Pancreatic polypeptide – induces hunger
What are intercalated ducts?
Portion of the exocrine gland leading directly from the acinus to striated ducts. Forms part of the intralobular duct
What is the function of intercalated ducts?
Makes and released bicarbonate into the duct via ductal cells which buffers acidic environment to optimal pH for enzyme function
What is secretin?
A hormone that regulates water homeostasis and secretions in the stomach and duodenum
Which cells produce secretin?
S cells in duodenum
What causes cystic fibrosis?
Frameshift mutation in the CFTR channel gene
What does CF cause?
No movement of Cl- into cell and expulsion of HCO3- and H2O
- Forms thick, viscous secretions that block exocrine movement of digestive enzymes Leads to LT fibrosis (collagen in pancreas)
What is CCK?
Cholecystokinin.
A hormone released from duodenum; acts on the pancreas; responsible for digestion of fat and protein
Which hormone binds to acinus cells and triggers digestive enzyme release?
CCKProduced when food is in stomach
What is pancreatin?
Drug used as substitute to natural enzymesIt is used for digestion of fat and protein
What do pancreatic delta cells produce?
Somatostatin – growth hormone
What do pancreatic alpha and beta cells produce?
Alpha – glucagonBeta – insulin
What do pancreatic epsilon cells produce?
Ghrelin which increases appetite
What do PP cells secrete?
Pancreatic polypeptide
Which endocrine pancreatic cells are more common?
Insulin-secreting beta-cells
Which organ doesn’t have insulin receptors?
Brain.
Glucose uptake not controlled by insulin
Upon release from the pancreas where does insulin travel and act?
Enters portal circulation and is carried to the liver Liver – prime target organ
Where does the proportion of insulin not broken down in the liver go?
Kidneys
In which 2 forms does insulin exist in?
Hexametric (inactive) and monomeric (active)
Where is hexametric insulin stored?
Secretory granules
In hexametric insulin, what holds together the 6 insulin molecules?
Central zinc moleculeHistidine bonds
Why does monomeric insulin have a high diffusion rate?
Because it’s a small molecule
What is insulin synthesised as?
A single 22aa polypeptide chain called pre-proinsulin
What does CCK do to hunger?
Suppresses it
What signal releases insulin from granules to blood?
Vagal nerve stimulation
Name the 29aa polypeptide produced by alpha cells
Glucagon
What is glucagon cleaved into in intestinal L cells?
GLP-1 (an incretin), GLP-2 (promotes intestinal growth), IP-2
What is GLP-1?
Glucagon like peptide 1
What is the function of incretin hormones?
Reduce appetite by acting on hypothalamus, Slow gastric emptying,Reduce glycogenolysis, Stimulates insulin secretion
How is type 2 diabetes controlled?
Anti-hyperglycaemic agents:
- Metformin
- Sulphonylureas
- Glitazones- GLP-1 agonist
- DPP-4 inhibitor
- Insulin analogues
What does incretin promote?
Satiety and reduces appetite
What is metformin?
Biguanide
How does metformin work?
Improves insulin resistance in skeletal muscles and liver so more glucose uptake In GIT prevents glucose absorption leading to lowering blood glucoseDecreases gluconeogenesis and glycolysis
What are side-effects of metformin?
Lactic acidosis – rare but 50% mortality rate once acquired.
Vitamin B12 deficiency – LT
What are PPAR γ agonists?
Peroxisome proliferator-activated receptor agonists.
Nuclear receptor that modulates transcription of insulin sensitising genes and insulin sensitised in liver, muscles and adipose tissue
What is the pampiniform plexus?
Venous network in the scrotum; drains testes to testicular vein
What do theca cells correspond to in males?
Leydig cells (found in males)
What do sertoli cells correspond to in females?
Granulosa (found in females)
How does sildenafil work?
Phosphodiesterase (E5) inhibitor PDE5 is inhibited in cavernosal smooth muscles through 2nd messengers he smooth muscle contracts and penis becomes erect
Name 3 drugs for erectile dysfunction
- Phosphodiesterase (E5) inhibitors – sildenafil
- Prostaglandin-E1 agonists – alprostadil
- Dopamine receptor agonists – apomorphine
Why is oxytocin important in pregnancy?
Contracts uterine muscles (delivery), and breast muscles (milk)
