The reproductive system and sex hormones Flashcards
What does seminal fluid contain?
Bicarbonate and fructose.
What is the function of bicarbonate in seminal fluid?
Neutralise acidic environment in female vagina.
What does the spermatic cord contain?
Testicular artery, lymph vessels and vas deferens.
What is the function of vas deferens?
Carry sperm from testes to penis.
What nerves result in an erection? How does it result in an erection?
Parasympathetic. Dilates arteries in penis. More blood and less venous drainage leads to an erection.
What nerves result in ejaculation?
Sympathetic nervous system.
What lymph nodes drain lymph from testes and ovaries?
Para aortic lymph nodes.
What lymph nodes drain uterus and vagina?
Sacral and para aortic lymph nodes.
How are fallopian tubes adapted?
Contain cilia and spiral muscle. Waft egg.
Where does fertilisation occur?
Ampulla (widest part of fallopian tubes).
What causes endometrium to shed?
Vasoconstriction of arteries supplying it due to drop in progesterone.
What part of the female reproductive system is not sterile?
Vagina
What part of the female reproductive system is sterile?
Superior to cervix.
Where is sperm produced in the testes?
Seminiferous tubules.
What are the two main cells in the seminiferous tubules?
Leydig cells (between seminiferous tubules) and sertoli cells.
What are some androgens?
Testosterone, androstenedione and DHT.
What does inhibin do?
Suppresses FSH.
What does activin do?
Stimulates FSH.
What is a germ cell?
Cell that gives rise to gametes
What receptors do sertoli cells contain?
FSH receptors.
What do sertoli cells do? How do they do it?
Support developing germ cells.
- Assist movement of germ cells to tubular lumen
- Transfer nutrients from capillaries to developing germ cells
- Phagocytosis of damaged germ cells
What hormones do sertoli cells produce?
Inhibin and activin. Anti-mullerian hormone. Androgen binding hormone.
What receptors do leydig cells contain?
LH receptors.
What is the function of leydig cells?
Hormone synthesis.
Why are leydig cells pale?
Cholesterol rich.
What stimulates hormone synthesis in leydig cells?
LH binding to leydig cells.
What are some hormones produced by leydig cells?
Testosterone, androstenedione.
What are polar bodies?
Cytoplasmic structures shed during meiotic division during oogenesis.
What is menarche?
First menstrual period.
When does 2nd meiosis division and differentiation of oocytes occur?
After sperm fusion.
Simple pathway for folliculogenesis?
Ovarian follicle to oocyte to corpus luteum.
Describe folliculogenesis?
Primordial follicle to primary follicle. Primary follicle contains layers of granulosa and theca cells. Development of secondary follicle; contains fluid filling cavity, FSH and LH receptors. Surge of LH results in development of mature follicle. Follicle ruptures allowing ovum to leave. Formation of corpus luteum which produces progesterone and oestrogen.
What is secreted after fertilisation to keep corpus luteum alive?
hCG.
What does the female hormome relaxin do?
Relaxes muscles during pregnancy.
What do theca cells do?
Provides structural support of growing follicle. Androgen synthesis.
What stimulates theca cells?
LH stimulates theca cells to produce androgens.
What do overactive theca cells result in?
High androgen.
What occurs in granulosa cells?
Aromatisation.
What stimulates granulosa cells?
FSH.
How do granulosa cells regulate FSH?
Secretion of inhibin and activin.
What occurs to granulosa cells after ovulation?
Formation of corpus luteum. Granulosa lutein cells inside the corpus luteum produce the hormone progesterone which maintains the endometrium. They also produce relaxin.
What happens to the Hypothalamic-Pituitary-Gonadal (HPG) Axis during ovulation?
Switch to positive feedback due to rise in oestrogen.
What hormones part of Hypothalamic-Pituitary-Gonadal (HPG) Axis can you not measure in blood and why?
Kisspeptin and GNRH. Part of local circulation; present in too little concentration in systemic circulation.
Describe Hypothalamic-Pituitary-Gonadal (HPG) Axis
Kisspeptin stimulates GnRH release; this occur in the hypothalamus. GnRH acts on gonadotrophs in anterior pituitary gland to produce LH and FSH. LH and FSH target gonads. Gonads produce oestrogen, progesterone and androgens; inhibit LH/FSH and GnRH release.
How is GnRH, LH and FSH released?
Pulsatile release.
Explain Hypothalamic-Pituitary-Gonadal (HPG) Axis in hyperprolactinaemia.
Prolactin inhibits kisspeptin. Decrease in downstream hormones - GnRH, FSH, LH, Testosterone, oestrogen.
Symptoms of hyperprolactinaemia
Amenorrhoea, low libido and osteoporosis.
How do you check if a woman has ovulated?
Day 21 progesterone test (High = has ovulated). Ultrasound.
Where does seminal fluid come from?
Seminal vesicles, prostate, bulbourethral glands.
What is capacitation?
Prerequirement for fertilisation.
Process of sperm capacitation
Loss of glycoprotein coat. Develop whiplash movements of tail.
What is required for sperm capacitation?
Calcium and oestrogen.
Describe the acrosome reaction
Sperm binds to ZP3 receptor on ovum. Ca2+ influx into sperm stimulated by progesterone. Release of proteolytic enzymes from acrosome that break down glycoprotein coat around ovum. Sperm can now penetrate zona pellucida.
What occurs in fertilisation?
Haploid to diploid. Triggering of cortical reaction.
Describe the cortical reaction
Cortical granules release molecules which degrade zona pellucida. Prevents further sperm binding as no receptors.