reproductive system Flashcards
1
Q
- What is the function of the epididymis?
- What does the seminal fluid contain?
A
Transports, stores and matures spermatozoa produced in testes
Bicarbonate (neutralise vaginal acidity), fibrinogen, fructose, citrate and fibrinolytic enzymes
2
Q
- What does the bulbo-urethral gland secrete?
- Which nervous systems stimulate erection and ejaculation?
A
Sugar-rich mucus into urethra for lubrication and contribute to pre-ejaculatory emissions from penis (seminal fluid)
Erection - Parasympathetic Ejaculation - Sympathetic
3
Q
- Why is the testes suspended in the the scrotum?
- Where is the spermatic cord formed and what does it contain?
A
Keep temperature 2-3 degrees lower than body
If temperature increases then sperm production ceases
formed at the deep inguinal ring Contains the testicular artery, pampiniform plexus (V), autonomic and GF nerves, lymph vessels and the vas deferens
4
Q
- What is the vas deferens?
- List the muscles of the penis
A
Tube from epididymis into seminal vesicle transporting mature sperm
2x Corpora cavernosa 1x Corpora spongiosum
5
Q
- Outline the arterial blood supply and lymphatic drainage of the testes
- Which connective tissue layer of the testes contains blood vessels?
- Which organ can allow male sterilisation by vasectomy?
A
Arterial blood supply - Testicular arteries from the aorta via spermatic cord
Lymphatic drainage - Para-aortic lymph nodes
Tunica vasculosa
Vas deferens (minimal incision required)
6
Q
- What do the ovaries sit inside?
- Where does fertilisation usually occur?
- Which muscles is the uterus supported by?
A
Peritoneal cavity (remainder of organs outside)
Ampulla (widest section) of the fallopian tube
Levator ani and coccygeus (tone of pelvic floor) and ligaments (broad, round, uterosacral)
7
Q
- What does the fallopian tube have that helps to move the oocyte down the tube?
- What is the uterus lined by?
- List the layers of the uterus
A
Cilia and spiral muscle (If motility of oocyte is slow then susceptible to ectopic pregnancy)
Endometrium
Perimetrium, myometrium (smooth muscle layer sensitive to hormones) and endometrium
8
Q
- Which layer of the uterus is shed during menses and why?
A
Endometrium
Due to vasoconstriction of arterioles
causes Ischaemia/necrosis
which causes shedding and haemorrhage of menstruation
9
Q
- Outline the arterial blood supply and lymphatic drainage of the ovaries and uterus/vagina
A
Arterial blood supply:
Ovaries → Ovarian arteries from aorta Uterus/vagina → Uterine arteries (from internal iliac artery) Lymphatic drainage: Ovaries → Para-aortic LNs Uterus/vagina → iliac, sacral, aortic and inguinal LNs
10
Q
- How much mature sperm is produced per second?
- Explain why in general, men are continuously fertile?
A
Around 1500
Spermatogonia undergo differentiation and self-renewal
pool available for subsequent spermatogenic cycles throughout life
11
Q
- Before birth, describe how the number of female gametes changes?
A
Multiplication of Oogonia to 6 million/ovary
Form Primary Oogocytes within ovarian follicles (=primordial follicles) These begin meiosis Some primordial follicles degenerate (atresia) At birth 2 million/ovary remain
12
Q
- Describe the process of spermatogenesis
A
Diploid germ cell (spermatogonium) divides to form diploid Primary Spermatocytes via mitosis
Diploid Primary Spermatocytes divide via meiosis to form Haploid Secondary Spermatocytes Haploid Secondary Spermatocytes undergo 2nd meiotic division to form Haploid Spermatids Haploid Spermatids differentiate to form Haploid Spermatozoa
13
Q
- Which reproductive hormones are released by the Testes?
A
Androgens
Testosterone Dihydrotestosterone Androstenedione Inhibin + Activin (for FSH production regulation) Oestrogens (from androgen aromatisation)
14
Q
- What are the names of the cells that have FSH and LH receptors respectively?
A
Sertoli - FSH receptor
Leydig - LH receptor
15
Q
- How do Sertolil cells support developing germ cells?
- Which hormones are synthesised by Sertoli cells?
A
Assist in movement of germ cells to tubular lumen
Transfer nutrients from capillaries to developing germ cells
Phagocytosis of damaged germ cells
Inhibin & Activin
Anti-Mullerian Hormone (AMH)
Androgen Binding Protein (ABP)
16
Q
- On LH stimulation, which androgens are secreted by Leydig cells?
A
Testosterone
Androstenedione Dehydropiandrosterone (DHEA)
17
Q
- what are the stages of Oogenesis occur?
A
In second trimester of pregnancy, all Diploid Oogonia in foetus develop into Diploid Primary Oocytes (forming primordial follicles) by mitosis
By Menarche, the Primary Oocytes divide into Haploid Secondary Oocytes via meiosis Secondary Oocytes are divided into Haploid Ootids via meiosis Ootids differentiate into Ova
18
Q
- Describe the steps involved in folliculogenesis
A
- Primordial follicle (Primary Oocyte at birth)
- becomes a Primary (Preantral) follicle, which is a Primary Oocyte with layers of granulosa cells and outer theca cells
- It then becomes a Secondary (Antral) follicle, where a Fluid-filled cavity (antrum) forms, and it develops FSH and LH receptors
- it matures to a Mature (Graafian/Preovulatory) follicle, forming due to a LH surge Secondary Oocyte is formed by this stage.
- ovum Ruptures surface of ovary
- Corpus Luteum, secretes Progesterone and oestrogen (stim by LH/HCG). In pregnancy, progesterone and oestrogen production taken over by placenta
19
Q
- What reproductive hormones are produced by the ovaries?
A
Oestrogens
- Oestradiol - Oestrone - Oestriol
Progestogens
- Progesterone
Androgens
- Testosterone - Androstenedione - DHEA (not in adrenals)
Relaxin
Inhibin
20
Q
- How do Theca cells support folliculogenesis?
- What hormones are produced by the Theca cells
- What is the name of the condition caused by increased androgen production by Theca cells?
- where are theca cells in ovarian follicles
A
Structural and nutritional support of growing follicle
LH stimulates synthesis of androgens Polycystic Ovary Syndrome
outer part
21
Q
- Which hormones are produced by the granulosa cells (pre ovulation) ?
- What function do granulosa cells have after ovulation?
A
FSH stimulates granulosa cells to convert androgens to oestrogens by aromatase
Secrete Activin and Inhibin
Turn into granulosa lutein cells that produce: Progesterone (-ve feedback, promote pregnancy by maintaining endometrium) Relaxin (helps endometrium prepare for pregnancy and softens pelvic ligaments/cervix)
22
Q
- Describe the Hypothalamic-Pituitary-Gonadal (HPG) Axis
A
Kisspeptin neurons in the hypothalamus release kisspeptin
Kisspeptin stimulates the release of GnRH in the hypothalamus GnRH travels through the Hypophyseal-Portal Circulation to the Anterior Pituitary GnRH Binds to Gonadotrophs to stimulate the release of LH and FSH LH and FSH travels in systemic circulation to the testes in men and ovaries in women to produce testosterone and oestrogen respectively Oestrogen/progesterone leads to negative feedback against GnRH in hypothalamus and LH and FSH in the gonadotrophs
23
Q
- Can GnRH be detected in blood tests?
- When should Testosterone levels be tested?
A
No, because it is only released locally into the hypophyseal circulation and not the systemic circulation
In the morning as they are the highest here
24
Q
- How does Hyperprolactinaemia inhibit Kisspeptin Neurons?
What are the consequences of this?
A
Prolactin binds to prolactin receptors on the kisspeptin neurons in the hypothalamus
Inhibits kisspeptin release
Decreases in downstream GnRH/LH/FSH/T/Oest Leading to oligo (>35d menses) or amenorrhea (3-6m no menses) / Low libido / Infertility / Osteoporosis
25
What are the three main stages of Ovulation stage
Follicular Phase: Primordial follicle, primary follicle, Secondary follicle, Mature follicle
Ovulation - This surge of FSH and LH causes a rupture of the ovarian follicle and the Oocyte is released
Luteal Phase → Corpus Luteum → Regression → Corpus Albicans
26
- What are the Hormone changes during the Follicular Phase
FSH increases from days 1-7 as it can bind to the FSH receptors on the granulosa cells to produce aromatase
LH binds to LH receptors on the Theca cells to produce Androstenedione which is converted into Oestrogen by Aromatase
Oestrogen negatively feedbacks to reduce the FSH and LH released by the Anterior Pituitary
Follicle with most FSH receptors at this point continues to grow (Dominant Follicle) and the rest die off
Dominant follicle produces more oestrogen and this positively feedbacks to produce more LH and FSH
27
- what are the Hormone changes during Luteal phase
Hints:
- luteinised theca and granulosa cells
- progesterone
- inhibition
- corpus luteum to albican
The remenants of the ovarian follicle forms a Corpus Luteum which is made up of leutinised theca and granulosa cells which continue forming androstenedione and oestrogen
Leutinised Granulosa cells increase the activity of enzymes responsible for converting cholesterol into pregnenolone so more Progesterone is produced than oestrogen
Progesterone inhibits the release of LH and FSH
Leutinised Granulosa cells also release inhibin which reduces the secretion of FSH
Since less Oestrogen is produced, Progesterone becomes the dominant hormone in the luteal phase
Corpus Luteum → Corpus Albicans which doesn't make hormones so low oestrogen and progesterone so spiral arteries collapse and functional layer of endometrium sheds
28
- Describe the three stages of the uterine cycle
Menstrual phase - Old Endometrial lining sheds and causes menstrual bleeding (5 days)
Proliferative Phase - High Oestrogen levels stimulate: thickening of endometrium, growth of endometrial glands and emergence of spiral arteries, raises lining of cervical mucus (more hospitable to sperm) - Day 11-Day 15
Secretory Phase - High progesterone so: spiral arteries grow longer and uterine glands secrete more mucus (thickens - less hospitable for sperm) - After day 15, window for fertilisation starts to close
29
- Does body temperature increase after ovulation?
- How much of its length does a sperm travel from the Testis to the Fallopian tube?
- Proportionally approximately how many spermatozoa reach the ovum?
Body temperature increases by at least 0.5 degrees Celcius due to Progesterone
100,000x its length
1 in a million
30
- Where is Seminal Fluid released from?
Mainly from Accessory Sex Glands
Seminal Vesicles
Prostate
Bulbourethral glands
Small contribution from epididymis/testis
31
- What is the purpose of the bicarbonate in the seminal fluid?
- What is the purpose of the Capacitation of sperm?
Neutralises the vaginal pH
Achieve fertilising capability in the female reproductive tract
32
- What occurs in the Capacitation of sperm?
- Where does the Capacitation of Sperm occur?
- What 2 chemicals is the Capacitation of Sperm reliant on?
Loss of glycoprotein 'coat'
Change in surface membrane characteristics
Develop whiplash movements of tail
In ionic and proteolytic environment of the Fallopian tube
Oestrogen
Ca2+
33
- Describe the Acrosome Reaction?
Sperm binds to ZP3 (Sperm receptor)
Ca2+ influx into sperm stimulated by progesterone
Release of hyaluronidase and proteolytic enzymes from acrosome
Spermatozoon penetrates the Zona Pelllucida
34
- What triggers the cortical reation?
| - What is the cortical reaction?
Fertilisation
cortical granules release molecules which degrade the Zona Pellucida after sperm enters ovum
there are no receptors so any further binding of sperm to ZP2 or ZP3 is prevented
35
- What is meant by the conceptus?
- What occurs in the Attachment phase of Implantation?
- What occurs in the Decidualisation phase of Implantation?
The conceptus includes all the structures that develop from the zygote, both embryonic and extraembryonic
Outer trophoblast cells contact uterine surface epithelium
Changes in underlying uterine stromal tissue
36
What happens during the development of the conceptus and how long does this phase last?
Moves down the fallopian tube for 3-4 days while it continues dividing
receives nutrients from uterine secretions
free living phase for 9-10 days
37
- What hormones do both phases of Implantation of the blastocyst require?
- During the attachment of the blastocyst to the endometrial lining, what are the factors involved that aid this adhesion?
Progesterone domination in the presence of oestrogen
Leukaemia Inhibitory Factor (LIF)- stimulates adhesion of blastocyst to endometrial cells
Interleukin-11 (IL-11)
Sometimes HB-EGF
38
- How does the endometrial (Decidualisation) change due to progesterone?
Glandular epithelial secretion
Glycogen accumulation in stromal cell cytoplasm
increases the nutrients available to a potential implanted embryo due to growth of capillaries
Increased vascular permeability (oedema) favours passage of nutrients and oxygen to the potential implanted embryo
39
- What factors are involved in the Decidualisation phase?
IL-11, Histamine, Certain Prostaglandins, TGFb (promotes angiogenesis)
40
- In the first 40 days how is oestrogen and progesterone produced during pregnancy?
- From day 40 of pregnancy how is progesterone and oestrogen produced?
Produced in corpus luteum
Stimulated by hCG (produced by trophoblasts) which act on LH receptors
Inhibits LH and FSH so no periods
By the Placenta
41
- Which hormones are increased during pregnancy?
AAPPII
ACTH - placental synthesis and release of biologically active CRH
Adrenal Steroids
Prolactin - increased lactotrophs in response to physiological need to develop breast tissues and to prepare for milk production
PTH related peptides - provides Ca2+ for growth of bone
IGF1 - stimulated by placental GH variant
Iodothyronines (T4 and T3)
AA PP II
42
- Which hormones are decreased during pregnancy?
LH and FSH: due to negative feedback from Progesterone
Pituitary GH - Placenta makes own GH
TSH - hCG has same alpha sub-unit as TSH so similar structure and less TSH needed
43
- What processes does oxytocin stimulate during partruition?
- What is Prolactin responsible for when there is a suckling stimulus on the nipple?
- What is Galactorrhea a symptom of?
Uterine contraction
Cervical dilation
Milk ejection
Milk production
Hyperprolactinaemia
