The Reproductive System

Question 1

Male germ cell levels

Answer 1

Gametogenesis begins at puberty
Constantly fertile as spermatogonia occurs
1500 sperm made per second d

Question 2

Female gamete changes

Answer 2

• Before birth, multiplication of oogonia to 6 mil/ovary
• Form primary oocytes within ovarian follicles which begin meiosis (halted in prophase)
• Some primordial follicles degenerate (atresia) leaving 2 million/ovary at birth
• Due to further atresia, by puberty 0.5 mil/ovary remain

Question 3

Spermatogenesis

Answer 3

Spermatogonium (diploid) → Primary Spermatocyte (diploid) → Secondary Spermatocyte (haploid) → Spermatids (haploid) → Spermatozoa (haploid)

Question 4

Where does spermatogenesis occurr

Answer 4

Seminiferous tubules
These are made of tunica propria which are several layers of flattened cells

Question 5

Why hormones are replaced by testes

Answer 5

1. Androgens
   
   • Testosterone
   • Dihydrotestosterone (DHT)
   • Androstenedione
2. Inhibin + Activin (for FSH production regulation)
3. Oestrogens
   Aromatherapy converts androgen too estrogen

Question 6

Sertoli cells

Answer 6

FSH receptors in seminiferous tubules
Makes inhibin and activin
Anti mullerian hormone which aid regression of mullerian ducts
Androgen binding proteins direct testosterone from leydig cells

Question 7

How do Sertoli cells support developing germ cells

Answer 7

Assist in movement of germ cells to tubular lumen

Transfer nutrients from capillaries to developing germ cells

Phagocytosis of damaged germ cells

Question 8

Leydig cells

Answer 8

Found between seminiferous tubules
LH receptors
Have a pale cytoplasm because it’s cholesterol rich
Releases testosterone androstenedione and dehydroepiandrosterone

Question 9

What makes up semen

Answer 9

• 15-120 mil/ml spematozoa
• 2-5ml seminal fluid
• leukocytes
• potentially viruses like hep B, HIV

Question 10

What path do spermatozoa take after the testis?

Answer 10

Into efferent ducts where tubular fluid is reabsorbed induced via estrogen
Then Exeter epididymis where nutrients and glycoproteins are this is induced by androgen

Question 11

Oogenesis

Answer 11

Oogonium (diploid) → Primary Oocyte (diploid) → Secondary Oocyte (haploid) → Ootids (haploid) → Ova (Ovum singular) (haploid)

Question 12

Polar bodies

Answer 12

Small haploid cells with virtually no cytoplasm as oocyte cytoplasm doesn’t divide evenly- they undergo apoptosi

Question 13

Describe the steps involved in folliculogenesis

Answer 13

1) Primordial follicle (primary oocyte at birth)

2) Primary (aka preantral) follicle → primary oocyte and layers of granulosa and outer theca cells

3) Secondary (aka antral) follicle → fluid-filled cavity (antrum) develops

4) Mature (aka Graafian/preovulatory) follicle → secondary oocyte formed

5) Ruptured follicle, ruptures surface of ovary

6) Corpus Luteum → produces progesterone and oestrogen (stimulated by LH/hCG) and in pregnancy, production of these is taken over by placenta

Question 14

When does mature follicle for

Answer 14

During LH surge

Question 15

• What reproductive hormones are produced by the ovaries?

Answer 15

Oestrogens

Oestradiol

Oestrone

Oestriol

Progestogens

Progesterone

Androgens

Testosterone

Androstenedione

DHEA (not the DHEAS made in adrenals)

Relaxin

Inhibin

Question 16

Granulosa cells

Answer 16

Associated with inner ovarian follicles
FSH receptors
Stimulates androgen conversion into oestrogen
After ovulation turn into granulosa lutein cells which. Make progesterone and relaxin

Question 17

What does progesterone do

Answer 17

(-ve feedback, promote pregnancy by maintaining endometrium)

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Question 18

What does relaxin do

Answer 18

helps endometrium prepare for pregnancy and softens pelvic ligaments/cervix)

Question 19

Theca cells

Answer 19

Outer part of ovarian follicles
LH receptors
Support folliculogenesis by structural and nutritional support

Question 20

Overactivity of theca cells

Answer 20

Hyperadrogenism due to PCOS

Question 21

What are two made gonadal hormones

Answer 21

Oestradiol
Testosterone

Question 22

Hypothalamic pituitary gonadal axis

Answer 22

Kisspeptin neurones release kisspeptin→ GnRH (Gonadotrophin releasing hormone) (travels down Hypophyseal-Portal Circulation to the Anterior Pituitary)→ LH/FSH (released from Gonadotrophs of anterior pituitary)→ Gonads (target glands)→ oestrogen/progesterone/androgen (target hormones)

Question 23

How does hyperprolactinaemia affect the pathway

Answer 23

Prolactin binds to prolactin receptors on kisspeptin inhibiting it’s release
Leads to oligomenorrhoea or amenorrhea low libido infertility or osteoporosis

Question 24

What kind of release does GnRH and FSH + LH have

Answer 24

Pulsatile release

Question 25

Can GnRH be detected in blood tests?

Answer 25

No, because it is only released locally into the hypophyseal circulation and not the systemic circulation

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Question 26

Capacitation of sperm

Answer 26

Loss of glycoprotein coat
Change in surface membrane characteristics
Develop whiplash movements of tails
Oestrogen dependent
Ca2+ dependent

Question 27

Acrosome reaction

Answer 27

Sperm binds to ZP3
Calcium influx into sperm stimulated by progesterone
Release of hyaluronidase and proteolytic enzymes
Spermatazoon penetrates zona pellucida

Question 28

Implantation

Answer 28

Attachment phase where outer trophoblast cells contact uterine surface epithelium and then decidualisation phase where changes in underlying uterine stromal tissue occur
Needs progesterone domination

Question 29

What promotes attachment

Answer 29

Leukaemia inhibitory factor from endometrial cells stimulates adhesion of blastocyst to endometrial cells
Interleukin 11 is released into uterine fluid

Question 30

What is the substrate for oestrogen

Answer 30

DHEAS made by mother and fetus

Question 31

Endocrine control of lactation

Answer 31

Stimulation causes hypothalamus to be activated and pituitary causes neurohypophysis which releases oxytocin and adenohypophysis releases prolactin

Question 32

How does deciduoaistaion change due to progesterone

Answer 32

Glandular epithelial secretion

Glycogen accumulation in stromal cell cytoplasm

Growth of capillaries increases the nutrients available to a potential implanted embryo

Increased vascular permeability (→ oedema) to increase nutrients and O2 going to potential implanted embryo

Question 33

What 4 factors are involved in decidualisation phase

Answer 33

• IL-11
• Histamine,
• Prostaglandins
  TGFbbeta which promotes angiogenesis

Question 34

the first 40 days how is progesterone and oestrogen produced during pregnancy?

Answer 34

Produced in corpus luteum

Stimulated by hCG (which is produced by trophoblasts) which act on LH receptors of corpus luteum (since hCG is similar to LH)

Essential for developing fetoplacental unit

Inhibits LH and FSH so no periods

Question 35

From 40 days onwards how is progesterone and oestrogen produced

Answer 35

By placenta
Main substrate is DHEAS made by mother and fetus

Question 36

What (6) maternal hormones increase in pregnancy?

Answer 36

• ACTH, meaning raised urinary free cortisol (UFC)
• Adrenal steroids
• Prolactin- suppresses HPG axis
• IGF-1 (Stimulated by placental GH)
• Iodothyronines due to increased requirement- driven by hCG which has same alpha subunit as TSH- leads to lower TSH
• PTH related peptides- produced mainly in breast tissue and can increase Ca2+ for foetal skeleton

Question 37

What (3) effects does oxytocin have on pregnant women (What processes does oxytocin stimulate during parturition)?

Answer 37

• Uterine contraction- with increased numbers of oxytocin receptors in late pregnancy
• Milk ejection
• Cervical dilation

Question 38

Name a condition related to milk production, that hyperprolactinaemia can cause?

Answer 38

You get excess milk production and can get galactorrhoea- leaking of milk even outside of pregnancy

Question 39

Male reproductive system

Answer 39

Testes make sperm and testosterone
Epididymis stores and matures sperm as well as absorbing fluid to concentrate sperm
Seminal vesicles make seminal fluid which nourishes sperm
Vas deferens transports mature sperm from epididymis to urethra during ejaculation

Question 40

Female reproductive

Answer 40

The ovaries produce eggs (ova) and hormones such as estrogen and progesterone. The fallopian tubes (oviducts) capture the released egg during ovulation and provide a site for fertilization to occur. Ovulation is indeed triggered by a surge in luteinizing hormone (LH). If fertilization does not occur, the thickened lining of the uterus (endometrium) is shed during menstruation, along with the unfertilized egg.

Question 41

Human placental lactogen

Answer 41

Made by placenta and modulates maternal metabolism to provide nutrients for fetus eg causes insulin resistance so more insulin is circulating for fetus