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s4 - Repro, Develop, Ageing, Pharm > REPRO - Male > Flashcards

REPRO - Male Flashcards

1
Q

What is the normal volume of the testes, measured using?

A
  • 15-25ml

- Orchidometer

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2
Q

Where in the testis does spermatogenesis occur?

A

-Semineferous tubules

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3
Q

Sperm develop between the Sertoli cells, what happens to the spermatogonium (1ry germ cells) at the inner edge of the tubule?

A
  • They divide by mitosis to increase in number lots

- Some commit to meiosis to develop into sperm, and enter lumen to rete testis-epidid-release

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4
Q

What do the leydig cells outside the tubule produce?

A

Testosterone

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5
Q

What type of cell are Sertoli Cells?

A

Tall, columnar endothelial cells that make up the wall of the sn. tubules

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6
Q

What makes the adluminal compartment in the sn lobule?

A

-tight junctions between sertoli cells that keep developing sperm in confined compartments

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7
Q

The luminal compartment, interstitial space on outside and adluminal compartment form what immunity structure?

A
  • blood-testis barrier

- so immune system never contacts gametes

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8
Q

What may compromise the blood-testis barrier leading to subfertility?

A

-Vasectomy as testis leaks into circulation, antibodies against own sperm

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9
Q

What are A vs B spermatogonia?

A

A divide mitotically to replenish themselves

B are commited to meiosis

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10
Q

Spermatogenesis goes through a new cycle every 16 days, how many days does the process take

A

apporx 74

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11
Q

What are the 3 stages of spermatogenesis?

A
  • mitotic proliferation of spermatogonia
  • meiosis and development of spermatocytes
  • spermiogenesis, elongation, loss of cytoplasm
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12
Q

Each cell division of a spermatogonium makes an incomplete spermatid, -how?

A

-cells remain connected to each other by cytoplasmic bridges forming a syncytium allowing synchronous development

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13
Q

LH binds to Leydig cells which makes testosterone which circulates peripherally bound to what?

A

ABP - androgen binding protein

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14
Q

What effect does FSH have when binding to Sertoli Cells?

A

maintains their population and converts androgens to oestrogens via aromatase

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15
Q

Why do anabolic steroids cause testicular atrophy?

A

-Neg feedback on hypothal so less FSH

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16
Q

What 3 changes occur to make an erection?

A
  • cavernosal arteries dilate so BF increases
  • venous return of penis constricts
  • higher BP in c.cavernosum
17
Q

approx 120million sperm in ejaculate of 1.5-6ml. Which part of the ejaculate is the most sperm rich?

A

-The initial part of the ejaculate

18
Q

In the vas defs, the small amoun of sperm in the epidymal fluid is mixed with other secretions from where to make “seminal fluid”? 3

A
  • seminal vesicles
  • prostate
  • bulbourethral gland
19
Q

What is the bulbourethral glads clear viscous secretion AKA? 2 Functions?

A
  • Pre-ejaculate
  • rich in salt
  • lubricates urethra for spermatozoa to pass
  • neutralises traces of acidic urine
20
Q

What 5 things are in the seminal vesicle secretions which join at the ejac. duct? This makes up 50-70% of ejaculate. pH = high (protects vs acidic vagina)

A
  • proteins
  • enzymes
  • fructose
  • mucus
  • vit C
  • prostoglandins
21
Q

The prostate contributes 30% of ejaculate. What 4 things are in this milky fluid and why?

A

-proteolytic enzymes
-prostatic acid phosphotase
-prostate specific antigen (PSA)
Liquefaction/more runny
-high zinc conc

22
Q

What is the acrosome of the mature spermatazoom for?

A

-bursts near egg and enzymes cut through the outer layer of the egg

23
Q

What is capacitation (reason a fresh ejaculated sperm cant fertilise an egg)?

A

-4-18hr time requirement for acrosome properties to change as you dont want it bursting before it reaches egg

24
Q

What coagulates the ejaculated sperm and why?

A
  • the prostatic and seminal vesicle secretions

- so semen stays together and helps target ejaculate to cervix entrance

25
Q

Sperm may travel due to uterine/tubal cilia or by chemoattractants (unknown) what 3 changes happen as they undergo capacitation near target?

A
  • become hyperactive
  • tail beats more forcefully and more amplitude
  • by influx of Ca2+ via Cat Sper channels (alkaline pH change triggers it)
26
Q

What does the acrosomal membrane on the sperm head contact with for the acrosomal reaction to occur?

A

-zona-cumulus complex

27
Q

What does acrosin cound to the inner acrosmal membrane do?

A

Digests the zona pellucida so sperm can enter

28
Q

NB: sperm binding is species specific. What does redendency refer to?

A

Redendency = sperm may bind multiple ZP proteins

29
Q

What 2 enzymes are released in the acrosome reaction?

A
  • Hyaluronidase

- Acrosin - cuts through ZP

30
Q

What happens as the sperm nucleus enters the egg (via phagocytosis) in terms of Ca2+?

A
  • huge Ca2+ spike via PLC..
  • phospholipase zeta is activated by basal Ca2+ in egg
  • PIP2 –> IP3 + DAG so big Ca2+ rise and spike
31
Q

What does the massive Ca2+ rise wave in the egg caused by the sperm nucleus entering signal/cause?

A
  • signals fertilisation

- causes completion of meiosis II (+ 2nd polar body is extruded, oocyte is truly haploid)

32
Q

The Ca2+ wave in egg at ferlitsation also causes cortical granules under oocyte membrane to release enzymes into perivitelline space..name 3 enzymes and what is this process called?

A

-mucopolysaccarides
-proteases (cleave adhesion molecules that sperm bind to)
-peroxidases (cause cross linkage in ZP–> V. hard)
this is the CORTICAL REACTION

33
Q

What term refers to the fusion of 2 cells/their nuclei in reproduction?

A

-Syngamy

34
Q

The 2 sets of haploid chromosomes become surrounded by distinct membranes 4-7hrs post fertilisation, what are these? What happens to them?

A
  • pronuclei, each starts to replicate its DNA preparing for the first mitotic division
  • The 2 pronuclei fuse, chromosomes align on the mitotic metaphase spindles
35
Q

After the 2 pronuclei fuse, what do each daughter cell have? What does the 1 cell zygote become?

A
  • they each recieve the chromosomes with their homologous pairs (23 materal, 23 paternal)
  • mitosis is completed. 1 cell zygote –> 2 cell embryo

s4 - Repro, Develop, Ageing, Pharm (14 decks)

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