Repro 3 Flashcards

1
Q

What stimulates GnRH neurons to release GnRH

A

Pulsatile activity in kisspeptin neurons

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2
Q

LH and FSH act on

A

Gonads to stimulate hormone secretion and facilitate gamete production

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3
Q

What is the least understood influence on reproductive hormones

A

Environmental

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4
Q

What can be studied for environmental influences

A

Nutritional status, PA, change of day/light cycle, travelling, night shifts

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5
Q

Environmental estrogens

A

Can bind and activate estrogen receptors
- some are anti estrogens
- may influence developing embryo or fetus

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6
Q

Anti estrogens

A

Interfere with second messenger pathways

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7
Q

Examples of environmental estrogens

A

Pesticides, phytoestrogens, processed foods

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8
Q

Testes

A

Produce hormones and gametes

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9
Q

Male External genitalia

A

Penis, urethra, corpus spongiosum, corpora cavernosa, glans, prepuce (foreskin), scrotum

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10
Q

What are 2 erectile tissue

A

Corpus spongiosum, corpora cavernosa

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11
Q

Why is prepuce removed

A

Hygiene, cancer, STI, UTI, HIV

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12
Q

What is primary erectile tissue

A

Corpora cavernosa

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13
Q

What keeps urethra open

A

Corpus spongiosum

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14
Q

3 accessory glands

A

Seminal vesicle (pair)
Prostate gland
Bulbourethral gland

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15
Q

What connects testes to urethra

A

Vas deferens and epididymis

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16
Q

When do testes migrate to scrotum

A

By 8 months of fetal development

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17
Q

What temp does sperm development require

A

2-3 F lower

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18
Q

What is failure to descend

A

Cryptprchidism (usually resolves itself in year)
- if not moved with testosterone treatment or surgically
- unable to produce sperm but still produce androgens

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19
Q

What is problem in many men over 50

A

Benign prostatic hypertrophy

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20
Q

What is involved in prostate development

A

DHT

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21
Q

What shrinks hypertrophied prostate

A

Administration of 5a-reductase inhibitor (finasteride) blocks DHT production

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22
Q

What do testes produce

A

Sperm and hormones

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23
Q

Testes are

A

Paired ovoid structures ~2.5 x 5m
Tough fibrous capsule split into 250-300 compartments

24
Q

Where does final maturation and storage of sperm occur

A

Epididymis

25
Q

What is within compartments of testes

A

Seminiferous tubules
- 400-600
- 80% of testicular mass
- 0.3-1 meter long each

26
Q

where do seminiferous tubules empty

A

Into epididymis

27
Q

What lies between seminiferous tubules

A

Interstitial tissue with blood vessels and Leydig cells

28
Q

What is site of sperm production

A

Seminiferous tubule

29
Q

Where are developing spermatocytes in seminiferous tubules

A

Stack in columns from outer edge to lumen with Sertoli cells between each column

30
Q

Leydig cell

A

Found in interstitial tisssue produce testosterone during development then again after puberty

31
Q

What does basal lamina of seminiferous tubule do

A

Keep out large particles but allows testosterone to enter

32
Q

Sertoli cells contain

A

Tight junctions with adjacent Sertoli cells forming a blood testis barrier between tubule lumen and interstitial space

33
Q

What do Sertoli cells regulate

A
  • Sperm development
  • provide sustenance or nourishment
34
Q

What do Sertoli cells produce

A

Hormones (activin and inhibin), growth factors, enzymes, androgen binding protein

35
Q

What does androgen binding protein do

A

Binds to testosterone to keep it in the tubule lumen

36
Q

Where do male germ cells (spermatogonium) reside

A

Inside basal lamina of seminiferous tubules
- some remain to undergo mitosis to produce more germ cells some enter meiosis to become primary spermatocytes

37
Q

As spermatocytes differentiate to sperm where do they move

A

Towards tubule lumen (cells push)

38
Q

What do Sertoli cells do around migrating sperm

A

Tight junctions break and reform around migrating cells

39
Q

What happens to one spermatogonium when reaching lumen

A

Becomes 4 spermatids

40
Q

What do spermatids do at apical membrane

A
  • remain embedded in apical of Sertoli cells while completing transformation
41
Q

What transformations happen to spermatids at apical membrane (still not motile)

A
  • lose most of cytoplasm
  • develop flagellated tail
  • chromatin condenses
  • microtubule extension
  • acrosome forms cap over nucleus
  • midpiece has mitochondria for energy
42
Q

How long is spermatogonium to free sperm

A

~64 days (200 million produced/day)

43
Q

Where are sperm released from

A

Sertoli cells before reaching maturing

44
Q

How is sperm pushed out of Sertoli cells if no motility

A

Out of tubule lumen by other developing sperm, bulk flow of other fluids, and contraction

45
Q

Where do sperm mature

A

Epididymis (cells secrete proteins)
- during 12 days of transit time

46
Q

What does spermatogonia is require

A

Gonadotropins and testosterone

47
Q

What does FSH do in males

A
  • bind to receptors on Sertoli cells causing them to generate paracrine molecules needed for spermatogonia mitosis and spermatogenesis
  • also produces ABP and inhibin
48
Q

LH does what in males

A
  • targets interstitial Leydig cells resulting in production of testosterone
  • essential for spermatogenesis
49
Q

What do spermatocytes not have

A

Receptors for FSH, LH or androgens

50
Q

Sperm leading via vas deferens is joined by

A

Secretions of accessory glands to make semen

51
Q

Semen

A

Liquid medium for delivering sperm (99% accessory)

52
Q

What is other role of semen

A

Protect reproductive tract fro pathogens ascending urethra

53
Q

What chemical substances do accessory gland secretions contain

A
  1. Nutrients
  2. Buffers for protection against acidic vaginal environment and residual acidic urine in urethra
  3. Chemical to increase sperm motility
  4. Prostaglandins (motility and contraction of male and female reproductive tracts)
  5. Immunoglobulins, lysozyme and other antibacterial compounds
54
Q

What secondary sex characteristics are affected by androgens

A

Body shape, facial and body hair growth, muscular development, thickening of vocal cords, behavioural effects (i.e. libido)

55
Q

Androgens promote what

A

Anabolism
Anabolic hormones and promote protein synthesis

56
Q

What other structures have androgen receptors

A

Brain, kidneys, heart, skin, liver, bones