Coitus And Fertilisation Flashcards

1
Q

Approximately how long does it take from spermatogonium to mature spermatozoa?

A

74 days

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2
Q

Which cells secrete androgen binding protein?

A

Sertoli cells

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3
Q

If the pituitary gland was removed, what would we need to give to initiate spermatogenesis?

A

FSH and testosterone

Giving testosterone directly bypasses need for LH

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4
Q

What is the role of oestrogen in males?

A

Increases sperm viability

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5
Q

Which cells secrete inhibin?

A

Sertoli cells

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6
Q

What is spermiogenesis?

A

The process from spermatid to spermatozoan

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7
Q

What happens during spermiogenesis?

A
Head undergoes nuclear condensation
Acrosome develops 
Mitochondria packed around contractile filaments 
Flagellum produced by microtubules 
Gains motility and becomes 'fertile'
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8
Q

What happens in epididymis during sexual arousal?

A

Contraction of epididymal wall
Expel spermatozoa into vas deferens
Non-expelled sperm undergo phagocytosis

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9
Q

How many phases of coitus are they and what are they?

A
4
Excitement 
Plateau 
Orgasmic 
Resolution
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10
Q

Describe the male excitement phase

A

Sensory and psychological stimulation of limbic system
Activate sacral PNS (inhibit SNS)
NO production and arteriolar vasodilation in corpora cavernosa
Increased penile blood flow, testes elevate and engorge
(Erection reversible at this stage)

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11
Q

Describe male plateau phase

A

Sacrospinous reflex
Contraction of ischiocavernosus - engorgement of penis
Increased penile pressure
Accessory glands secrete - Cowper’s and Littre’s
Loss of erection unlikely

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12
Q

What are the 2 parts that the male orgasmic phase is divided into?

A

Emission

Ejaculation

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13
Q

What happens in the emission phase?

A

SNS reflex
Contraction of SM in vas deferens, ampulla, seminal vesicle and prostate
Internal and external urethral sphincters contract
Semen pooled in urethral bulb

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14
Q

What happens in the ejaculation phase?

A
Spinal reflex with cortical control
SNS L1 and L2
Contraction of glands and ducts and IUS
Filling of urethra stimulates pudendal nerve -> contraction 
EUS relaxes
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15
Q

What happens in the resolution phase for males?

A
SNS pathway 
Contraction of SM in corpora cavernosa - increase venous return 
Detumescence and flaccidity 
Refractory period 
Testes descend and shrink
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16
Q

What happens in female excitement phase?

A

Sensory and psych stimulation - activated sacral PNS, inhibit SNS
Vaginal lubrication begins - increased blood flow
Clitoris engorges with blood
Uterus elevates
Increased muscle tone, HR and BP
Inner 2/3 vagina lengthens and expands

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17
Q

Describe the plateau phase for females

A

Further increase in tone, HR and BP
Labia minora deepen in colour
Clitoris withdraws
Bartholin’s glands secrete vestibule for entry of penis
Orgasmic platform forms in lower 1/3 vagina
Uterus fully elevated

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18
Q

Describe the orgasm phase in females

A

Orgasmic platform contracts rhythmically 3-15 times
Uterus contracts, anal sphincter contracts
Clitoris remains retracted
No refractory period - multiple orgasms possible
Uterine contractions beginning at top and moving down

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19
Q

Describe resolution phase in females

A

Clitoris descends and engorgement subsides
Labia return to unaroused size and colour
Uterus descends
Vagina shortens and narrows

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20
Q

Describe the changes in breast during excitement phase

A

Breast size increased
Nipples erect
Veins more distinct

21
Q

Describe changes in breast in plateau/orgasm phase

A

Greater size increase
Areola size increase
Sex flush on breasts and upper abdo

22
Q

Describe changes in breast in resolution phase

A

Return to unaroused size

Disappearance of sex flush

23
Q

What is the G spot?

A

Female equivalent of prostate

Area of erotic sensitivity located in anterior wall of vagina

24
Q

What affect does ageing having on female sexual habits?

A

Decreased desire
Decreased vasocongestion response so less lubrication
Vagina and urethra lose elasticity
Length and width of vagina decrease
Decreased number of orgasmic contractions
More rapid resolution

25
Q

What is nymphomania?

A

Uncontrollable sexual desire

26
Q

What is Kluver Bucci Syndrome?

A

Bilateral medial temporal lobe lesions

Hyperphagia/hypersexuality/hyperorality

27
Q

Causes of impotence in males….

A

Psychological
Tears in corpora cavernosa
Vascular - atherosclerosis/diabetes
Alcohol, antihypertensives

28
Q

How does viagra work?

A

Inhibits cGMO breakdown

Increases NO stimulated vasodilation

29
Q

How much semen is there usually per ejaculate?

A

2-4 ml

30
Q

How many sperm are there per ml of ejaculate?

A

20 - 200 x 10^6 sperm per ml

31
Q

What percentage of sperm in semen has an abnormal pathology?

A

30%

32
Q

What is the numerical definition of oligozoospermia?

A

< 20 x 10^6 sperm per ml

33
Q

Describe secretion from bulbourethral glands

A

5% total volume
Alkaline
Lubricates tip of penis and urethra

34
Q

Describe secretion from seminal vesicles

A
60% total volume 
Alkaline 
Fructose - for ATP production 
Prostaglandins - increased sperm motility and female SM contraction 
Clotting factors
35
Q

Describe secretion from the prostate

A

25% total volume
Milky, slightly acidic
Proteolytic enzymes - reliquify semen
Citric acid

36
Q

Where is semen usually deposited?

A

High in the vagina

37
Q

What hormone stimulation uterine contractions?

A

Oxytocin

38
Q

Which days of the menstrual cycle will sperm get through most easily?

A

7-14 days

Clear, non-viscous mucus

39
Q

Approximately how many sperm are sacrificed to disperse the zona pellucida?

A

299

40
Q

How long can sperm survive in female tract?

A

Up to 5 days

41
Q

How long does an oocyte survive before phagocytosis?

A

6 - 24 hours

42
Q

When is the fertile period for women?

A

3 days prior to or on day of ovulation

43
Q

Approximately how long does it take for the oocyte to travel for the ovary to body of uterus?

A

3 - 4 days

44
Q

What is the corona radiata of the oocyte made of?

A

Follicular cells

45
Q

After fertilisation, what are the 2 ways of preventing polyspermy?

A

Fast block

Slow block

46
Q

How does a fast block of polyspermy occur?

A

Electrical changes in membrane
Na+ channels open
Wave of depolarisation propagates across cytoplasm

47
Q

How does a slow block of polyspermy occur?

A

Calcium released from ER
Local exocytosis of cortical granules
Released enzymes to stimulate adjacent granules to do the same
Wave to exocytosis in 3 dimensions

48
Q

What is syngamy?

A

Oocytes completes meiosis II and expels second polar body

Union of male and female pronuclei

49
Q

What is polyploidy and what are the commonest ways it can occur?

A

Embryos containing 3 or more pronuclei

Entry of more than one sperm or failure of extrusion of polar body