4: Control of Reproduction Flashcards

(88 cards)

1
Q

Where are the main reproduction hormones released from?

A

Anterior pituitary

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2
Q

What are the two groups of reproduction hormones?

A
  1. Glycoprotein hormones
  2. Polypeptide hormones
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3
Q

What are the glycoprotein reproduction hormones? (3 things)

A
  1. FSH
  2. LH
  3. TSH (thyroid stimulating hormone)
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4
Q

Where are FSH and LH produced?

A

Gonadotrophs in anterior pituitary

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5
Q

What hormones are termed “gonadotropins”

A

FSH & LH

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6
Q

Where is TSH (thyroid stimulating hormone) released from?

A

Thyrotrophs in anterior pituitary

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7
Q

What controls FSH and LH release?

A

Gonadotropin Releasing Hormone (GnRH)

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8
Q

Where is Gonadotropin Releasing Hormone (GnRH) secreted from?

A

Hypothalamus

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9
Q

What is the purpose of Gonadotropin Releasing Hormone (GnRH)?

A

Controls secretion of FSH and LH

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10
Q

What are the fuctions of FSH and LH? (2 things)

A
  1. Control gamete production
  2. Stimulate gonadal steroid secretion (testosterone / oestrogen / progesterone)
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11
Q

Where do FSH and LH act?

A

Gonads

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12
Q

What are the polypeptide reproduction hormones? (3 things)

A
  1. Growth Hormone
  2. ACTH
  3. Prolactin
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13
Q

Where is Growth Hormone released from?

A

Somatotrophs in anterior pituitary

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14
Q

Where is ACTH released from?

A

Corticotrophs in anterior pituitary

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15
Q

Where is prolactin released from?

A

Lactotrophs in anterior pituitary

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16
Q

What is testosterones effect on GnRH secretion?

A

Inhibits GnRH secretion

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17
Q

What is oestrogens effect on GnRH secretion?

A

Inhibits GnRH secretion

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18
Q

What is progesterones effect on GnRH secretion? (2 things)

A
  1. ncreasing oestrogens inhibitory effect on GnRH secretion
  2. Reduces the frequency of pulses
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19
Q

What does a moderate vs high oestrogen concentration do to GnRH secretion?

A

Moderate oestrogen: causes low amount of GnRH secretion per pulse

High oestrogen: promotes GnRH secretion (surge)

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20
Q

What inhibits the GnRH surge caused by high oestrogen concentration?

A

Progesterone

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21
Q

What is inhibin?

A

Hormone that reduces the amount of FSH released in response to GnRH

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22
Q

Where is inhibin released from?

A

Granulosa cells in ovaries

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23
Q

What are the 3 stages of the Reproductive cycle?

A
  1. Preparation
  2. Ovulation
  3. Waiting
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24
Q

How long is the Preparation phase of the Reproductive cycle?

A

12 days

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25
What happens in the Preparation stage of the Reproductive cycle?
1. Follicles grow in the ovary 2. Uterus prepares for sperm transport and implantation
26
What is the Preparation stage called in the Ovary?
Follicular stage
27
What happens in the Follicular (Preparation) phase in the ovary?
Follicles grow in the ovary
28
What hormone mash up causes the follicles to develop? (3 steps)
1. Low oestrogen + progesterone + inhibin --\> causes GnRH secretion 2. GnRH --\> FSH and LH release 3. FSH binds to granulosa cells in the ovary and causes: 1. Follicular development 2. Inhibin Secretion
29
What hormone mash up causes oestrogen release? (3 steps)
1. Low oestrogen + progesterone + inhibin --\> causes GnRH secretion 2. GnRH --\> FSH and LH release 3. LH binds to Theca Interna Cells --\> help with oestrogen production
30
What does the oestrogen (released as a result of LH release) do?
Has a negative feedback effect on hypothalamus --\> reduces amount of GnRH released
31
How does the body ensure only 1 follicle develops per cycle?
Inhibin (released as a result of FSH) inhibits FSH --\> inhibits further follicular development
32
What is the Preparation stage called in the uterus?
Proliferative phase
33
What happens in the Proliferative (Preparation) stage in the uterus?
Uterus prepares for sperm transport and implantation
34
What is the function of oestrogen in the Preparation stage? (6 things)
1. Fimbriae become more motile in fallopian tube 2. Thickening of endometrium 3. Growh + motility of myometrium 4. Thin, alkaline cervical fluid produced 5. Vaginal changes 6. Changes to skin / hair / metabolism Visualise it from fallopian tube --\> uterus --\> cervix --\> vagina --\> outside body
35
What happens in the Ovulation Stage of the Reproductive cycle? (2 things)
1. Brief period of fertility 2. Formation of corpus luteum
36
When is the corpeus luteum formed?
In the Ovulation (2nd) stage of the Ovarian Cycle
37
What happens 12-14 days into the cycle?
Oestrogen levels rise enough to cause an LH surge which causes: 1. Ovum to be released 2. Corpus luteum formed 3. Oestrogen levels to decrease
38
What happens in the Waiting stage of the Reproductive cycle?
Changes occur to prepare for pregnancy
39
What is the Waiting Stage called in the ovary?
Luteal stage astanayaloo6i
40
What is the Waiting Stage called in the uterus?
Secretory phase
41
What is the function of progesterone in the Luteal (Waiting) stage? (6 things)
1. Thickening & sustaining of endometrium 2. Thickening of myometrium 3. Thick acidic cervical mucus produced 4. Increases body temperature 5. Changes in mammary tissue 6. Metabolic and electrolyte changes
42
What happens after 14 days if no implantation occurs?
Corpus Luteum kills himself by: - Producing prostaglandins --\> cuts of own blood supply
43
What follows the Reproductive cyle if no implantation occurs?
Menstruation
44
What does the corpus luteum produce?
1. Progesterone --\> inhibits FSH and LH 2. Oestrogen 3. Inhibin
45
What does the death of the Corpus Luteum cause? (3 things)
1. Reduced progesterone + oestrogen 2. Triggers menstrual menses (bleeding) 3. Inhibition of FSH & LH releaved --\> cycle repeated
46
What happens if implantation occurs?
Implanted embryo develops a placenta --\> secretes Human Chorionic Gonadotropin (hCG)
47
What does hCG secreted by the placenta do?
Preserves the Corpus Luteum
48
How does the Corpus Luteum help in pregnancy?
Secretes oestrogen and progesterone --\> suppors early weeks of pregancy and suppresses ovarian cycle
49
What are the 2 categories of Testosterone effects?
1. Determinative Effects 2. Regulatory Effects
50
Which of the types of testosterone effects is more reversible?
Regulatory effects (highly reversible) The determinative effects are only *partially* reversible
51
What are the determinative effects of testosterone?
Mostly secondary sexual characteristics e.g deepening of voice
52
What do the regulatory effects of testosterone rely on for maintenance?
Continous hormonal stimulation
53
What are the regulatory effects of testosterone? (3 things)
1. Maintenace of male internal genitalia 2. Metabolic effects (anabolic action) 3. Behavioural effects (aggression / sexual activity)
54
What is the feedback control of gonadal steroids in males?
Testosterone reduces GnRH secretion
55
What is the feedback control of gonadal steroids in females? (6 points)
1. Moderate oestrogen concentration --\> reduces GnRH (negative feedback) 2. High oestrogen concentration --\> increases GnRH secretion (positive feedback) 3. High oestrogen concentration --\> LH surge 4. Progesterone prevents positive feedback and surge 5. Oestrogen affects amount of GnRH released per pulse 6. Progesterone affects frequency of pulses
56
What is puberty?
A sequence of events called Tanner stages
57
What is puberty controlled by?
HPG axis activation
58
What are the 5 Tanner stages?
1. Hormone release begins 2. First physical changes noticeable 3. Growth spurts, Physical change progression 4. Key functional events 5. Adult physical appearance & function
59
What happens in the first Tanner stage?
Hormone release begins But NO physical changes
60
What happens in the 2nd Tanner stage?
First physical changes visible: Girls: breast bud Boys: testes and scrotum enlargement
61
What happens in the 3rd Tanner Stage?
Growth spurts, Physical change progression: Girls: Fat deposits on hips Boys: Voice cracking and nocturnal ejaculations
62
What happens in the 4th Tanner stage?
Key functional events Girls: Menarche (first period) Boys: Spermatogenesis
63
What happens in the 5th Tanner stage?
Adult physical appearance and function Girls: Regular periods and ovulation Boys: Facial hair and musculature
64
What is early puberty called?
Precocious puberty
65
What happens in Precocious puberty?
Signs of puverty before age of 8 (girls) and 9 (boys)
66
What are the causes of Precocious puberty? (2 things)
1. Neurological issues impact central maturation signalling - Pineal tumours - Meningitis 2. Uncontrolled gonadotropin / steroid release - Hormone secreting tumours of pituitary / gonads
67
What is the treatment for Precocious puberty?
Blocking gonadotropin release from pituitary
68
What is Delayed puberty?
No testicular development in boys by age 14 No breast development in girls by 13 or menarche by 15
69
What are the causes of Delayed puberty? (3 things)
1. Malnutrition and chronic illness 2. Issues with gonads / thyroids / pituitary glands 3. Genetic conditions (Androgen insensitivity / Klinefelters syndrome)
70
What is the treatment for Delayed puberty?
Pulsative GnRH infusions
71
What age is pre-menopause?
40's
72
What changes to the menstrual cycle occur in Pre-menopause?
1. Follicular phase shortens (ovulation occurs early / absent) 2. Reduced oestrogen secretion 3. Increased FSH & LH because reduced negative feedback 4. Reduced fertility
73
What is menopause?
Cessation of menstrual cycle
74
What is the usual age of menopause?
49-50 years old
75
What happens to oestrogen levels in menopause?
Oestrogen levels drop a lot
76
What happens to FSH and LH levels in menopause and why?
Increase a lot Because there is no negative feedbak via gonadal steroids and inhibin
77
What are vascular changes that occur at menopause?
Hot flushes caused by because increased skin temperature
78
What are the hot flushes of menopause relieved by?
Oestrogen treatment
79
What changes occur to the uterus at menopause? (2 things)
1. Regression of the endometrium 2. Shrinkage of the myometrium
80
What happens to the cervix at menopause?
Becomes thinner
81
What happens to breast tissue at menopause?
Shrinks
82
What other changes occur at menopause?
Skin and bladder changes
83
How are bones changes at menopause? (3 things)
1. Bone mass declines by 2.5% per year 2. Increased reabsorption relative to production 3. Oesteoporosis --\> increased risk of fractures
84
How can the changes to bone at menopause be limited?
Oestrogen therapy
85
When does Post-menopause start?
After there hasn't been any periods for 12 consecutive months
86
What are the benefits of Hormone Replacement Surgery?
1. Relieves menopause symptoms 2. Increases well being 3. Limits osteoporosis
87
What are the risk factors of Hormone Replacement Surgery?
1. Increased risk of **malignancy** (especially in breast tissue because they are stimulated to grow by oestrogen) 2. Women who have NOT had hysterectomies should NOT be given oestrogen only preparations because risk of **endometrial thickening**
88