PBL 38 Flashcards

1
Q

What is adrenarche?

A

The period preceding puberty

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2
Q

The onset of puberty is associated with which hormone increase?

A

GnRH

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3
Q

High GnRH leads to the rise in which sex hormones?

A

LH and FSH

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4
Q

Where is GnRH released from?

A

The hypothalamus

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5
Q

The cells in the … … respond to GnRH release from the hypothalamus by secreting … and …

A

Anterior pituitary
LH
FSH

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6
Q

The ovaries or testes respond to rising amounts of LH and FSH by growing and beginning to produce … and …

A

oestradiol and testosterone

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7
Q

Rising levels of which hormones produce the body changes of female and male puberty?

A

oestradiol

testosterone

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8
Q

Signs of male puberty

A

Voice breaks
Growth of muscle tissue
Enlargement of genitalia
Facial, pubic and axillary hair

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9
Q

Signs of female puberty

A

Broadening of hips
Menstruation begins
Development of breasts
Pubic and axillary hair

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10
Q

What is the name of the growth hormone?

A

Somatotropin

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11
Q

Where is somatotropin synthesised and secreted from?

A

Somatotrophic cells in the anterior pituitary gland

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12
Q

What are the direct and indirect effects of growth hormone?

A

Direct: result of growth hormone binding to its receptor on target cells e.g. adipocytes have growth hormone receptors which are stimulated by growth hormone to break down triglyceride and suppresses their ability to take up and accumulate circulating lipids

Indirect: mediated by IGF-1, a hormone secreted from the liver and other tissues in response to growth hormone. A majority of growth promoting effects of growth hormone is due to IGF-1 acting on its target cells

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13
Q

Effects of IGF-1 on growth

A
  1. Stimulates proliferation of chondrocytes (cartilage cells), resulting in bone growth
  2. Stimulates differentiation and proliferation of myoblasts in muscle growth
  3. Stimulates amino acid uptake and protein synthesis in muscle and other tissue
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14
Q

Production of GH is modulated by which alternate factors?

A
Stress
Exercise
Nutrition
Sleep
GH itself
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15
Q

Primary modulators of GH release

A
  1. Growth hormone releasing hormone (GHRH) - made by the hypothalamus, it stimulates synthesis and secretion of GH
  2. Somatostatin (SS) - produced by several types of tissues, including the hypothalamus. It inhibits GH release in response to GHRH and other stimulatory factors such as low blood glucose
  3. Ghrelin - peptide hormone secreted from the stomach. It binds to receptors on somatotrophs and potently stimulates GH secretion
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16
Q

High blood levels of IGF-1 lead to decreased secretion of GH, this is a negative feedback loop, but how?

A

Directly suppresses somatotrophs

Stimulates release of SS

17
Q

Causes of short stature

A

Hormone disorders: hypopituitarism, hypothyroidism, Cushing’s syndrome

Chronic disease: CF, sickle cell, RA, heart and kidney problems

Genetic conditions: Turners syndrome

Poor nutrition

Failure to thrive

Complications during pregnancy - IUGR, infections

Bone disorders - skeletal dysplasia

18
Q

Causes of tall stature

A

Hormone disorders: hyperpituitarism (acromegaly and gigantism), androgen/oestrogen deficiency

Genetic conditions: Marfan syndrome, Klinefelter’s syndrome

Foetal overgrowth syndromes: maternal diabetes, cerebral gigantism, IGF excess syndrome

19
Q

Causes of puberty delay

A
  1. Constitutional delay: pattern of growth and development in the family
  2. Chronic illness: diabetes, CF, kidney disease, asthma
  3. Malnourished
  4. Genetic conditions - Turners, Klinefelters
  5. High level of physical exertion in females
  6. Hypothalamic, pituitary and/or gonadal defects and diseases
  7. Hormone deficiencies and imbalances – hypothyroidism, Cushing’s syndrome
20
Q

Is growth hormone effective at increasing final adult height in children with short stature who are normal (lack disease)?

A

No

21
Q

Medications for short stature. Explain for which deficiencies they are used

A

Recombinant human growth hormone therapy - for short stature caused by growth hormone deficiency, Turner’s syndrome, Prader-WIlli syndrome and CKD

Mecasermin (recombinant human insulin-like growth factor 1) - for short stature caused by IGF-1 deficiency

Thyroid hormone replacement therapy - for short stature caused by hypothyroidism

22
Q

When can surgery be used as short stature treatment?

A

If it is a brain tumour which is causing the growth hormone deficiency

23
Q

Side effects of human growth hormone use

A
  1. Nerve, muscle, or joint pain
  2. Oedema
  3. Carpal tunnel syndrome
  4. Numbness and tingling of skin
  5. High cholesterol
24
Q

Parental influences on childrens health

A
  1. Parental involvement: less likely to participate in risky behaviours, have better self esteem, perform better in school
  2. Lack of parental involvement: more likely to participate in risky behaviour, have a sedentary life, more likely to be withdrawn or suffer from depression
  3. Habits: children observe parents behaviour, affect a child’s eating habits, exercise habits, and dental hygiene. Children of smokers are more likely to smoke
  4. Income: On average, the higher the income, the healthier the child
  5. Parents education: More educated parents may be better informed about the availability and use of health care, or have better health behaviour