Lect 23 Flashcards

1
Q

Growth hormones has indirect effects on growth through what hormone

A
  • Insulin-like growth factor
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2
Q

function of Insulin-like growth factor

A
  • stimulates linear growth of bones
  • hypertrophy and hyperplasia of tissues
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3
Q

are levels of GH higher in children, adults, or elderly

A
  • highest in children
  • decline with aging
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4
Q

what does decline of GH lead to in the body

A
  • loss of lean body mass, fitness, protein synthesis, metabolic rate
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5
Q

When are levels of IGF-1 highest in a person’s lifespan

A

pubertal peak rate of growth

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6
Q

a GH secreting pituitary adenoma can lead to GH excess which can cause what condition?

A
  • acromegaly
    • occurs after puberty when linear growth is complete
      • increase in bone size, organ size, hand and foot size, enlargement of tongue
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7
Q

acromegaly occurs with GH hypersecretion when epiphyses are ? This results in

A
  • closed in adults
  • results in
    • bone and soft tissue deformities
    • increased protein, decreased fat content
    • propensity to be diabetic
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8
Q

what condition can occur if GH excess occurs before puberty

A
  • gigantism
    • increased linear grwoth because of stimulation of epiphyseal plates
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9
Q

what is hypopituitarism

A

deficiency of one/more anterior pitiuitary hormones

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10
Q

what is panhypopituitarism

A

deficiency of ALL anterior pituitary hormones

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11
Q

List some effects of panhypoituitarism

A
  • adrenal cortex atrophies: secretion of sex hormones decreases
  • gonads atrophy: amenorrhea, impotence in men
  • thyroid atrophies: cold intolerance, dry skin, mental dullness
  • sensitive to stress: (illness, surgery, trauma)
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12
Q

GH deficiency in children can lead to

A
  • failure to grow, short stature
  • mild obestiy
  • delayed puberty
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13
Q

GH deficiency before puberty results in what condition

A

Dwarfism

  • defects:
    • GH secretion, reduced IGF
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14
Q

African pigmy have what defect

A
  • normal GH levels but do not exhibit the normal rise in IGFs with puberty
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15
Q

what is Laron dwarfism

A
  • GH resistant
    • genetic defect in expression of GH receptor
    • do not produce IGFs in response to GH
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16
Q

GH/IGF-1 alone are not wholly responsible for growth, what role does the thyroid hormone have

A
  • permissive role in skeletal growth
  • critical in CNS growth
17
Q

what role do steroids have in growth

A
  • role in prepubertal growth
  • promote weight gain and increase in muscle mass
18
Q

hyperinsulinemia during pregnancy can result in

A
  • increased fetal growth
    • insulin deficiency during childhood will diminish growth
19
Q

muscle protein synthesis occurs how long after resistance exercise

A

hours to days

20
Q

both exercise and stimulate muscle protein synthesis

A

amino acids

21
Q

does insulin play a role in muscle protein synthesis

A

yes

22
Q

What myokine has an important role in regulating muscle and bone growth and collagen synthesis

A

IL-6

23
Q

When is Myostatin levels increased? effect?

A
  • elevated levels with stressful conditions (CA, disease)
  • negative regulator of muscle growth
    • elevated levels suppress bone formation
24
Q

myostatin is derived from

A

skeletal muscle

25
Q

glucocorticoids have what effect on myostatin

A
  • stimulate it
    • thus glucocorticoid administration to children inhibits growth
26
Q

muscle contraction (exercise) stimulates the release of what myokines that alter bone metabolism

A
  • IL-6: increases osteoclast activity
  • leukemia inhibitory factor (LIF): stimulates bone formation
  • IGF-1
  • fibroblast growth factor (FGF-2): stimulate bone formation
27
Q

Brain-derived neurotrophic factor (BDNF) has what function

A
  • secreted by brain to promote growth and maintenance of neurons
  • role in learning and memory
28
Q

Brain-derived neurotrophic factor (BDNF) is also produced where

A
  • skeletal muscle
  • increased production with contraction of skeletal muscle