Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Gabe's Endocrinology > Pituitary Function and Failure > Flashcards

Pituitary Function and Failure Flashcards

1
Q

What does the posterior pituitary release?

A

Vasopressin and oxytocin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does vasopressin do?

A

Increases collecting duct permeability, reducing urine volume.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does oxytocin do?

A

Stimulates milk ejection from the breast and contraction of the uterus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where are posterior pituitary hormones synthesised?

A

In the hypothalamus and packaged in the cell body of the neuron.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are neurohormones synthesised and packaged?

A

In the cell body of the neuron.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens to neurohormones after synthesis?

A
  1. They are transported down to the posterior pituitary.
  2. The vesicles are stored in the posterior pituitary.
  3. Hormones are released into general circulation where they travel in tissues to where the receptors are.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which neurons produce and control the posterior anterior pituitary?

A

Supraoptic and paraventricular nuclei.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which neurons are concerned with the anterior pituitary?

A

Arcuate and other nuclei.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the hypothalamic-hypophyseal portal system?

A

The connection of the hypothalamus to the anterior pituitary.

  1. Neurons synthesising trophic hormones release them into capillaries of the portal system.
  2. Portal vessels carry the trophic hormones directly to the anterior pituitary.
  3. Endocrine cells release their hormones into the second set of capillaries for distribution to the rest of the body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which hormones are in the hypothalamus?

A
  • PRFs
  • Dopamine
  • TRH
  • CRH
  • GHRH
  • GnRH
  • Somatostatin.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which hormones are in the anterior pituitary?

A
  • Prolactin
  • TSH
  • ACTH
  • GH
  • FSH
  • LH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the pathway for IGF release?

A

Hypothalamus releases GHRH into the hypothalamic-hypophyseal portal system to the anterior pituitary, which release GH. GH travels via circulation to liver, inducing it to synthesise and release IGF.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is thyroid hormone released?

A

TSH from anterior pituitary is released into circulation, it acts at the thyroid gland to release T3 and T4 thyroid hormones.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is cortisol released?

A

ACTH is released from anterior pituitary and stimulates the adrenal cortex to release cortisol, which then modulates metabolic actions and stress responses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the action of prolactin?

A

Stimulates mammary glands to increase breast growth and milk secretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is the hypothalamus linked to the posterior pituitary gland?

A

Via a neural link

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is the hypothalamus linked to the anterior pituitary gland?

A

Via a vascular link - hypothalamic-hypophyseal system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does the final organ producing the hormone act on the structures stimulating it?

A
  • It often feeds back onto the anterior pituitary and hypothalamus, via negative feedback.
  • This allows for 2 layers of control.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What effect does somatotropin (GH) have on the liver?

A

Stimulates release of somatomedins, which stimulate bone and soft tissue growth, e.g. IGF-1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where are LH and FSH released from?

A

Anterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where do LH and FSH act?

A

At the gonads (ovaries or testes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the effects of LH stimulation of the gonads?

A

Sex hormone secretion (oestrogen and progesterone in females; testosterone in males).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the effects of FSH stimulation of the gonads?

A

Gamete production (ova in females; sperm in males)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What factors can influence hypothalamic regulation of the pituitary?

A

Neighbouring structures, such as the optic chiasm, pre-optic areas, areas for smell, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the afferents for regulation of thyroid stimulating hormone (TSH) via TRH?

A

Temperature receptors in infants, perhaps others.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the integrating centre for regulation of thyroid stimulating hormone (TSH) via TRH?

A

Paraventricular nuclei and neighbouring areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where do ACTH and beta-lipotropin via CRH receive afferents from?

A
  • Limbic system (emotional stimuli)
  • Reticular formation (systemic stimuli)
  • Hypothalamic and anterior pituitary cells sensitive to circulating blood cortisol level
  • Suprachiasmatic nuclei (diurnal rhythm)
28
Q

What is the integrating centre for afferents affecting ACTH and beta-lipotropin levels via CRH?

A

Paraventricular nuclei

29
Q

What are the afferents affecting FSH and LH via GnRH?

A

Hypothalamic nuclei sensitive to oestrogen, eyes, touch receptors and genitalia of reflex ovulating species.

30
Q

What are the integrating centres for afferents affecting FSH and LH?

A

Pre-optic areas; other areas

31
Q

What are the afferents affecting Prolactin release via PIH and PRH?

A

Touch receptors in breasts

32
Q

What are the integrating receptors for afferents affecting FSH and LH release?

A

Arcuate nucleus; other areas (hypothalamus inhibits secretion)

33
Q

What are the integrating centres for afferents affecting GH release via somatostatin and GRH?

A

Periventricular nucleus; arcuate nucleus

34
Q

What is Kallmann syndrome?

A
  • Embryologically GnRH neurons failed to migrate via olfactory pathway
  • Hypogonadotropic hypogonadism
  • Hyposmiaoranosmia (loss of smell)
35
Q

What are the requirements for growth?

A
  • Growth hormone (somatotropin) is essential
  • Other important factors:
    • Genetic determination
    • Adequate diet
    • No chronic disease or stressful environment
    • Normal mix of growth‐influencing hormones
      • Thyroid hormone, insulin, sex hormones
36
Q

What is size at birth determined by?

A
  • Genetics
  • Environmental (e.g. drug exposure)
  • Nutritional (under‐nourished mother)
  • Research: Small birth weight = adult disease
37
Q

When are the 2 major growth spurts?

A

Postnatal and pubertal.

38
Q

What happens during the post-natal growth spurt?

A

70% of brain growth.

39
Q

What happens during the pubertal growth spurt?

A
  • Adolescence
  • Lengthening of long bones increases growth
  • Genetic and hormonal factors
  • Testosterone and oestrogen
  • Full adult height at end of adolescence
40
Q

What happens between the two major growth spurts?

A
  • Little sex difference in height & weight
  • Rate of linear growth declines
41
Q

What are the metabolic effects of growth hormone?

A
  • Increased blood fatty acid and glucose – anti insulin
  • During prolonged fasting or when body’s energy needs exceeded
42
Q

What are the soft tissue and skeletal effects of growth hormone?

A
  • Hyperplasia and hypertrophy on soft tissues & skeleton
  • Increased protein synthesis
43
Q

What is the half-life of GH?

A

18 minutes

44
Q

How is GH transported in the circulation?

A

Half is dissolved in plasma, half is bound to a binding protein whose structure is identical to that of the GH receptor.

45
Q

What factors affect the release of GH?

A

Circadian rhythm of tonic secretion; influenced by circulating nutrients, stress and other hormones in a complex fashion.

46
Q

What are the target cells or tissues of GH?

A
  • Trophic on liver for IGF-1 production
  • Also acts directly on many cells.
47
Q

What is the control pathway for GH?

A

GHRH, somatostatin (hypothalamus) → growth hormone (anterior pituitary)

48
Q

What is the target receptor for GH?

A

Membrane receptor with tyrosine kinase activity.

49
Q

What is the whole body or tissue action for GH with IGFs?

A
  • Bone and cartilage growth
  • Soft tissue growth
  • Increased plasma glucose.
50
Q

What is the action of GH at the cellular level?

A

Receptor linked to kinases that phosphorylate proteins to initiate transcription.

51
Q

What are some somatomedins?

A
  • Insulin‐like growth factors (IGF‐I and IGF‐II)
  • Polypeptide growth factor
52
Q

What are somatomedins stimulated by?

A

Growth hormone

53
Q

What are the actions of GH via IGF-1?

A
  • Insulin-like activity
  • Antilipolytic activity
  • Protein synthesis
  • Epiphyseal growth
54
Q

What are the actions of GH that don’t act via IGF-1?

A
  • Na+ retention
  • Decreased insulin sensitivity
  • Lipolysis
  • Protein synthesis
  • Epiphyseal growth
55
Q

What is the growth hormone control pathway?

A
  • Somatostatin = Growth hormone inhibiting hormone (GHIH)
  • Somatotropin = Growth hormone
  • Somatomedin = insulin‐like growth factors (IGF‐I and IGF‐II)
  • See image
56
Q

What does tissue and bone growth require?

A

Hormones and paracrines:

  • GH and IGFs required for protein and cell division
  • Thyroid hormone plays permissive role
  • Insulin supports tissue growth
  • Oestrogen close epiphyseal plates of long bones
  • Bone growth requires calcium
57
Q

Which hormone determines height?

A

Oestrogen, because it closes epiphyseal plates of long bones.

58
Q

What is dwarfism a result of?

A

Decreased GH as a child.

59
Q

What is Laron dwarfism?

A

Growth hormone insensitivity, GH receptors are unresponsive to normal GH.

60
Q

What is the result of adult onset GH deficiency?

A

Very little effects

61
Q

What is the treatment for GH deficiency?

A

Genetically engineered human GH

62
Q

What are GH-independent causes of short stature?

A
  • Cretinism: childhood hypothyroidism
  • Precocious/early puberty
  • Gonadal dysgenesis: XO chromosomes
  • Constitutional delayed / stunted growth
  • Psychosocial dwarfism: chronic abuse or neglect
  • Achondroplasia
    • Most common form of dwarfism in humans
    • Fibroblast growth factor receptor 3 mutation (cartilage & brain)
    • FGF receptor III mutation
63
Q

What are two disorders due to growth hormone excess?

A

Gigantism and acromegaly

64
Q

What is gigantism due to?

A

Overproduction of GH as a child before puberty

65
Q

What is acromegaly?

A
  • Overproduction GH in adult; bone and soft tissue deformities
  • Increased viscera size & protein content
  • Progression of acromegaly in one woman
66
Q

What is the relative importance of hormones in human growth at various stages?

A

See image.

Gabe's Endocrinology (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions