Pituitary Function and Failure Flashcards

1
Q

What is the posterior pituitary?

A

Neurohypophysis
Outgrowth of brain - nervous tissue
Neural link to hypothalamus

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

What is the anterior pituitary?

A

Adenohypophysis
From glandular epithelial tissue, ectodermal cells
Vascular link to hypothalamus

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

In what ways are the anterior and posterior pituitary different?

A

Embryologically
Structurally
Functionally

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

What is the infundibulum?

A

Stalk connecting pituitary to brain

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

What does the posterior pituitary release?

A

Vasopressin/ADH

Oxytocin

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

What does ADH do?

A

Increases collecting duct permeability

Decreases urine volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does oxytocin do?

A

Breasts - contracts myoepithelial cells along ducts to eject milk
Uterus - contraction

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

Which hormone makes milk?

A

Prolactin

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

From what are the hormones of the posterior pituitary released into the general circulation?

A

Endings of supraoptic and paraventricular neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

From what are trophins of the hypothalamus secreted?

A

Endings of arcuate and other hypothalamic neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

To where are trophins of the hypothalamus secreted?

A

Portal hypophysial circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where are the arcuate, supraoptic, and paraventricular nuclei?

A

Hypothalamus

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

What is the synthesis, storage, and release of posterior pituitary hormones?

A
  1. Hormone made and packaged in cell body of neuron in hypothalamus
  2. Vesicles transported down cell
  3. Vesicles containing hormone stored in posterior pituitary
  4. Hormones released into blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the steps involved in the activation of the anterior pituitary via the hypothalamic-hypophyseal portal system

A
  1. Neurons synthesising trophic hormones release them into capillaries of portal system
  2. Portal vessels carry trophic hormones directly to anterior pituitary
  3. Endocrine cells release hormones into second set of capillaries for distribution to rest of body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the hypothalamic-hypophyseal portal system?

A

Vascular system connecting hypothalamus to anterior pituitary

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

Why don’t you need much trophic hormone to be released from the hypothalamus?

A

Because hormone concentrated and rapid

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

What kinds of effects do the hormones released from the hypothalamus have on the anterior pituitary?

A

Sometimes releasing hormone
Sometimes inhibiting hormone
Both control anterior pituitary function

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

Is the action of dopamine on the breast direct or indirect?

A

Direct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the target pituitary cell of corticotropin-releasing hormone (CRH)?

A

Corticotroph

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

What are the hormone products of corticotrophs?

A
Adrenocorticotropic hormone (ACTH)
Beta-lipotropin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the target tissue of ACTH?

A

Adrenal cortex > cortisol

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

What is the target tissue of beta-lipotropin?

A

Adipose tissue

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

What is the target pituitary cell of thyrotropin-releasing hormone (TRH)?

A

Thyrotroph

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

What are the hormone products of thyrotrophs?

A

Thyrotropin/thyroid stimulating hormone (TSH)

Prolactin

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

What is the target tissue of TSH?

A

Thyroid gland > thyroid hormones

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

What is the target pituitary cell of gonadotropin-releasing hormone (GnRH)?

A

Gonadotroph

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

What are the hormone products of gonadotrophs?

A
Luteinising hormone (LH)
Follicle stimulating hormone (FSH)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the target tissue of LH and FSH?

A

Gonads > sex steroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the target pituitary cell of growth hormone-releasing hormone (GHRH)?

A

Somatotroph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the hormone product of somatotrophs?

A

Somatotropin/growth hormone (GH)?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the target tissue of GH?

A

All tissues

32
Q

What is the target pituitary cell of somatostatin/growth hormone-inhibiting hormone?

A

Somatotroph

33
Q

What is the target pituitary cell of prolactin-releasing factor (PRF)?

A

Mammotroph

34
Q

What is the hormone product of mammotrophs?

A

Prolactin

35
Q

What is the target tissue of prolactin?

A

Breasts

Gonads

36
Q

Does the hypothalamus-pituitary-adrenal cortex axis have short-loop negative feeedback?

A

No

37
Q

What impacts on the function of the hypothalamus and pituitary?

A

Many structures

38
Q

What is Kallmann syndrome?

A

Embryologically GnRH neurons failed to migrate via olfactory pathway
Hypogonadotropic hypogonadism
Hyposmia or anosmia = loss of smell

39
Q

What is growth?

A

Net synthesis of proteins
Lengthening of long bones
Increased size and number of cells in soft tissues

40
Q

What is needed for growth?

A

GH = essential
Other important factors
- Genetic determination
- Adequate diet
- No chronic disease/stressful environment
- Normal mix of growth-influencing hormones

41
Q

What are some of the hormones influencing growth, other than GH?

A

Thyroid hormones
Insulin
Sex hormones

42
Q

What determines size at birth?

A

Genetics
Environment; eg: drug exposure
Nutrition of mother

43
Q

What has small birth weight been linked with in adulthood?

A

Risk of disease

44
Q

When is the post-natal growth spurt?

A

First two years

45
Q

What happens during the post-natal growth spurt?

A

70% brain growth

46
Q

What is the growth from two years to adolescence?

A

Little sex difference in height and weight

Rate of linear growth declines

47
Q

Can catch-up growth happen if you are born small?

A

Yes, if provided with adequate post-natal environment

48
Q

When does the pubertal growth spurt happen?

A

Adolescence

49
Q

What happens during the pubertal growth spurt?

A

Lengthening of long bones
Genetic and hormonal factors
Testosterone and oestrogen
Full adult height at end of adolescence

50
Q

What are the metabolic effects of GH?

A

Increased blood fatty acid and glucose

During prolonged fasting/body’s energy needs exceeded

51
Q

What are the effects of GH on soft tissue and the skeleton?

A

Hyperplasia and hypertrophy of soft tissues and skeleton

Increased protein synthesis

52
Q

What is the effect of GH on insulin-like growth factors (IGFs)?

A

Increased IGFs from liver

53
Q

What type of chemical is GH?

A

Peptide

54
Q

How is GH transported in the circulation?

A

Half dissolved in plasma, half bound to binding protein

55
Q

What is the half-life of GH?

A

18 min

56
Q

What affects the release of GH?

A
Circadian rhythm of tonic secretion
Influenced by
- Circulating nutrients
- Stress
- Other hormones
57
Q

What are the target tissues of GH?

A

Trophic on liver for IGFs

Acts directly on many cells

58
Q

What controls GH?

A

GHRH

Somatostatin

59
Q

What is the target receptor of GH?

A

Membrane receptor with tyrosine kinase activity

60
Q

What are somatomedins?

A

IGFs: IGF-I and IGF-II = polypeptide growth factor

61
Q

What are the effects of IGF?

A

Insulin-like activity
Antilipolytic activity
Protein synthesis
Epiphysial growth

62
Q

What is required for protein and cell division in tissues?

A

GH

IGFs

63
Q

What is the role of thyroid hormone in IGF activity?

A

Permissive

64
Q

What is the role of insulin in tissue growth?

A

Supports growth

65
Q

What is the role of oestrogen in bone growth?

A

Closes epiphyseal plates of long bones - in males and females

66
Q

What nutrient is required for bone growth?

A

Ca

67
Q

What is the relative importance of thyroid hormones in growth and development?

A

Important very early on in foetal and post-natal development

68
Q

What is the relative importance of GH in growth and development?

A

Important in

  • Brain development
  • Juvenile and childhood life
69
Q

What causes dwarfism?

A

Low levels of GH as child

70
Q

What is Laron dwarfism?

A

GH insensitivity
GH receptors unresponsive
Normal GH

71
Q

What is the effect of GH deficiency in adult onset?

A

Few effects

72
Q

How is GH deficiency treated?

A

Genetically engineered human GH administered

73
Q

What is cretinism?

A

Childhood hypothyroidism > no permissive activity

74
Q

What is achodroplasia?

A

Most common form of dwarfism in humans

Fibroblast growth factor receptor 3 mutation

75
Q

What are some GH independent causes of short stature?

A
Cretinism
Precocious/early puberty
Gonadal dysgenesis
Constitutional delayed/stunted growth
Psychosocial dwarfism
Achondroplasia
76
Q

What is gigantism?

A

Overproduction of GH as child before puberty

77
Q

What is acromegaly?

A

Overproduction of GH as adult
Bone and soft tissue deformities
Increased viscera size and protein content