Endocrine system II - Pituitary hormones Flashcards

1
Q

Pituitary Gland

A

Anterior (glandullar cells)
Adenohypophysis (gland)

Posterior (neural)
Neurohypophysis

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2
Q

Hypothalamus-Pituitary

A

Cell bodies and the neurons responsible for the secretion of hypothalamic releasing factors (hormones)

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3
Q

Anterior
Hypothalamus-Pituitary

A

Releasing factors pass along the portal vessels to reach capillary bed of the anterior pituitary, to control secretion of anterior pituitary hormones

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4
Q

Posterior
Hypothalamus-Pituitary

A

Paraventricular (PVN) and supraoptic (SON) nuclei, and the neurons carrying oxytocin and ADH (vasopressin) to the posterior pituitary, where they are stored/ released

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5
Q

Anterior pituitary hormones

A

somatotrophs somatotropin GH

corticotrophs corticotropin ACTH

thyrotrophs thyrotropin TSH

gonadotrophs gonadotropins LH, FSH

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6
Q

Pituitary Gland

A

Pituitary tumours are mostly benign and
slow-growing

Over/under production of hormones (Hyper/Hypo)

Local effects: pressure on surrounding structures
– headaches, visual disturbances

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7
Q

Somatotropin, GH

A

It is stored in the cells as granules. Growth hormone production is pulsatile

Peptide hormone: 21.5 K Da single-chain polypeptide (190 AA) with 2 disulphide bridges)

Major role in growth (linear) & metabolism

Drop in blood glucose

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8
Q

GH, Function

A

Protein synthesis increases in muscle, so does gluoconeogenesis in liver and blood glucose increases

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9
Q

Direct GH

A

on metabolism

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10
Q

Indirect GH

A

growth

Insulin-like growth factors (somatomedins) from liver

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11
Q

Whta influences GH release?

A

Blood glucose, free fatty acids and amino acid levels

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12
Q

List GH, diseases

A

a) Dwarfism (stunted growth)

b) Gigantism in children/Acromegaly in adults

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13
Q

a) Dwarfism (stunted growth)

A

Psychological changes

Malaise, excessive tiredness, anxiety and depression

Osteoporosis

Poor muscular tone, decrease in lean body mass

Impaired hair growth

Increase in adipose tissue (especially around the waist)

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14
Q

b) Gigantism in children/Acromegaly in adults

A

coarsening of facial features

enlarged hands and feet

headaches, vision disturbance

sleep apnoea, general tiredness

hypertension, cardiomegaly

glucose intolerance (diabetes)

irregular or loss of periods (females); impotence (males)

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15
Q

Thyroid hormones” – thyroxine (T4) and tri-iodothyronine (T3) - calcitonin & parathyroid hormone (PTH)

A

Calcitonin produced by parafollicular C cells (acts to reduce plasma calcium)

PTH is produced by parathyroid glands (4x small glands located in posterior surface of thyroid gland, they increase plasma calcium (oppose calcitonin effect)

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16
Q

one iodination = MONO-iodotyrosine

A

Tyrosine, iodinated at 3’ of ring = MIT

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17
Q

T3

A

active hormone
Synergistic effect with sympathetic/catecholamine
(T3 increase the expression adrenergic receptors)
Basal Metabolic Rate (BMR): Sugar, Fat, Protein
Growth & Development: CNS

18
Q

T4

A

circulating as a pro hormone

19
Q

Goitre – enlarged thyroid gland

A

DIFFUSE
NODULAR

20
Q

DIFFUSE

A

Cause
Primary failure of thyroid gland
(~ 90%: Hashimoto’s thyroiditis)

Secondary to hypothalamic or ant. pituitary failure

Lack of dietary iodine (simple non-toxic goitre)

Drug-induced
(e.g. anti-thyroid drugs, lithium, amiodarone)
Radioactive iodine therapy, surgery
Thyroid hormone resistance

Plasma [ ] of hormones + Goitre present?
Less T3 and T4, more TSH, Yes

less T3 and T4, less TSH, No

less T3 and T4, more TSH, Yes

21
Q

NODULAR

A

Cause:
Abnormal levels of thyroid-stimulating immunoglobulins
(Graves’ disease)

Secondary to excess hypothalamic or
ant. pituitary secretion

Hyper-secreting thyroid tumour
(Toxic multinodular goitre, toxic adenoma)

Iatrogenic causes (e.g. amiodarone, lithium)

Plasma [ ] of hormones + Goitre present?

^T3 and T4, low TSH, Yes

^T3 and T4, ^TSH, Yes

^T3 and T4, low TSH, Yes

22
Q

What is T3 function?

A

BMR (basic metabolic rate);
Body core temperature
Sweating
Thermal discomfort
Appetite
Body weight
Bowels

Hyperthyroid

Heat intolerance

Weight loss
Diarrhoea
INCREASE in HR, MAP (palpation)

Hypothyroid
decrease
cold intolerance
decrease
weight gain
constipation

23
Q

The function of T3 - growth and development: CNS

A

Anxiety, emotional, irritable, restless, tremor
Growth acceleration

Depression, confusion, poor memory, difficulty in concentrating Cretinism (perinatal)
Growth deficiency (childhood)
Dry skin, hoarse voice, menstrual problems

24
Q

T3 ______ the expression adrenergic receptors

A

increases

[synergistic effect with sympathetic/catecholamine]

25
Q

Relate hyperthyroid to the digestive system?

A

BMR is higher, even though the individuals have a bigger appertite and consume more they do not gain weight at their metabolism is faster.

Food&raquo_space;> diarrhoea

26
Q

Hyperthyroid, increase or decrease in HR/MAP?

A

INCREASE
= palpitation

27
Q

Hypothyroid ______ in HR and MAP. What does this cause?

A

decrease - hypotension

28
Q

What is most common hyperthyroidism?

A

Thyroid Stimulating Immunoglobulins (TSI) activate the thyroid gland to produce and release thyroid hormones

(Autoimmune disease)

29
Q

What are the symptoms of autoimmune disease?

A

nervousness
palpitations
weight loss
tremor
sweating
heat intolerance & goitre

(Also, exophthalmos)

30
Q

What is the process of Hypothalamic releasing hormones and anterior pituitary tropic hormones??

A

hormones in the hypothalamus gets released to the Anterior pituitary

These are the n transferred to Peripheral endocrine gland

31
Q

Hormones from the anterior pituitary go to …..

A

glands

32
Q

LH + DSH hormones are received by which gland?

A

Gonads > Sex hormones

33
Q

GH hormone is received by:

A

the liver > IGF - 1

34
Q

TSH hormone goes to:

A

Thyroid > thyroid hormones

35
Q

Prolactin hormone thats found in the:

A

breast tissue

36
Q

ACTH hormone»»

A

Adrenal cortex&raquo_space;> cortisol

37
Q

What is prolactin for?

A

stimulates lactation in mammary glands (produce milk)
promotes growth & development of the breasts

38
Q

High secretion of prolactin INHIBITS;

A

Growth hormone-releasing hormone )GnRH release)

39
Q

What is Prolactinoma ?(Excess/Hyperprolactinaemia)

A

Loss of fertility/ libido, galactorrhea

(common in women)

40
Q

Hypothalamus releases dopamine to poituitary and ______ is secreted

A

prolactin ( in breast tissue)
prolactin controls the dopamine release from the hypothalamus in the brain

41
Q

Process of secretion of prolactin = wha happens to breast?

A
  • breast differentiation
  • duct proliferation and branching
  • glandular tissue development
  • milk protein synthesis
  • lactogenic synthesis