Chapter 33 Pituitary Flashcards

1
Q

Describe the biological function of ADH

A

It has two effects on the body, one on the kidney and one on the vascular system

ON the kidney
-It conserves body water by reducing the loss of water in urine
-To maintain a normal plasma osmolality (solute concentration by increasing water reabsorption by the kidney

On the Vascular system
Vasoconstriction leading to increase in systemic vascular resistance and increase in blood pressure

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2
Q

Describe the regulation of ADH secretion by plasma osmolality

A

Water deprivation leads to increase in plasma osmolality which then effects the osmoreceptors neurons in the hypothalamus to detect that the plasma osmolality is higher than normal so it stimulates and increases ADH secretion which leads to more water reabsorption and it returns to the normal plasma osmolality

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3
Q

Describe the regulation of ADH secretion by blood pressure and blood volume

A

When both blood pressure and blood volume decreases, the drop is detected by the baroreceptors and stretch receptor so that stimulates the hypothalamus ADH neuron which then stimulates the increase in ADH secretion which then causes both the Blood pressure and blood volume to increase and return to the normal range

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4
Q

Describe abnormally increased hormone secretion caused by pituitary adenoma

A

It is a hormone secreting adenoma that secrets 4 major hormones

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5
Q

Name 3 major hormones that are secreted by pituitary adenoma

A

Prolactin secreting adenoma (prolactinoma)-most common
Growth hormone
ACTH

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6
Q

Describe how the mass effect of pituitary adenoma causes visual field defects

A

The mass causes compression on the optic nerve which effects the vision

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7
Q

Describe how the mass effect of pituitary adenoma causes hypopituitarism

A

Because the destruction of pituitary happens and lose of one or more pituitary hormones occurs due to the compression of the pituitary cells

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8
Q

Describe 2 clinical consequences of hyperprolactinemia

A

Galactorrhea
-which is the production and discharge milk or a milk like liquid, unrelate to breast feeding

Impaired reproductive function
-Amenorrhea, irregular menses, infertility

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9
Q

Describe the pharmacological treatment (medication) for hyperprolactinemia

A

As mentioned before prolactin secretion is inhibited by Dopamine so,

The dopamine agonists bind to the dopamine receptors in the anterior pituitary and decrease prolactin synthesis, limits cell multiplication and reduce tumour size

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10
Q

Describe the major cause of and clinical consequences of excessive secretion of GH

A

Gigantism and Acromegaly

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11
Q

Describe the difference between acromegaly and gigantism

A

Gigantism happens before puberty and acromegaly happens between the ages of 20-40

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12
Q

Describe the 3 possible complications of acromegaly

A

Sleep apnoea
type 2 diabetes
Heart disease

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13
Q

Describe the treatment options for acromegaly

A

-Surgery (removal of tumor)
- Radiation therapy
- Medications: Somatostatin analogue- which helps inhibit growth hormone

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14
Q

Describe the causes of hypopituitarism

A
  1. Most common cause is pituitary adenoma (mass effect)
  2. Head injury , brain surgery , radiation treatment , etc.
  3. Genetic mutations (genes involved in endocrine cell development )
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15
Q

Describe the clinical consequences of GH deficiency ( in children and adults)

A

Children : dwarfism and delayed puberty
Adults : Low bone density , decreased muscle mass and strength

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16
Q

Describe the clinical features of diabetes insipidus

A

Urine output increase

Fluid intake increase

Plasma osmolality increase

Urinary osmolality is lowered becuase of less water reabsorption

Urine specific gravity decrease

Serum concentration of sodium increases

17
Q

Describe the difference between central and nephrogenic diabetes insipidus

A

Central is damage caused in the brain and nephrogenic is defect caused in the kidney

Central is reduced ADH secretion and nephrogenic is normal or elevated ADH secretion

18
Q

Describe the treatment of central diabetes insipidus

A

Hormone replacement therapy (ADH analogue treatment)