Overview of Endocrinology and Pituitary

Question 1

Describe the endocrine system

Answer 1

• The endocrine system is a system of glands that release hormones
• There are relatively low concentrations of hormones at target and the receptors have high affinity to them

Question 2

What are components of the endocrine system?

Answer 2

• Pineal gland
• Hypothalamus
• Pituitary gland
• Thyroid gland
• Thymus
• Pancreas
• Adrenal glands
• Testes/ ovaries

Question 3

Define hormones and describe how they work

Answer 3

• Hormones are chemical messages released by the endocrine glands

• The goal of a hormone is to mediate changes within a target cells. It does this by binding to specific hormone receptors on the cell
• When hormones bind to the receptor, a signal transduction is activated that leads to a response
• The hormones can work by activating genes or activating secondary messengers

Question 4

Explain the feedback control of hormone secretion

Answer 4

• Mostly, it is a negative feedback loop
• Normally, the hypothalamus secretes hormones to the pituitary which impacts the endocrine cells of the pituitary. Here, the pituitary releases the secondary wave of hormone release
• The hypothalamus releases the “releasing hormone” which signals the anterior pituitary to release the “stimulating hormone”
• The “stimulating hormone” works on the target organ/ cell. The target organ begins releases its “endocrine hormones”.
• The presence of this hormone has an inhibitory effect on the hypothalamus and anterior pituitary release of the precursor hormones

Question 5

Describe the relationship of the hypothalamus and pituitary gland

Answer 5

• The hypothalamus receives signals from the nervous system and funnels these signals to the pituitary gland
• The pituitary gland will then control the hormone response
• There are two parts to the pituitary glands; anterior and posterior

Question 6

Describe how the hypothalamus interacts with the anterior pituitary gland

Answer 6

• Hypothalamus interacts with this through the hypophyseal portal system
• It is a system if capillaries
• The hypothalamus secretes hormones into this system and it travels down to the anterior pituitary gland

Question 7

Describe how the hypothalamus interacts with the posterior pituitary gland

Answer 7

• Hypothalamus interacts with this by sending signals down the nerves in the infundibulum (pituitary stalk)
• This causes the pituitary gland to release hormones
• These hormones are made in the hypothalamus but are stored in the pituitary

Question 8

List disorders of the pituitary gland (3)

Answer 8

• Pituitary adenomas
• Hypopituitarism
• Cancer
• Acromegaly

Question 9

Describe pituitary adenomas

Answer 9

• A growth or tumour on thepituitary.

* It can cause over-production of hormones, such as too much GH = giantism, or too much ACTH = Cushing’s disease

Question 10

Describe hypopituitarism and list a condition associated with it

Answer 10

• Gland doesn’t produce enough hormones = Diabetes insipidus(DI), a condition characterized by large amounts of dilute urine and increased thirst

Question 11

Differentiate gigantism and acromegaly

Answer 11

Gigantism happens during childhood while acromegaly happens in adulthood

Question 12

List the oral manifestations associated with gigantism

Answer 12

• Interdental spacing, malocclusion
• Teeth size are proportional to enlarged body size
• Hypercementosis of roots

Question 13

List the oral manifestations associated with acromegaly

Answer 13

• Thick lips
• Macroglossia
• Enlarged prognathic mandible
• Class III malocclusion
• Hypercementosis
• Salivary gland enlargement
• Spacing
• Anterior open bite

Question 14

List the oral manifestations associated with hypopituitarism

Answer 14

• Delayed eruption
• Smaller clinical crown, smaller roots and smaller arches
• Crowding and malocclusion
• Retarded growth of mandible