lecture 5 part 2

Question 1

Question 2

Question 3

Thyroid gland abnormalities

Answer 3

Hypothyroidism
Cretinism
Myxedema
hyperthyroidism

Question 4

Hypothyroidism

Answer 4

Causes
Primary failure of thyroid gland
Secondary to a deficiency of TRH, TSH, or both
Inadequate dietary supply of iodine

Question 5

Cretinism

Answer 5

Results from hypothyroidism from birth
Dwarfism & mental retardation

Question 6

Myxedema

Answer 6

Puffy appearance primary in face, hands and feet
Infiltration of skin with complex water-containing carbohydrates
Treatment
Replacement therapy
Dietary iodine

Question 7

Hyperthyroidism

Answer 7

Most common cause is Graves’ disease
Autoimmune disease
Body erroneously produces thyroid-stimulating immunoglobulins (TSI)
Characterized by exopthalmos
Complex water-retaining carbohydrates are deposited behind the eyes
Treatment
Surgical removal of a portion of the over-secreting thyroid
Administration of radioactive iodine
Use of antithyroid drugs

Question 8

Hyperthyroidism symptoms

Answer 8

Increases oxygen consumption and metabolic heat production
Warm, sweaty skin
Intolerant to heat

Net degradation of carbohydrate, fat and protein stores

Increase protein catabolism may cause muscle weakness
Patients report weight loss

Hyperexcitable reflexes and psychological disturbances
Irritability, insomnia, psychosis
Mechanisms unclear – morphological changes in hippocampus & effects on β-adrenergic receptors

Influence B-adrenergic receptors in the heart
Rapid heartbeat & + force of contraction – upregulation of β1-receptors in myocardium

Question 9

Hypothyroidism symptoms

Answer 9

Slow metabolic rate and oxygen consumption
Patients intolerant to cold
Gain excessive weight (not burning fuels at normal rate)
Easily fatigued (lower energy production)

Decreased protein synthesis
In adults: brittle nails, thinning hair, dry thin skin

Accumulation of mucopolysaccharides under skin – puffy appearance of myxedema

Slowed reflexes, slow speech and thought processes, and feelings of fatigue

Bradycardia – slow heart rate, slow weak pulse

Cretinism in infants – decreased mental capacity (thyroid hormone – essential for normal development of CNS): dwarfism
Children: slow bone & tissue growth – shorter than normal for their age

Question 10

A goiter can occur in both hyperthyroidism and hypothyroidism
- Hypothyroidism:

Answer 10

primary hypothyroidism
I2 shortage
- is a trophic hormone, this affects all the way through to thyroid gland

Question 11

A goiter can occur in both hyperthyroidism and hypothyroidism
- Hyperthyroidism:

Answer 11

Grave’s Disease (hyperthyroidism)
- bodies produce antibodies (TSI) which stimulates the thyroid gland
- these antibodies are an outside source and thus aren’t apart of the negative feedback mechanism = goiter

Question 12

Answer 12

Exophthalmus, caused by hypertrophy of tissues in the eye socket due to complex water-containing carbohydrates deposited behind the eye, a sign of hyperthyroidism

Question 13

Hashimoto disease

Answer 13

opposite of graves disease = hypothyroidism
- antibodies destroy the thyroid gland
- which decreases T3 and T4 levels

Question 14

Hypothyroidism

Answer 14

Primary failure of thyroid gland
Secondary failure of thyroid gland
Lack of dietary iodine

Question 15

Hyperthyroidism

Answer 15

Grave’s disease
Secondary hypersecretion
Hypersecreting thyroid tumour

Question 16

Therapy

Answer 16

Hypothyroidism: oral T4 = inactive form

Hyperthyroidism:
Surgical removal of gland
Destruction of thyroid cells by radioactive iodine
Drugs block hormone synthesis (thiourea drugs)
Drugs block peripheral conversion of T4 to T3 (target deiodinase)

Question 17

PP5 from slide 30 - end