Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Human Development > Thyroid Gland > Flashcards

Thyroid Gland Flashcards

1
Q

Where is the thyroid gland

A

Sits on trachea - two lobes joined by isthmus

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

When is the thyroid gland enlarged

A

Adolescence, pregnancy, lactation, later portion of menstrual cycle

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

What is the blood supply of the thyroid

A

superior (from external carotid) and inferior (from subclavian artery) thyroid arteries
Blood flow 4-6 ml/min/g tissue

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

What does the thyroid gland make

A

T4 and T3
Calcitonin - involved in Ca2+ metabolism ( opposing action of PTH)
Functions: neural development n foetus, growth in the young child, controls basal metabolic rate
Concentrates iodine for incorporation into thyroid hormones

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

What does PTH do

A

secreted in response to low blood serum Ca2+ levels, indirectly stimulates osteoclast activity within bone marrow

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

Describe thyroid hormone cycle

A

TRH stimulates thyrotrophs in anterior pituitary to produce TSH. TSH stimulates thyroid gland to synthesise and release thyroid hormones
Main hormone released is T4íT3 in the periphery
T3 more potent at thyroid receptors than T4
T3 acts on the thyrotrophs to decrease release of TSH/decrease release of TRH from hypothalamus

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

What does the colloid contain

A

Precursor to thyroid hormones

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

What does the parafollicular do

A

Secrete calcitonin

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

What does the phagosome/lysosome do

A

break down thyroglobulin to release T3 and T4

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

How are thyroid hormones synthesised

A

Active uptake of iodine
Synthesis of glycoprotein thyroglobulin
Organification of iodine by thyroid peroxidase in the presence of hydrogen peroxides

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

Describe thyroid hormone binding

A

Thyroid hormones interact with nuclear receptors
Enters cell by diffusion or by specific carrier
T3 enter the nucleus and binds to thyroid receptor
Hormone receptor complex binds to thyroid hormone responsive element on DNA

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

What are the effects of thyroid hormones

A 
O2 consumption and heat production
Cardiac muscle contractility
Sensitivity to catecholamines
Maintenance of hypoxic and Hypercapnic drive in respiratory centre
Gut motility
Erythropoiesis
Bone turnover
Protein turnover - decrease in muscle mass
Cholesterol degradation
Metabolic turnover of hormones and drugs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the signs of hypothyroidism

A

Cold intolerance, weight gain, constipation, slow reflexes, hypercholesterolemia, hyperprolactinaemia, dry skin, hoarse voice, slow movements, coarse hair and skin, periorbital puffiness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the usual range of T4

A

9-23.8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the usual range of TSH

A

0.49-4.67

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

What are the serum levels for primary hypothyroid

A

High TSH, low T4

17
Q

What are the serum levels for primary hyperthyroid

A

High T4, low TSH

18
Q

Describe the types of hypothyroidism

A

Usually primary autoimmune (destruction of thyroid)
Atrophic thyroiditis: small and shrivelled thyroid
Hashimoto thyroiditis: enlarged thyroid
Thyroid peroxidase antibodies present

19
Q

What is the treatment for hypothyroidism

A

Treat with levothyroxine 75-125 mcg per day, check treatment with TFTs blood tests

20
Q

What is the difference between thyrotoxicosis and hyperthyroidism

A

Thyrotoxicosis is the clinical syndrome of too much thyroid hormone
Hyperthyroidism is case where thyroid is making too much thyroid hormone

21
Q

What are the signs of hyperthyroidism

A

Mood and behavioural changes, restlessness, shaking, sweating, palpitations, breathlessness, diarrhoea, muscle stiffness and weakness
Lid retraction from sympathetic activation
Lid lag
Pre-tibial myxoedema

22
Q

What is the most common cause of hyperthyroidism

A

Grave’s disease (most common) - stimulating antibodies to TSH receptor. Can also get tearing of eyes and thyroid acropachy (clubbing of fingernails) and Grave’s dermopathy

23
Q

What investigations should be done for Grave’s

A

TFTs, antibodies, thyroid uptake scan, ultrasound of thyroid

24
Q

What is the treatment for Grave’s

A

Carbimazole 40mg or propylthiouracil 200mg for 6-12 months
Radio-iodine - avoid in thyroid eye disease
Surgery

25
Q

What are the other causes of TNG

A

Unregulated TSH excess
hCG mediated
Excess thyroid hormone medication
Thyroiditis: can fluctuate between hyper, eu and hypo
Painless - lymphocytic thyroiditis (post-partum), Hashimoto’s thyroiditis
Painful - granulomatous thyroiditis, radiation induced thyroiditis

26
Q

What is a toxic thyroid nodule

A

Hyper-functioning nodule develops within a longstanding goiter. This results in hyperthyroidism, without the eye bulging effects seen in Grave’s disease

27
Q

Describe thyroid cancer

A

Main type is papillary thyroid cancer
Others: follicular, medullary (linked with MEN2, tumour marker is calcitonin), anaplastic
Prognosis of PTC is excellent

28
Q

What are the side effects of hyperthyroidism treatment

A

neutropenia and angranulocytosis (severe and dangerous leukopenia)

Human Development (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions