Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pathophysiology > Thyroid and Parathyroid > Flashcards

Thyroid and Parathyroid Flashcards

(76 cards)

Start Studying
1
Q

The thyroid gland is made up of many spherical reservoirs called _____.

A

acini

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

Acini are filled with _____.

A

colloid

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

What is colloid made up of?

A

thyroglobulin (thyroid binding protein)

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

What does thyroglobulin bind to?

A

thyroid hormone (T3 and T4)

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

What type of thyroid disorder is Grave’s disease?

A

hyperthyroidism

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

What is the function of thyroid follicular cells?

A

these cells surround the colloid. They transport iodine into the colloid space, create thyroglobulin and secrete it into the colloid space and release thyroid hormone from the colloid into the bloodstream.

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

How is iodide transported into the colloid space?

A

Uses a Na+/K+ ATPase pump to transort iodide into the follicular cell (active transport) then into the colloid (secondary active transport)

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

What do the Na+/K+ ATPase pumps on the membrane of the follicular cells respond to?

A

TSH from the anterior pituitary

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

Why is there a massive amount of Golgi, Rough ER, and ribosomes in the follicular cells?

A

to create thyroglobulin (the binding protein) and secrete it into the colloid space

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

Where is thyroid hormone made?

A

WITHIN THE COLLOID!

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

What enzyme is used to make thyroid hormone?

A

Thyroid Peroxidase (TPO)

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

What type of receptor is the TSH receptor?

A

G protein

it works via a signal transduction that increases gene transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the half life of TSH?

A

1 hour

within that time it must bind to a TSH receptor in order to be effective

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

What are four roles of TSH?

A
  1. increases the activity of the Na+/K+ ATPase pump that moves iodine into the thyroid gland
  2. increases production of TPO (thyroid-hormone synthesis protein on the surface of colloid cells)
  3. increases endocytosis of colloid (leads to T3 and T4 entering the blood stream)
  4. stimulates thyroid cell hypertrophy (why a goiter happens when there’s too much of it)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

T1 T2 T3 and T4 are all created within the colloid but which are the only ones that can cross the cell membrane and enter the capillaries?

A

T3 and T4

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

What happens to any T1 and T2 (MIT or DIT) that is brought into the colloid cells?

A

it is digested and its pieces put back into the colloid

this process is controlled by TSH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Malnutrition can affect thyroid function by:

A

decreasing available iodine

decreasing transport protein availability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What essential amino acid is thyroid hormone made from?

A

tyrosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why does thyroid hormones act like a steroid hormone?

A

because it is hydrophobic and non-polar) walks through w

alls and must be bound to a transport protein in the bloodstream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Between T3 and T4, which is faster acting and which has the longer half life?

A

T3 acts faster but T4 has the longer half life (T4 is more protein bound)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does thyroid hormone do when it gets to a target cell?

A

moves into cell passively or through specific transport channels

in the cytoplasm T4 is converted to T3 (the more active version)

binds to receptors within the nucleus

increases gene expression of specific genes to mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is thyroid dysgenesis?

A

absent or hypo functional fetal thyroid tissue?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When would fetal hypothyroidism become an issue for the fetus/infant?

A

since the fetus gets TH from the placenta, it doesn’t rely on its own thyroid for supply until a couple days after delivery

(thyroid testing of newborns is mandatory in all 50 states)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When can the fetus start marking its own thyroid hormone with an intact H-P-T axis?

A

20 weeks gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Thyroid hormone is vital for normal fetal _________.
brain development | significantly affects development of the cerebellum, cell migration, and cell myelination
26
If congenital hypothyroidism is left untreated, what can it cause?
``` jaundice mental retardation excessive sleep poor muscle tone poor feeding low body temp not reaching developmental milestones ```
27
What are effects of thyroid hormone on the cardiac system?
enhance responses to circulating catecholamines
28
What are effects of thyroid hormone on metabolic processes?
catabolic (stimulates lipolysis) it revs up metabolism this is why you would gain weight with hypothyroidism and lose weight with hyperthyroidism
29
What are the effects of thyroid hormone on muscles?
catabolic (protein breakdown) more metabolic effect
30
What is the most common cause of hypothyroidism in the U.S.?
Hashimoto's thyroiditis (autoimmune)
31
What is the most common cause of hypothyroidism worldwide?
iodine deficiency
32
What drugs can cause hypothyroidism?
lithium and antithyroid medications
33
What is Hashimoto's thyroiditis caused by?
antibodies directed against thyroid hormone production (Anti-TPO antibodies) (TPO is the enzyme that synthesizes T1, T2, T3, and T4)
34
Symptoms of Hypothyroidism?
``` lethargy dry skin, thickened hair, hair loss, broken nails diminished food intake but WEIGHT GAIN constipation menorrhagia, diminished libido cold intolerance ```
35
If untreated, hypothyroidism can lead to ______.
myxedema coma
36
What is myxedema coma?
weakness, confusion, swelling, AMS with one or more of the following: ``` hypoglycemia hypotension hyponatremia hypothermia hypocarpnia hypoxia ```
37
What is the most common cause of hyperthyroidism in the U.S.?
Grave's Disease (TSH receptor stimulating antibody) | these antibodies mimic TSH----too much thyroid hormone production
38
Some thyroid masses make thyroid hormone autonomously...what is this classified as?
toxic multinodular goiter
39
When you're thinking of hyper or hypothyroidism, what should you think of first? (as an etiology)
pituitary or hypothalamic tumors
40
There is a definite relationship between the development of Grave's Disease and what part of the immune system?
MHC proteins
41
What is exophthalmos in Grave's disease usually caused by?
muscle cell damage and swelling of extra ocular muscles (probably due to cytotoxic T cells that interact with an antigen in the orbit that's morphologically similar to the TSH receptor)
42
What are some symptoms of hyperthyroidism?
``` weight loss but voracious appetite palpitations heat intolerance poor concentration alertness, emotional lability muscular weakness hyper-defecation ```
43
Is a goiter associated with excess thyroid hormone, normal thyroid hormone, or decreased production of thyroid hormone?
all of them
44
What are some things that cause hypothyroidism with a goiter? (think of processes in which the thyroid is being stimulated but cannot release hormone)
1. iodine deficiency 2. goitrogenic medication 3. lithium (TSH hammering on the thyroid but lithium blocks secretion of hormone)
45
What are some things that cause hyperthyroidism with a goiter? (think of processes in which thyroid is overactive, either in isolated areas or all over)
1. Grave's disease (TSH receptor antibody stimulation) 2. toxic multinodular goiter (autonomous hyperfunction) 3. germ cell tumor (hCG stimulation of gland) 4. thyroiditis
46
Where is 99% of the body's calcium found?
bone and teeth the other 1% is in blood/extracellular fluid
47
In the blood, how is calcium distributed?
50% bound to proteins 50% ionized (traveling as Ca++) a little bit (5% or less) is in salts like CaCO3 or CaHCO3
48
Which type of calcium in the blood is metabolically active?
ionized calcium
49
What parts of the body does PTH affect?
bones, kidneys, and intestines
50
What effect does PTH have on bone?
increased osteoclast activity | increases both Ca++ and PO4 ^-3 in extracellular fluid
51
What effect does PTH have on the kidneys?
increases Vitamin D activation | increases calcium reabsorption
52
What effect does PTH have on the intestines?
absorb more calcium from food
53
What cells make most of the PTH in response to changes in calcium levels?
chief cells
54
What happens with chronic hypocalcemia?
PARATHYROID GLANDS HYPERTROPHY to cause more PTH production so that calcium can be released from storage
55
What is the goal of calcitonin?
lower calcium levels when they're too high
56
What causes the release of calcitonin and where does it come from?
chemoreceptors in C cells cause them to release calcitonin in response to high calcium levels
57
What is the goal of Vitamin D?
increase blood/ECF levels of Ca++
58
What is the source of Vitamin D?
dietary (fish, meat vitamins) OR sunlight conversion of cholesterol to 25-OHD3 kidney conversion to 1,25(OH)D3 (vitamin D)
59
What is the mechanism of action for vitamin D?
1. increase absorption of calcium in the GI tract 2. stimulates osteoblasts stimulates osteoclasts (encouraging bone remodeling)
60
Why does Vitamin D act like a steroid?
it's a cholesterol-based compound so it crosses cell membranes into the nucleus and directly alters DNA expression
61
What does Rickets (in children) and osteomalacia (in adults) have in common?
both are deficient bone mineralization (bones are soft and easily fractured)
62
What is the major cause of rickets and osteomalacia?
Vitamin D deficiency
63
What is osteoporosis?
decrease in bone mass and strength (leads to increased incidence of fractures)
64
What is a common cause of osteoporosis?
too little bone use too much reabsorption or too little of a hormone favoring bone formation
65
Bone is remodeled all the time. What are the jobs of osteoclasts and blasts?
class break down an area of bone blasts come in to replace the bone (they do this work using Ca++ and PO4^-3)
66
What is the age of peak bone mass?
28 yo
67
What is a common cause of osteoporosis in women?
decreased levels of estrogen (estrogen increases osteoclast apoptosis and decreases osteoblast apoptosis....so without estrogen osteoclasts liver longer and blasts are short-lived)
68
Bone density is governed by the amount of available: (4 things)
calcium phosphorous vitamin D PTH
69
Primary Hyperparathyroidism can be due to....
a single adenoma can also be genetically based (MEN-1, MEN-2a, MEN-2b)--genetic predispositions to particular constellations of endocrine disorders
70
What is the most common cause of secondary hyperparathyroidism?
kidney failure can also be caused by chronic bone disease
71
What are symptoms of hyperparathyroidism?
bones, stones, groans, and psychic moans ``` kidney stones osteoporosis elevated serum Ca++ fractures bone pain fatigue depression arrhythmia ```
72
What is the most common symptom of hyperparathyroidism?
no symptom at all or nonspecific systems RISKS for all the symptoms but don't actually have to see them
73
What are some causes of hypercalcemia?
primary hyperparathyroidism (benign tumor in one of the four parathyroid glands) cancer can lead to hypercalcemia of malignancy excessive ingestion of vitamin D (even though PTH levels will be very low)
74
What are symptoms of hypercalcemia?
tiredness lethargy with muscle weakness nausea and vomiting
75
What is pseudohypoparathyroidism?
plenty of PTH but tissues are resistant to its effects ----hypocalcemia (usually without osteoporosis)
76
What are some symptoms of hypocalcemia?
increased excitability of nerves and muscles (seizures, muscle spasms, hypocalcemia tetany, nerve excitability)

Pathophysiology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions