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Endocrine Physiology > VePHY M3 > Flashcards

VePHY M3 Flashcards

1
Q

Function of thyroid hormones in the body

A

Growth regulation, differentiation, metabolism of lipids, proteins, and carbohydrates

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2
Q

In these species, the main
lobe of the thyroid is on the midline in the ventral cervical
region with dorso-lateral projections from each side

A

pigs

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3
Q

thyroid gland major supply of blood

A

cranial thyroid artery

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4
Q

thyroid gland principal venous drainage

A

caudal thyroid vein

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5
Q

True or False. The thyroid has a rich supply of sympathetic nerves associated with blood vessels thought to regulate the blood supply to the
organ

A

True

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6
Q

Components of thyroid glands in adult animals

A

follicular cells, parafollicular cells, colloid, interstitial CT

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7
Q

common in the dog and may be located anywhere from the larynx to the diaphragm

A

accessory thyroid tissue

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8
Q

the right lobe of the thyroid is situated slightly cranial to the left lobe and almost touches the caudal aspect of the larynx

A

dogs

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9
Q

its role is for the synthesis and packaging of
substantial amounts of proteins primarily thyroglobulin

A

Follicular cells

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10
Q

its vascular supply fluctuates considerably depending upon the activity of the gland

A

thyroid

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11
Q

majority of the epithelial cells and the most important functional cells of the thyroid

A

follicular cells

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12
Q

caused by iodine deficiency in the diet

A

diffuse thyroid hyperplasia or goiter

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13
Q

Example of goitrogenic substances

A

thiouracil, sulfonamides, complex anions, plants from family brassicacceae

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14
Q

the only tissue of the body which is able to accumulate iodine in large quantities and incorporate it into hormones

A

thyroid gland

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15
Q

peptide hormone of the mammalian thyroid that has been shown to be secreted by C-cells

A

calcitonin

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16
Q

assembly of thyroid hormones within the follicular lumen is made possible by a unique protein

A

thyroglobulin

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17
Q

thyroglobulin is synthesized in?

A

RER of Follicular cells

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18
Q

essential component of thyroid hormones, is incorporated within the molecular structure of thyroglobulin

A

tyrosine

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19
Q

MIT and DIT combine to form the two biologically active

A

iodothyronines

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20
Q

essential for maintaining constant blood levels of thyroid hormones in vertebrates under conditions of varied intake of iodine and varying metabolic demand for T4 and T3

A

extracellular storage of thyroglobulin

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21
Q

comprise a second endocrine cell population in the mammalian thyroid gland

A

C cells

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22
Q

active transport of iodine has been shown to be associated with

A

NIS

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23
Q

These other glands have the capacity to actively transport iodide, albeit at a much lower level than the thyroid

A

salivary gland, gastric mucosa, and lactating mammary gland

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24
Q

These chemicals effectively block the ability of the gland to synthesize thyroid hormones

A

Perchlorate, Thiocyanate

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25
Q

accomplished by the coordinated response of the adenohypophysis and hypothalamic nuclei to circulating levels of T4 and T3

A

negative feedback control

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26
Q

binds to receptors on the plasma membrane of thyrotropic basophils in the adenohypophysis and activates adenylate cyclase

A

thyrotropin releasing hormone

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27
Q

Where does clearance of thyroglobulin from the circulation take place

A

Kupffer cells of liver

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28
Q

incorporated not only into newly synthesized thyroglobulin recently delivered to the follicular lumen but also into molecules already stored in the lumen

A

iodine

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29
Q

function as coupling enzyme to combine MIT and DIT to form T3

A

thyroperoxidase

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30
Q

daily maintenance requirement of iodine of 10 to 15 kg adult dog

A

140

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31
Q

Most of the iodine in the diets is reduced to iodide in this organ

A

GI tract

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32
Q

Which glands clear iodide from plasma

A

thyroid gland, salivary gland, gastric mucosa

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33
Q

how much is the net daily uptake of iodide in a dog

A

75

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34
Q

Two-thirds of the iodine is in the form of

A

MIT and DIT

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35
Q

About one-fourth of iodine is in these forms, all of which are incorporated in thyroglobulin molecules in the follicular colloid

A

T3 and T4

36
Q

About 40 percent of the extrathyroidal T4 in the dog is present in

A

plasma

37
Q

60 percent of extrathyroidal T4 is taken up by which organ

A

liver

38
Q

total plasma equivalent space of distribution of T4 is about

A

12 percent of bw

39
Q

peak concentration usually occurs at about

A

midday

40
Q

most important enzyme in the synthetic pathway of thyroid hormones

A

thyroperoxidase

41
Q

m

A
42
Q

About 45 percent of the turnover of T4 is via

A

deiodination

43
Q

55 percent of T4 turnover is via

A

fecal excretion

44
Q

70 percent of T3 turnover is via

A

deiodination

45
Q

30 percent turnover of T3 is via

A

fecal excretion

46
Q

ratio of T4 to T3 in thyroglobulin

A

3.6 is to 1

47
Q

ratio of the daily production rates, based on plasma concentration and turnover of T3 and T4

A

2 is to 1

48
Q

stimulates oxygen utilization and heat production by many different cells of the body

A

thyroxine

49
Q

Functions of thyroxine

A

increased utilization of carbohydrates, increased protein catabolism and excretion of nitrogen, oxidation of fats, and loss in body weight

50
Q

increase the heart rate by a direct effect on heart muscle cells

A

thyroxine

51
Q

Effects of thyroxine deficient

A

CNS fail to function, lethargy, dull, mentally deficient, myelin fiber content decreased, cortical neurons smaller and fewer, vascularity of CNS is reduced

52
Q

True or False. The neuronal dysfunction caused by thyroxine deficiency is reversible in the adult animal but not in the
young growing animal

A

True

53
Q

effects of thyroxine excess secretion to animals

A

Nervous, jumpy, irritable and hyperactive

54
Q

These dog breeds are commonly affected with hypothyroidism

A

Doberman pinschers, golden retrievers, beagles

55
Q

is the result of primary diseases of the thyroid gland, especially idiopathic follicular atrophy

A

clinical hypothyroidism

56
Q

closely resembles Hashimotos disease in humans and appears to be genetically conditioned

A

lymphocytic thyroiditis

57
Q

caused by production of autoantibodies directed against
thyroglobulin

A

chronic lymphocytic thyroiditis

58
Q

Many clinical signs associated with hypothyroidism are due to

A

reduction in basal metabolic rate

59
Q

Clinical signs of hypothyroidism in dogs

A
60
Q

Clinical signs of hypothyroidism in cats

A

prolonged periods of apathy, poor hair growth, severe seborrhea, and myxedema of the face

61
Q

Hypothyroidism in chicken observed signs

A

small, moderately obese with increased accumulations of abdominal fat, have a small, dry comb, and an abnormally silky plumage

62
Q

other terms for idiopathic follicular atrophy

A

follicular collapse, lymphocytic thyroiditis

63
Q

Severe hypothyroidism and long standing hyperlipidemia may result to

A

atherosclerosis of coronary and cerebral vessels

64
Q

Tx of hypothyroidism

A

oral administration of synthetic thyroxine or triiodothyronine on a daily basis

65
Q

most common in adult cats and often related to adenomas composed of hyperactive follicular cells

A

hyperthyroidism

66
Q

clinical term for a non-neoplastic and non-inflammatory enlargement of the thyroid gland

A

goiter

67
Q

it is a potent thioglycoside from plants excreted in milk

A

goitrin

68
Q

associated with weight loss in spite of a normal or increased appetite and with restlessness and increased activity

A

hyperthyroidism

69
Q

associated with prolonged low-level exposure to thiocyanates produced by the ruminal degradation of cyanogenic glucosides

A

hyperplastic goiter in ruminants

70
Q

Congenital hypothyroidism in domestic animals may be associated with

A

iodine deficient hyperplastic goiter

71
Q

Effects of iodine deficient goiter in foals

A

moderately enlarged thyroids, are weak at birth, frequently die within a few days after birth

72
Q

these species with goiter born partially or completely hairless and are
either born dead or die soon after birth

A

calves

73
Q

effects of goiter in newborn pig, goats, and lambs

A

myxedema and hair loss

74
Q

endocrinologically inactive and encountered as an incidental lesion at necropsy

A

multinodular goiter

75
Q

one of the two most common endocrine diseases in adult-age cats

A

hypperthyroidism

76
Q

Congenital goiter is inherited as an autosomal recessive gene in these animals

A

sheep, afrikander cattle, saanen dwarf goats

77
Q

characterized by the inability of the animal to synthesize and secrete adequate amounts of thyroid hormones prior to or at birth

A

congenital dyshormonogenetic goiter

78
Q

plasma half life of T4 in rats

A

12 to 24 hours

79
Q

these species do not synthesize high affinity for transport proteins of T3 and T4

A

rodents, birds, amphibians, fish

80
Q

functions primarily as a prohormone and undergoes a single deiodination of the phenolic ring in extrathyroidal tissues to form the metabolically more active T3

A

T4

81
Q

disrupt one or more steps in the synthesis and secretion of thyroid hormones

A

exobiotics and drugs

82
Q

frequently used for the diagnosis of thyroid diseases in animals

A

thyroid function tests

83
Q

plasma half life of T4 in monkeys and humans

A

5-9 days

84
Q

most direct indicator of hypothyroidism

A

measurement of basal oxygen consumption

85
Q

most sensitive and accurate method for measurement of circulating levels of total thyroxine and triiodothyronine

A

radioimmunoassay

86
Q

a useful and reliable aid in the diagnosis of thyroid disease in animals

A

histological examination of biopsy of thyroid gland

Endocrine Physiology (5 decks)

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