Brainscape's Knowledge GenomeTM

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


See full index

General Pathology VDMP832 > Thyroid (Endocrine 2) > Flashcards

Thyroid (Endocrine 2) Flashcards

1
Q

Thyroid Gland:

Structure

A
  • Two lobes with narrow isthmus
  • Thyroid epithelail cells
    • arranged in follicles
    • produce thyroid hormone
  • Thyroid-C cells
    • Small affrefates of cells between follicles
    • Produce calcitonin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Thyroid Gland:

Function:

Thyroid Hormones

A
  • Increased metabolism
  • Stimulate heart and neural function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Thyroid Gland:

Function:
Calcitonin

A
  • Regulateion of serum calcium concentrations
    • inhibition of osteoclasts and bone resorption and synergistic with parathormone to decrease renal phosphorus absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Thyroid Gland:

Function:

Regulation of Adrenal Function

A
  • Hypothalamic releasing factors
  • Pituitary hormones
    • TSH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Thyroid Gland:

Dysfunction:

Hyperfunction (Hyperthyroidism)

A
  • Usually primary thyroid involvement
  • Polyphagia, weight loss, weak, thachycardia
  • Most common in cats
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Thyroid Gland:

Dysfunction:

Hypofunction (Hypothyroidism)

A
  • usually primary thyroid involvement
  • Inactivity, alopecia, lethargy, weight gain, obesity
  • Most common in dogs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Thyroid Gland:

Pathogenesis:

Metabolic

A

Thyroid dysfunction will result in metabolic alterations

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

Thyroid Gland:

Pathogenesis:

Neoplasia

A

Usually functional, sometimes non-functional

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

Thyroid gland:

Pathogenesis:

Cell Alteration and injury

A

Hyperplasia and atrophy are common

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

Thyroid Gland:

Pathogenesis:

Immunopathology

A

Autoimmune destruction of the thyroid

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

Thyroid Glands:

Pathogenesis:

Developmental

A

Ectopic Thyroid tissue

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

Thyroid Gland:

Causes:

Genetic Predisposition

A
  • Thyroid neoplasia, hyperplasia, and autoimmunity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Thyroid Gland:

Causes:

Nutritional

A
  • Deficiency of Iodine, tyrosine or other thyroglobulin components
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Thyroid Gland:

Causes:

Chemical

A
  • Goitrogenic compounds
    • thiouracil, sulfonamides, cyanogenic plants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Thyroid Gland Neoplasia:

Thyroid Follicular adenoma and Carcinoma

A
  • Most common in old cats
    • these are often functional resulting in hyperthyroidism
    • There can be nodules in one or both lobes
    • Distinction between hyperplasia is sometimes difficult
  • Less common in dogs
    • These are often large, invasive, and metastatic to regional lymph nodes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Thyroid follicular adenoma/carcinoma

A
17
Q

Thyroid Gland Hyperplasia:

Thyroid Follicular nodular hyperplasia

A
  • Most common as an age-related change in horses, dogs, and cats
  • Most are non-functional and of minimal significance
    • in cats, some of these may progress to adenoma
18
Q

Hyperthyroidism

A
  • Functional neoplasms result in hyperthyroidism
    • increased basal metabolic rate
    • Polyphagia with weight loss
    • Hyperacticity and nervousness
    • Weakness and heat intolerance
    • Tachycardia
  • May be due to mutation in the gene coding for the TSH receptor
    • this is different than Graves disease in humans since theera re no auto-antibodies to the TSH receptor in cats
19
Q

Thyroid Gland C-Cell Neoplasia:

Parafollicular C-cell Neoplasia

A
  • Most common in old bulls and horses
    • often amlignant in bulls, but incidental in horses
  • Bulls:
    • these may arise due to long-term infestion of high calcium rations
      • high calcium rations also induce hyperplasia initially
    • Pituitary or adrenal medulla neoplasia may occur concurrently
  • Some can be functional:
    • Hypercalcitoninism
      • Vertebral osteophytes and osteosclerosis
20
Q

Goiter

A
  • Inhibition of thyroid hormone formation
    • nutritional deficiency of iodone or tyrosine
    • Goitrogenic compound ingestion
      • cruciferous plants
      • Drugs
21
Q

Goiter:

Diffuse

A

Excessive TSH stimulus due to decreased thyroid hormones

Iodine deficiency is a common cause

22
Q

Goiter:

Multinodular

A

Idependent of TSH

Mainly in old cats

23
Q

Goiter:

Dyshormonogenic

A

Defective synthesis with normal iodine levels

Due to genetic defect in thyroglobulin synthesis or thyroid peroxidase

Autosomal recessive in sheep and goats

24
Q

Goiter:

Thyroid Hyperplasia is the lesion

A
  • cause varies
  • Results in hypothyroidism in postnatal animals
    • Stillbirth is most common when affected in utero
    • Neonates can also hav esigns of hypothyroidism
      • myxedema
25
Q

Goiter:

Images

A
26
Q

Thyroid Gland Atrophy:

Idiopathic Follicular Atrophy

A
  • Most common in dogs
  • There is primary degeneration and atrophy of the thyroid gland
  • Results in hypothyroidism
    • accounts for approximately 50% of hte cases of canine hypothyroidism
27
Q

Thyroid Gland Atrophy:

Lymphocytic thyroiditis

A
  • Most common in dogs
  • Autoimmune destruciton of the thyroid gland
    • there is fibrosis, atrophy, and lymphocytic infiltration of the gland
  • Results in hypothyroidism
    • Accounts for approximately 50% of these cases in dogs
  • Similar to Hashimoto’s thyroiditis
    • Auto-antibodies to thyroglobulins
28
Q

Lymphocytic Thyroiditis

A
29
Q

Hypothyroidism

A
  • Clinical syndrome characterized by decreased T3/T4 levels
  • Signs include:
    • weight gain
    • inactivity
    • Alopecia
    • Reproductive abnormalities
    • Hypercholesterolemia
30
Q

Hypothyroidism:

Systemic lesions associated with disease

A
  • Hyperkeratosis and adnexal atrophy of the skin
  • Myexedema
  • Atherosclerosis
  • Hepatic lipidosis

Is the cause for approximately 50% of the cases of hypothyroidism in dogs

31
Q

Parathyroid Gland:

Structure

A
  • Chief cells:
    • comprise most of the gland
    • Produce parathormone
  • Oxyphil Cells
    • modified cheif cells
32
Q

Parathyroid Gland:

Function

A
  • Control and maintenance of serum calcium levels
    • Parathyroid Hormone
      • Released in response to low serum calcium
      • Stimulates GI absorption and resorption of Ca++ from none, increased renal retention of Ca++ and inhibits phophorus reabsorption
    • Calcitonin
      • Released in response to high serum Calcium
      • Decreased GI absorption and resorption from bone, decreased renal retention
    • Viramin D
      • conversion to calcium in the kidney
      • Synergistic wth parathormone
33
Q

Parathyroid Gland:

Dysfunction:

Hyperfunction

A
  • Primary or secondary parathyroid involvement
    • usually secondary
  • Increased lameness and fractures, facial bone enlargement and weakening
34
Q

Parathyroid Gland:

Dysfunction:

Hypofunction

A
  • Usually primary parathyroid involvement
  • Variable signs, including anorexia, weakness, or tetany of convulsions

General Pathology VDMP832 (26 decks)

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