Endocrine Flashcards
(76 cards)
1
Q
Endocrine System:
Structure
A
- Derived from neural ectoderm
- strong association with vascular and neural tissue
- Endocrine organs include:
- pituitary gland
- Thyroid gland
- Parathyroid gland
- Adrenal gland
- Gonads
- Endocrine pancrease
- Chemoreceptors organs
- Pineal gland
- Adipose tissue
2
Q
Endocrine System:
Funciton
A
- Maintenance of homestasis:
- Hormones are the mediators of homeostasis
- polypeptides
- Steroids
- Catecholamines and iodothyronines
- Feedback systems regulate most hormone concentrations
- hypothalamus - pituitary - target tissue axis
- Some hormones respond to plasma concentrations of various products of nervous stimuli
- thyroid C-cells, Parathyroid cheif cells, adrenal medulla
- Hormones are the mediators of homeostasis
3
Q
Endocrine System:
Dysfunction:
Increased Function
A
- Primary Hyperfunction
- increased hormones secretion by an abnormal gland
- Secondary Hyperfunction
- increased hormone secretion by a normal endocrine gland that is excessively stimulated
4
Q
Endocrine System:
Dysfunction:
Decreased Function
A
- Primary hypofunction
- decreased hormone secretion by an abnormal gland
- Secondary hypofunction:
- decreased hormone secretion by a normal endocrine gland that is inadequately stimulated
5
Q
Endocrine System:
Patterns of Disease
A
- Metabolic processes are altered with any endocrine abnormality
- Neoplasia is the most common pathology pattern
- Cell adaptation is fairly common, atrophy, hyperplasia
- Immunopathology (autoimmunity) is relatively common as a pattern of endocrine disease
- Developmental, cell injury, vascular distrubances and inflammation are less common patterns associated with endocrine disease
6
Q
Endocrine System:
Causes of Disease
A
- Genetic alterations are important as predisposing factors for neoplasia, immunopathologic and developmental endocrine diseases
- Nutritional factors can have significant impact of hormone-regulated homeostasis
- Infectious, chemical and physical insults are less common causes of endocrine disease
7
Q
Pituitary Gland
A
8
Q
Pituitary Gland
Structure:
Anterior Lobe
A
-
Pars Distalis:
- acidophils
- GH and LTH
- Basophils:
- Lh, FSH, TSH
- Chromophobes
- ATCH, MSH
- acidophils
-
Pars Intermedia
- melanotrophs
- Pars Tuberalis
9
Q
Pituitary Gland:
Structure:
Posterior Lobe
A
- Hypothalamic Neurosecretory neurons
- paraventricular and supraoptic nuclei
- ADH, Oxytocin
- Infundibular stalk
- Pars Nervosa
- paraventricular and supraoptic nuclei
10
Q
Adenohypophysis:
Growth Hormone
A
Regulates growth and metabolism
Somatotropin
11
Q
Adenohypophysis:
Luteotropic Hormone
A
Stimulates progesterone secretion
12
Q
Adenohypophysis:
Luteinizing Hormone
A
Stimulates estrogen secretion
13
Q
Adenohypophysis
Follicle Stimulating Hormone
A
Stimulates ovarian follicle growth and spermatogenesis
14
Q
Adenohypophysis:
Thyroid Stimulating Hormone
A
Thyrotrophin, TSH
Stimulates thyroid hormone secretion
15
Q
Adenohypophysis
Adrenocorticotrophic Hormone
A
Stimulates glucocorticoid secretion
16
Q
Adenohypophysis
Melanocyte Stimulating Hormone
A
Stimulates melanocytes
17
Q
Neurohypophysis:
Antidiuretic hormone
A
regulates water excretion
18
Q
Neurohypophysis
Oxytocin
A
Stimulates smooth muscle contraction
19
Q
Pituitary Gland:
Dysfunction
Increased Hormone Activity
A
Functional neoplasia
Increased stimulation hy hypothalamus
AnteHormone-like substances
20
Q
Pituitary Gland:
Dysfunction:
Decreased Hormone Activity
A
Destructive lesions
Non-Responsive target cells
21
Q
Pituitary Gland
Pathogenesis
Neoplasia
A
functional or non-functional
22
Q
Pituitary Gland
Pathogenesis
Cell Adaptation
A
Hyperplasia and atrophy
23
Q
Pituitary Gland
Dysfunction
Developmental Anomalies
A
Aplasia, hypoplasia, cysts
24
Q
Pituitary Gland
Dysfunction
Immunopathology
A
Autoimmunity
25
Pituitary Gland
Dysfunction
Inflammation
Uncommon
26
Pituitary Gland
Dysfunction
Metabolic
All hormonal dysfunctions will result in metabolic alterations
27
Pituitary Gland
Causes
* Genetic Injury
* inherited or acquired
* Infectious Agents
* Uncommon
* Nutritional
* Chemical
28
Chromophobe adenoma in dogs
Functional adenoma
* Neoplastic chormophobes are unregulated and produce large amounts of ACTH
* Excessive ACTH causes diffuse adrenocortical hyperplasia
* hyperadrenocorticism (Cushing Disease)
* Approximately 80-90% of cases of canine hyperadrenocorticism are dut to pituitary neoplasia
29
Chromophobe adenoma in dogs:
Most common pituitary tumor of dogs
* Increased frequency in Boston Terriers, Beagles, Boxers, Dachshunds, and Miniature Poodles
* May arise from hyperplasitc nodules that mutae and become clonal
* Microadenoma
* more likely to be functional and produce excess ACTH
* Macroadenoma
* Less likely to be functional, and act as space-occupying mass
* Hypopituitarism or hypothalamic compression
30
pars intermedia ademona
* Pars intermedia is the second most common location for chromophobe adenoma in dogs
* These can be functional or compressive, just like those of the pars distalis
* compressive = hypoptiutarism or diabetes insipidus due to pressure of the hypothalamus or destructiono f the neurohypophysis
* Pars intermedia dysfunction is the most common endocrine abnormality of horses
* Most common in older horses
* Possibly due to age-related oxidative injury of dopaminergic neurons
31
Pituitary Pars Intermedia Dysfunction in Horses
* Decreased dopamine production results in increased activity of melanotrophs
* melanotrophs produce proopiomelanocortin (POMC)
* POMC \> ACTH \> a-MSH \> B-endorphin + corticotrophin-like intermediate peptide
* Signs include increased hair growth (Hypertrichosis/hirsutism) increaed adipose tissue deposition, weight loss
* Pituitary lesions ranges from diffuse hyperplasia to micro/macro adenoma
* Hirsutism may be due to increased POMC activity or hypothalamic compression
* compression can interfere with thermoregulation and appetite centers
* Melanotrophs are regulated by dopaminergic-pituitary-adrenal axis
* adrenal glands are usually normal
32
Somatotroph Adenoma
* Arise from somatotrophs (Acidophils)
* uncommon, mainly cats, dogs, sheep
* Functional adenoma in cats
* increased production of insulin-like growth factor 1 by the liver
* growth of soft tissue and bone
* Insulin-resistant diabetes mellitus (Type 2)
* Non-functional adenoma can cause panhypopituitarism and hypothalamic compression
* Basophil ademona
* Rare
33
Pituitary Cysts
* Mainly in brachycephalic dogs
* Abnormal Development in or around the pituitary gland
* craniopharyngeal duct cyst
* Pharyngeal hypophyseal cyst
* Orapharyngeal ectoderm cyst
* These can compress and damage surrounding sturcutes
34
Pituitary Cysts:
Major Types:
Craniopharyngeal duct cysts
Diabetes insipidus, pituitary hypofunction
35
Pituitary Cysts:
Major types:
Pharyngeal Hypophyseal cysts
Respiratory distress
36
Pituitary cysts:
Major types:
Oropharyngeal ectoderm cysts
Panhypopituitarism
Junenile hypopituitarism in German Shepherds
37
Pituitary Dwarfism
* Failure of Rathkes pouch ectoderm to differentiate into the adenohypophysis
* Autosomal Recessive in german shepherds
* also occurs in spitz, toy pinschers, and karelian bead dogs
* Generally normal until 2 months of age
* Manifestations due to decreased growth hormone
* decreased insulin-like growth factor 1
* Decreased growth (retain infantile characteristics)
* Retention of puppy hair progressing to alopecia
38
Craniopharyngioma
* Neoplastic Remnants of Rathkes pouch oropharyngeal ectoderm
* young dogs, rare
* Hypothalamic destruction and decreased hypothalamic trophic hormones
39
Non-functional Adenoma
* Dogs, cats, and others
* These can arise from any cell, but often of chromophobe origin
* Hypopituitarism with endocrine gland atrophy and hypofunction
40
Pituitary Gland Inflammation
* Pituitary Abcesses
* most common in cattle
* secondary to nasal septal infections
* Acts as a space occupying lesion
* Blindness, depression, drooling, tongue prolapse
* these signs can mimic rabies
41
Neurohypophysis Disease:
Pituitary Diabetes Insipidus
* Destruction of the neurohypophysis or supraoptic nuclei of hte hypothalamus
* decreased ADH production or release
* polyuria, polydipsia, dilute urine
* Decreased oxytocin
42
Neurohypophysis Disease:
Nephrogenic Diabetes Insipidus
Primary renal disease ADH is normal
43
Adrenal Gland:
Structure:
Cortex
Zona Glomerulosa
Mineralocorticoids
44
Adrenal Gland
Structure
Cortex
Zona fasciculata
Glucocorticoids
45
Adrenal Gland
Structure
Cortex
Zona reticularis
Sex steroids
46
Adrenal Gland
Structure
Medulla
Catecholamines
47
Adrenal Gland:
Function:
Mineralicorticoids
* Aldosterone
* regulates blood pressure
* Promotes sodium retention and potassium excretion by renal tubules
* increaes intracellular fluid volume and regulates extracellular fluid volume
48
Adrenal Gland
Function
Glucocorticoids
* Cortisol and Corticosterones
* Gluconeogenesis, protein and fat catabolism, suppressive for inflammation and immunity
49
Adrenal Gland
Function
Sex Steroids
Progesterone, estrogen, and androgens
50
Adrenal Gland
Function
Catecholamines
Epinephrine and norepinephrine
51
Adrenal Gland
Function
Regulation of Adrenal Function
* Pituitary hormones
* ACTH
* Renin-angiotensin system
* renin cleaves angiotensinogen
* Angiotensin 1 and 2 contracts vascular smooth muscle and stimulates aldosterone secretion
* Neural Controls
* catecholamine secretion
52
Adrenal Gland:
Dysfunction:
Hyperfunction
* Primary or secondary adrenal involvement
* Polyuria, polydipsia, increased appetite, weakness, alopecia, increased infection
* Cushings Disease
53
Adrenal Gland:
Dysfunction:
Hypofunction (Hypoadrenocorticism)
Primary or secondary adrenal involvement
Anorexia, weight loss, GI disturbances, Dehydration
Addisons Disease
54
Adrenal Gland:
Dysfunction:
Hypofunction (Hypoadrenocorticism)
Primary or secondary adrenal involvement
Anorexia, weight loss, GI disturbances, Dehydration
Addisons Disease
55
Adrenal Gland:
Pathogenesis:
Metabolic
Adrenal dysfunction will result in metabolic alterations
56
Adrenal Gland:
Pathogenesis:
Neoplasia
Functional or non-functional
57
Adrenal Gland:
Pathogenesis:
Cell Alteration and Injury
Secondary hyperplasia is common secondary to pituitary diesease
Secondary atrophy due to hypopituitarism
58
Adrenal Gland:
Pathogenesis:
Developmental Anomalies
Aplasia
Hypoplasia
Cysts
59
Adrenal Gland:
Pathogenesis:
Immunopoathology
Autoimmunity
60
Adrenal Gland:
Causes
* Genetic Predisposition:
* pituitary neoplasia causing adrenal hyperplasia
* Chemical:
* exogenous administration of glucocorticosteroids
61
Adrenal Cortical Neoplasia
* Adrenal coritcal adenoma or carcinoma
* most arise from zona fasciculata
* Adenomas are more common than carcinomas
* Can be multiple or single, unilateral or bilateral
* contralateral adrenal gland atrophy occurs with functional unilateral neoplasms
62
Adrenal Cortical Neoplasia:
Functional Neoplasia
* Polyuria and polydipsia
* Increased appetite
* Muscle atrophy and weakness
* Alopecia
* Increased incidence of infections
63
Hyperadrenocorticism
Clinical syndrome characterized by increased cortisol/glucocorticosteroid
64
Hyperadrenocorticism:
Functions of Glucocorticosteroids
Gluconeogenesis
Lipogenesis
Protein catabolic
Anti-inflammatory
Immunosuppressive
Inhibition of fibroplasia
65
Hyperadrenocorticism:
Cause
Most often due to ACTH-secreting pituitary adenoma
Less often due to adrenal cortical adenoma or carcinoma
66
Hyperadrenocorticism:
Lesions
Hepatic lipidosis and glycogenosis
Epidernal and adnexal atrophy
Systemic mineralization
Lymphoid tissue depetion
67
Adrenal Gland Hypoplasia:
* Diffuse adreanal coritcal hyperplasia
* common in dogs
* Occurs secondary to functional chromophobe adenoma of hte pituitary gland
* excessive and unregulated secretion of ACTH
* Hyperadrenocorticism isthe results
* signs and lesions are the same as those of hyperadrenocorticism caused ny primary adrenal neoplasia
68
Adrenal Cortical Nodular Hyperplasia
common age-related change in dogs, cats, and horses
Some of these are functional
Some are non-functional and of minimal to no clinical significance
69
Adrenal Medulary neoplasia:
Pheochromocytoma
Arise in chromaffin cells of the medulla
Most common in dogs and cattle
70
Adrenal medullary neoplasia:
Ganglioneuroma and neuroblastoma
uncommon
Neuroectoderm origin
71
Pheochromocytoma
* Most are non-functional
* functional neoplasia results in systemic hypertension due to norepinephrine secretion
* They can be benign or malignant
* malignant neoplasms often invade the greater vessels
* 50% metastasize in dogs
72
Adrenal Gland abnormal development:
Adrenal hypoplasia or agenesis
Rare conditions in dogs
Total agenesis is fatal
Hypoplasia resutls in variable degrees of hypoadreocorticism
73
Adrenal Gland Atrophy
* Diffuse adrenal cortical atrophy
* most common in dogs on long-term glucocorticosteroid therapy
* Exogenous glucocorticosteroids result in inhibition of adrenal cortical function and subsequent atrophy
74
Adrenal Gland Atrophy:
Idiopathic adrenal cortical atrophy
* Uncommon condition of dogs and cats
* Immune-mediated damage and atrophy of hte adrenal cortex
* may also result from destruation of non-functional neoplasia of the pituitary gland
* Signs usually occur only after 90% of the cortex is destroyed or atrophied
* Results in hypoadrenocorticism
* anorexia and weight loss
* Diarrhea and dehydration
75
Adrenal Gland Destruction:
* A wide variety of porcesses periodically affect the adrenal gland
* this is mainly due to the rich vascular network at the cortico-medullary junciton
* Examples include:
* thrombosis due to DIC
* Adrenalitis due to infections embolis
* Metastatic neiplasia
76
Hypoadrenocorticism
* Clinical syndrome characterized by decreased adrenocortical homrones
* Addisons Disease
* Mainly affects the Zona glomerulosa
* immune-mediated most common in portuguese water dogs, bearded collies, standard poodles
* Hypoaldosteronism
* hypoantremia and hyperkalemai
* Decreased cortisal is also present
