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Flashcards in Endocrine #1 Deck (81):

What is your best definition for an endocrine gland?

A ductless gland that secretes its products (hormones) into the blood stream


What are the only "types" of hormones released from the pituitary gland?

Proteins & polypeptides


What are other examples of organs or areas in the body where protein or polypeptide type hormones are released or secreted?

C-cells of the thyroid gland

Islet of langerhans of the pancreas

Parathyroid gland



  1. What are two organs that secrete amino acid derived hormones?
  2. What are the hormones their secreting?

  1. Adrenal medulla  &  Thyroid
  2. Thyroxine (thyroid)  &  Epinephrine/norepinephrine (adrenal medulla)


What is the mechanism of action of protein and polypeptide hormones?

Bind to target cell surface receptors


What is the mechanism of action of a steroidal hormone?

Binds target cell cytoplasmic receptors


  1. What is the best example of an endocrine organ that secretes steroidal hormones?
  2. What hormones is that secreting?

  1. Adrenal cortex
  2. Aldosterone, cortisol, estrogens, androgens


True or False:

  1. Steroidal hormones are lipid soluble, which mean they can get through the cell membrane and act quickly!
  2. Steroidal hormones have to get into the nucleus to exert their activity.

  1. FALSE : although steroidal hormones ARE lipid soluble and ARE able to pass through the cell membrane, they do have a DELAYED REACTION 
  2. TRUE : steroidal hormones do have to get into the nucelus to exert their activity, which is actually the main reason for their delayed activity


Which type of endocrine lesion results in an increase in size OR magnitude of a gland?

Productive lesions


What are 2 examples of productive lesions in an endocrine gland?

  1. Hyperplasia
  2. Neoplasia 


What are some examples of a destructive lesion of an endocrine gland?

  1. Hypoplasia
  2. Atrophy
  3. Inflammation
  4. Neoplasia
  5. Amyloidosis
  6. Necrosis
  7. Surgical misadventure


  1. Which type of endocrine glands are known for accumulating amyloid?
  2. Give an example of one of these organs or specific cell types.

  1. Those that produce protein or polypeptide type hormones
  2. Islet of langerhans, parathyroid gland, c-cells of the thyroid, pituitary gland


More commonly are beign and malignant tumors functional or non-functional?

Benign = functional

Malignant = non-functional


What are the general causes of hyperfunction of an endocrine organ?

  1. Increased production of hormone
    • Primary = uncontrolled production
    • Secondary = increased trophic stimulus
  2. Decreased breakdown
  3. Production of hormone like molecules
  4. Latrogenic/exogenous intake


The following scenerio is an example of which type of hyperfunction of an endorcine gland:

Parathyroid adenoma: producing PTH uncontrollably so the animal becomes hypercalcemic as a result

Primary hyperfunction

(Uncontrollable production)


The following scenerio is an example of which type of hyerfunction OR hypofunction of an endrocrine gland:

The thyroid gland is making thyroxine at its normal level, however, the half-like of the hormone is prolonged. 


Hyperfunction due to decreased breakdown


The following scenerio is an example of which type of hyerfunction or hypofunction of an endocrine gland:

Tumor of the pituitary gland is making ACTH uncontrollably and is causing an increase in cortisol levels.

Secondary hyperfunction

(Increased production due to increased trophic stimulus)


The following is an example of what "type" of hypofunction of an endocrine gland?

An autoimmune disease is attacking the thyroid gland, killing off the follicular cells.  This is decreasing the production of thyroid hormone.

Primary hypofunction

(Decreased produciton due to destruction of a gland)


With an endocrine disease, what type of lesions might you find in other tissues/with what clinical signs might the animal present?


Epidermal atrophy

Bilaterally symmetrical alopecia

Hepatic lipidosis

Soft tissue mineralization




Muscle atrophy



  1. What specific type of endocrinopathy is most often associated with epidermal atrophy?
  2. Which hormone caues this manifestation?

  1. Hypothyroidism
  2. Increased cortisol levels


When it comes to alopecia, what is its hallmark feature when associated with an endocrine disease?

Bilaterally symmetrical


What about endocrine disease causes bilateral alopecia?

There is a lack of the appropriate stimulation to a hair follicle

|-->  Hair follicles become atrophied

|-->  Hair is rubbed off

|-->  And hair is NOT replaced


What are the manifestations of hepatic lipidosis?

Enlarged liver

Increased lipid content in the liver


Which hormone is particular stimulates the breakdown of muscle in some endocrinopathies?



In which endocrinopathy would you most likely see cataracts clinically?

Diabetes mellitus


  1. From what is the adenohypophysis derived?
  2. From what is the neurohypophysis derived?

  1. Adenohypophysis = oral ectoderm
  2. Neurohypophysis = neuroectoderm (down growth from the hypothalamus)


Pituitary and brainstem, normal dog.

What is labeled?




A.  Optic chiasm

B.  Pars distalis (of the anterior pituitary)

C.  Pars nervosa (of the posterior pituitary)


Pituitary and brainstem, normal dog.

What is labeled?



A.  Hypothyalamus

B.  Pars intermedia (of the anterior pituitary)


From this pituitary gland, label the following parts:




A.  Pars nervosa (posterior pituitary)

B.  Pars intermedius (anterior pituitary)

C.  Pars distalis (anterior pituitary)


What is the area circled in red?

The 3rd ventricle


This is from the Pars Distalis of the anterior pituitary.

What cells should be present?

Basophils (dark cells)

Acidophils (red cells)

Chromophobes (all other cells)


Again, this is a slide from the pars distalis.  Recognize the rich capillary network.

What is the significance of the close association these cells have with the capillaries?

This close associated allows hormones to be released quickly!


Being shown is a slide of the pars intermedia and the pars nervosa.

Which is which?

A.  Pars nervosa

B.  Pars intermedius (notice the abundancy of chromophobe cells)


What nuceli are present within "A" and what hormones do those nuclei produce?

Supraoptic nucleus --> ADH

Paraventricular nucleus --> Oxytocin


Which sections of the pituitary gland are represented here?




A.  Pars nervosa

B.  Pars intermedius


What is the typical outcome of animals with an aplastic pituitary gland?

Becuase the pituitary gland is important in stimulating parturition, these animals typically do NOT make it to term


There is an invagination that you get from the oral ectoderm on the roof of the mouth during fetal development.  This invagination will migrate up to make the adenohypophysis.

  1.  If the invagination persists, what is that called?
  2. What affect does this have on the pituitary?
  3. What affect does this have on development?

  1. Cystic Rathke's Pouch
  2. Compresses the pituitary gland
  3. Resulting in incomplete development


What are the typical some broad characteristics of neoplasms of the adenohypophysis?

Usually chromophobes

Adenoma OR carcinoma

Functional OR non-functional


With a functional tumor of the anterior pituitary, production of which hormones are typically increased?





  1. What change in the adrenal gland would increased ACTH cause?
  2. What hormone imbalance would this change cause?

  1. Adrenal cortical hyperplasia
  2. Hypercortisolism


Which two conditions can an increase in growth hormone cause, depending on the age of the animal?




  1. In which species is acromegaly most common?
  2. What does an increase in GH downregulate?
  3. This downregulation causes a refractory form of what condition to develop?

  1. Cats
  2. GH downregulates the ability of peripheral tissue to use insulin properly
  3. Diabetes mellitus


Another manifestion of neoplasms in the anterior pituitary would be overall expansion of the gland.

  1. What affect does this have on adjacent parenchyma?
  2. If the pars nervosa is compressed, production of which hormone will be suppressed?
  3. The decrease in this hormone could lead to what condition?

  1. Adjacent parenchyma could potentially be compressed & destroyed
  2. Damage to the pars nervosa --> decrease in ADH production
  3. Decrease in ADH production would leads to the development of diabetes insipidus


Explain why with an animal with polydipsia and polyuria you would want an anterior pituitary gland tumor on your differencial list

Tumor of the anterior pituitary gland

Expansion of that tumor

Compression of adjacent parenchyma

Pars nervosa gets compressed & destroyed

Production of ADH is decreased due to destruction

Animal develops diabetes insipidus

Unable to conserve water



Let us say an anterior pituitary gland tumor is damaging TSH producing cells.

  1. Which gland will no longer be getting its appropriate stimuli?
  2. Production of which hormones will then decrease?
  3. What clinical condition will these changes cause?

  1. Thyroid gland will not get the appropriate stimuli
  2. T3 & T4 will be decreased
  3. Hypothyroidism will develop


What are the results of panhyopituitarism?

Stunted growth

Retained puppy hair coat


Which dog breed is more predisposed to developing panhypopituitarism?

German shepherds


Juvenile panhypopituitarism is typically associated with ____ of the pituitary gland and ____ formation of the Rathke's pouch.

Juvenile panhypopituitarism is typically associated with hypoplasia of the pituitary gland and cyst formation of Rathke's pouch.


Which hormones are typically decreased with juvenile panhypopituitarism?

Typically ALL pituitary gland hormones are decreased

Particularly GH, ACTH, TSH, FSH, and LH


Is Equine chromophobe adenoma of the pars intermedia a functional or non-functional tumor?



Equine chromophobe adenoma of pars intermedia are known for their expansion into the hypothalamus.

Production of which hormone is impaired due to to this expansion?



Becuase equine chromophobe adenomas of the pars intermedia are functional tumors, production of which hormones are increased?


& / or

POMC (pro-opiomelanocortin)


  1. What effect might equine chromophobe adenomas of the pars intermedia have on the adrenal glands?
  2. Production of what will then increase?

  1. Adrenal cortical hyperplasia
  2. Cortisol


You have a horse present with hirsutism, hyperhidrosis (excessive sweating), lethargy, polyuria, and polydipsia.  You suspect an endocrinopathy.

  1. Which pituitary gland tumor in horses is associated with these clinical signs?
  2. What adrenal lesion might you see on necropsy?



  1. Equine chromophobe adenoma of the pars intermedia
  2. Adrenal cortical hyperplasia


Again, what are the clinical signs and lesions associated with equine chromophobe adrenoma of the pars intermedia?





Adrenal cortical hyperplasia


True or False:

  1. Equine chromophobe adenoma of the pars intermedia is a functional tumor.
  2. Canine chromophobe adenoma is a non-functional tumor.

  1. TRUE
  2. FALSE : canine chromophobe adenoma is a FUNCTIONAL tumor


  1. Because canine chromophobe adenomas are functional tumors, production of which hormone will be increased?
  2. What effect does this hormone have on the adrenal gland?
  3. Production of what substance is increased becuase of the change in the adrenal gland?

  1. ACTH
  2. Diffuse adrenal cortical hyperplasia 


You diagnose a dog with hyperadrenocorticism:

What do you have to figure out next?

Is the hyperadrenocorticism pituitary dependent OR is there a tumor of the adrenal gland 

(OR is the animal getting too much cortisol exogenously)


You have diagnosed your dog with hyperadrenocorticism AND figured out that it is pituitary-dependent.

What is one of your diagnoses?

(Canine, increased ACTH production, pituitary-dependent hyperadrenocorticism)

Canine chromophobe adenoma 


In which "type" of horses is equine chromophobe adenoma of the pars intermedia most common?

Older horses


  1. Based on the gross lesion, what is your diagnosis?
  2. How might this affect development?

  1. Pituitary hypoplasia
  2. Could result in incomplete development


These pups are littermates.  The smaller of the two is nearly 1/7th the weight of his littermate and has retained his puppy hair coat.

  1. What is your diagnosis?
  2. In what breed is this condition most common?

  1. Panhypopituitarism ("pituitary dwarfism")
  2. Most common in German Shepherds 


  1. There is a fluid filled cavity where the adenohypophysis should be - what is this called?
  2. What else is abnormal about the pituitary gland? (Most likely in association with the change refferred to in #1)

  1. Cystic remnant of Rathke's pouch
  2. Hypoplasitic pituitary gland overall


This is tissue from an 25 year old horse.

  1. What is your most likely diagnosis?
  2. What structures might this negatively affect?

  1. Neoplasm (adenoma) of the pars intermedia
  2. Hypothalamus or optic nerve could be compressed eventually, which often leads to some of the clinical signs seen in these guys


This is tissue from an old horse with chromophobe adenoma of the pars intermedia.

Label the parts of the pituitary:




A.  Pars distalis

B.  Pars intermedia

C.  Pas nervosa


  1. Which 2 parts of the pituitary gland are being illustrated here?
  2. What are the bright pink to red cells on the left called?
  3.  Which characteristic feature of endocrine neoplasms can be seen next to the blue lines?

  1. Pars distalis (left) & pars intermedia (right)
  2. Red cells = acidophils
  3. With endocrine neoplasms, it is very characteristic for cells next to blood vessels to oritent themselves perpendicular to those vessels


  1. What is your diagnosis?
  2. What is the structure at the end of the arrow?
  3. Which structures are likely being compressed?

  1. Pituitary gland adenoma
  2. Arrow = optic chiasm
  3. Hypothylamus and optic chiasm are clearly being compressed.  The anterior and posterior pituitary have also been destroyed by this neoplasm


Let us say this lesion is compressing the optic nerve and has destroyed the posterior pituitary gland.

What 2 clinical conditions might develop?

  1. Blindness (due to compression of the optic nerve)
  2. Diabetes insipidus (due to destruction of the posterior pituitary gland and decrease in ADH production)


  1. What is your morphologic diagnosis?
  2. Is this likely to follow a functional or a non-functional pituitary adenoma?

  1. Bilateral, hypertrophy/hyperplasia of the adrenal glands
  2. Functional pituitary adenoma


  1. What is your morphologic diagnosis?
  2. Is likely to follow a function or a nonfunctional pituitary adenoma?

  1. Bilateral, trophic atrophy of the adrenal cortex of the adrenal glands
  2. Non-functional pituitary adenoma


A lack in what hormone would cause this gross lesion?



Which cells of the thyroid make colloid?

Follicular cells


  1. What are the active forms of thyroxine?
  2. Where can they be found?


  1. T3  &  T4
  2. Found in the blood


  1. What produces TSH?
  2. If thyroid hormone production is dimished, what effect does that have on the hypothalamus?

  1. TSH is produced by the anterior pituitary gland in response to TRH (thyrotropin releasing hormone) from the hypothalamus.
  2. When thyroid hormones decrease in the blood, the hypothalamus will increase its production of TSH releasing factor (this will increase TSH)


Where are the cells that produce TSH?

In the pars distalis of the anterior pituitary


  1. An increase in TSH production will stimulate which cells of the thyroid?
  2. What is then produced?

  1. TSH will stimulate follicular cells
  2. They are stimulated to produce mroe colloid, and thus more T3 and T4 will be produced


  1. Where are C-cells (parafollicular cells) located?
  2. What do C-cells produce?
  3. What is this antagonistic to?

  1. C-cells are located in the thyroid gland
  2. C-cells produce calcitonin
  3. Calcitonin is antagonisitc to PTH


  1. An increase in ingested calciumw would increase or decrease calcitionin?
  2. What effect does this have?

  1. Calcitonin increases in response to hypercalcemia
  2. This drives down serum calcium levels


  1. Which cells of the thyroid gland consist of a single layer of cuboidal secretory epithelium?
  2. Which cells of the thyroid gland are polygonal cells between the follicles?


  1. Follicular cells
  2. C-cells (parafollicular cells)


  1. Based on what you know, is this normal thyroid tissue?
  2. What substance is denoted with a yellow "x"?
  3. Is the blood supply rich or poor in this area?

  1. This is NORMAL thyroid tissue
  2. Yellow "x's" = COLLOID
  3. Blood supply is RICH


This is normal thyroid tissue.

What are the following cell types?

Yellow outline = _____

Blue outline = _____

Yellow outline  =  C-cells (parafollicular cells)

Blue outline  =  Follicular cells