[M] Week 7: Endocrine System - Part 1 Flashcards
What are the parts of endocrine system?
- Pituitary gland
- Thyroid gland
- Parathyroid gland
- Endocrine pancreas
- Adrenal glands
- Pineal gland
The endocrine signaling mechanism occurs through the action of?
HORMONES
Hormones trigger biochemical signals upon interacting with cell-surface receptors
Most of the regulation of the endocrine system is through?
feedback inhibition
Diseases within the endocrine system may be due to three patterns, what are those?
- Under-production of hormones
- Over-production of hormones
- Development of mass lesions
Small, bean-shaped organ encased by the brain within the sella turcica
Pituitary Gland
- It measures 1 cm, and weighs 0.5 grams.
- Consists of the anterior and posterior lobe
Pituitary Gland
- Otherwise known as ADENOPHYPOPHYSIS.
- It is where most of the hormones that stimulate signaling come from.
Anterioir Lobe
Pituitary Gland
Match
- Somatotrophs
- Lactotrophs
- Corticotrophs
- Thyrotrops
- Gonadotrophs
A. Basophils, produce adrenocorticotropic hormone (ACTH), proopiomelanocortin (POMC), melanocyte-stimulating hormone (MSH), endorphins, and lipotropin
B. Basophils, produce thyroid-stimulating hormones (TSH)
C. Acidophils; produce growth hormones (GH)
D. Basophils, produce follicle-stimulating hormone (FSH), and luteinizing hormone (LH)
E. Acidophils, produce prolactin
- C
- E
- A
- B
- D
check niyo nalang pic sa trans
Most of the hormones are released through positive signaling, EXCEPT for prolactin and growth hormone.
Pituitary Gland
Also known as the NEUROHYPOPHYSIS, as it is a direct continuation of the hypothalamus
Posterior Lobe
Pituitary Gland
Cells of the posterior pituitary are less than that of the anterior portion, wherein it only consists of what cells
- modified glial cells (pituicytes)
- axonal processes
Pituitary Gland
What does posterio lobe of pituitary gland secrets?
- ADH controls the excretion of urine or diuresis for the maintenance of blood volume levels.
- Oxytocin assists during cervical dilation when giving birth or parturition
PITUITARY ADENOMAS AND YPERPITUITARISM
What are the most common cause of hyperpituitarism
adenoma arising in the anterior lobe
**Pituitary adenoma **
Adenoma is defined as a benign lesion secreting extra hormones
what is the morphology of a pituitary adenoma
soft, well-circumscribed with sparse reticulin framework
TOF
The physical adenoma impinges on the adjacent structures of the brain, and is considered to be 30% invasive
True
Pituitary adenoma is benighn, what will be shown in the histology?
monomorphic pattern– appearing the same, and with no mitosis
However, a benign adenoma that is impinging and is infiltrating structures within the brain will be treated as a malignant adenoma.
CLINICAL COURSE OF PITUITARY ADENOMA
Adenomas are diagnosed through:
- Stereotactic biopsy
- Transphenoidal biopsy–which enters through the nose and punctures the bony sphenoid to reach the sella turcica
- Radiation therapies measure the amount of radiation to actually hit the adenoma and lyse the tumor
What are the types of pituitary adenomas
- Prolactinoma
- Growth Hormone or Somatotroph Cell Adenomas
- Corticotroph Cell Adenomas
TYPES OF PITUITARY ADENOMAS
this is the most frequent type - comprising 30% of all clinically recognized pituitary adenomas
Prolactinoma
TYPES OF PITUITARY ADENOMAS
- Small to large, expansile tumors
- Weakly acidophilic or chromophobe cells
- Propensity of dystrophic calcification–psammoma bodies to pituitary stone
- Characterized by its efficiency and proportionality.
Prolactinoma
In prolactinoma this secretes excess prolactine resulting in?
PROLACTENEMIA which may result to amenorrhea, galactorrhea, loss of libido, and infertility
- Galactorrhea is defined as the secretion of milk which may be seen in women after giving birth.
- Amenorrhea is the absence of menses which may result to infertility.
TYPES OF PITUITARY ADENOMAS
identify what prolactenemia
- Due to pregnancy
- Due to to lactotroph hyperplasia, stalk effect, drugs, estrogens, renal failure, and hypothyroidism.
- Physiologic Prolactinemia
- Pathologic Prolactinemia
Treatment includes surgery or bromocriptine
TYPES OF PITUITARY ADENOMAS
- the second most common type
- Manifestations are subtle but large on the diagnosis–meaning that effects are very visible.
- Histologic subtypes consist of densely (acidophilic) and sparsely (chromophobe) granulated
Growth Hormone or Somatotroph Cell Adenomas
Growth Hormone or Somatotroph Cell Adenomas
Bihormonal mammosomatotroph adenomas (acidophilic)
are due to
excess of both GH and prolactin
Growth Hormone or Somatotroph Cell Adenomas
The persistent hypersecretion of GH may lead to?
hepatic secretion of insulin-like growth factor (IGF-1) or
somatomedin C
Growth Hormone or Somatotroph Cell Adenomas
The persistent hypersecretion of GH may lead to the hepatic secretion of insulin-like growth factor (IGF-1) or
somatomedin C that may result in
GIGANTISM or ACROMEGALY
Growth Hormone or Somatotroph Cell Adenomas
If it occurs BEFORE the closure of the epiphysis of the long bones, the patient will suffer from
GIGANTISM
Growth Hormone or Somatotroph Cell Adenomas
If it occurs AFTER the closure of the epiphysis of the long bones, the patient will suffer from.
ACROMEGALY
Growth Hormone or Somatotroph Cell Adenoma
Diagnosis are confirmed how?
elevated serum GH and IGF-1 levels
TYPES OF PITUITARY ADENOMAS
Excess production of ACTH by functioning corticotroph adenomas leads to adrenal hypersecretion of cortisol and the development of hypercortisolism–also known as the CUSHING SYNDROME.
Corticotroph Cell Adenomas
TYPES OF PITUITARY ADENOMAS
- Diagnosed through the presence of microadenomas.
- Often basophilic (densely granulated), occasionally chromophobe (sparsely)
- Periodic acid schiff (PAS) positive (+) due to carbohydrate in POMC
Corticotroph Cell Adenomas
Corticotroph Cell Adenomas
When hypercortisolism is due to the excessive production of ?
ACTH by the PITUITARY it is designated as a CUSHING
DISEASE.
Corticotroph Cell Adenomas
If it is due to the excessive production by the ADRENAL, it is designated as?
Cushing SYNDROME.
Decreased secretion of pituitary hormones due to hypothalamus or pituitary diseases
Hypopituitarism
A person suffers from hypopituitarism when ____ of parenchyma is lost, absent, or nonfunctional
75%
When accompanied by evidence of posterior pituitary dysfunction in the form of diabetes insipidus, hypopituitarism is almost always of
hypothalamic origin
OTHER MECHANISMS OF HYPOPITUITARISM
Most cases of hypopituitarism arise from destructive processes involving the anterior pituitary, as follows:
- Tumors and other tumor masses
- Pituitary surgery or radiation
- Pituitary apoplexy
- Ischemic necrosis and Sheehan syndrome
- Rathke cleft cyst
- Empty sella syndrome (rare)
- Genetic defects
- Hypothalamic lesion
OTHER MECHANISMS OF HYPOPITUITARISM
postpartum hypopituitarism caused by necrosis of the pituitary gland, which usually happens in pregnant women.
Sheehan’s syndrome
CLINICAL MANIFESTATIONS OF HYPOPITUITARISM
Match
- GH Deficiency
- Gonadotropin (GnRH) (LH and FSH) deficiency
- TSH deficiency
- ACTH deficiency
- Prolactin deficiency
- MSH deficiency
A. Amenorrhea and infertility in women; decreased libido, impotence, and loss of pubic and axillary hair in men
B. Hypothyroidism
C. Failure of postpartum lactation
D. Hypoadrenalism
E. Pallor
F. Pituitary dwarfism
- F
- A
- B
- D
- C
- E
POSTERIOR PITUITARY SYNDROMES
Enumerate all the syndrome mentioned
- Diabetes Insipidus
- Secretion of Inappropriately High Levels of ADH
POSTERIOR PITUITARY SYNDROMES
- Characterized by polyuria (same manifestation with Diabetes Mellitus)
- Mostly due to a problem with ADH
- Causes: head trauma, tumors and inflammatory lesions and surgery of hypothalamus and pituitary;spontaneously
- Central, if due to ADH deficiency, or nephrogenic, if due to renal tubular unresponsiveness to ADH
Diabetes Insipidus
POSTERIOR PITUITARY SYNDROMES
- causes resorption of excessive amounts of free water, giving rise to hyponatremia
- Serum Na+ is diluted, thus decreased in levels
- Causes: ectopic ADH by neoplasms, non-neoplastic diseases of the lung, local injury to hypothalamus or posterior pituitary or both
- Signs and Symptoms: hyponatremia, cerebral edema and neurologic dysfunction; total body water increased; blood volume, normal; no peripheral edema
Secretion of Inappropriately High Levels of ADH
- An organ located in the middle of the neck with two bulky lateral lobes, thin isthmus
- Arise from evagination of pharyngeal epithelium that descends from foramen cecum as part of thyroglossal duct
Thyroid Gland
What are the two important hormones secreted by the thyroid gland
T3 (triiodothyronine) and T4 (thyroxine)
In the synthesis of the thyroid hormones, the presence of what is required?
iodine
What causes the transient hyperplasia
- Puberty
- Pregnancy
- Stress
Function of Thyroid gland
- Up-regulation of carbohydrate and lipid catabolism
- Stimulation of protein synthesis
- Brain development (1 & 2 increase BMR)
The function of the thyroid gland can be inhibited by a variety of chemical agents, collectively referred to as goitrogens. Because they suppress T3 and T4 synthesis, the level of
TSH increases, causing subsequent?
hyperplastic enlargement of the gland (goiter)
The thyroid gland follicles also contain a population of ____ or ____ which synthesize and secrete calcitonin
parafollicular cells or C cells
- Thyrotoxicosis: hypermetabolic state due to elevated circulating levels of T3 and T4 (to compensate baba TSH)
- due to hyperfunction of thyroid gland
Hyperthyroidism
Most common causes of hyperthyroidism
- diffuse hyperplasia (common,
abnout 85%) - hyperfunctional multinodular goiter
- hyperfunctional adenoma of thyroid
CLINICAL FEATURES: HYPERYHYROIDISM
Excessive levels of thyroid
hormone result in?
- increase in the basal
metabolic rate
170 - 200
eto lang pinatanda ni maam
Laboratory findings that support the diagnosis of hyperthyroidism includes?
low TSH value accompanied by an
increase in free T4
In occasional patients, hyperthyroidism results predominantly from increased circulating levels of ____ In these cases, free T4 levels may be decreased, and direct measurement of serum T3 is useful.
T3 (“T3 toxicosis”)
- a condition caused by a structural or functional derangement that interferes with the production of
thyroid hormone. - can result from a defect anywhere in the hypothalamic-pituitary-thyroid axis
Hypothyroidism
Identify what classification of hypothyrodism
- intrinsic thyroid abnormality
- pituitary and hypothalamic disease
- Primary
- Secondary
Primary hypothyroidism can be congenital, autoimmune, or iatrogenic
Types of Hypothyroidism
- Congenital Hypothyroidism (iodine deficiency in the diet.)
- Autoimmune Hypothyroidism (most common cause of hypothyroidism in iodinesufficient areas of the world)
- Iatrogenic Hypothyroidism (surgical or radiation-induced ablatio)
what are the clinical manifestaion of hypothyroidism
- Creatinism
- Myxedema
CLINICAL MANIFESTATIONS OF HYPOTHEROIDISM
refers to hypothyroidism that develops in infancy
or early childhood
CRETINISM
CLINICAL MANIFESTATIONS OF HYPOTHEROIDISM
Sporadic cretinism is due to
enzyme deficiency
Clinical features of cretinism include severe intellectual disability, short stature, coarse facial features, a protruding tongue, and umbilical hernia.
CLINICAL MANIFESTATIONS OF HYPOTHEROIDISM
applied to hypothyroidism developing in the older child or adult.
MYXEDEMA (GULL DISEASE)
CLINICAL MANIFESTATIONS OF HYPOTHEROIDISM
Myxedema is marked by a
slowing of physical and mental activity
CLINICAL MANIFESTATIONS OF HYPOTHEROIDISM
- Early symptoms include generalized fatigue, apathy, and mental sluggishness, which may mimic depression. Speech and intellectual functions are slowed, and patients are listless, cold intolerant, and frequently overweight.
- Reduced cardiac output probably contributes to shortness of breath and decreased exercise capacity, two frequent complaints.
- Decreased sympathetic activity results in constipation and decreased sweating.
MYXEDEMA (GULL DISEASE)
Diagnosis of Hypothyroidism are through?
Measurement of the serum TSH level is the most sensitive screening test for this disorder
The TSH level is increased in ____ ____ as a result of a loss of feedback inhibition of TRH and TSH production by the hypothalamus and pituitary, respectively
primary hypothyroidism
The TSH level is not increased in persons with
hypothyroidism due to?
hypothalamic or pituitary disease
T4 levels are decreased in individuals with?
hypothyroidism
What are the three most common and clinically signioficant subtypes of thyroiditis
- Hashimoto Thyroiditis
- Granulomatous (De Quervain) Thyroiditis
- Subacute Lymphocytic Thyroiditis
- ‘Chronic Lymphocytic Thyroiditis’
- autoimmune disease that results in destruction of the thyroid gland and gradual and progressive thyroid failure.
- It is the most common cause of hypothyroidism in areas of the world where iodine levels are sufficient
- It is most prevalent between 45 and 65 years of age and is more common in women than in men, with a female predominance of 10:1 to 20:1.
- SIGNIFICANT GENETIC COMPONENT: Multiple Genes; Turner Syndrome and Trisomy 21; Chromosome 6p & 12q
Hashimoto Thyroiditis
MORPHOLOGY: HASHIMOTO THYROIDITIS
The thyroid is usually?
usually diffusely enlarged.
MORPHOLOGY: HASHIMOTO THYROIDITIS
The capsule is ____, and the gland is well demarcated from adjacent structures The cut surface is?
- Intact
- pale, yellow-tan, firm, and somewhat nodular.
MORPHOLOGY: HASHIMOTO THYROIDITIS
There is extensive infiltration of the parenchyma by a
mononuclear inflammatory infiltrate
Containing small lymphocytes, plasma cells, and well-developed germinal centers
MORPHOLOGY: HASHIMOTO THYROIDITIS
What will be the morphology of thyroid follicles?
HÜRTHLE CELLS
atrophic and are lined in many areas by epithelial cells with abundant eosinophilic, granular cytoplasm
MORPHOLOGY: HASHIMOTO THYROIDITIS
They are also at increased risk for development of?
extranodal marginal zone B-cell lymphoma (B-cell hodgkin lymphoma)
- ‘De Quervain Thyroiditis ‘
- The disorder is most common between 30 and 50 years of age and, like other forms of thyroiditis, affects women more often than men. (female:male ratio is 3-5:1)
Granulomatous Thyroiditis
PATHOGENESIS: GRANULOMATOUS THYROIDITIS
Granulomatous thyroiditis is believed to be triggered by a?
viral infection or a post viral inflammatory process
stimulates a cytotoxic T-lymphocyte response to one or more thyroid antigens that damages
thyroid follicle cells
- painless or silent thyroiditis, is a presumed autoimmune disease
- Uncommon cause of hyperthyroidism
- Although it can occur at any age, it is most often seen in middle-aged adults and is more common in women. Some patients transition from hyperthyroidism to hypothyroidism before recovery.
- Pathogenesis is still unknown
- Comes to medical attention due to mild hyperthyroidism, goiter, or both
- A similar disease process can occur during the postpartum period in up to 5% of women (postpartum thyroiditis)
Subacute Lymphocytic (Painless) Thyroiditis
most common cause of
endogenous hyperthyroidism
Graves Disease
Graves Disease is characterozed by a triad of clinical findings, what are those?
- Hyperthyroidism
- Infiltrative ophtalmopathy
- Localized, infiltrative dermopathy, sometimes called pretibial myxedema
What are the genetic factors of grave disease?
- family members
- HLA-B8 & -DR3
- CTLA-4 gene polymorphism - chromosome 6p and 20q
MORPHOLOGY: GRAVES DISEASE
What are the main characrterization of grave disease? (highlighted ni maam)
- Too many cells, crowding
- Pale, scalloped colloid (prominent)
Enlargement of thyroid (goiter) is most common manifestation of?
THYROID DISEASE!!!!
bobo kaba kung dimo nasagot
Impaired synthesis of hormone caused by dietary iodine deficiency leads to compensatory rise in TSH, which, in turn causes hypertrophy and hyperplasia of follicular cells→
goiter→?
euthyroidism
Congenital biosynthetic defect or endemic iodine deficiency results in
goitrous hypothyroidism
Enlargement proportional to duration of thyroid hormone (Deficiency or Efficiency)
Deficiency
Goiter can be divided into 2 types, what are those:
diffuse nontoxic and multinodular
Goiter <3
- causes enlargement of the entire gland without producing nodularity.
- Because the enlarged follicles are filled with colloid, the term colloid goiter has been applied to this condition.
- This disorder occurs in both an endemic and a sporadic distribution
Diffuse Nontoxic (Simple) Goiter
Endemic or Sporiadic Goiters
occurs in geographic areas where the soil, water, and food supply contain low levels of iodine. The term ____ is used when goiters are present in more than 10% of the population in a given region.
Endemic goiter
Endemic or Sporiadic Goiters
occurs less frequently than does
endemic goiter. There is a striking female preponderance and a peak incidence at puberty or in young adult life.
Sporadic goiter
Goiter <3
- produce the most extreme thyroid enlargements and are more frequently mistaken for neoplasms than any other form of thyroid disease
- Occurs when the simple goiter involutes or increases in size, and it may produce hemorrhage and scarring with calcification.
- Due to recurrent episodes of hyperplasia and involution of simple goiter
Multinodular Goiter
Multinodular or Diffuse nontoxic - MORPHOLOGY
- It may be hanging on the thoracic cavity that may compress other structures causing difficulty breathing, swallowing, hoarseness of
voice, - Multilobulated, asymmetrically enlarged glands
- Intrathoracic or plunging goiter -goiter grows behind the sternum
- Irregular nodules, variable amount of colloid
- Hemorrhage, fibrosis, calcification, cyst
- Colloid-rich follicles flattened, inactive epithelium, areas of hypertrophy, hyperplasia
MULTINODULAR GOITER
Multinodular or Diffuse nontoxic - MORPHOLOGY
- Hyperplastic phase or colloid involution phase; abundant colloid flattened, cuboidal epithelium
- Enlargement of the thyroid gland with abundant colloid flattened epithelium
DIFFUSE NONTOXIC GOITER
- Comprise only 1.5% of all cancers
- Comprises only 1.5% of thyroid cancer
- Mostly adults, papillary Ca may be in childhood
- Female, early and middle-adult years
- Mostly well-differentiated
- Most are derived from thyroid follicle epithelium (except medullary carcinoma, which is derived from parafollicular C cells)
Thyroid Carcinoma
Thyroid Carcinoma - Major Subtypes
- Papillary carcinoma
- Follicular carcinoma
- Medullary carcinoma
- Poorly differentiated and anaplastic (undifferentiated) carcinoma
C. 5%
A. >85%
D. <5%)
B. 5-15%
- A
- B
- C
- D
Thyroid
Most common form of thyroid cancer and is said to be indolent, accounting for nearly 85% of primary thyroid malignancies in the United States
Papillary Carcinoma
Thyroid Cancer
Named by the appearance of the tumor; some sections would appear like papillae or finger-like projections.
Branching papillae have a fibrovascular stalk covered by a single to multiple layers of cuboidal epithelial cells.
Papillary Carcinoma
Thyroid Cancer
- They are lined by cells with empty nuclei or grooved nuclei (MOST COMMON FINDING)
- Due to the nuclei with finely dispersed chromatin and an optically clear or empty appearance, it is sometimes called as Orphan Annie eye nuclei
Papillary Carcinoma
Thyroid Cancer - Papillary Carcinoma
Concentrically calcified structures termed ____ ____ are often present, usually within the cores of papillae strong indication that it is a papillary carcinoma, when present in fine-needle aspiration material
psammoma bodies
Thyroid Cancer
One of the nicest course of carcinoma
˚ʚ♡ɞ˚˚ʚ♡ɞ˚˚ʚ♡ɞ˚˚ʚ♡ɞ˚
❤︎ Papillary Carcinoma ❤︎
˚ʚ♡ɞ˚˚ʚ♡ɞ˚˚ʚ♡ɞ˚˚ʚ♡ɞ˚
Just like any other malignancies, when caught late, then the prognosis is not good
Thyroid Cancer
- account for 5% to 15% of primary thyroid cancers, but are more frequent in areas with dietary iodine deficiency, where they constitute 25% to 40% of thyroid cancers.
- It is more common in women (1:3), in older age groups compared to papillary carcinoma; its peak incidence is between 40s to 60s
Follicular Carcinoma
Thyroid Cancer
- Composed of neuroendocrine neoplasms derived from the parafollicular cells (C cells).
o They account for 5% of thyroid neoplasms - They secrete calcitonin, which is measured for diagnosis and post-operative follow-up; other polypeptide (PP) hormones such as serotonin, ACTH, and vasoactive
intestinal peptide (VIP)
Medullary Carcinoma
what to remember about the morphology of MEDULLARY CARCINOMA
- Formation of nests, trabeculae, or follicles by polygonal to spindle-shaped cells in medullary carcinomas
- Acellular amyloid deposits in the stroma
Thyroid Cancer
- Undifferentiated tumors of thyroid follicular epithelium
- Aggressive tumors with almost 100% mortality rate
- Mean age: 65 y/o
- 50%, history of multinodular goiter
- 20%, history of differentiated carcinoma
- 20-30%, with concurrent differentiated cancer, frequently papillary CA
- one of the most aggressive cancers known; in most cases death occurs in less than 1 year.
Anaplastic Carcinoma
Thyroid Carciinoma - Morphology
Anaplastic, Medullary, Follicular, or Papillary
- Orphan Annie eye nuclei
- Minimally and Widely invasive follicular carcinoma
- nests, trabeculae, or follicles by polygonal to spindle-shaped cells in medullary carcinomas
- Large, pleomorphic giant cells, Spindle cells with sarcomatous appearance, Mixed spindle and giant cells, and Small cells
- Papillary
- Follicular
- Medullary
- Anaplastic
