T1 L3 histology

Question 1

endocrine glands and hormones

Answer 1

ductless
Hormones: organic chems released at specific times in small amounts into tissue fluids/ BVs
Pancreas: has exocrine and endocrine function

Question 2

endocrine definition

Answer 2

action of hormone on target organ away from secreting cell

Question 3

autocrine definition

Answer 3

action on self cell

Question 4

paracrine definition

Answer 4

adjacent cell

Question 5

neuroendocrine

Answer 5

neural stimulation of endocrine cells to secrete hormones (medulla of adrenal)

Question 6

structure of endocrine glands

Answer 6

• cuboidal secretory cells w/ lumen at centre, supported by myoepithelial cells
• all have lumen except pituitary and parathyroid

Question 7

clinical manifestations of endocrine diseases

Answer 7

1. hormone overproduction
2. hormone underproduction
3. tumor/ mass lesion (ass. w/ overproduction of hormones, if non-functional there is a pressure effect)

Question 8

pituitary gland divisions

Answer 8

1. adenohypophysis: anterior lobe

2. neurohypophysis: posterior lobe

Question 9

anterior pituitary gland (adenohypophysis) cells present in relation to staining patterns

Answer 9

1. acidophils: take up acid dyes
2. basophils: take up basic dyes
3. chromophobe: no staining features

Question 10

staining method to identify specific hormone secreting cells

Answer 10

Antibody staining against specific hormone (antibodies to GH identify cells secreting GH)

Question 11

hormones from ant. pituitary, cells responsible and target organ

Answer 11

1. GH secreted by somatotroph, targets bones
2. prolactin secreted by lactotroph targets breasts
3. ACTH secreted by corticotroph targets adrenal gland
4. FHS secreted by gonadotroph targets ovaries and testes
5. TSH secreted by thydotroph targets thyroid gland

Question 12

hormones of posterior pituitary (neurohypophysis)

Answer 12

1. ADH: facilitates H2O absorption in kidneys, makes more concentrated (lack in diabetes insipidus = increase in vol, decrease in conc)
2. oxytocin: contraction of smooth muscle in uterus during birth and myoepithelial cells in breast (feeding)

Question 13

pituitary adenomas (benign tumors)

Answer 13

arise from anterior lobe
can be functional/ non-functional
-Functional: productive, cause hyperpituitarism
-non-fucntional: pressure effects and hypopituitarism bc space occupying lesion. Space occupying effects of functional/ non-functional adenomas (headache, nausea, vomiting, diplopia, vision impairment)

Question 14

compression of optic chiasm due to pituitary adenoma

Answer 14

bitemporal hemianopsia

Question 15

Thyroid gland synthesises:

Answer 15

1. T4 (thyroxine)
2. T3 (triiodothyroxine)
   which stimulate metabolic rate, synthesis of these require iodine

Question 16

goitre

Answer 16

thyroid enlargement due to lack of iodine, thyroid enlarges to absorb max conc of iodine

Question 17

normal thyroid gland

Answer 17

• 2 lobes and isthmus
• tissue comprised of follicles w/ variable sized lumina
• lined by cuboidal cells
• follicles stain pink

Question 18

features of thyroid cells

Answer 18

• v. vascular
• endothelial cells lining capillaries (fenestrated)
• parafollicular cells (C cells/ clear cells) found between follicles

Question 19

fenestration of endothelial cells lining capillaries

Answer 19

allows passage of hormone into circulation

Question 20

parafollicular cells, C cells/ clear cells

Answer 20

• found between follicles

- secrete calcitonin which promotes reduction of Ca2+ conc in blood

Question 21

patholigies of thyroid gland (5)

Answer 21

1. Goitre- euthyroid (no symptoms), enlargement of gland
2. Graves disease: hyperthyroid
3. hashimoto’s disease: Hypothyroid
4. adenoma: euthyroid
5. cancer: euthyroid

Question 22

multinodal goitre

Answer 22

• lack of iodine, enlarged thyroid (hyperplasia and hypertrophy)
• increase amount of iodine absorbed
• increase in size overcomes hormonal deficiency and pts are euthyroid (no symptoms)

Question 23

multinodal goitre compresses trachea

Answer 23

• pt may arrest after successful thyroidectomy due to tracheomalacia
• softening of trachea bc pressure causes a collase and obstruction of airways

Question 24

graves disease

Answer 24

• autoantibodies stimulate TSH receptors
• diffuse enlargement of thyroid bc hyperplasia of htyroid cells
• INFILTRATIVE OPTHALMOPATHY: accumulation of soft tissue and inflammation behind eye, proptosis (displacement of eye)
• INFILTRATIVE DERMOPATHY: thickening and induration of skin (ant. skin => pretibial myxoedema)

Question 25

Hashimoto's Thyroiditis

Answer 25

- Most common cause of hypothyroidism where iodine is readily available - autoimmune disease: immune system destroys own thyroid tissue - progressive depletion of thyroid cells by inflammation and replaced by fibrosis - decrease in T3/4 (hypothyroidism) - increase in TSH due to loss of negative feedback from T3/T4

Question 26

steps of hashimoto's hypothyroidism

Answer 26

1. inflammation 2. depletion of thyroid cells 3. replaced by fibrosis 4. decrease in T3/4 , increase in TSH

Question 27

histology of hashimoto's disease

Answer 27

- prominent lymphocytic infiltrate | - bc lymphoid tissue destroys thyroid tissue

Question 28

Tumors: (follicular adenomas)

Answer 28

benign tumor of the thyroid follicular cells

Question 29

Tumors: carcinomas (4 types)

Answer 29

1. papillary (most common, increased risk of lymph metastasis) 2. Follicular (metastasis to bone, lung and liver 3. medullary: C cells 4. anaplastic: older patients, poor prognosis

Question 30

parafollicular cells/ clear cells/ c cells

Answer 30

- secrete calcitonin - promotes reduction of Ca2+ conc in blood (decreases risk of tetanic contraction) - found between follicles - c cells are origin of medullary carcinoma of thyroid

Question 31

parathyroid glands

Answer 31

- secrete PTH - controls levels of Ca2+ in blood - decreases in Ca2+ conc stimulates PTH secretion - chief cells w/ no lumen (prominent vascularity)

Question 32

pathologies of parathyroid glands

Answer 32

all cause hypercalcaemia - adenoma: involves 1 gland - hyperplasia: involves 4 glands

Question 33

adrenal glands

Answer 33

- paired, upper poles of kidneys | - consist of adrenal cortex (derived from mesoderm) and medulla (derived from neural crest cells)

Question 34

normal colour of adrenal glands

Answer 34

yellow bc rich in lipids

Question 35

cortex of adrenal gland 3 zones

Answer 35

GFR (the deeper you go the sweeter it gets) 1. zona glomerulosa: SALT - aldosterone for absorption of Na+ - mineralocorticoids 2. zona fasiculata: SUGAR - cortisol/ corticosterone - glucocorticoids (+ some sex hormone) 3. zona reticularis: SEX - 17 ketosteroids - sex hormones (testosterone)

Question 36

pathology of adrenal gland | adrenocortical hyperactivity

Answer 36

due to hyperplasia, adenoma or cancer (rare) - CUSHING'S SYNDROME (excess cortisol) - CONN'S SYNDROME (excess aldosterone) - ADRENOGENITALSYNDROME (excess androgens)

Question 37

pathology of adrenal gland: adrenocortical insufficiency

Answer 37

addison's disease

Question 38

adrenal cortex adenoma

Answer 38

- non-functional - incidental findings on abdo imaging - functional adenomas: CUSHINGS (cortisol excess) CONN'S (aldosterone excess)

Question 39

compact cells

Answer 39

- secrete adrenaline and NA - fight or flight response/ intense emotional reaction - result in vasoconstriction, ^ HR, ^ BGL (defense to stress)

Question 40

phaechomocytoma

Answer 40

tumor or adrenal medulla - 10% tumor- 10% familial, 10% extraadrenal, 10% bilateral, 10% malignant, 10% childhood - due to high levels of catecholamines - precipitous ^ BP, tachycardia - sweating, tremor, sense of apprehension

Question 41

complications of BP as a result of phaechomocytoma

Answer 41

1. congestive cardiac failiure 2. ischaemic heart disease 3. arrhythmias 4. CVA