endocrine System

Question 1

Mixed gland in our bodies

Answer 1

1. Islets of langerhans .
2. Leyding cells .
3. Corpus lutetium .

Question 2

Endocrine glands aggregation

Answer 2

1. Cords & clumps .

2. Follicles ( thyroid glands ) & the intermediate lobe of pituitary gland .

Question 3

Pituitary gland weight

Answer 3

0.5 g in adult

Question 4

Pituitary gland parts and their embryonic origin

Answer 4

1. adenohypophysis (ant. lobe ) —> rathke’s pouch .

2. Neurohypophysis ( post. lobe ) —> diencephalon of the developing brain .

Question 5

Pituitary gland histology

Answer 5

1. Capsule of c.t .
2. Adenohypophysis :
   a. Pars distalis .
   b. Pars tubularis .
   c. Pars intermedia .
3. Neurohypophysis :
   a. Pars nervosa .
   b. Fundibular stalk .
   c. Median eminence .

Question 6

Pars distalis histology

Answer 6

1. Cords of epi. cells (hormone secreting cells):
   a. Chromophils ( acidophilic & basophilic ) .
   b. Chromophobs .
2. Reticular fibers .
3. Fenestrated & sinusoidal capillaries .

Question 7

PAS stain

Answer 7

1. Acidophilic —> bright purple color .

2. Basophilic —> bluish color .

Question 8

Chromophobs

Answer 8

1. Weakly staining .
2. Few or no granules .
3. Not yet differentiated into hormone producing cells .

Question 9

Acidophilic cells

Answer 9

1. Somatotropes .

2. Mammo(lacto)tropes .

Question 10

Basophilic cells

Answer 10

1. Thyrotropes .
2. Gonadotropes .
3. Corricotropes .

Question 11

Pars tubularis histology

Answer 11

1. Gonadotropes , thyrotropes & chromophobes .

2. Hypophyseal portal vessels .

Question 12

Pars intermedia histology

Answer 12

1. Hypophyseal cleft .

2. Large pale cells surround follicles filled with colloid material .

Question 13

Hormone secreted by pars intermedia

Answer 13

MSH ( melanocyte stimulating hormone )

Question 14

Upper section of beurohypophysis above pars tubularis

Answer 14

Median eminence .

Question 15

Part of neurohypophysis connects the pars nervosa with the base of the brain .

Answer 15

Infundibular stalk

Question 16

The pars nervosa differs from adenohypophysis

Answer 16

It does not have secretory cells that secret hormones .

Question 17

Pars nervosa histology

Answer 17

1. Neural tissue
   a. unmylinated axons of supraoptic nuclei .
   b. Pituicytes ( highly branched glial cells ) —>
   most abundant .
2. Herring bodies : dilated area of the terminal
   portion of axons ( neurosecretory granules)

Question 18

Herring bodies function

Answer 18

1. ADH secretion .

2. Oxytocin .

Question 19

Suprarenal gland ( shape & weight )

Answer 19

Pyramidal in shape , 4g in weight .

Question 20

Adrenal gland histology

Answer 20

1. Stroma :
   a. Dense c.t capsule with trabeculae .
   b. Reticular fibers .
2. Parenchyma :
   a. Cortex .
   b. Medulla .

Question 21

Adrenal gland cortex criterias

Answer 21

1. 80-90% .

2. derived from mesoderm .

Question 22

Adrenal gland medulla criterias

Answer 22

1. 10-20% .
2. Derived from neural ectoderm (considerd as
   a modified sympathetic ganglion ) .

Question 23

Type of adrenal cortical hormones

Answer 23

Steroid hormones

Question 24

Zona glomerulosa histology

Answer 24

Its cells are columnar in shape & in irregular cords pattern .

Question 25

Zona fasiculata histology

Answer 25

Its cells are polyhedral , have foamy appearance & arranged in straighted cords pattern .

Question 26

Zona fasiculata cells have foamy appearance . Explain why .

Answer 26

Due to abundant lipid droplets

Question 27

Zona reticularis histology

Answer 27

1. Cells arranged in cords project in many directions & anastomose with each other . 2. Its cells are smaller than fasiculata . 3. Eosinophilic . 4. Few lipid droplets .

Question 28

Chromaffin cells histology

Answer 28

Large , polyhedral , supported by reticular fibers & located in adrenal medulla .

Question 29

From where the chromaffin cells arise

Answer 29

Neural crest , considered as modified sympathetic postganglionic neurons lacking axons & dendrites & specialized as secretory cells .

Question 30

Why cromaffin cells called like that ?

Answer 30

Because derive from fixative solution containing chromium salts .

Question 31

Why chromaffin cells have brownish appearance ?

Answer 31

Due to oxidation of catecholamines to melanin .

Question 32

Sympathetic ganglion cells histology

Answer 32

Round or polyhedral with prominent nuclei .

Question 33

Pineal body capsule histology

Answer 33

1. Capsule of c.t with its trabeculae . 2. The paranchyma is homogenous . 3. Blood vessles . 4. Two cell types ( pinealocytes & astrocytes ) .

Question 34

Pinealocytes histology

Answer 34

Large , light & round nuclei .

Question 35

Astrocytes histology

Answer 35

Glial cells , dark & elongated nuclei .

Question 36

Brain sands

Answer 36

A characteristic feature of the pineal gland & considered as Ca & Mg salts of different sizes .

Question 37

Thyroid gland weight

Answer 37

20 g

Question 38

Thyroid gland histology

Answer 38

1. Fibrous capsule . 2. Spherical follicles separated from each other inter follicular c.t . 3. Viscous substances in the lumen of the follicles .

Question 39

Follicular cells histology

Answer 39

Simple squamous to simple columnar epi. according to their activity .

Question 40

Paradollicular cells ( C cells ) location

Answer 40

Between the follicular cells & the basal lamina or outside the basal lamina in the interfollicular c.t .

Question 41

Parathyroid gland weight

Answer 41

About 130g .

Question 42

Parathyroid gland histology

Answer 42

1. Delicate c.t septa . 2. Capillaries . 3. Fat cells . 4. Chief ( principal cells ) . 5. Oxyphil cells .

Question 43

Chief cells histology

Answer 43

Small , polygonal with round central nucleus & weakly acidophilic .

Question 44

Oxyphil cells histologically

Answer 44

As clusters between chief cells , much larger with strongly acidophilic cytoplasm .