Histology of thyroid

Question 1

What surrounds the thyroid gland?
A) A layer of adipose tissue
B) A thin connective tissue capsule
C) A cartilage sheath
D) A layer of smooth muscle

Answer 1

Answer: B) A thin connective tissue capsule

Question 1

What is the functional unit of the thyroid gland?
A) Parafollicular cells
B) Colloid
C) Thyroid follicles
D) Trabeculae

Answer 1

Answer: C) Thyroid follicles

Question 2

Where is the thyroid gland located?
A) Posterior to the trachea
B) Anterior to the neck, adjacent to the larynx and trachea
C) Inside the cranial cavity
D) Near the pancreas

Answer 2

Answer: B) Anterior to the neck, adjacent to the larynx and trachea

Question 3

When does the thyroid gland begin to develop during gestation?
A) Week 2
B) Week 4
C) Week 8
D) Week 12

Answer 3

Answer: B) Week 4

Question 3

The thyroid gland originates from which embryonic layer?
A) Mesoderm
B) Ectoderm
C) Endoderm
D) Neural crest cells

Answer 3

Answer: C) Endoderm

Question 4

What is the name of the structure that forms as the thyroid primordium grows caudally?
A) Thyroid sinus
B) Thyroglossal duct
C) Laryngeal pouch
D) Parathyroid invagination

Answer 4

Answer: B) Thyroglossal duct

Question 5

By which week of development do well-developed thyroid follicles contain colloid?
A) Week 10
B) Week 12
C) Week 14
D) Week 16

Answer 5

Answer: C) Week 14

Question 6

What is the function of the thyroid follicle?
A) To store hormones and produce T3 and T4
B) To filter blood
C) To produce insulin
D) To secrete digestive enzymes

Answer 6

Answer: A) To store hormones and produce T3 and T4

Question 7

What is the approximate weight of each lobe of the thyroid gland?
A) 5-10 g
B) 10-15 g
C) 20-30 g
D) 40-50 g

Answer 7

Answer: C) 20-30 g

Question 8

What is contained inside the lumen of the thyroid follicle?
A) Blood plasma
B) Connective tissue
C) Colloid
D) Cartilage

Answer 8

Answer: C) Colloid

Question 8

The thyroid follicle is lined by which type of epithelium?
A) Stratified squamous epithelium
B) Simple cuboidal or low columnar epithelium
C) Pseudostratified columnar epithelium
D) Transitional epithelium

Answer 8

Answer: B) Simple cuboidal or low columnar epithelium

Question 9

What are the two types of cells found in the follicular epithelium?
A) Parafollicular and follicular cells
B) Chief and oxyphil cells
C) Hepatocytes and Kupffer cells
D) Beta and alpha cells

Answer 9

Answer: A) Parafollicular and follicular cells

Question 10

What is the role of the parafollicular cells in the thyroid gland?
A) They produce insulin
B) They secrete digestive enzymes
C) They regulate calcium homeostasis
D) They filter waste

Answer 10

Answer: C) They regulate calcium homeostasis

Question 11

How does the shape of follicular cells change with activity?
A) They become more prismatic during secretion and flatter at rest
B) They become rounder during secretion and elongated at rest
C) They do not change shape
D) They shrink when secreting hormones

Answer 11

Answer: A) They become more prismatic during secretion and flatter at rest

Question 11

What feature is present on the surface of follicular epithelial cells?
A) Long cilia
B) Short microvilli
C) Flagella
D) Pseudopodia

Answer 11

Answer: B) Short microvilli

Question 11

What is the primary function of follicular (principal) cells in the thyroid gland?
A) Production of insulin
B) Secretion of calcitonin
C) Production of thyroid hormones T3 and T4
D) Regulation of blood glucose levels

Answer 11

Answer: C) Production of thyroid hormones T3 and T4

Question 12

What structures send trabeculae into the thyroid parenchyma?
A) Thyroid follicles
B) Connective tissue capsule
C) Lymphatic vessels
D) Nerve fibers

Answer 12

Answer: B) Connective tissue capsule

Question 12

What type of staining reaction does colloid in the thyroid follicles show?
A) Hematoxylin-negative
B) PAS-positive
C) Eosin-negative
D) Silver stain-positive

Answer 12

Answer: B) PAS-positive

Question 13

What is the location of the nucleus in follicular cells?
A) Basally located
B) Apically located
C) Peripherally located
D) Centrally located

Answer 13

Answer: D) Centrally located

Question 14

Where is the Golgi apparatus found in follicular cells?
A) In the basal region
B) In the supranuclear region
C) Near the cell membrane
D) Distributed throughout the cytoplasm

Answer 14

Answer: B) In the supranuclear region

Question 15

How do follicular cells obtain colloid for thyroid hormone secretion?
A) They release enzymes to break it down externally
B) They extend pseudopods into the lumen and take in colloid
C) They absorb it through active transport proteins
D) They rely on C cells to absorb the colloid

Answer 15

Answer: B) They extend pseudopods into the lumen and take in colloid

Question 16

Where are T3 and T4 hormones released after processing?
A) Into the follicle lumen
B) Into the bloodstream from the basal side of the cell
C) Into the surrounding connective tissue
D) Into the lymphatic system

Answer 16

Answer: B) Into the bloodstream from the basal side of the cell

Question 17

Where are parafollicular (C) cells located?
A) Inside the follicular lumen
B) In the periphery of the follicular epithelium, within the follicle basal lamina
C) In the thyroid capsule
D) In the interstitial spaces between follicles

Answer 17

Answer: B) In the periphery of the follicular epithelium, within the follicle basal lamina

Question 18

What is the function of parafollicular (C) cells?
A) Production of T3 and T4
B) Secretion of calcitonin
C) Absorption of iodine
D) Regulation of glucose metabolism

Answer 18

Answer: B) Secretion of calcitonin

Question 19

What is the primary function of calcitonin? A) Regulation of blood glucose levels B) Stimulation of thyroid hormone production C) Regulation of calcium metabolism D) Promotion of red blood cell production

Answer 19

Answer: C) Regulation of calcium metabolism

Question 20

How do parafollicular (C) cells appear in routine H&E staining? A) Dark-staining and clustered together B) Pale-staining and found as solitary or small clusters of cells C) Large and darkly stained D) Similar in appearance to follicular cells

Answer 20

Answer: B) Pale-staining and found as solitary or small clusters of cells

Question 21

What characterizes hyperthyroidism (Graves’ disease)? A) Decreased secretion of thyroid hormones B) Excessive release of thyroid hormones into circulation C) Lack of iodine absorption D) Shrinkage of the thyroid gland

Answer 21

Answer: B) Excessive release of thyroid hormones into circulation

Question 21

What is a common cause of hypothyroidism? A) Excessive iodine intake B) Insufficient dietary iodine or autoimmune diseases C) Overproduction of thyroid hormones D) Parathyroid gland dysfunction

Answer 21

Answer: B) Insufficient dietary iodine or autoimmune diseases

Question 22

What is the most common symptom of thyroid disease? A) Hyperpigmentation B) Hypoglycemia C) Goiter (enlargement of the thyroid gland) D) Hypertension

Answer 22

Answer: C) Goiter (enlargement of the thyroid gland)

Question 23

What is another name for iodine-deficiency goiter? A) Toxic goiter B) Endemic goiter C) Multinodular goiter D) Autoimmune goiter

Answer 23

Answer: B) Endemic goiter

Question 24

Which autoimmune disease is associated with hypothyroidism? A) Graves’ disease B) Hashimoto’s thyroiditis C) Addison’s disease D) Cushing’s syndrome

Answer 24

Answer: B) Hashimoto’s thyroiditis

Question 25

What effect do low thyroid hormone levels have on TSH secretion? A) Decrease TSH release B) Increase TSH release C) No effect on TSH levels D) Suppress TSH completely

Answer 25

Answer: B) Increase TSH release

Question 25

What is the structural boundary of each parathyroid gland? A) Thick muscular layer B) Cartilage sheath C) Thin connective tissue capsule D) Smooth muscle covering

Answer 25

Answer: C) Thin connective tissue capsule

Question 26

What divides the parathyroid gland into poorly defined lobules? A) Trabeculae B) Septa from the capsule C) Follicular cells D) Blood vessels

Answer 26

Answer: B) Septa from the capsule

Question 27

What is the embryological origin of the superior parathyroid glands? A) First pharyngeal pouch B) Second pharyngeal pouch C) Third pharyngeal pouch D) Fourth pharyngeal pouch

Answer 27

Answer: D) Fourth pharyngeal pouch

Question 27

The inferior parathyroid glands originate from which embryonic structure? A) First pharyngeal pouch B) Second pharyngeal pouch C) Third pharyngeal pouch D) Fourth pharyngeal pouch

Answer 27

Answer: C) Third pharyngeal pouch

Question 28

What happens to thyroid cells in Hashimoto’s thyroiditis? A) They undergo hypertrophy B) They increase hormone production C) They undergo apoptosis and follicular destruction D) They produce excess calcitonin

Answer 28

Answer: C) They undergo apoptosis and follicular destruction

Question 29

When do oxyphil cells of the parathyroid gland differentiate? A) During fetal development B) At birth C) At puberty D) During old age

Answer 29

Answer: C) At puberty

Question 30

What is the main function of principal (chief) cells in the parathyroid gland? A) Production of calcitonin B) Regulation and secretion of parathyroid hormone (PTH) C) Storage of thyroid hormones D) Protection against infections

Answer 30

Answer: B) Regulation and secretion of parathyroid hormone (PTH)

Question 31

What is the role of oxyphil cells in the parathyroid gland? A) Secretion of parathyroid hormone (PTH) B) Production of calcitonin C) No known secretory function D) Regulation of calcium levels

Answer 31

Answer: C) No known secretory function

Question 31

What is the function of PTH (parathyroid hormone)? A) Increases calcium levels in the blood B) Decreases calcium levels in the blood C) Increases sodium levels in the blood D) Decreases sodium levels in the blood

Answer 31

Answer: A) Increases calcium levels in the blood

Question 32

How does PTH increase calcium levels in the blood? A) By promoting calcium release from bone and increasing vitamin D3 formation in the kidney B) By stimulating thyroid follicular cells C) By decreasing the absorption of calcium in the intestines D) By preventing calcium reabsorption in the kidneys

Answer 32

Answer: A) By promoting calcium release from bone and increasing vitamin D3 formation in the kidney

Question 33

How do oxyphil cells appear in comparison to principal cells? A) Smaller and basophilic B) Larger and strongly acidophilic C) Smaller and pale-staining D) Identical in size and staining properties

Answer 33

Answer: B) Larger and strongly acidophilic

Question 34

What organelles are abundant in oxyphil cells? A) rER and Golgi B) Secretory vesicles C) Mitochondria D) Lysosomes

Answer 34

Answer: C) Mitochondria

Question 34

Where are the adrenal glands located? A) In the thoracic cavity B) In the pelvic region C) In the retroperitoneal space of the abdominal cavity D) Behind the thyroid gland

Answer 34

Answer: C) In the retroperitoneal space of the abdominal cavity

Question 34

How are oxyphil cells arranged within the parathyroid gland? A) In follicles B) As a single continuous layer C) Singly or in clusters D) Surrounding blood vessels

Answer 34

Answer: C) Singly or in clusters

Question 35

What type of hormones do the adrenal glands secrete? A) Only peptide hormones B) Only steroid hormones C) Only catecholamines D) Both steroid hormones and catecholamines

Answer 35

Answer: D) Both steroid hormones and catecholamines

Question 36

What structure covers the adrenal gland? A) A thick connective tissue capsule B) A layer of smooth muscle C) A fibrous cartilage sheath D) A layer of squamous epithelium

Answer 36

Answer: A) A thick connective tissue capsule

Question 37

What is the embryonic origin of the adrenal cortex? A) Neural crest cells B) Mesodermal mesenchyme C) Endoderm D) Ectoderm

Answer 37

Answer: B) Mesodermal mesenchyme

Question 38

What is responsible for the strong acidophilia of oxyphil cells? A) Presence of rER B) Presence of mitochondria C) Large glycogen granules D) High lipid content

Answer 38

Answer: B) Presence of mitochondria