Histology Certification Organ Histology 3 â Questions and Answers
Question 1: The tunica media of large elastic arteries such as the aorta is characterized by:
- Dense irregular connective tissue with fibroblasts
- Alternating layers of elastic lamellae and smooth muscle (Correct answer)
- A single internal elastic lamina
- Abundant collagen type I with sparse elastin
Correct answer: Alternating layers of elastic lamellae and smooth muscle
Large elastic arteries have a thick media composed of concentric elastic lamellae alternating with smooth muscle cells that buffer pulsatile blood flow.
Question 2: In the small intestine, which cells secrete defensins and lysozyme to protect the intestinal crypts?
- Goblet cells
- Enteroendocrine cells
- Paneth cells (Correct answer)
- M cells
Correct answer: Paneth cells
Paneth cells reside at the base of intestinal crypts and secrete antimicrobial peptides including defensins and lysozyme.
Question 3: The glomerular podocyte foot processes are interconnected by which specialized junction?
- Tight junction (zonula occludens)
- Slit diaphragm (Correct answer)
- Gap junction (nexus)
- Desmosome
Correct answer: Slit diaphragm
Slit diaphragms bridge adjacent foot processes and are composed of nephrin, podocin, and other proteins, forming a key filtration barrier.
Question 4: Which histological stain is most appropriate for identifying reticular fibers forming the framework of lymph nodes and spleen?
- Masson's trichrome
- Periodic acidâSchiff (PAS)
- Gomori reticulin (silver impregnation) (Correct answer)
- Hematoxylin and eosin
Correct answer: Gomori reticulin (silver impregnation)
Gomori reticulin stain selectively impregnates type III collagen (reticular fibers) with silver, rendering them black.
Question 5: The zona pellucida surrounding an oocyte is composed primarily of:
- Type IV collagen and laminin
- Glycoproteins ZP1, ZP2, and ZP3 (Correct answer)
- Fibronectin and vitronectin
- Hyaluronic acid and proteoglycans
Correct answer: Glycoproteins ZP1, ZP2, and ZP3
The zona pellucida is a glycoprotein coat synthesized by the oocyte, consisting of ZP1, ZP2, and ZP3 that mediate sperm binding.
Question 6: In the testis, which cells form the bloodâtestis barrier by creating tight junctions between adjacent cells?
- Leydig cells
- Sertoli cells (Correct answer)
- Spermatogonia
- Myoid cells
Correct answer: Sertoli cells
Sertoli cell tight junctions divide the seminiferous epithelium into basal and adluminal compartments, creating an immunologically privileged site.
Question 7: The portal triad of the liver classically contains which three structures?
- Portal vein branch, hepatic artery branch, bile ductule (Correct answer)
- Central vein, sinusoid, space of Disse
- Hepatic vein, lymphatic vessel, nerve
- Kupffer cell, Ito cell, hepatocyte
Correct answer: Portal vein branch, hepatic artery branch, bile ductule
Each portal triad contains a branch of the portal vein, hepatic artery, and bile ductule embedded in loose connective tissue.
Histology Certification Organ Histology 3
The tunica media of large elastic arteries such as the aorta is characterized by: