QuestionSBA
QuestionChoice
This is not the correct answer. This describes the epithelium of the cutaneous zone, which is below the pectinate line. the cutaneous zone is histologically equal to the skin, is strongly pigmented and is associated with skin-associated structures such as sweat glands, sebaceous glands, hair follicles, and other structures.
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c
Stratified squamous keratinized epithelium
QuestionChoice
This is not the correct answer. The upper two-thirds of the anal canal, which is derived from endoderm and lies above the pectinate line, is lined by simple columnar epithelium.
10027255
e
Simple cuboidal epithelium
QuestionChoice
This is the correct answer. The anal canal is divided into the colorectal, transitional, anoderm ("white zone"), and cutaneous (squamous) zones. The pectinate (dentate) line divides the anal canal into upper two-thirds (derived from endoderm) and lower one-third (derived from ectoderm). The colorectal zone lies above the pectinate line and has simple columnar epithelium. The transitional zone has a mix of simple columnar and stratified squamous epithelium. The anoderm has stratified non-keratinized epithelium and lastly, the cutaneous zone has stratified squamous keratinized epithelium.
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a
Simple columnar epithelial cells
QuestionChoice
This is not the correct answer. This describes the epithelium of the transitional zone, which contains transverse mucous folds with crypts and anal glands.
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d
A mix of simple columnar and stratified squamous epithelia
QuestionChoice
This is not the correct answer. This describes the epithelium of the anoderm, which is below the pectinate line. The anoderm is densely packed with sensory neurons that detect whether the intestinal content is solid, liquid or gaseous.
10027252
b
Stratified squamous non-keratinized epithelium
Concept
Chapter
2693
5343
Anal canal
Topic
197
Abdominal anatomy
17848
What type of epithelium lines the anal canal proximal to the pectinate line?
a