QuestionSBA
QuestionChoice
Endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels.
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e
Endothelium
QuestionChoice
These are flat cells commonly found in the upper part of the epidermis. The vaginal epithelium consists of multiple layers of squamous cells.
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c
Squamous cells
QuestionChoice
Schwann cells are principal cells of the peripheral nervous system and are responsible for the myelination of axons.
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d
Schwann cells
QuestionChoice
Goblet cells are a type of intestinal mucosal epithelial cell
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b
Goblet cells
QuestionChoice
The annotation points to the middle portion of the male urethra which is a dynamic fibromuscular tube which serves as the terminal region of both the male urinary and reproductive systems. The average male urethra is 20 cm long and begins within the bladder wall and ends in the distal glans of the penis. The proximal two-thirds of the urethra is lined by transitional epithelial cells, while the distal third is lined by stratified squamous epithelial cells..
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Transitional epithelium
Concept
Chapter
## Summary

The male urethra is an epithelium-lined tube that connects the base of the bladder to the external urethral meatus. It is approximately 20cm long and is incorperated within the prostate in parts. It's main funciton is to facilitate the transit of urine out of the body but also has a similar role in ejaculation.

## Anatomy

The male urethra has three sections.

- **Prostatic urethra** - the widest and most distensible part. 
	- It has a long ridge on its posterior wall known as the urethral crest. 
	- The prostatic urethra connects the neck of the bladder through the prostate gland. 
	- It is approximately 3cm in length and ends in the membranous urethra. 
	- The two openings of the ejaculatory duct lie on either side of the summit of the urethral crest. 
	- This portion of the urethra is lined with **transitional epithelium**. 
- **Membranous urethra** 
	- Connects the prostatic and penile urethra. 
	- It is the narrowest part of the urethra and is enclosed by the **external urethral sphincter**. 
	- The membranous urethra is named as such due to its course through the perineal membrane. 
	- It is approximately 1-2cm and is lined with **pseudostratified columnar** and **pseudostratified epithelium**.
- **Penile (spongy) urethra** 
	- It passes through the corpus spongiosum of the penis and terminates in the **external urethral orifice**. 
	- It is 15-25cm in length and receives secretions from the bulbourethral glands before dilating in the glans of the penis to create the navicular fossa. 
	- It is lined by **pseudostratified columnar epithelium** proximally and **nonkeratinising stratified squamous epithelium** distally.

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## Blood supply

Arterial supply depends on the portion:
- Prostatic - **inferior vesical artery**
- Membranous - **bulbourethral artery**
- Penile - **internal pudendal artery**

## Functions
Transit of:
- Urine from the bladder to the external urethral orifice
- Semen from the ejaculatory ducts and prostate to the external urethral orifice.

## Clinical points
- The most likely site of injury in traumatic urethral injury is the membranous urethra.
- Post-infection (most commonly gonorrheal) urethral stricture is most likely to affect the penile urethra.
3018
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9/cJBIChvYiIeHe/V3egdwy7uQ==
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male urethra2.gif
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NwgKBACgfoiHiXeId5dvePd0Zw==
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male urethra.gif
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9gcKB4D1iZlUuYead5eZl3eIWE+UC70I
5001
Male urethra
Topic
237
Pelvic Anatomy
15394
Picture
1979
9 - Male urethra (penile urethra).png
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Topic
237
Pelvic Anatomy
What type of cells line the annotated structure?

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a