Question
Which part of the fallopian tube functions as a functional and anatomical sphincter controlling the passage between the uterus and the tube?
| A. |
Isthmus
|
| B. |
Intramural
|
| C. |
Ampulla
|
| D. |
Infundibulum
|
Show Answer
|
Correct Answer » B
Explanation
|
|
- The intramural (interstitial) part of the fallopian tube lies within the muscular wall of the uterus.
- It acts as a functional and anatomical sphincter controlling:
- Passage of sperm
- Passage of ovum/zygote
- Flow between uterine cavity and fallopian tube
- Its surrounding myometrial muscle fibers provide sphincteric action.
Reasons to Rule Out Other Options
A. Isthmus
- Narrow medial part of the tube adjacent to the uterus
- Functions mainly in transport of gametes and embryo
- Does not serve as the principal uterotubal sphincter
C. Ampulla
- Widest and longest part of the tube
- Most common site of fertilization
- No sphincteric function
D. Infundibulum
- Funnel-shaped distal end near ovary
- Contains fimbriae that capture ovum after ovulation
- No role in sphincteric control
