Anus, Rectum & Prostate Flashcards
What forms the terminal portions of the GI tract?
rectum and anus
How long is the anal canal?
2.5 to 4 cm and opens onto the perineum
What is the characteristic of the tissue visible at the external margin of the anus?
moist and hairless mucosa
What is the characteristic of the juncture with the perianal skin?
increased pigmentation and in the adult, presence of hair
What normally keeps the anal canal closed?
concentric rings of muscle- the internal and external sphincters
Which concentric ring is under involuntary autonomic control?
the internal ring
What causes the URGE to defecate?
when the rectum fills with feces and causes reflective stimulation that relaxes the internal sphincter
What controls defecation?
controlled by the striated external sphincter which is under voluntary control
What supplies the lower half of the canal making it sensitive to painful stimuli?
somatic sensory nerves
What supplies the upper half of the canal, making it relatively insensitive to pain?
autonomic control
What lines the anal canal that fuse to form the anorectal junction?
lined by columns of mucosal tissue (columns of Morgagni) that fuse to form the anorectal junction
What are the spaces between the columns of Margagni called that anal glands empty into?
crypts
What can be the result of inflammation of the crypts?
fistula or fissure formation
What is it called when anastomosing veins cross the columns forming a ring?
zona hemorrhoidalis
Dilation of the zonal hemorrhoidalis veins causes what?
internal hemorrhoids
The lower segment of the anal canal contains a venous plexus that drains into the ___ ____ ____.
inferior rectal veins
Dilation of the inferior rectal veins results in what?
external hemorrhoids
How long is the rectum?
12 cm long
The proximal end of the rectum is continuous with the ______.
sigmoid colon
Is the distal end of the rectum at the anorectal junction, is the sawtooth- like edge palpable?
NO just visual on proctoscopic exam
Above the anorectal junction, the rectum ____ and turns ___ into the hallow of the coccyx and sacrum, forming the ____ ____.
dilates, posteriorly, rectal ampulla
What is stored in the rectal ampulla?
flats and feces
What are the 3 semilunar traverse folds of the rectal wall?
Houston valves
The prostate is ____ and divided by a shallow median sulcus into ______.
convex; right and left lateral lobes
Is the third or median lobe palpable on examination?
No
What composes the median lobe of the prostate and where is it located?
glandular tissue and lies between the ejaculatory duct and urethra.
What extends outward from the prostate?
seminal vesicles
How does the prostate contribute to ejaculatory fluid?
it contains active secretory alveoli
What causes retention of stool in older adults?
degeneration of afferent neurons in the rectal wall interferes with relaxation of the internal sphincter in response to dissension of the rectum.Higher pressure threshold.
What can cause fecal incontinence in older adults?
the autonomically controlled internal sphincter loses tone, the external by itself cannot control the bowels
What replaces the muscular component of the prostate?
collagen
What often obscures the atrophy of aging of the prostate?
benign hyperplasia of the glandular tissue
What are the risk factors of prostate cancer?
age
more common in African Americans
common in north america and northwestern Europe, Australia and Caribbean
family history
inherited BRCA or hereditary non polyposis colorectal cancer
gonadectomy in transgender women does not decrease the risk
What are the risk factors of anal cancer?
HPV multiple sex partners receptive anal intercourse ciggs immunosuppression of HIV more common in women
What might indicate that a pt is in pain during the exam?
with acute rectal problem the pt will shift uncomfortably from side to side sitting
How should transgender pts be examined for rectal exam?
in the position of their identified gender
What type of infection at the dscrococcygeal and perianal areas are more common in adults? children?
adults: fungal infections in pts with DM
children: pinworms
IF tenderness and inflammation are found at the sacrococcygeal and perianal areas would should you consider?
perianal abscess, anorectal fistula/fissure, pilondial cysts or pruritus ani
What might be an indication with a lax sphincter?
neurologic deficit or sexual abuse
An extremely tight sphincter might be the result of what?
scarring, spasticity caused by a fissure or other lesion, inflammation or anxiety about the exam
Rectal pain is almost always indicative of ______.
local disease.
When are internal hemorrhoids felt?
NOT ordinarily felt unless they are thrombosed
How far can an examining finger palpate into the rectum?
6 to 10 cm
what technique is useful for detecting a perianal abscess?
bidigital palpation
What may produce such extremes tenderness the you are unable to complete the exam without local anesthesia?
anal fistula or fissure
Asking the pt to bear down when palpating the anterior rectal wall does what?
allows you to reach a few centimeters farther into the rectum, you may be able to detect tenderness of peritoneal inflammation and nodularity of peritoneal mets
What are the hard nodules called that are palpable in the peritoneal cup de sac?
shelf lesions
How should the prostate feel on examination?
like a pencil eraser- firm, smooth, slightly moveable and non tender
A healthy prostate has a diameter of ____cm, with less than ____cm protrusion into the rectum.
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