Lecture 11 pt 3

Question 1

1) What causes internal hemorrhoids?
2) What causes external hemorrhoids?

Answer 1

1) Prolapses of rectal mucosa
2) Thrombi

Question 2

1) What veins are involved in internal hemorrhoids?
2) What veins are involved in external hemorrhoids?

Answer 2

1) Veins of internal rectal venous plexus
2) External rectal venous plexus

Question 3

1) Where are internal hemorrhoids?
2) Where are external hemorrhoids?

Answer 3

1) Prolapse thru anal canal
2) Covered in skin

Question 4

1) What do internal hemorrhoids do?
2) What do external hemorrhoids do?

Answer 4

1) Strangulate, ulcerate, bleed
2) Increase portal or abdominal pressure

Question 5

1) Are external hemorrhoids painful or painless? Why?
2) What innervation is responsible in this area?

Answer 5

1) Painful, b/c they’re below pectinate line
2) Somatic fibers from inferior rectal nerves

Question 6

1) Are internal hemorrhoids painful or painless? Why?
2) What innervation is responsible in this area?

Answer 6

1) Painless; above pectinate line
2) Visceral afferents above pectinate line

Question 7

In the parasympathetic defecation reflex:
1) What is the stimulus?
2) What are the receptors?
3) What are the afferents?
4) What center is involved?
5) What are the efferents?
6) What are the effectors?
7) What is the response?

Answer 7

1) Feces enters the rectum, distention of rectal wall
2) Stretch receptors in the rectal wall
3) Sensory fibers terminating in S2-4 spinal cord level
4) S2-4 spinal cord segments
5) Pelvic parasympathetic nerves
6) Smooth muscle cells of descending, sigmoid colon, and rectum
7) Peristaltic waves forcing feces towards rectum; relaxation of internal anal sphincter.

Question 8

In the intrinsic defecation reflex:
1) What is the stimulus?
2) What are the receptors?
3) What are the afferents?
4) What center is involved?
5) What are the efferents?
6) What are the effectors?
7) What is the response?

Answer 8

1) Feces enters the rectum, distention of rectal wall
2) Stretch receptors in the rectal wall
3) Sensory fibers terminating in the MYENTERIC plexus
4) MYENTERIC plexus
5) Motor signals to smooth muscles
6) Smooth muscle cells of descending, sigmoid colon, and rectum
7) Peristaltic waves forcing feces towards rectum; relaxation of internal anal sphincter.

Question 9

What is overriding voluntarily when someone chooses to ignore defecation reflex?

Answer 9

Puborectalis muscle at anorectal flexion

Question 10

What are the 6 palpable structures rectally? (in males)

Answer 10

1) Posterior prostate: CZ and PZ*
2) Seminal glands
3) Pelvic surface of sacrum and coccyx*
4) Ischial spines and tuberosities
5) Enlarged Internal iliac LN
6) Inflamed appendix