Anatomy
Large Intestine
Compiled By Muchiri Simon
Edition: 2024/25
, Medical & Nursing | Anatomy I of V pages
1. What are the 8 different components of the large intestine / colon?
Caecum
Appendix
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anus
2. What are the 4 functions of the large intestine
digestion- minimal- enteric bacteria ferment some indigestible carbohydrates and synthesize vitamin B and K
absorption- most remaining water- electrolytes- vitamins produced by bacteria
Propulusion- haustral contractions and mass movements propel faeces to rectum
Defecation
3. What are the 2 types of contractions in the LI?
Haustral contractions:
every 30 minutes
short lived slow contractions
mostly in ascending and transverse colon
initiated by ENS when individual haustra fill with food
Mass movements:
3 to 4 times daily
powerful prolonged contractile waves
gastrocolic reflex: presence of food in stomach produces reflex mass movement
4. What is the gastrocolic reflex?
presence of food in stomach produces reflex mass movement to propel food in large intestine towards rectum
5. What is the defecation reflex?
mass movement of faeces into rectum stimulates visceral afferent neurons (distension)
visceral afferents initiates PNS spinal reflex at S2-4
PNS initiates contraction of rectum, and relaxation of internal anal sphincter
message also reaches brain to allow conscious decision on relaxation of external anal sphincter
6. Describe the caecum including the location, ileocecal junction, nerve supply, and vascular supply
Anatomy:
first part of LI
between ileum of SI and ascending colon
7.5 cm length and breadth
Location:
right inguinal region
Anatomy to right iliac fossa
corresponds 2024/25 Edition
Ileocecal junction:
ileocecal vavle controls passage of chyme through ileocecal orifice
Large Intestine
Compiled By Muchiri Simon
Edition: 2024/25
, Medical & Nursing | Anatomy I of V pages
1. What are the 8 different components of the large intestine / colon?
Caecum
Appendix
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anus
2. What are the 4 functions of the large intestine
digestion- minimal- enteric bacteria ferment some indigestible carbohydrates and synthesize vitamin B and K
absorption- most remaining water- electrolytes- vitamins produced by bacteria
Propulusion- haustral contractions and mass movements propel faeces to rectum
Defecation
3. What are the 2 types of contractions in the LI?
Haustral contractions:
every 30 minutes
short lived slow contractions
mostly in ascending and transverse colon
initiated by ENS when individual haustra fill with food
Mass movements:
3 to 4 times daily
powerful prolonged contractile waves
gastrocolic reflex: presence of food in stomach produces reflex mass movement
4. What is the gastrocolic reflex?
presence of food in stomach produces reflex mass movement to propel food in large intestine towards rectum
5. What is the defecation reflex?
mass movement of faeces into rectum stimulates visceral afferent neurons (distension)
visceral afferents initiates PNS spinal reflex at S2-4
PNS initiates contraction of rectum, and relaxation of internal anal sphincter
message also reaches brain to allow conscious decision on relaxation of external anal sphincter
6. Describe the caecum including the location, ileocecal junction, nerve supply, and vascular supply
Anatomy:
first part of LI
between ileum of SI and ascending colon
7.5 cm length and breadth
Location:
right inguinal region
Anatomy to right iliac fossa
corresponds 2024/25 Edition
Ileocecal junction:
ileocecal vavle controls passage of chyme through ileocecal orifice
