Large intestine Flashcards
What is the sharp turn to the liver called?
Hepatic flexure
What is the sharp turn around level of spleen called?
Splenic flexure
What are taenia coli and where are they found?
Pale bands of longitudinal muscle found on only one side of the large intestine
What are the pale bands of longitudinal muscle found on one side of the large intestine?
Taenia coli
What are the 3 main portions of the large intestine?
Caecum, Colon, and Rectum
What are the 4 sections of the colon?
Ascending, Transverse, Descending, Sigmoid
What shape is the sigmoid portion of the colon?
S shape
What are haustra?
Bulges caused by circular muscle tightening
What are the pouches/buldges cause by circular muscle tightening?
Haustra
What is present in the small intestine but not in the large intestine?
Villi
What are the fatty tags in the large intestine called?
Appendices epiploicae
What are the 4 structural differences between the small intestine and large intestine?
Presence of:
- Taenia coli
- Haustra
- Appendices epiploicae
Absence of:
-Villi
What sphincter in the rectum is involuntary?
Internal sphincter
What sphincter in the rectum is voluntary?
External sphincter
What is the ileo-caecal junction?
A fold of mucosa that allows chyme to pass from the small to large intestine. BUT NOT VICE VERSA
What is the main function of the large intestine?
Fluid absorption
What cell type is abundant in the large intestine and what is the function of its secretion?
Goblet cells.
Mucus acts as a lubricant.
What type of epithelium is present in the large intestine?
Simple columnar
Where does chyme enter the large intestine from?
Ileum
What does the colon absorb from chyme?
Fluid and electrolytes
What does failure in colon absorption result in?
Diarrhoea
Approximately how much chyme enters the large intestine?
0.5 - 1 litre
What is present in the large intestine responsible for making vitamins B and K?
Resident bacterial flora
What vitamin plays a role in cell metabolism?
Vitamin B
What vitamin is essential for blood clotting?
Vitamin K
What is vitamin K responsible for?
Blood clotting
What area of the large intestine is prone to cancer if a change in epithelium occurs?
Recto-anal junction
What side of the recto-anal junction is simple columnar epithelium present?
Rectum side
What side of the recto-anal junction is stratified squamous epithelium present?
Anus side
What are the 2 motility actions of the large intestine?
Peristalsis and mass movements
Where is the primary site of mixing movements?
Caecum and ascending colon
Where does peristalsis occur?
What happens during it?
The transverse and descending colon
Semi-solid faecal matter is moved towards the rectum
When do mass movements usually occur? What is this reflex called?
After meals.
Gastro-colic reflex
What is the purpose of mass movements?
To move chyme
When does chyme turn into faeces during mass movements?
When its moves from the proximal colon to the distal colon
What type of muscle is present in the external sphincter?
Striated muscle
What anal sphincter has striated muscle?
External sphincter
What muscle type is present in the rectum and internal anal sphincter?
What part of the nervous system are they controlled by?
Smooth muscle
Autonomic nervous system
What can increased fluid absorption in the large intestine lead to?
Constipation
