Large intestine No villi on mucosa Short glands
- Slides: 10
Large intestine
No villi on mucosa Short glands with numerous goblet cells
Functions • Absorption of water and electrolytes. • Storage of fecal matters. • Synthesis of various substances. Vit B complex, Vit K , Gases like CO 2, H 2 S etc • Secretion Watery fluid containing K+ & HCO 3 - + Mucin
• Bacterial digestion. Cellulose, Hemicellulose, some undigested Fat, Proteins, Carbohydrates.
Movements are sluggish. 2 types : 1. Mixing movements / Haustrations. 2. Propulsive movement / Mass movement.
Mixing movements /Haustrations: • Same as that of segmental movements in small intestine but involve larger segments. • Bag like sac =Haustrations formed.
Functions: • Faecal matter is slowly dug into and rolled over so that the faecal matter is exposed to the large intestinal mucosa and this facilitates fluid absorption. • Cause slow forward propulsion of the colonic contents
Mass peristalsis: • Occurs once or twice a day in an adults and several times a day in infants Stimulus: Filling of the stomach /over distention of the colon. Ø Evacuation of the colon contents.
Applied aspects: § Constipation - motility is less. § Diarrhoea – motility is more. § A ganglionic megacolon: congenital absence of the ganglionic cells in myenteric and submucosal plexus of a segment of the distal colon. • Faecal matter accumulates in this region.
