Changes

==Introduction==

==Introduction==

[[Image:Puppy rectum-anus.JPG|thumb|right|250px|Section of puppy showing rectum and anus- copyright RVC 2008]]

[[Image:Puppy rectum-anus.JPG|thumb|right|250px|Section of puppy showing rectum and anus- copyright RVC 2008]]

'''Defeacation'''

'''Defeacation'''

After the mass movements of the [[Large Intestine - Anatomy & Physiology|large intestine]], the rectum becomes filled with faeces. This stimulates pressue sensitive cells in the wall of the rectum and initiates the defeacation reflex. The reflex causes a forceful contraction of the rectum, and relaxation of the internal anal sphincter. This produces the conscious sensation of the need to empty the bowel. Some species (see [[#Species Differences|species differences]]) are able to voluntarily keep the external anal sphincter closed if defeacation is not suitable in the situation. This reduces the defeaction reflex and reduces the conscious perception of needing to empty the bowel, until another mass movement occurs and a fresh reflex is created.

After the mass movements of the [[Large Intestine - Anatomy & Physiology|large intestine]], the rectum becomes filled with faeces. This stimulates pressue sensitive cells in the wall of the rectum and initiates the defeacation reflex. The reflex causes a forceful contraction of the rectum, and relaxation of the internal anal sphincter. This produces the conscious sensation of the need to empty the bowel. Some species (see [[#Species Differences|species differences]]) are able to voluntarily keep the external anal sphincter closed if defeacation is not suitable in the situation. This reduces the defeaction reflex and reduces the conscious perception of needing to empty the bowel, until another mass movement occurs and a fresh reflex is created.

[[Category:Large Intestine - Anatomy & Physiology]]

[[Category:Large Intestine - Anatomy & Physiology]]

[[Category:To Do - AimeeHicks]]

[[Category:To Do - AimeeHicks]][[Category:To Do - Review]]