Sphincter

1. Describe the structure and function of sphincter.

Structure: Sphincter is made up of smooth muscle that encloses a duct, tube or orifice

Function: the contraction of sphincter constricts the lumen of the tube

2. Describe the cell types of the sphincter.

Mouth: orbicularis oris muscle

Oesophagus: upper oesophageal sphincter - striated muscle (under conscious control)

Lower oesophageal sphincter - smooth muscle (not under conscious control)

Stomach: pyloric sphincter - smooth muscle (not under conscious control)

Intestine: ileocecal sphincter - smooth muscle (not under conscious control)

(Junction between small and large intestines, limited reflux)

Common bile duct: sphincter of Oddi - smooth muscle (not under conscious control)

Anus: internal anal sphincter - smooth muscle (not under conscious control)

external anal sphincter - skeletal muscle (under conscious control)

3. Describe what will happen to the souvlaki in sphincter

-allow the passage of the bolus (oesophagus) and chime (stomach and intestine)

-increase the time of digestion in the stomach

-allow the bile and enzyme to enter the duodenum as to facilitate digestion

-the external anal sphincter help to override the defecation reflex

4. Briefly describe the digestive condition -IBS

- Irritable bowel syndrome (IBS) is one form of functional bowel disease, i.e. function is abnormal without any distinctive organic pathology and with a poor response to treatment. It is a diagnosis of exclusion, i.e. other possible causes of symptoms cannot be found. Most people can control their symptoms with diet, stress management, and prescribed medications. For some people, however, IBS can be disabling. They may be unable to work, attend social events, or even travel short distances.

- Aetiology

A low-fibre diet

Infection

Sensitivity and reactivity to certain food and stress

Disorder of smooth muscle function

5-HT (serotonin) -> affect guts movement

Celiac disease (autoimmune disorder of the small intestine)

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