- Section 1 ICU organization and management
- Section 2 Pharmacotherapeutics
- Section 3 Resuscitation
- Section 4 The respiratory system
- Section 5 The cardiovascular system
- Section 6 The gastrointestinal system
- Part 6.1 Physiology
- Chapter 172 Normal physiology of the gastrointestinal system
- Chapter 173 Normal physiology of the hepatic system
- Part 6.2 Gastrointestinal monitoring
- Part 6.3 Gastrointestinal haemorrhage
- Part 6.4 Disordered gastric motility
- Part 6.5 The acute abdomen in the ICU
- Part 6.6 Pancreatitis
- Part 6.7 Jaundice
- Part 6.8 Acute hepatic failure
- Part 6.9 Acute on chronic hepatic failure
- Section 7 Nutrition
- Section 8 The renal system
- Section 9 The neurological system
- Section 10 The metabolic and endocrine systems
- Section 11 The haematological system
- Section 12 The skin and connective tissue
- Section 13 Infection
- Section 14 Inflammation
- Section 15 Poisoning
- Section 16 Trauma
- Section 17 Physical disorders
- Section 18 Pain and sedation
- Section 19 General surgical and obstetric intensive care
- Section 20 Specialized intensive care
- Section 21 Recovery from critical illness
- Section 22 End-of-life care
(p. 811) Normal physiology of the gastrointestinal system
- Chapter:
- (p. 811) Normal physiology of the gastrointestinal system
- Author(s):
Annika Reintam Blaser
and Adam M. Deane
- DOI:
- 10.1093/med/9780199600830.003.0172
The gastrointestinal (GI) system is responsible for digestion and absorption, but also has important endocrine, immune and barrier functions. Additionally, the GI system plays a major role in fluid, electrolyte and acid-base balance. The GI system is regulated by complex myogenic, neural and humoral mechanisms, and, in health, these are affected by the presence of luminal nutrient, thereby modulating function of the GI system. Accordingly, GI function varies depending on whether a person is fasted or in the postprandial state. Adequate fasting and postprandial perfusion, motility and exocrine secretion are required for ‘normal’ functioning. The protective mechanisms of the GI system consist of physical (intact gut mucosa), non-immune (gastric acid, intestinal mucin, bile and peristalsis) and immune (gut-associated lymphoid tissue, GALT) elements. Disruption of GI protection is a putative mechanism underlying the development of multiple-organ dysfunction syndrome. Maintenance of GI function is increasingly recognised as an important factor underlying survival in critical illness.
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- Section 1 ICU organization and management
- Section 2 Pharmacotherapeutics
- Section 3 Resuscitation
- Section 4 The respiratory system
- Section 5 The cardiovascular system
- Section 6 The gastrointestinal system
- Part 6.1 Physiology
- Chapter 172 Normal physiology of the gastrointestinal system
- Chapter 173 Normal physiology of the hepatic system
- Part 6.2 Gastrointestinal monitoring
- Part 6.3 Gastrointestinal haemorrhage
- Part 6.4 Disordered gastric motility
- Part 6.5 The acute abdomen in the ICU
- Part 6.6 Pancreatitis
- Part 6.7 Jaundice
- Part 6.8 Acute hepatic failure
- Part 6.9 Acute on chronic hepatic failure
- Section 7 Nutrition
- Section 8 The renal system
- Section 9 The neurological system
- Section 10 The metabolic and endocrine systems
- Section 11 The haematological system
- Section 12 The skin and connective tissue
- Section 13 Infection
- Section 14 Inflammation
- Section 15 Poisoning
- Section 16 Trauma
- Section 17 Physical disorders
- Section 18 Pain and sedation
- Section 19 General surgical and obstetric intensive care
- Section 20 Specialized intensive care
- Section 21 Recovery from critical illness
- Section 22 End-of-life care