Human Physiology

Summary and Exam Tips for Human Physiology

Human Physiology is a subtopic of Option D - Human Physiology, which falls under the subject Biology in the IB DP curriculum. This section covers essential aspects of human nutrition, digestion, liver functions, cardiac physiology, hormonal regulation, and respiratory gas transport. Essential nutrients like certain amino acids and fatty acids must be included in the diet as they cannot be synthesized by the body. Malnutrition results from nutrient imbalance, leading to conditions like obesity or anorexia. The digestive system utilizes exocrine glands and villi adaptations to efficiently absorb nutrients, while gastric secretions are regulated by nervous and hormonal mechanisms. The liver plays a crucial role in blood regulation, receiving dual blood supply via the hepatic artery and portal vein. The heart functions through specialized cardiac muscle cells and valves, with its activity mapped on an ECG. Hormones from endocrine glands, including steroid and peptide hormones, regulate growth, metabolism, and homeostasis. Lastly, the transport of respiratory gases involves oxygen dissociation curves and the Bohr effect, with carbon dioxide carried in multiple forms in the blood.

Exam Tips

• Understand Essential Nutrients: Focus on the differences between essential and non-essential nutrients, and their roles in human health. Remember that carbohydrates are not essential as energy can be derived from other sources.

• Malnutrition and Its Effects: Be able to explain how malnutrition can lead to both undernutrition and overnutrition, and the associated health risks like obesity and anorexia.

• Digestive System Adaptations: Memorize the features of villi (using the mnemonic MR SLIM) and their role in nutrient absorption. Understand how gastric secretions are regulated.

• Cardiac and Respiratory Physiology: Familiarize yourself with the structure and function of cardiac muscle cells and the significance of heart sounds. Practice interpreting ECG traces and oxygen dissociation curves.

• Hormonal Regulation: Know the differences between steroid and peptide hormones, and how they interact with target cells. Use the mnemonic MARGE to remember pituitary hormone functions.

By focusing on these key areas, you'll be well-prepared to tackle questions on human physiology in your exams.