Nutrition and the Human Body Systems

Nutrition and the Human Body

• Unicellular organisms directly absorb nutrients, while multicellular organisms have complex systems (digestive, respiratory, circulatory, and excretory) to transport nutrients to cells.

• Nutrition's main functions include providing nutrients for growth, repair, and energy production, and eliminating waste products (like CO2 and metabolic by-products) to prevent toxicity.

Systems Involved in Nutrition

• Digestive System: Breaks down food into nutrients, absorbs these nutrients into the bloodstream, and transports them to cells.

• Respiratory System: Supplies oxygen for metabolism, and expels carbon dioxide produced during metabolic activities.

• Circulatory System: Transports oxygen, nutrients, and waste products throughout the body.

• Excretory System: Removes waste products (like urea and CO2) from the body.

Interconnection of Systems

• Digestive system extracts nutrients from food.
• Circulatory system delivers nutrients and oxygen from the digestive and respiratory systems to cells.
• Respiratory system provides oxygen for energy production, and removes CO2.
• Excretory system filters and eliminates waste products.

Digestive System (Structure and Function)

• Digestive Tract:

  • Mouth: Food enters; teeth (incisors, canines, molars) mechanically break down food.
  • Pharynx and Esophagus: Swallowing (peristalsis) moves food.
  • Stomach: Secretes gastric juice containing pepsin (protein breakdown), hydrochloric acid (activates pepsin, destroys bacteria), and rennin (milk coagulation).
  • Small Intestine: Absorbs most nutrients through villi and microvilli, with digestive juices mixing with chyme.
  • Large Intestine: Absorbs water and forms feces.
  • Rectum and Anus: Expel waste.

• Digestive Glands:

  • Salivary glands: Produce saliva, starting carbohydrate digestion.
  • Liver: Produces bile, detoxifies substances, and stores nutrients.
  • Pancreas: Produces enzymes and hormones (like insulin).

Diseases of the Digestive System

• Teeth: Cavities (decay).
• Stomach: Gastritis (inflammation) and Ulcers (erosion of the stomach lining).
• Intestines: Gastroenteritis (inflammation due to bacteria/viruses), Diarrhea (rapid food movement preventing water absorption), Coeliac disease (autoimmune reaction to gluten).
• Liver: Hepatitis (inflammation, often due to viruses), Cirrhosis (scarring of liver tissue, often from alcohol abuse).

Respiratory System (Function and Structure)

• Function: Supplies oxygen for cellular energy and removes carbon dioxide.
• Structure:
  • Airways: Nostrils warm, filter and humidify air, Pharynx directs air to larynx, Larynx protects airways, Trachea branches into bronchi, Bronchi and bronchioles lead air to alveoli in lungs.
  • Lungs: alveoli are where oxygen is absorbed and carbon dioxide is expelled. Right lung has 3 lobes, left lung has 2.

Diseases of the Respiratory System

• Chronic Bronchitis: Persistent inflammation of the bronchi, often due to smoking.
• Asthma: Bronchial constriction caused by allergens/irritants.
• Flu: Viral infection, causing fever, fatigue, and respiratory problems.
• Pneumonia: Infection of alveoli, often caused by bacteria/viruses.
• Emphysema: Loss of elasticity in alveoli, reducing oxygen exchange, frequently linked to smoking
• COVID-19: Viral infection affecting respiratory function, with mild to severe symptoms.

Explore the intricacies of how different systems in the human body contribute to nutrition. From the digestive system breaking down food to the circulatory system transporting nutrients and waste, this quiz covers the critical functions of each system involved in nutrition. Test your understanding of these interconnected processes and stay informed about the essential roles they play in maintaining health.