SP25_CH4_Body+Basics

Body Basics Chapter 4 Overview

Discuss fundamentals of chemistry and physiology.
Identify major organs of the digestive system:
- Describe primary functions of each organ.
- Identify accessory organs and their roles in digestion.
Discuss nutrient digestion processes, absorption, transport, and waste elimination.
Explore gut microbiota and its role in health.

Chemical Level:
- Atoms combine to form molecules; structure determines function.
- Example: Water molecules and their importance.
Cellular Level:
- Cells are basic units of life consisting of organelles that perform specific functions.
- Formation of tissues from communities of similar cells.
Tissue Level:
- Different tissues combine to form organs.
- Example: Smooth muscle, connective tissue.
Organ Level:
- Organs are composed of multiple tissue types working together.
- Example: Bladder, stomach.
Organ System Level:
- Organ systems consist of two or more organs working together.
- Example: Digestive system, nervous system.
Organismal Level:
- All organ systems function collectively to support life.

Chemistry:
- Study of matter's composition and properties.
- All foods and bodily functions are based on chemicals.
Human Physiology:
- Study of body functions and their chemical basis.
- Principles of chemistry and physiology form the foundation of nutrition.

Totality of chemical reactions in cells, converting nutrients into energy.
Anabolic Processes:
- Build larger molecules from smaller ones (e.g., muscle repair post-weight lifting).
Catabolic Processes:
- Break down larger molecules into smaller molecules (e.g., digestion of starch into sugars).

Small Intestine Absorption:
- Nutrients absorbed primarily through villi in the small intestine.
- Water-soluble nutrients enter blood; fat-soluble nutrients form chylomicrons and enter the lymphatic system.

Large intestine houses diverse bacteria that:
- Ferment undigested food.
- Produce vitamins (K, B-12) and gases.
Gut health is important; imbalances can lead to dysbiosis, influenced by diet, stress, and antibiotics.

Probiotics:
- Beneficial live microbes, available in supplements/foods.
- May help in gut health and disorders.
Prebiotics:
- Dietary fibers that nourish beneficial gut bacteria (e.g., inulin).

Structure: Gastrointestinal (GI) tract and accessory organs.
Length: About 9 meters (30 feet), processes food from mouth to anus.
Digestion begins in the mouth, involving both mechanical (chewing) and chemical (enzymes in saliva) processes.
Esophagus transports food to the stomach; stomach aids in further digestion through mechanical churning and chemical secretions.

Mechanical Digestion: Churning of food.
Chemical Digestion: Hydrochloric acid (HCl) and pepsin assist protein breakdown.
Chyme Formation: Partially digested food mixed with gastric juices.

Three sections: Duodenum, Jejunum, Ileum.
Most digestion and nutrient absorption occur in the duodenum and jejunum, aided by pancreatic and biliary secretions.
Segmentation: Movement mixes chyme without pushing it forward, enhancing absorption.

Limited absorption; primary role is fecal formation.
Contains gut microbiota that facilitates further digestion.
- Imbalance can lead to digestive disorders.

Inflammatory Bowel Disease (IBD): Chronic inflammation, affects nutrient absorption (examples: Ulcerative Colitis, Crohn's Disease).
Gastroesophageal Reflux Disease (GERD): Acid reflux causing esophageal damage.
Peptic Ulcers: Sores in stomach/intestine lining due to HCl and infections.
Irritable Bowel Syndrome (IBS): Non-damaging, characterized by cramps and abnormal bowel function.
Colorectal Cancer: Requires early detection and treatment options such as surgery, chemotherapy.