Body Cells Form tissues Tissues form Organs Organs form Systems (e.g., digestive) Turnover Require energy, adenosine triphosphate Require nutrients

Cell Membrane Double layers of lipid, CHO, and protein Controls passage of substances Distinct identification structures

Organelles Cytoplasm Mitochondria—Power plant Major site for energy production Nucleus DNA Endoplasmic reticulum - communication network Rough endoplasmic reticulum - protein synthesis Smooth endoplasmic reticulum -fat synthesis

Organelles Golgi Complex Packaging site for protein Lysosomes Cell’s digestive system Peroxisomes Detoxify harmful chemicals

Four Types of Tissues Epithelial Lines the outside surfaces and external passages Connective Holds structures together Muscle Able to contract Nervous Transport nerve impulses

Circulatory System Heart and blood vessels Systemic circuit Pulmonary circulation Lymphatic system Blood

Blood Circulation

Cardiovascular System Heart to the lungs Arteries Capillaries Veins

Portal Circulation Transports nutrients From the small intestine Delivers to the liver Allow liver to process nutrients before returning it to the bloodstream

Exchange of Nutrients Insert Fig. 3-4

Exchange of Nutrients Insert Fig. 3-4

The Digestive System

Digestive System Mouth to anus Epithelium lines the lumen Barrier to invaders Submucosal layer Muscularis Taste and smell

The Mouth Mastication Saliva Enzymes to help breakdown simple sugars Mucus to lubricate the food for easier swallowing Lysozyme to kill bacteria Tongue Taste receptors Enzymes to help breakdown fatty acids

The Esophagus Long tube Connects pharynx to the stomach Epiglottis prevents choking Peristalsis, muscle contraction Lower esophageal sphincter Heartburn

The Stomach Lower esophageal sphincter and pyloric sphincter Capacity of ~4 cups Secretion of acid, enzymes, and intrinsic factor Holds food for 2-4 hours Formation of chyme Mucus layer prevents autodigestion

Physiology of the Stomach

Stomach Acid Destroys activity of protein Activates digestive enzymes Partially digests dietary protein Assists in calcium absorption Makes dietary minerals soluble for absorption

The Small Intestine The walls are folded Villi projections are located on the folds Absorptive cells are located on the villi Increases intestinal surface area by 600x Rapid cell turnover

The Small Intestine

Nutrient Absorption Passive diffusion Active absorption Phagocytosis and pinocytosis

Nutrient Absorption

The Large Intestine ~3 1/2 feet in length No villi or enzymes present Little digestion occurs Indigestible food stuff Absorption of water, some minerals, vitamins Contains bacteria Formation of feces for elimination

Rectum Stool remains Stimulates elimination Muscle contraction Anal sphincters

Movement Along the Intestine Peristalsis A ring of contraction propelling material along the GI tract Mass movement Peristaltic wave that contracts over a large area of the large intestine to help eliminate waste

Movement

Site of Absorption

Accessory Organs Pancreas Gallbladder Liver

The Liver Produces bile Enterohepatic circulation

The Pancreas Manufactures digestive enzymes Produces glucagon and insulin Secretes pancreatic juices Bicarbonate needed to neutralize chyme

Storage Capabilities System of maintaining reserves Adipose tissue Glucose Amino acids in the blood Vitamins and minerals in the liver Calcium in bones