Human Nutrition: Body Systems and Digestion Overview

Tissue

Collection of cells performing a specific task.

Organ

Group of tissues performing a common function.

Organ System

Groups of organs with similar functions.

Plasma Membrane

Phospholipid bilayer separating cytoplasm from outside.

Cytoplasm

Fluid and organelles within the cell, excluding nucleus.

Anaerobic Respiration

Metabolism occurring without oxygen in the cytoplasm.

Mitochondria

Site for ATP synthesis; requires oxygen.

Nucleus

Contains genetic material; controls cell actions.

Chromosomes

46 structures containing genetic information in DNA.

RNA Transcription

Process of transcribing DNA into messenger RNA.

Endoplasmic Reticulum (ER)

Network of membranes for protein and lipid synthesis.

Smooth ER

Lipid synthesis and detoxification; no ribosomes.

Rough ER

Protein synthesis site with ribosomes on surface.

Golgi Complex

Packages and exports proteins to other cell parts.

Peroxisome

Detoxifies harmful chemicals; contains catalase enzyme.

Lysosome

Contains digestive enzymes to break down organelles.

Cell Metabolism

Chemical processes maintaining life in cells.

Anabolic Metabolism

Requires energy to build molecules.

Catabolic Metabolism

Releases energy by breaking down molecules.

Vitamins and Minerals

Regulate enzyme activity in metabolic reactions.

Cardiovascular System

Transports nutrients, waste, gases, and hormones.

Hepatic Portal Circulation

Flow of nutrient-rich blood from intestines to liver.

Lymphatic System

Drains fluid surrounding cells; contains lymph.

Lymphatic vessels

Transport lymph fluid into bloodstream.

Elephantiasis

Swelling caused by lymphatic obstruction.

Lacteals

Lymphatic vessels that absorb dietary fats.

Urinary system

Filters blood waste and regulates body balance.

Erythropoietin

Hormone stimulating red blood cell production.

Cranberry consumption

May protect kidney health.

Central nervous system

Integrates internal and external body information.

Neurons

Cells generating electrical currents for communication.

Sodium and potassium

Nutrients used by neurons for electrical currents.

Neurotransmitters

Chemicals for brain function from nutrients.

Glucose

Preferred fuel source for the brain.

Endocrine system

Regulates metabolism and produces hormones.

Permissive hormones

Hormones that activate other hormones.

Antagonistic hormones

Hormones that inhibit other hormones.

Synergistic hormones

Hormones that work together for effect.

Insulin

Lowers blood glucose by promoting glycogen synthesis.

Glucagon

Raises blood glucose by converting glycogen.

Immune system

Defends against pathogens with innate and adaptive immunity.

Innate immunity

Nonspecific defenses against pathogens.

Adaptive immunity

Specific response by white blood cells.

Antibodies

Blood proteins binding foreign proteins.

Antigens

Substances inducing immune sensitivity or resistance.

Digestion

Breakdown of large molecules into nutrients.

Absorption

Uptake of nutrients into bloodstream or lymph.

Gastrointestinal tract

Organs for digestion and nutrient absorption.

Motility

Movement of food through the GI tract.

Mastication

Chewing process to break down food.

Bolus

Food mass mixed with saliva, swallowed.

Chyme

Mixture of gastric juices and partially digested food.

Peristalsis

Muscular contractions moving food through GI tract.

Cecum

First part of the large intestine.

Ascending Colon

Section of colon moving upward from cecum.

Transverse Colon

Horizontal section of the large intestine.

Descending Colon

Colon section moving downward toward sigmoid.

Sigmoid Colon

S-shaped section before the rectum.

Rectum

Final section of the large intestine.

Anal Canal

Last part of the digestive tract.

Oral Cavity

Mouth area where food is chewed.

Taste Buds

Receptors on tongue sensing food flavors.

Umami

Savory flavor associated with brothy foods.

Oleogustus

Flavor associated with fat.

Saliva

Watery fluid aiding food digestion.

Amylase

Enzyme breaking down starch in saliva.

Lipase

Enzyme breaking down fat in digestive tract.

Esophagus

Tube connecting pharynx to stomach.

Pharynx

Organ connecting oral and nasal cavities.

Epiglottis

Flap preventing food from entering trachea.

Cardiac Sphincter

Muscle controlling entry from esophagus to stomach.

Intrinsic Factor

Substance enhancing Vitamin B12 absorption.

Microvilli

Folds increasing surface area for nutrient absorption.

Colon

Final segment of the large intestine, absorbs water.

Gut Flora

Bacteria in the colon producing vitamins.

Flatulence

Gas produced from undigested sugars fermentation.

Feces

Waste material containing water, fiber, and bacteria.

Anal Sphincters

Muscles controlling feces elimination from the rectum.

Hygiene Hypothesis

Over-sanitization may increase allergies and autoimmune diseases.

Peptic Ulcers

Stomach ulcers caused by H. pylori bacteria.

H. pylori

Bacteria causing increased stomach acid and ulcers.

Acid Reflux

Gastric acid backing up into the esophagus.

GERD

Gastroesophageal reflux disease, severe acid reflux.

Gallstones

Cholesterol crystals causing abdominal pain and discomfort.

Gallbladder Removal

Common treatment for symptomatic gallstones.

Constipation

Difficult or infrequent bowel movements.

Diarrhea

Increased frequency or fluidity of bowel movements.

Celiac Disease

Immune reaction to gluten in genetically predisposed individuals.

Gluten

Protein in wheat, rye, and barley.

Nonceliac Gluten Sensitivity

Gastrointestinal distress without intestinal damage from gluten.

Villi

Intestinal projections that absorb nutrients.