NUTR 210 ch3

Atoms, Molecules, Cells, Tissues, Organs, Organ System, Organism;

The six levels of organization in the human bod

Nervous System

Responds to stimuli; conducts impulses to activate muscles and glands; integrates activities of other system

Respiratory System

Supplies the blood with oxygen and removes carbon dioxid

Urinary System

Eliminates wastes and regulates the balance of water, electrolytes, and acid in the blood

Reproductive System

Responsible for producing offspring

Cardiovascular/Circulatory System

Transports blood, which carries oxygen, nutrients, and wastes

Lymphatic/Immune System

Defends against foreign invaders; picks up leaked fluid; transports fat-soluble nutrients

Muscular System

Provides movement and structure

Skeletal System

Protects and supports the body; provides a framework for movement

Endocrine System

Secretes hormones that regulate processes such as growth, reproduction, and nutrient use

Integumentary System

Covers and protects the body; helps control body temperature

Digestive System

Ingests and digests food; absorbs nutrients into the blood; eliminates non-absorbed food wastes

Digestion

The process by which food is broken down into smaller pieces that can be absorbed

Gastrointestinal (GI) Tract

A hollow tubular passageway about 30 feet long running from mouth to anus

Lumen

The opening inside the GI tract through which material can pass

Mucosa

The tissue layer lining the lumen; it has high nutrient needs and cells live only 2–5 days

Transit Time

he time it takes food to travel the length of the GI tract from mouth to anus

Mouth (Mechanical Digestion)

The teeth crushing and grinding food into smaller pieces

Mouth (Chemical Digestion)

Salivary glands releasing enzymes to break down carbohydrates and fats

Salivary Amylase

An enzyme in saliva that begins the chemical breakdown of carbohydrates

Epiglottis

A flap that covers the passageway to the lungs during swallowing to prevent choking

Peristalsis

Rhythmic contractions of smooth muscle that propel food down the esophagus

Gastroesophageal Sphincter

The muscle that relaxes to allow a bolus of food to enter the stomach from the esophagus

Gastrin

A hormone that triggers an increase in the release of gastric juice in the stomach

Chyme

The semi-liquid mass of partially digested food produced in the stomach

Villi

Finger-like protrusions on the circular folds of the small intestine that increase surface area for absorption

Microvilli

Tiny projections on the surface of mucosal cells (the brush border)

Simple Diffusion

Movement of molecules (like fatty acids) from high to low concentration without energy

Osmosis

The movement of water molecules across a membrane

Facilitated Diffusion

The use of a carrier molecule to move nutrients (like fructose) down a concentration gradient

Active Transport

Movement of nutrients (like amino acids) against a concentration gradient using energy (ATP)

Lacteals

Lymph vessels in the small intestine that absorb lipid-soluble nutrients

Capillaries (Small Intestine)

Small blood vessels that absorb water-soluble nutrients

Large Intestine (Colon)

Responsible for absorbing water and housing intestinal microbiota

Probiotics

Live beneficial bacteria found in food or supplements

Prebiotics;

Food or supplements that promote a healthy microbiota environment

Metabolism;

The series of biochemical reactions needed to go from a raw material to a final product

ATP (Adenosine Triphosphate);

The high-energy molecule used by the body to perform work like muscle contraction

Catabolic Reactions

Metabolic reactions where nutrients are used as fuel to produce ATP

Anabolic Reactions

Metabolic reactions where nutrients are used as raw materials to synthesize needed molecules

Oxidized

Refers to a compound that has lost an electron or reacted with oxygen

Reduced

Refers to a substance that has gained an electron

Mitochondrion

The cell organelle where the Citric Acid Cycle and ATP production occur

GERD (Gastroesophageal Reflux Disease)

Condition where acidic stomach contents move into the esophagus, causing frequent heartburn

Peptic Ulcers

Sores that can occur in the lining of the GI tract

Diarrhea;

Frequent, watery stools occurring when substances move too quickly for water absorption

Constipation;

Hard, dry stools caused by insufficient water, fiber, or exercise

Hepatic Portal Vein;

The vein that carries molecules from the intestine directly to the liver

Liver (as Gatekeeper)

Determines if nutrients are stored or delivered to cells and detoxifies harmful substances