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

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

MasticationSaliva

Enzymes to help breakdown simple sugarsMucus to lubricate the food for easier swallowingLysozyme to kill bacteria

TongueTaste receptorsEnzymes 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