DIGESTIVE SYSTEM

im gonna eat someone

INGESTION

Complex foods are taken into the GI (gastrointestinal) tract.

DIGESTION

Group of processes that break complex nutrients into simpler ones.

MECHANICAL DIGESTION

Breaks large chunks of food into smaller bits.

CHEMICAL DIGESTION

Breaks large molecules into smaller ones.

MOTILITY

• A number of GI movements resulting from muscular contraction.

• Refers to the movement of food through the digestive tract by swallowing, mixing, and peristalsis.

SECRETION

• Release of digestive juices and hormones that facilitate digestion.

• Release of substances such as saliva, stomach acid, enzymes, bile, and mucus into the digestive tract.

ABSORPTION

• Movement of digested nutrients into the internal environment of the body.

• Movement of digested nutrients, water, and electrolytes from the digestive tract into the blood or lymph.

REGULATION

Neural, hormonal, and other mechanisms that regulate digestive activity.

ALIMENTARY CANAL

• An irregular tube, another term for gastrointestinal (GI) tract.

• Runs from the mouth to the an/us.

• SALIVARY GLANDS

• LIVER

• GALL BLADDER

• PANCREAS

What are the four types of accessory organs? (4):

ROOF

Formed by hard and soft palate.

HARD PALATE

Consists of parts of maxillary and palatine bones.

SOFT PALATE

An arch-shaped muscle separating mouth from pharynx.

UVULA

Downward projection of soft palate.

FLOOR

Formed by tongue and its muscles.

PAPILLAE

• Small elevations on mucosa of tongue.

• Taste buds.

LINGUAL FRENELUM

Fold of mucous membrane that helps anchor tongue to floor of mouth.

• CROWN

• NECK

• ROOT

Three main parts of a tooth:

ENAMEL

The hardest tissue in the body. It covers the crown.

DECIDUOUS (BABY) TEETH

A set of 20 teeth, usually the first set of teeth to develop in humans.

PERMANENT TEETH

What is the second set of teeth that grows in to replace the baby teeth?

32

How many sets of teeth do adults usually have?

SALIVA

A type of exocrine gland secretion that flows into ducts.

SEROUS-TYPE SALIVA

• Watery and contains enzymes (salivary amylase) but no mucus.

• Produced by serous-type secretory cells

MUCOUS-TYPE SALIVA

• Thick, slippery and contains mucus but no enzymes.

• Lubricates food during mastication.

• Produced by mucus-type secretory cells.

PAROTID GLANDS

• Largest salivary glands.

• Produces serous-type saliva.

MUMPS

• A viral infection where your parotids are infected.

• Most common with babies.

SUBMANDIBULAR GLANDS

• A type of salivary gland that produces both serous-type and mucous-type saliva.

• Located below mandibular angle.

SUBLINGUAL

A type of salivary gland that produces a mucous-type saliva.

PHARYNX

• A tubelike structure made of muscle and lined with mucus membrane.

• A common passageway for solid food, liquids, and air.

NASOPHARYNX

The upper part of the throat (pharynx).

OROPHARYNX

• The middle part of the throat (pharynx).

• Most involved segment in digestive process of swallowing or deglutition.

LARYNGOPHARYNX

• The lower part of the throat (pharynx).

• AKA Hypopharynx.

SWALLOWING (DEGLUTITION)

The movement of food from the mouth through the pharynx and esophagus into the stomach.

ESOPHAGUS

• Muscular, mucus-lined tube that connects the pharynx to the stomach.

• Dynamic passageway for food.

• UPPER ESOPHAGEAL SPHINCTER

• LOWER ESOPHAGEAL SPHINCTER

Two ring-shaped muscle valves located at the top and bottom of your esophagus.

STOMACH

Where chemical digestion takes place.

• FUNDUS

• BODY

• PLYORUS

Three divisions of the stomach:

CARDIAC SPHINCTER

• Food enters stomach through ______.

• Also known as the lower esophageal sphincter or gastroesophageal sphincter.

PYLORIC SPHINCTER

• A muscle that closes/opens between pylorus (lower part of stomach) and duodenum.

• A gatekeeper.

SMALL INTESTINE

A long, coiled tube that absorbs nutrients and water.

VILLI

• Microscopic finger-shaped projections.

• Greatly increases the surface area for absorption.

MICROVILLI

What covers the villi?

DUODENUM

• First 25 cm of the small intestine.

• Very little absorption occurs in this region.

JEJENUM

• Primary function is the absorption of nutrients.

• Has many folds and villi.

ILEUM

• Primary responsibility is the absorption of vitamin B12 and bile salts (main component of bile).

• Contains lymphoid tissue which protects the small intestine from bacteria found in the large intestine.

• PROTECTIVE FUNCTION

• ENDOCRINE FUNCTION

• MOVEMENT

• DIGESTION

• ABSORPTION

Main functions of the small intestine.

PEYER’S PATCHES

Group of lymphoid follicles in the mucus membrane that lines your small intestine.

PANCREAS

• Both an exocrine & endocrine gland.

• Releases enzymes to help with digestion.

ACINAR CELLS

Specialized exocrine cells in the pancreas that synthesize, store, and secrete digestive enzymes into the small intestine.

ISLETS OF LANGERHANS

Specialized endocrine cells in the pancreas that secretes hormones, glucagon, and insulin into the blood.

PANCREATIC JUICE

• Watery and rich in bicarbonate, which makes it alkaline and neutralizes the acidity of chyme.

• Fluid secreted by the pancreas into the duodenum.

LIVER

• The largest internal organ in the human body

• Produces bile while detoxifying your body from harmful metabolic wastes.

BILIRUBIN

A yellow pigment made when old red blood cells break down.

GALLBLADDER

• A pear-shaped organ located on the undersurface of the liver.

• Concentrates and stores bile produced in the liver.

BILE

A bitter, yellow-green alkaline fluid produced by the liver, stored in the gallbladder, and released into the small intestine to break down fats.

LARGE INTESTINE

The final section of the human gastrointestinal tract which absorbs water from the residual undigested food and turning it to feces for defecation.

• CECUM

• COLON

• RECTUM

The three main sections of the large intestine:

• ASCENDING COLON

• TRANSVERSE COLON

• DESCENDING COLON

• SIGMOID COLON

Four parts of the colon:

APPENDIX

Serves as an incubator or “breeding ground” for the nonpathogenic intestinal bacteria.

• MUCOSA

• SUBMUCOSA

• MUSCULARIS EXTERNA

• SEROSA

The four main layers of tissue in the wall of the digestive tract (from top to bottom):

MUCOSA

• Mucous membrane that produces mucus.

SUBMUCOSA

• Connective tissue layer.

• Duct from gland.

MUSCULARIS

• Circular, longitudinal, and oblique (in stomach) layers of muscle.

• Important in GI motility.

SEROSA

• Serous membrane that covers outside of abdominal organs.

• Visceral peritoneum.

PERISTALSIS

A series of wave-like, involuntary muscle contractions that pushes food through the digestive tract.

• DIGESTION

• ABSORPTION

• MOTILITY

• EXCRETION

• SECRETION

Major functions of the digestive system (5):