OTHER NAMES OF

DIGESTIVE SYSTEM?

1. Alimentary canal

           2. Gastronintestinal syste

3. GI tract

Breaking down found

mechanically & chemically

Digestion

Elimination of waste from digestive

process

Defacation

Movement of simple food substances from

GI tract into the blood

Absorption

Use of simple food

substances by the cells

Metabolism

What are the 4 functions of the

digestive system?

1. Digestion

  2. Defacation

  3. Absorption

  4. Metabolism

Main organs of digestive system

-Mouth

-Pharynx

-Esophagus

-Stomach

-Sm. & lg. intestine

Accessory organs of digestive system

-Teeth

-Tongue

-Salivary glands

-Liver

-Gallbladder

-Pancreas

-Appendix

5 functions of the oral cavity/mouth

1. Ingestion of food

2. Mechanically digest food from chewing/mixing

3. Chemically digest carbs (CHO) w/ salivary amylase

4. Speech

5. Sense of taste

Oral cavity

-Lined w/ mucous membranes

-Hard & soft palate=roof of mouth w/ uvula in center of soft

-Direct food/fluids into oropharynx to prevent

them going into nasopharynx & nasal cavity

1.What is made up of skeletal muscle

& covered w/ mucous membrane?

2.What bone is it attached to?

1. Tongue

2. Hyoid bone

What attaches tongue to floor of mouth?

Frenulum

Sensory nerves for taste

1. Facial nerve

2. Glossopharyngeal

Motor nerve for tongue movement

Hypoglossal

Salivary glands

-Secrete saliva which moistens chewed food

-contains enzyme that digests CHO

(salivary amylase or ptyalin)

3 pairs of salivary glands and where located

1. Parotid gland--largest---just below & in front of ears

2. Submandibular glands--posterior corners of mouth

3. SL glands--below tongue

4 major types of teeth

1. Incisors (front teeth)

2. Canine (cuspids)

3. Premolars (bicuspids)

4. Molars (Tricuspids)

What are the 2 sets of teeth

                  1. Deciduous (baby teeth)

                    -20 by age 2-2.5

                          -Cut 1st tooth-6 mos.

2. Permanent

                     -32 by age 17-24

                     -Cut perm.-6 yrs.

Visible portion above gum

Crown

1. Narrow portion surrounded by gum

2. Portion that fits into socket of jaw

3. Makes up bulk of tooth

4. Very hard substance that covers crown

1. Neck

2. Root

3.Dentin

4. Enamel

1. Outer covering of neck & root of tooth

2. Lines socket & anchors tooth in place

1. Cementum

2. Periodontal membrane

Inner portion of tooth made up of

connective tissue

-has blood, lymphatic vessels & sensory nerves

Pulp cavity

Receives food from mouth

Oropharynx

Connects to esophagus

-No digestion occurs here

-only swallowing

Larynogopharynx

Coordinates swallowing action

Mendula oblongata

Swallowing process

1. Bolus of food pushed into pharynx by tongue

2. Muscles in pharynx contract

3. Breathing stops momentarily

4. Soft palate & larynx elevate

(keeps food from entering lungs)

5. Epiglottis closes off larynx

6. Smooth muscles of esophagus begins to move bolus

-10" long tube from pharynx to stomach

-smooth muscle in wall moves bolus to stomach

-mucous membrane lining -mucus lubricates

-0 digestion occurs here

Esophagus

4 layers of wall of digestive tract

1. Mucosa

-mucus membrane lining w/ mucus that coats GI tract

2. Submucosa

-Connective tissue w/ many blood vessels & nerves

3. Muscularis

-Smooth muscle layer has longitudinal & circular fibers

4. Serosa

-Serous membrane covering of organs & peritoneum lining of abd. cavity

Where is stomach located

Upper abd. cavity under diaphragm

-LUQ

Function of stomach

1. Temporary storage tank of food

2. Mechanically digests-churns & mixes bolus to a thick creamy consistency=chyme

3.Chemically digests proteins

4. Produces intrinsic factor

-chem. needed for Vit. B12

5. Produces hydrochloric acid

-kills bacteria & softens meat fibers

3 parts of the stomach

1. Fundus

-enlarged portion to lt. & above esophageal opening

2. Body

-Central portion of stomach

3. Pyloris

-lower narrow sections that connects to sm. intestin

2 sphincters of stomach

1. Cardiac

-b/w esophagus & stomach

2. Pyloric

-b/w stomach & sm. intestine

3 layers of smooth muscle in stomach

1. Longitudinal fibers

2. Circular fibers

3. Oblique fibers (diagonal)

Functions of small intestines

1. Receives chyme from stomach

2. Chemically digests

3. Very little mech. digestion

4. Most abosorption occurs here

Small intestine includes what 3 areas

1. Duodenum: 10-12"

2. Jejunum: 8'

3. Ileum: 11'

When stomach empty

lies in folds called

Rugae

Mucosa lays in circular folds called

Plicae

Most of chem. digestion occurs

Duodenum

What absorbs fatty acids, glycerol, fat soluble vit.

Lacteals

(lymph capillaries)

3 functions of lg. intestines

1. Receives residue from sm. intestines

2. Absorption of H20 & dissolves substance like min./vit.

(natural bacteria in lg. intestine helps in synthesis of Vit k)

3. Elimination of undigested materials (defacation)

(2.5" diameter/5' long)

Muscle b/w sm. intestine & lg. intestine

Ileocecal valve

S-shaped that connects to rectum

Sigmoid colon

Bend of colon b/w ascending & transverse colon

Hepatic flexure

Bend of colon b/w transverse & descending colon

Splenic flexure

2 sphincters of the anal canal

1. Internal anal sphincter

-smooth muscle

2. External anal sphincter

-anus-skeletal muscle

Serous membrane that lines abd. cavity

& covers the organs in cavity

Peritoneum

2 layers of peritoneum

1. Parietal layer

               -lines abd. cavity

2. Visceral layer

-line outer layer or covering of organs

Organs outside of peritoneum

Retro peritoneal

ex. kidneys

3 parts of extensions of peritoneum

1. Mesentery

-dbl layers fan-folded extension of peritoneum

-attaches to wall of abd. cavity & envelopes sm. intestines

2.Greater omentum

-attaches to lower edge of stomach & drapes over intestines (apron)

3. Lesser omentum

-lower edge of liver to upper curve of stomach

Where is liver located

RUQ of abd.

-extends to lt.

Functions of liver

1. Production of bile

2. stores excess glucose as glycogen

3. Processes a.a. for use by body & forms waste urea

4.Involved in fat metabolism-forms lipoproteins

5. process bilirubin

6. Synthesis of plasma proteins

(albumin, globulins, clotting factors)

7. Phagocytosis of old RBC

2 ways metabolism is done

1. Catabolism

-Release of energy from food breakdown

2. Anabolism

-building food molecules into complex substances

How are carbs metabolized

--Mainly catabolized for energy

--Glucose + O2 = energy

-if excess glucose-anabolized into glycogen

How is fat metabolized

--Mainly catabolized for enery & anabolized for adipose tissue

-but produces waste (acid ketones)

fats (fatty acids & glycerol) + O2 = energy + acid

- if excess fatty acids & glycerol then-anabolized as adipose tissue

How is protein metabolized

Anabolized

-for protein synthesis

3 series of chemical reactions in glucose metabolism

1. Glycolysis

2. Citric acid (Krebs) cycle

3. Electron transfer system

-Changes glucose to pyruvic acid

-Anaerobic

-sm. amt. of energy- generates 2 ATP

-Occurs in cytoplasm

Glycolysis

-Changes pyruvic acid to carbon dioxide

-Aerobic

-yields lg. amt. of energy

-occurs in mitochondria

Citric acid (Krebs) cycle

-T/f enery from high energy electrons (from citric acid cycle) to ATP molecules

-Aerobic

- Located in mitochondria

Anabolic process of joining glucose molecules together in a chain to form glycogen

Glycogenesis

Catabolic process of breaking apart glycogen chains

releasing individual glucose molecules for use in ATP

Glycogenolysis