The Digestive System

Introduction-FUNCTION

Preparing Preparing food for food for absorption absorption and use by and use by body cellsbody cells

Vocab 17Quiz on Friday 3/28

1.1. arteri/o- arteri/o- arteryartery2.2. bio- bio- lifelife3.3. cheil/o- cheil/o- lipslips4.4. clysis- clysis- washing or washing or

irrigationirrigation5.5. col/o- col/o- large intestinelarge intestine6.6. ecstasia- ecstasia- dilation or dilation or

stretchingstretching7.7. gingiv/o- gingiv/o- gumsgums8.8. hem/o- hem/o- bloodblood9.9. hemat/o- hemat/o- bloodblood10.10.lys- lys- destructdestruct

11.11.myc/o- myc/o- fungusfungus12.12.o- o- eggegg13.13.Orrhagia – Orrhagia – hemorrhagehemorrhage14.14.orrhaphy- orrhaphy- suture, stitchsuture, stitch15.15.pancreat/o- pancreat/o- pancreaspancreas16.16.proct- proct- rectum and anusrectum and anus17.17.rect/o- rect/o- rectumrectum18.18.scop/o- scop/o- examineexamine19.19.spermat/o- spermat/o- spermsperm20.20.ur/o- ur/o- urineurine21.21.ureter/o- ureter/o- ureterureter22.22.urethr/o- urethr/o- urethraurethra

Introduction-DIVISIONS

1. Alimentary canal 1. Alimentary canal aka gastrointestinal aka gastrointestinal tract (GI)- approx. 9 tract (GI)- approx. 9 m longm long Digests foodDigests food Absorbs digested food Absorbs digested food

through liningthrough lining Mouth, pharynx, Mouth, pharynx,

esophagus, stomach, esophagus, stomach, small intestine, large small intestine, large intestineintestine

Introduction-DIVISIONS

2. Accessory 2. Accessory digestive organsdigestive organs TeethTeeth tongue,tongue, gall bladdergall bladder salivary glandssalivary glands LiverLiver pancreaspancreas

Introduction-DIGESTIVE PROCESSES

1. ingestion1. ingestion 2. propulsion via 2. propulsion via

swallowing and swallowing and peristalsisperistalsis

3. mechanical 3. mechanical digestion e.g. digestion e.g. mastication, mastication, stomach churningstomach churning

Introduction-DIGESTIVE PROCESSES

4. chemical digestion via enzymes –ase4. chemical digestion via enzymes –aseExamples: lipase, amylase, proteases like Examples: lipase, amylase, proteases like

pepsin and trypsinpepsin and trypsin

Very specific in actionVery specific in action

Function at a specific pHFunction at a specific pH

5. absorption5. absorption

6. defecation6. defecation

Introduction-4 tissue layers of GI

1. mucosa- innermost; 1. mucosa- innermost; epithelial; secretion epithelial; secretion of dig juices; of dig juices; absorption; protection absorption; protection against infectionagainst infection

2. submucosa- 2. submucosa- connective; vascularconnective; vascular

3. muscularis- smooth 3. muscularis- smooth muscle; mixes and muscle; mixes and propels food; propels food; sphincterssphincters

4. serosa- 4. serosa- outermost;areolar + outermost;areolar + squam.squam.

Mouth

Aka oral cavity or Aka oral cavity or buccal cavitybuccal cavity

Functions- Functions- IngestionIngestion PropulsionPropulsion mechanical digestionmechanical digestion chemical digestionchemical digestion deglutition deglutition

(swallowing)(swallowing)

Mouth-LIPS

Aka labia; skeletal m. covered by Aka labia; skeletal m. covered by skinskin

1. actually extends from inferior 1. actually extends from inferior nose to superior chin. The nose to superior chin. The reddened part is the red margin.reddened part is the red margin.

Philtrum- shallow vertical groove Philtrum- shallow vertical groove of upper lipof upper lip

Labial frenulum- median fold that Labial frenulum- median fold that joins each lip to the gumjoins each lip to the gum

Mouth- CHEEKS

Mostly buccinator Mostly buccinator muscle and fatmuscle and fat

Mouth-PALATE

Roof of mouthRoof of mouth

1. hard palate- 1. hard palate- underlain by bone; underlain by bone; midline ridge is the midline ridge is the rapheraphe

2. soft palate- 2. soft palate- mostly sk. Musclemostly sk. Muscle

fingerlike uvula fingerlike uvula closes of closes of nasopharynx when nasopharynx when swallowing swallowing

Mouth-TONGUE

1. mostly skeletal 1. mostly skeletal musclemuscle

2. mixes food with 2. mixes food with saliva to form saliva to form bolusbolus

3. Lingual frenulum 3. Lingual frenulum secures tongue secures tongue to mouthto mouth

4. Root, tip, body4. Root, tip, body

Mouth-TONGUE

5. papillae- 5. papillae- projectionsprojectionsVallate- v-shaped; Vallate- v-shaped;

at back of tongue; at back of tongue; taste budstaste buds

Fungiform- taste Fungiform- taste buds; mushroom-buds; mushroom-shapedshaped

Filiform- roughness Filiform- roughness to tongue; to tongue; conical- shapedconical- shaped

Mouth-SALIVARY GLANDS

1. functions of saliva1. functions of salivaCleans mouthCleans mouth

Dissolves food so it Dissolves food so it can be tastedcan be tasted

Moistens food and Moistens food and aids in compacting aids in compacting it into a bolusit into a bolus

Contains enzymes Contains enzymes (amylase) to break (amylase) to break down starchesdown starches

Mouth-SALIVARY GLANDS

2. types2. types1.1. Parotid glandsParotid glands

2.2. Submandibular glandsSubmandibular glands

3.3. Sublingual glandsSublingual glands

MOUTH-Teeth

1. Allow for 1. Allow for mastication mastication (chewing)(chewing)

2. typical tooth2. typical toothCrown- exposed portionCrown- exposed portion

Neck- surrounded by Neck- surrounded by gingivae (gums)gingivae (gums)

Root- fits into sockets Root- fits into sockets (alveoli)(alveoli)

MOUTH-Teeth

3. deciduous teeth aka milk or baby 3. deciduous teeth aka milk or baby teeth; approx 20teeth; approx 20

4. permanent teeth- 324. permanent teeth- 32

5. dental formula for perm. Teeth:5. dental formula for perm. Teeth:

2I, 1C, 2 PM, 3M2I, 1C, 2 PM, 3M x 2 = 32 teeth x 2 = 32 teeth

2I, 1C, 2 PM, 3M2I, 1C, 2 PM, 3M

Esophagus

25 cm25 cm

A. with cardiac or A. with cardiac or gastroesophageal gastroesophageal sphinctersphincter

B.Peristalsis- wave-B.Peristalsis- wave-like ripple in like ripple in hollow organshollow organs

Stomach

A. Size varies because of distension- A. Size varies because of distension- holds 1-1.5 Lholds 1-1.5 L

B. DivisionsB. Divisions1. Cardiac region- eso dumps into stomach1. Cardiac region- eso dumps into stomach2. Fundus- enlarged part to L & above 2. Fundus- enlarged part to L & above

opening of the eso to the stomachopening of the eso to the stomach3. Body- central3. Body- central4. Pylorus- lower portion4. Pylorus- lower portion5. Greater (lateral) & lesser (medial) 5. Greater (lateral) & lesser (medial)

curvatures with greater & lesser omentacurvatures with greater & lesser omenta

Stomach

C. SphinctersC. Sphincters1. Cardiac- eso into 1. Cardiac- eso into

stomachstomach

2. Pyloric- stomach into 2. Pyloric- stomach into duodenum of small duodenum of small intestineintestine

Talk about hard to swallow!!!

Stomach

D. FunctionsD. Functions1. Food storage1. Food storage

2. secretes gastric juice- pepsin2. secretes gastric juice- pepsin

3. churns the food (mechanical)3. churns the food (mechanical)

4. chemical digestion of proteins by 4. chemical digestion of proteins by pepsinpepsin

5. limited absorption5. limited absorption

6. destroys pathogenic bacteria6. destroys pathogenic bacteria

7. propulsion of food into small intestine7. propulsion of food into small intestine

Stomach: A closer look

Small Intestine

A. DivisionsA. Divisions1. duodenum- 1. duodenum-

uppermost; 25 cmuppermost; 25 cm

2. jejunum- middle; 2. jejunum- middle; 2.5 m2.5 m

3. ileum- end; 3.5 m3. ileum- end; 3.5 m

Small Intestine

B. Intestinal lining with plicae (folds) that B. Intestinal lining with plicae (folds) that contain villi. Villi increase surface area contain villi. Villi increase surface area which allows for more absorption.which allows for more absorption.

C. FunctionsC. Functions1. mechanical digestion1. mechanical digestion

2. propulsion2. propulsion

3. chemical digestion3. chemical digestion

4. absorption4. absorption

Large Intestine

A. DivisionsA. Divisions1. Cecum1. Cecum

Small (5-8 cm)Small (5-8 cm)

““blind pouch”blind pouch”

With vermiform With vermiform appendix (“worm-appendix (“worm-shape”) appendix- shape”) appendix- immunity? immunity? Intestinal flora?Intestinal flora?

Large Intestine

A. DivisionsA. Divisions2. Colon2. Colon

Ascending- vertical; Ascending- vertical; with ileocecal with ileocecal valvevalve

Transverse- Transverse- horizontal; above horizontal; above sm intsm int

Descending- Descending- verticalvertical

Sigmoid- s-shaped Sigmoid- s-shaped curvecurve

Large Intestine

B. FunctionsB. Functions

1. chemical digestion1. chemical digestion

2. absorption of 2. absorption of remaining water via remaining water via osmosisosmosis

3. propulsion3. propulsion

4. defecation4. defecation

Accessory Digestive Organs

A. Liver- largest gland in the bodyA. Liver- largest gland in the body1. Lobes1. Lobes

Right- R lobe proper, caudate lobe, quadrate lobeRight- R lobe proper, caudate lobe, quadrate lobe

LeftLeft

Accessory Digestive Organs

A. Liver- largest gland in the bodyA. Liver- largest gland in the body2. Functions2. Functions

1.1. detoxify substancesdetoxify substances

2.2. Secrete bile that will eventually go into the duodenum to break up fatSecrete bile that will eventually go into the duodenum to break up fat

3.3. Metabolism of proteins, fats, carbsMetabolism of proteins, fats, carbs

4.4. Store substances like Fe, vit A, vit DStore substances like Fe, vit A, vit D

5.5. Hematopoeisis in fetusHematopoeisis in fetus

Accessory Digestive Organs

B. Gall BladderB. Gall Bladder1. green sac about the size of a kiwi1. green sac about the size of a kiwi

2. stores 30-50 ml of bile2. stores 30-50 ml of bile

Accessory Digestive Organs

C. PancreasC. Pancreas1. resembles fish with head and neck in the C-shaped curve of 1. resembles fish with head and neck in the C-shaped curve of

the duodenumthe duodenum2. Functions2. Functions

Secrete pancreatic juice with digestive enzymes like trypsinSecrete pancreatic juice with digestive enzymes like trypsinSecrete insulin hormone that affects carb metabolismSecrete insulin hormone that affects carb metabolismSecrete glucagonSecrete glucagon