**A&P 2 Unit 23 (Lab) [Digestive System]

Question 1

2 Components of the Digestive System

Answer 1

• Digestive Tract (Alimentary Canal)
• Accessory Organs

Question 2

How does undigested food leave the system?

Answer 2

As feces.

Question 3

4 Main Layers of the Digestive Tract (From Inside to Outside)

Answer 3

1. Mucosa
2. Submucosa
3. Muscularis Externa
4. Serosa (Visceral Peritoneum)

Question 4

Answer 4

Mucosa

Question 5

Answer 5

Submucosa

Question 6

Answer 6

Muscularis Externa

Question 7

Answer 7

Serosa

Question 8

3 Layers of the Mucosa (From Inside to Outside)

Answer 8

1. A **Simple Columnar Epithelium **densely populated with goblet cells.
2. A Lamina Propria Connective Tissue Layer containing blood & lymphatic vessels
3. A Smooth Muscle Sheet called the Muscularis Mucosa

Question 9

Mucosal Epithelium (Functions)

Answer 9

• Secretion of digestive substances
• Absorption of nutrients

Question 10

Goblet Cells

Answer 10

Secrete mucus (a hydrated mucin protein), while other mucosal epitheial cells secrete digestive fluids & other substances such as water & salts

Question 11

Enteroendocrine Cells of the Mucosa

Answer 11

Secrete hormones into the blood.

Question 12

Absorption of Nutrients

Answer 12

Occurs through the mucosal epithelium & into either Capillaries (Most Nutrients) or Lacteal Lymphatic Vessels (Fats)

Question 13

The mucosal epithelial cells are mitotically active…

Answer 13

…thus the epithelium is replaced approximately every 3 to 6 days

Question 14

Double-Layered Muscularia Mucosa (Functions)

Answer 14

• To aid in digestion
• Absorption by moving the mucosal villi in the small intestine

Question 15

The muscularis mucosa has both…

Answer 15

• Inner Circular & Outer Longitudial Fibers that function in moving the villi to aid in digestion & absorption.
• The fibers in the two layers are arranged at right angles to each other

Question 16

Blood & lymph vessels as well as an intrinsic network of neurons (the _________) are located in the _______.

Answer 16

• Submucosal Plexus
• Submusoca

Question 17

The Two Types of Movements Produced by Contractions of the Muscularis Externa

Answer 17

• Peristalsis
• Segmentation

Question 18

Peristalsis

Answer 18

Wave-like contraction moving along the wall (Moving)

Question 19

Segmentation

Answer 19

Alternate areas contract & relax (Mixing)

Question 20

Myenteric Plexus

Answer 20

• Network of neurons in the muscularis externa
• It is in close communication with the submucosal plexus, and together, the two plexuses comprise the enteric nervous system.

Question 21

The Outermost Layer of the Digestive Tract Wall

Answer 21

Serous fluiding-producing Serosa which both lubricates & reduces friction of the digestive tract within the ventral body cavity.

Question 22

Ingestion occurs in the _____

Answer 22

Mouth

Question 23

The Mouth

Answer 23

With its Stratified Squamous Epithelium, is involved in both Chemical & Mechanical Digestion

Question 24

Bolus

Answer 24

A mass of food that has been chewed at the point of swallowing.

Question 25

Transition in the esophagus wall

Answer 25

Striated (skeletal) to smooth muscle

Question 26

Stomach (Functions)

Answer 26

* Chemical (Mostly proteins) Digestion * Mechanical Digestion * Storage of Food

Question 27

4 Specialized Areas of the Stomach

Answer 27

1. Cardia 2. Fundus 3. Body 4. Pyloric (w/antrum)

Question 28

3 Sheets of Muscle in the stomach's Muscularis Externa

Answer 28

1. Circular 2. Longitudinal 3. Oblique

Question 29

Rugae

Answer 29

The stomach can expand greatly because of internal folds called rugae

Question 30

Answer 30

Longitudinal Layer

Question 31

Answer 31

Circular Layer

Question 32

Answer 32

Oblique Layer

Question 33

Chyme

Answer 33

* Once food is moxed with gastric juices in the stomach it is called chyme * Which is then moved from the pylorus to the duodenum of the small intestine.

Question 34

The majority of chemical digestion & virtually all-nutrient absorption occur in...

Answer 34

The Small Intestines

Question 35

3 Regions of the Small Intestines

Answer 35

1. Duodenum 2. Jejunum 3. Ileum

Question 36

3 Modifications of the Inner Wall of the Small Intestine (& Functions) [From Macroscopic to Microscopic]

Answer 36

1. Plicae Circularis (Circular folds) 2. Villi 3. Microvilli Function to increase surface area of small intestine

Question 37

The Intestines aid the body in its defense against pathogens by secreting...

Answer 37

...Antibacterial enzymes & antibodies (immunoglobulins) & by providing specialized sites in the ileum (lymphoid nodules called Peyer's Patches) where leukocytes can fight pathogens

Question 38

The large intestine absorbs...

Answer 38

1. Water 2. Salt 3. Vitamins K & B

Question 39

5 Parts of Large Intestine

Answer 39

1. Cecum 2. Appendix 3. Colon 4. Rectum 5. Anal Canal

Question 40

Answer 40

Appendix

Question 41

Answer 41

Cecum

Question 42

Answer 42

Ascending Colon

Question 43

Answer 43

Transverse Colon

Question 44

Answer 44

Descending Colon

Question 45

Answer 45

Sigmoid Colon

Question 46

Answer 46

Rectum

Question 47

Answer 47

Anal Canal

Question 48

Taeniae Coli

Answer 48

Three bands of smooth muscle that cause the outer portion of the colon to be puckered into pockets called haustra.

Question 49

Epiploic Appendages

Answer 49

Fat storage areas located on the outside of the colon

Question 50

Brush Border

Answer 50

Formed by the microvilli of the small intestine's epithelial cells

Question 51

Anal Lining

Answer 51

Stratified Squamous Epithelium

Question 52

Feces Composition

Answer 52

Indigestible food, bacteria, inorganic substances, and sloughed off epithelial cells from the digestive tract wall.

Question 53

Sphincters (Functions)

Answer 53

Regulate the passage of food from one region of the digestive tract to the next and finally, out of the body as feces.

Question 54

7 Sphincters of the Digestive Tract

Answer 54

* Upper Esophageal Sphincter (UES) * Lower Esophageal Sphincter (LES) * Pyloric Sphincter * Ileocecal Sphincter or Valve * Internal Anal Sphincter (IAS) * External Anal Sphincter (EAS)

Question 55

Upper Esophageal Sphincter (UES)

Answer 55

* Circular Skeletal Muscle * Prevents air from entering the esophagus

Question 56

Lower Esophageal Sphincter (LES)

Answer 56

* Physiological Sphincter * Prevents acid reflux from the stomach into the esophagus

Question 57

Pyloric Sphincter

Answer 57

* Circular Smooth Muscle * Regulates passage of chyme from the stomach into the duodenum

Question 58

Ileocecal Sphincter or Valve

Answer 58

* Circular Smooth Muscle * Regulates passage of chyme from the ileum to the large intestine

Question 59

Internal Anal Sphincter (IAS)

Answer 59

* Circular Smooth Muscle * Under involuntary control * When relaxed, it produces the urge to defecate

Question 60

External Anal Sphincter (EAS)

Answer 60

* Circular Skeletal Muscle * Under voluntary control * When relaxed, it allows for defecation

Question 61

3 Accessory Glands

Answer 61

1. Salivary Glands (3 Pairs) 2. Liver 3. Pancreas

Question 62

Salivary Glands

Answer 62

* Moisten food * Cleanse & protect the mouth * Produce amylase to begin enzymatic digestion of starch

Question 63

Liver

Answer 63

* Produces bile, which emulsifies fats to increase their surface area for subsequent chemical digestion by lipases * Bile is stored in & released from the gall bladder into the duodenum

Question 64

Pancreas

Answer 64

* **Main digestive enzyme-producing exocrine organ in the body** * It releases a host of digestive enzymes into the duodenum via the pancreatic duct * It also produces bicarbonate to neutralize the chyme from the stomach