Digestive System

Question 1

Accessory digestive Organs

Answer 1

Other part of the digestive system. Includes things such as; teeth, tongue, gallbladder. Digestive glands; salivary glands, liver and pancreas

Question 2

Six essential Activities of Digestion process

Answer 2

1. Ingestion
2. Propulsion
3. Mechanical Breakdown (chewing-mouth, churning-stomach, segmentation-small intestine)
4. Digestion
5. Absorption
6. Defecation

Question 3

Peritalsis

Answer 3

adjacent segments of alimentary tract organs alternately contract and relax, moving food along the tract distally

Question 4

segmentation

Answer 4

nonadjacent segments of alimentary tract organ alternately contract and relax moving food forward then backward. Food mixing in the small intestine.

Question 5

Mechanoreceptors and chemoreceptors (within the GI tract)

Answer 5

respond to stretch, changes in osmolarity and pH, and presence of substrate and end products of digestion. Initiate reflexes that activate or inhibit digestive glands. Stimulate smooth muscle to mix.

Question 6

Short Reflexes

Answer 6

enteric nerve plexuses (gut brain) respond to stimuli in GI tract.

Question 7

Long Reflex

Answer 7

respond to stimuli inside or outside GI tract (juicy, nice smelling cheeseburger) involve CNS centers and autonomic nerves

Question 8

Four Basic layers of tunics

Answer 8

1. mucosa
2. submucosa
3. muscularis externa
4. serosa=visceral peritoneum

Question 9

Mucosa

Answer 9

Lines lumen.
Functions (different layer perform 1 or all three);
-secretes mucus, digetive enzymes and hormones
-absorb end products of digestion
-protects against infectious disease

Question 10

Submucosa

Answer 10

areolar connective tissue. Blood and lymphatic vessels lymphoid follicles, and submucosal nerve plexus.

Question 11

Muscularis Externa

Answer 11

Responsible for segmentation and peristalsis. Inner circular and outer longitudinal layers.

Question 12

Sphincters

Answer 12

Circular layer that thickens in some areas

Question 13

Tongue

Answer 13

made of skeletal muscle.
intrinsic muscles- change shape of tongue
extrinsic muscle-alter tongue’s position
Functions include;
repositioning and mixing food during chewing
Formation of bolus
Initiation of swallowing, speech and taste

Question 14

Lingual Lipase

Answer 14

Secreted by serous cells

Fat-digesting enzyme

Question 15

Salivary Glands

Answer 15

Produce saliva.

Parotid gland, submandibular gland, and sublingual gland

Question 16

composition of saliva

Answer 16

97-99.5% water, slightly acidic.

Make 1500 ml/day

Question 17

Stomach

Answer 17

Upper left quadrant of torso. It is where the bolus( food) is turned into CHYME. Autonomic Nerve Supply

Question 18

Mucosa

Answer 18

Covered with gastric Pits. made up of simple columnar epithelium composed of mucous cells. Gastric glands produce the gastric juices.

Question 19

Parietal cell secretions

Answer 19

Hydrochloric acid (HCL). pH 1.5-3.5denature protein, activates pepsin, breaks down plant cell walls, kills many bacteria. glycoprotien required for absorption of vitamin B12 (important for RBC production) in small intestine.

Question 20

Chief Cell Secretions

Answer 20

Pepsinogen- inactive enzyme.

Activated to pepsin by HCL and by pepsin itself (a positive feedback mechanism). Lipase’s (digest~15% of lipids)

Question 21

Enteroendocrine Cells

Answer 21

Secretes chemical messengers into lamina propria. Act as paracrine (respond to serotonin and histamine).

Question 22

Mucosal Barrier

Answer 22

Thick layer of bicarbonate-rich mucus

Tight junctions between epithelial cells

Question 23

Alimentary Canal

Answer 23

the digestive system. Mouth to anus. Digest food and absorbs fragments. Mouth, pharynx, esophagus, stomach, small intestine and large intestine.

Question 24

a patient with a low RBC count recieves vitamin B12 injection every 2 weeks. Why?

Answer 24

Parietal cells in the patients stomach have ceased producing intrinsic factor.

Question 25

Cephalic Phase (phases of gastric secretion)

Answer 25

conditioned reflex triggered by aroma, taste, sight and thought

Question 26

Gastric Phase (phase of gastric secretion)

Answer 26

2/3 gastric juice released. Simulated by distention, peptide, low acidity, and gastrin (major stimulus).
Gastrin-> enzyme and HCL release

Question 27

Intestinal Phase (phases of gastric secretion)

Answer 27

Stimulatory component. Partially digested food enters small intestine -> brief intestinal gastrin release.

Question 28

Which of the following phases of gastric secretion is a conditioned reflex?

Answer 28

Cephalic Phase (when you see food, or smell something good, that is a conditioned reflex)

Question 29

Bicarbonate

Answer 29

Most important buffer in the blood. Helps the blood from becoming too acidic