The digestive system (chapter 23)

Question 1

What are the six functions of the digestive system?

Answer 1

1. ingestion
2. movement
3. mechanical breakdown
4. Digestion
5. absorption
6. Defecation

Question 2

bringing food/fluid into the body

Answer 2

ingestion

Question 3

• food propelling through digestive system by peristaltic movement (wavelight contractions that push food in a single direction)
• All organs contribute to this in someway

Answer 3

Movement

Question 4

• food broken down into smaller pieces to increase efficiency of digestion
• Increasing surface area of solid food–> it is broken down more easily

Answer 4

mechanical breakdown

Question 5

• enzymes break down complex food molecules (proteins, carbs, etc) into building blocks
• monomers= building blocks

Answer 5

digestion

Question 6

• building blocks are passed from digestive system into blood or lymph
• lacteals

Answer 6

absorption

Question 7

get rid of what is not/cannot be used

Answer 7

Defecation

Question 8

serous membrane that covers organs of the abdominopelvic cavity

Answer 8

peritoneum

Question 9

covers organs

Answer 9

visceral peritoneum

Question 10

clings to body wall

Answer 10

parietal peritoneum

Question 11

• fluid-filled space between visceral and parietal peritoneum
• prevents fiction from organ/organ or organ/body wall contact
• make sure the organs are not damaged

Answer 11

peritoneal cavity

Question 12

• double layer of peritoneum extending from digestive organs to body wall
• holds organs in place
• providing pasage for blood/lymphatic
• fat storage (adipose tissue prevents physical trauma)

Answer 12

mesentery

Question 13

Portion of digestive system that forms one long tube in–> out of body

Answer 13

Alimentary canal

Question 14

name the alimentary canals

Answer 14

mouth, pharynx, esophagus, stomach, small intestine and large intestine

Question 15

name the accessory glands

Answer 15

tongue, salivary glands, teeth,liver, gallbladder, and pancreas

Question 16

Alimentary canal shares the same four layers

Answer 16

1. muscosa
2. submucosa
3. muscularis
4. serosa

Question 17

the innermost layer

Answer 17

mucosa

Question 18

Mucosa

• mostly simple columnar
• function: secretes mucosa, digestive enzymes, hormones and absorptive surface
• prevents abrasion inside organ
• EXCEPTION: mouth, esophagus and anus –> stratified squamous (protective measure inside mouth from solid food)

Answer 18

epithelia

Question 19

mucosa

• loose areolar connective tissue
• vascularized (Blood supply)
• lymph supply (MALT) –> tonsils and appendix

Answer 19

Lamina propria

Question 20

mucosa

• has smooth muscle cells (thin layer)
• creates movement to increase digestion anf secretion
• hormones and enzymes are secreted

Answer 20

muscularis mucosae

Question 21

• superficial to mucosa
• aerolar connective tissue with elastic fibers
• rich supply of blood and lymphatic vessels, lymphoid follicles, nerve fibers
• serve surrounding layers of GI tract

Answer 21

submucosa

Question 22

• muscular layer that generates movement in GI tract
• there are 2 layers the circular layer and the longitudinal layer (dont contract at the same time)

Answer 22

muscularis externa

Question 23

circular layer contracts

Answer 23

organs become narrow and long

Question 24

longitudinal layer contracts

Answer 24

organs become wide and short

Question 25

* thickening in the muscularis externa form.... * functions: control movement from one alimentary organ to another and prevents back movement of ingested food (allows small amount of food at a time to prevent it from being overwhelmed)

Answer 25

sphincters

Question 26

* outermost layer * visceral peritoneum * EXCEPTION: the esophagus doed not have this, instead it has adventitia * adventitia is dense connective tissue (thicker and tougher)

Answer 26

serosa

Question 27

blood supply to the digestive organ

Answer 27

Splanchnic circulation

Question 28

branches off the celiac trunk that serve spleen, liver and stomach

Answer 28

Arteries

Question 29

* collects nutrient rich blood draining from digestive organs and transports it to liver * the liver will be exposed of it first so it protects the brain

Answer 29

Hepatic portal circulation

Question 30

nerve supply of the alimentary canal

Answer 30

Enteric Nervous system

Question 31

The two major intrinsic nerve plexuses are the submucosal nerve plexus (found in submucosa) and the Myenteric nerve plexus (Found between circular and longitudinal muscle layers)

Answer 31

True

Question 32

* initiated by stimuli inside and outside the GI tract * involves CNS and extrinsic autonomic nerves * sympathetic stimulation- inhibits gastric activity * Parasympathetic stimulation- enhances gastric acitvity

Answer 32

Long reflex

Question 33

* Mediated entirely by enteric nervous system in response to stimuli within GI tract * Ex: **peristalsis**- wavelike contractions created by muscularis externa

Answer 33

Short reflex