Stomach anatomy

Question 1

The stomach is __-Shaped, It can hold ____ quarts of food, and changes shape when you eat

Answer 1

J

2-4

Question 2

The stomach is _______ in tall people, and more _____ in short people

Answer 2

vertical

horizontal

Question 3

Where does the esophagus meet the stomach?

Answer 3

Cardiac orifice

Question 4

What are the 4 regions of the stomach?

Answer 4

Cardia
Fundus
Body
Pylorus

Question 5

What is the cardia?

Answer 5

Small area where esophagus enters

Question 6

What is the fundus?

Answer 6

“Storage area” The dome superior to the esophageal opening

Question 7

What is the largest portion of the stomach?

Answer 7

The body

Question 8

What does pylorus mean, and what are it’s 3 subparts?

Answer 8

“Gatekeeper”
Pyloric Antrum
Pyloric canal
Pyloric sphincter

Question 9

What is the pyloric antrum?

Answer 9

“Funnel like” between the body and the pyloric canal

Question 10

What is the pyloric canal?

Answer 10

A narrowing down, as pylorus approaches pyloric sphincter

Question 11

What is the pyloric sphincter?

Answer 11

Muscle surrounding the very end of pylorus

A narrow passage into the duodenum

Question 12

What is the gastroduodenal sphincter?

Answer 12

AKA pyloric sphincter

Question 13

How is chyme made?

Answer 13

Smooth muscle in stomach creates chyme with enzymes, HCl, smooth muscle

Question 14

What are rugae and what do they do?

Answer 14

Conspicuous longitudinal folds in the stomach- allow stomach to stretch when we eat

Question 15

How is the stomach innervated?

Answer 15

PNS- Vagus (X) nerve

SNS- Celiac ganglion

Question 16

What is the stomach’s blood supply?

Answer 16

Mostly from celiac trunk

Blood drains to hepatic portal vein to live

Question 17

Where is the emetic center of the stomach?

Answer 17

In the medulla oblongata

Question 18

How does vomiting occur physiologically?

Answer 18

Causes forceful ejection of stomach contents through mouth
Abdominal contractions drive chyme up and out as both esophageal sphincters open
Salivation occurs to protect lining

Question 19

The _______ and _______ systems collaborate to increase gastric secretions and motility when food is eaten, AND to ________ them as the stomach empties.

Answer 19

nervous
endocrine
suppress

Question 20

What are the 3 phases of stomach secretions?

Answer 20

Cephalic
Gastric
Intestinal

Question 21

What activates the cephalic stage of stomach secretion?

Answer 21

Sensory receptors in head: Sight, smell, taste, and thought

Question 22

Cephalic stage signals converge on the ________ and relay to the ________ ________. The ______ nerve fibers then stimulate the G-cells, and thus, secretion

Answer 22

hypothalamus
medulla oblongata
vagus

Question 23

Gastric secretions begin before _____ enters stomach

Answer 23

food

Question 24

What are the two feedback cycles in the gastric stage of stomach secretion?

Answer 24

Neural negative feedback cycle

Hormonal negative feedback cycle

Question 25

What mechanisms activate the feedback cycles in the gastric stage of stomach secretion?

Answer 25

Activated by: Ingested food 1- Mechano receptors for stomach stretching 2- ↑ pH of contents of stomach, detected by chemoreceptors (add food, so pH ↑)

Question 26

The neural negative feedback loop is part of what nervous system?

Answer 26

PNS

Question 27

How does the neural negative feedback loop work?

Answer 27

Food in → distension → stretch receptors fire Plexus of Meissner ↑ gastric juice secretion Plexus of Auerbach- ↑ muscle churning As food moves on, no stretching, so feedback loop stops

Question 28

How does the hormonal feedback loop work?

Answer 28

Foods substances like alcohol, caffeine, partially digested proteins, or ↑ pH → stimulate G cells to release gastrin hormonally (↑ gastric juices, ↑ motility) As food moves on, pH ↓ (As food moves on, HCl ↑, so pH ↓)

Question 29

What controls the intestinal phase of gastric secretions?

Answer 29

Entrance of acidic chyme into duodenum | Receptors in duodenum send inhibitory signals to stomach

Question 30

What happens in the intestinal phase of gastric secretions?

Answer 30

1- Slow exit of chyme from stomach | 2- ↑ secretions of small intestine (and liver/pancreas)

Question 31

What reflex is a break on gastric activity?

Answer 31

Enterogastric reflex

Question 32

What three things happens in the enterogastric reflex?

Answer 32

1- Inhibit vagal nuclei in medulla oblongata 2- Inhibits local reflexes 3- Activate sympathetic fibers to tighten pyloric sphincter

Question 33

How long does it take for the stomach to empty? What goes faster/slower?

Answer 33

~4 hours Liquids go faster Solids, slower, remain in stomach until well churned and mixed with gastric juices