Module 9

Question 1

Name the four main layers or tunics of the gut wall:

Answer 1

1) mucosa 2) submucosa 3) muscularis externa 4) serosa or adventitia

Question 2

Name the individual components that comprise innermost Layer A:

Answer 2

Epithelium lamina propria muscularis mucosa

Question 3

In the basic plan of the gut, muscularis externa has two components. Identify them:

Answer 3

Inner circular layer Outer longitudinal layer

Question 4

Where in the digestive tract is muscularis externa composed of skeletal muscle i.e. under somatic control?

Answer 4

Pharynx, upper third of oesophagus, external anal sphincter

Question 5

Where in the digestive tract does muscularis externa have an extra component? In which organ is it located and why is it required?

Answer 5

Stomach – for mixing and churning

Question 6

For each of the following peritoneal folds state the specific organs that they are connected to or support. 1) greater omentum 2) lesser omentum 3) falciform ligmament 4) mesentery 5) mesocolon

Answer 6

1) Connects transverse colon and greater curvature of stomach 2)Connects stomach and duodenum to liver 3)Connects liver to anterior abdominal wall 4)Connects small intestine to posterior abdominal wall 5)Connects large intestine to posterior abdominal wall

Question 7

What does retroperitoneal mean?

Answer 7

What does retroperitoneal mean?

Question 8

What is peritonitis?

Answer 8

Inflammation of the peritoneum

Question 9

What type of epithelium is found on the surface of the tongue? Why?

Answer 9

stratified squamous, keratinised in parts (on the filiform papillae) permits wear & tear

Question 10

The tongue is a muscular structure; explain the difference between intrinsic and extrinsic muscles of the tongue?

Answer 10

Intrinsic lie entirely within tongue, extrinsic have attachments to bones of skull

Question 11

The palate forms the roof of the oral cavity, identify the parts of the palate labelled:

Answer 11

Hard palate, Soft palate, Uvula

Question 12

What is the function of structure 8?

Answer 12

Closes off nasopharynx during swallowing

Question 13

The salivary glands contain serous secretory cells, mucous secretory cells or a combination of both. What is the difference in the composition of the secretions produced by these cells?

Answer 13

Serous: water and amylase Mucus: mucin, water

Question 14

How may pairs of salivary glands are there?

Answer 14

Three

Question 15

What type of muscle (skeletal, smooth or cardiac) is found in the posterior walls of the pharynx? Why is this?

Answer 15

Skeletal, for voluntary control of food bolus

Question 16

What role does the epiglottis play in swallowing? What type of tissue is made from?

Answer 16

Prevents food entering the larynx; elastic cartilage

Question 17

Does the oesophagus lie anterior or posterior to the trachea?

Answer 17

Posterior

Question 18

Which muscular structure must the oesophagus pass through to enter the abdominal cavity?

Answer 18

diaphragm

Question 19

What is the hole or opening in this muscle called?

Answer 19

oesophageal hiatus

Question 20

What type of epithelium lines the oesophagus and what is its function?

Answer 20

Non-keratinised stratified squamous – allows wear and tear

Question 21

There are numerous glands in the submucosa - they may not be visible. What are their secretions made of and what purpose do they serve?

Answer 21

Mucus, for lubricating passage of food

Question 22

Can you think of a reason for this?

Answer 22

Upper 2/3s has skeletal muscle for voluntary control

Question 23

The outermost layer of the thoracic oesophagus consists of connective tissue that anchors it to surrounding structures (there is no serous membrane present). What is this layer called?

Answer 23

adventitia

Question 24

What role do the sphincters play?

Answer 24

Isolate acidic stomach environment from oesophagus and duodenum, regulate flow

Question 25

Are rugae permanent structures?

Answer 25

No ; permit the stomach to distend

Question 26

Name the two folds of peritoneum that are attached to the stomach:

Answer 26

To liver: lesser omentum greater omentum

Question 27

What type of epithelium is found here (stomach)?

Answer 27

Simple columnar

Question 28

Entero-endocrine cells (G cells) are also found in the glands but their secretions pass through the lamina propria into the blood, rather than going into the lumen of the stomach. What products do these cells secrete?

Answer 28

Gastrin

Question 29

What role do the secretions from G cells play in the digestive process?

Answer 29

Stimulates gastric activity

Question 30

Name the three layers of muscle that are found in the muscularis externa of the stomach.

Answer 30

Oblique, circular, longitudinal

Question 31

What purpose does the extra layer serve in the stomach?

Answer 31

Mixing and churning

Question 32

What MACROSCOPIC (visible to the naked eye) structures, found within the wall of the small intestine, increase its surface area?

Answer 32

Plicae circulares

Question 33

What other function do these structures perform?

Answer 33

Help to spiral chyme along length of intestine

Question 34

There are two more features of the epithelium that help to increase surface area, name them

Answer 34

Villi and microvilli

Question 35

One of these gives the internal surface of the small intestine a velvety appearance. Which one?

Answer 35

Villi (0.5-1.5mm, just visible to naked eye)

Question 36

Which structure/serous membrane attaches the small intestine to the posterior abdominal wall? (Hint: check your Prelab)

Answer 36

Mesentery

Question 37

What type of epithelium is found in the duodenum?

Answer 37

Simple columnar

Question 38

Are goblet cells present?

Answer 38

yes

Question 39

The intestinal glands (crypts of Lieberkuhn) secrete intestinal juice; what does it contain?

Answer 39

Serous fluid + enzymes from the intestinal mucosal cells

Question 40

Identify the duodenal (Brunner's) glands in the submucosa. What is the function of these glands?

Answer 40

Secrete alkaline mucus to neutralise gastric acid in chyme

Question 41

Why are these glands not found in the jejunum and ileum?

Answer 41

No longer an acidic environment

Question 42

What types of gut motility are found in the small intestine?

Answer 42

Peristalsis and segmentation

Question 43

What is the gastro-ileal reflex?

Answer 43

Food/activity in the stomach encourages material in the ileum to move on to the large intestine.

Question 44

Three distinctive external, macroscopic features (identified above) are associated with the large intestine. Name these features

Answer 44

taenia coli, haustra, epiploic appendages

Question 45

Name three main functions of the large intestine.

Answer 45

Absorption of remaining water and electrolytes, bacterial production of vitamins, formation and elimination of faeces

Question 46

Regarding water absorption, does the small intestine or the large intestine absorb the greatest volume?

Answer 46

Small

Question 47

Numerous bacteria are found within the large intestine. Identify 4 functions;

Answer 47

Breakdown amino acids, decompose bilirubin, produce vitamins B and K, indigestible CHOs (fibre, cellulose, resistant starch)

Question 48

Refer to the Pre-lab (Figure 9.1) and identify which structure/serous membrane attaches the large intestine to the posterior abdominal wall:

Answer 48

Mesocolon

Question 49

What type of epithelium is found in the large intestine?

Answer 49

Simple columnar

Question 50

Are goblet cells present? What is their role in the colon?

Answer 50

Yes ,to ease the passage of faeces

Question 51

How does the muscularis externa differ from the general histological plan?

Answer 51

Longitudinal layer reduced to three bands of muscle – taeniae coli

Question 52

Explain the puckered (existence of haustral pouches) appearance of the colon.

Answer 52

Contractions of the taeniae coli

Question 53

What types of motility do you find in the large intestine? Include reflexes in your answer

Answer 53

Mass movements (gastrocolic & duodenocolic reflexes); haustral churning; defaecation reflex.

Question 54

What are the four lobes of the liver?

Answer 54

right, left, caudate, quadrate

Question 55

Which lobe is the largest?

Answer 55

Right

Question 56

Identify the two ligaments on the liver

Answer 56

ligamentum teres, falciform ligament

Question 57

falciform ligament anchors the liver to which structure?

Answer 57

Anterior abdominal wall

Question 58

What is the function of the gallbladder?

Answer 58

Store and concentrate bile

Question 59

The liver receives blood from two sources. Name the two blood vessels that bring blood into the liver at the "porta hepatis"

Answer 59

Hepatic artery and hepatic portal vein;

Question 60

What is the difference in the composition of the blood from these two sources?

Answer 60

Artery rich in oxygen, vein rich in nutrients

Question 61

Blood leaves the liver through which blood vessel?

Answer 61

Hepatic vein

Question 62

What are pancreatic digestive enzymes produced by the exocrine secretory units called?

Answer 62

Pancreatic acini

Question 63

Are pancreatic acini and islets of langerhans exocrine or endocrine?

Answer 63

Acini- exo islets- endo

Question 64

Which three vessels are known as the portal triad?

Answer 64

Hepatic artery Hepatic portal vein Bile duct

Question 65

How would you distinguish between these vessels?

Answer 65

Shape of the cells in the wall: cuboidal for the duct, squamous for blood vessels and shape of lumen (round for artery, flattened for vein)

Question 66

In which direction does blood flow through the sinusoids between the hepatocytes?

Answer 66

From portal triad to the central vein flowing past the hepatocytes

Question 67

Through which structure do these two ducts enter the duodenum?

Answer 67

Duodenal papilla

Question 68

Name the sphincter that controls this opening?

Answer 68

Hepatopancreatic sphincter or (sphincter of Oddi)

Question 69

Small calculi known as gallstones, ranging from 6mm up to 5cm may form within the gallbladder; they usually contain cholesterol, calcium carbonate, bilirubin or other bile pigments. Name some other ducts or locations where you might expect gallstones to form.

Answer 69

Cystic duct, common bile duct, R & L hepatic ducts, common hepatic duct, HP ampulla, liver

Question 70

What characteristic of these ducts might make them susceptible to gallstone lodgement.

Answer 70

quite narrow; usual internal diameter of cystic duct is 2-3mm & common bile duct is 3-8mm

Question 71

A person with gallstones often experiences excruciating pain in the epigastric and right hypochondriac regions? Give an explanation for this.

Answer 71

location of gallbladder in these regions

Question 72

Confirmation of a doctor’s diagnosis of gallstones is made using an ERCP (Endoscopic Retrograde Cholangio-pancreatography). Which structures might such a tube pass through in an ERCP on its way to these ducts?

Answer 72

mouth, pharynx, oesophagus, stomach, duodenum; major duodenal papilla, sphincter of Oddi

Question 73

Current medical thinking is to remove the gallbladder; this is known as a cholecystectomy. How do you think people might cope without a gallbladder? Does bile still enter the duodenum?

Answer 73

The bile forms a continuous stream between liver and duodenal papilla, but not so concentrated

Question 74

Answer 74

Question 75

Answer 75

Question 76

Answer 76

Question 77

Answer 77

Question 78

Answer 78

Question 79

Answer 79

Question 80

Answer 80

Question 81

Answer 81

Question 82

Answer 82

Question 83

Answer 83

Question 84

Answer 84

Question 85

Answer 85

Question 86

Answer 86