Lab Five

Question 1

What are the anatomical relationships of the esophagus in the mediastinum?

Answer 1

The esophagus lies posterior to the trachea, anterior to the vertebral column, posterior to the heart, medial to the lungs, and the descending aorta lies slightly to the left-posterior side.

Question 2

At what level does the esophagus pass through the diaphragm?

Answer 2

The esophageal hiatus is located at T10. The abdominal portion of the esophagus is about 1 inch long and enters the stomach posterior to the seventh costal cartilage.

Question 3

Describe the location of the submandibular gland.

Answer 3

The submandibular gland may be found under the floor of the mouth and along the medial surface of the mandible.

Question 4

Where are taste buds found?

Answer 4

Taste buds are mainly found along the sides of the large circumvallate papillae and along the tops and sides of the fungiform papillae. There are approximately five taste buds per fungiform papilla, compared to almost one hundred per circumvallate papilla.

Question 5

What is the organization of the muscle layers of the stomach, along with their cellular makeup?

Answer 5

1. Inner oblique

2. Middle circular

3. Outer longitudinal

These three layers are all made up of smooth muscle.

Question 6

Describe the location of the sublingual gland.

Answer 6

The sublingual gland may be found anterior to the submandibular gland just below the tongue.

Question 7

What kind of cells make up the submandibular glands?

Answer 7

The submandibular glands are a mix between serous and mucous cells.

Question 8

Describe the histology of the taste buds.

Answer 8

The taste buds are composed of three main components: gustatory cells (gustatory receptors), supporting cells, and basal stem cells.

Question 9

Describe the histological organization of the stomach.

Answer 9

The mucosal lining of the stomach consists of simple columnar epithelium that is composed mainly of mucus surface cells. These epithelial cells invaginate the mucosal surface, forming gastric pits (lined with simple columnar cells). Each gastric pit leads into a gastric gland that extends into the lamina propria of the mucosal membrane.

Question 10

What is the pyloric sphincter?

Answer 10

The middle circular layer thickens to form the pyloric sphincter. This sphincter acts as a valve to control the movement of chyme from the stomach to the small intestine (duodenum).

Question 11

What kind of cells make up the parotid gland?

Answer 11

The parotid gland is mainly comprised of serous cells.

Question 12

What kind of cells make up the sublingual gland?

Answer 12

The sublingual gland is mainly composed of mucous cells.

Question 13

What are the four layers of the esophageal wall along with their characteristics?

Answer 13

1. Mucosa
   
   1. Made of stratified squamous epithelium
   2. Lamina propria (loose connective tissue)
   3. Muscularis mucosae (smooth muscle)
2. Submuscosa
   
   1. Dense irregular connective tissue
   2. Mucus-secreting glands
3. Muscularis externa
   
   1. ​​Made of an inner circular layer
   2. Made of an outer longitudinal layer
      
      1. Upper 1/3 is skeletal muscle
      2. Middle 1/3 is a mix of skeletal/smooth muscle
      3. Lower 1/3 is smooth muscle
4. Adventitia
   
   1. Dense, fibrous connective tissue

Question 14

What is the functional importance of mucosal neck cells, parietal cells, and chief cells?

Answer 14

1. Mucosal neck cells - produces and secretes mucous that protects the lining of the pits from acidic erosion.
2. Parietal cells - produce and secrete HCl and intrinsic factor (B12 absorption).
3. Chief cells - produce and secrete pepsinogen that is converted by HCl into pepsin, an active enzyme that breaks down proteins into their monomers amino acids.

Question 15

Which cranial nerve innervates the skeletal muscles of the tongue?

Answer 15

The hypoglossal nerve (CN XII) is responsible for the innervation of the skeletal muscle of the tongue. However, the palatoglossus is an exception and is innervated by the pharyngeal branch of the Vagus nerve (CN X).

Question 16

Name the two major curvatures of the stomach.

Answer 16

1. Lateral convex greater curvature
2. Medical concanve lesser curvature

Question 17

Which structures does the esophagus join with superiorly and inferiorly?

Answer 17

The esophagus joins with the laryngopharynx superiorly and the stomach inferiorly.

Question 18

Describe the anatomical relationships of the stomach.

Answer 18

The stomach occupies the left hypochondriac and epigastric portions of the umbilical and left lumbar regions (left upper quadrant). The stomach is covered by peritoneum and is nearly hidden by the liver and diaphragm. The fundus is in direct contact with the diaphragm, posterior to the left costal cartilages. The anterior surface of the stomach is in contact with the left lobe of the liver and the anterior abdominal wall. To the left of the fundic region is the spleen, which lies in front of the pancreas. The esophagus enters the stomach in the cardiac region, whereas the stomach is connected to the small intestine at the pyloric end of the organ.

Question 19

Note the histology of a typical adult human tooth.

Answer 19

The adult human tooth is normally comprised of three main parts:

1. Crown - enamel and dentin
2. Neck - Gingiva (Gum)
3. Root - Pulp cavity, cementum, periodontal ligament, root canal, nerve and blood vessels, and apical foramen

Question 20

What are the four major regions of the stomach?

Answer 20

1. Cardia
2. Fundus
3. Body
4. Pylorus

Question 21

What are the boundaries of the oral cavity?

Answer 21

Roof: Hard and soft palate

Lateral Walls: Cheeks

Floor: Tongue

Anterior: Labia

Question 22

Describe the location of the parotid gland.

Answer 22

The parotid gland may be found in front of the ear, between the masseter muscle and the skin on the side of the face. It extends between the inferior surface of the zygomatic arch and the anterior margin of the sternocleidomastoid muscle. Moreover, it extends from the mastoid process of the temporal bone anteriorly across the superficial surface of the masseter muscle.