To successfully complete this assignment, first read the following exercise from the Laboratory Manual: Exercise 38. Anatomy of the Digestive System.
Reference:
Marieb, E. N., Mitchell, S. J., & Smith, L. A. (2013). Human anatomy & physiology laboratory manual (11th ed.). [Fetal Pig version]. San Francisco, CA: Pearson Benjamin Cummings.
Student Discussion Assignment
- Trace and discuss the complete movement of a bolus of food entering and exiting the human via the digestive system.
- View the anatomical models Figure 38.6 (b),Figure 38.8 (b),and Figure38.14 (a)and(b)from Laboratory Manual and briefly identify the structures that are described by the following abbreviated statements. Post your brief responses in the threaded Discussion Area below:
- Smooth muscle layers of the muscularis
- Location and function of gastric pits
- Overall structure of the finger-like villi within the small intestine/increased absorption area
- Function and location of hepatic artery and vein
- Specific lobes of the liver
- Gallbladder relationship to bile and digestion
- View the histology slides Figure 38.6 (b),Figure 38.9 (a),and Figure 38.13in your Laboratory Manual and identify the microscopic structures indicated by a leader line, number, or bracket. In the threaded Discussion Area below, briefly describe the function of:
- Figure 38.6 (b) gastric glands
- Figure 38.9 (a) Brunner’s gland
- Figure 38.13 ductal cells
As in all assignments, cite your sources in your work and provide references for the citations in APA format. Support your work, using your course lectures and textbook readings. Helpful APA guides and resources are available in the South University Online Library. Below are guides that are located in the library and can be accessed and downloaded via the South University Online Citation Resources: APA Style page. The American Psychological Association website also provides detailed guidance on formatting, citations, and references at APA Style.
Expert Solution Preview
Introduction:
In this assignment, we will be addressing three different topics related to the anatomy and physiology of the digestive system. First, we will discuss the complete movement of a bolus of food as it enters and exits the human body through the digestive system. Next, we will identify and briefly describe various anatomical structures related to the digestive system using anatomical models. Finally, we will analyze histology slides and describe the functions of specific microscopic structures within the digestive system.
Answer to Question 1:
The movement of a bolus of food through the digestive system involves several stages. When food enters the mouth, it is mechanically broken down by the teeth and mixed with saliva, forming a bolus. The bolus then passes through the pharynx and enters the esophagus through peristaltic contractions.
The bolus is then transported through the esophagus to the stomach, aided by the lower esophageal sphincter. In the stomach, the bolus is mixed with gastric juices and converted into chyme through muscular contractions and enzymatic digestion.
From the stomach, the chyme enters the small intestine where further digestion and absorption of nutrients occur. The chyme is mixed with bile from the liver and digestive enzymes from the pancreas. It moves through the duodenum, jejunum, and ileum of the small intestine. Absorption of nutrients occurs primarily in the small intestine, facilitated by the finger-like structures called villi.
After passing through the small intestine, the remaining waste material enters the large intestine where water absorption and formation of feces occur. The waste material then moves through the colon and is eventually eliminated through the rectum and anus.
Answer to Question 2:
a) Smooth muscle layers of the muscularis: These layers of smooth muscle are a part of the muscularis externa in the digestive system. They are responsible for the peristaltic contractions that help propel food through the digestive tract.
b) Location and function of gastric pits: Gastric pits are found in the lining of the stomach. These pits contain gastric glands, which produce gastric juices that aid in the digestion of food.
c) Overall structure of the finger-like villi within the small intestine/increased absorption area: Villi are finger-like projections found in the small intestine. They greatly increase the surface area available for absorption of nutrients.
d) Function and location of hepatic artery and vein: The hepatic artery carries oxygenated blood to the liver, while the hepatic vein carries deoxygenated blood away from the liver. These blood vessels are located within the portal triads of the liver lobules.
e) Specific lobes of the liver: The liver is divided into four lobes: right lobe, left lobe, caudate lobe, and quadrate lobe.
f) Gallbladder relationship to bile and digestion: The gallbladder stores and concentrates bile, which is produced by the liver. Bile is released into the small intestine, where it aids in the digestion and absorption of fats.
Answer to Question 3:
a) Figure 38.6 (b) gastric glands: Gastric glands are found in the stomach lining and produce gastric juices containing enzymes and hydrochloric acid. These juices help break down food and aid in the digestion of proteins.
b) Figure 38.9 (a) Brunner’s gland: Brunner’s glands are located in the submucosa of the duodenum (part of the small intestine). They secrete mucus that helps protect the duodenal lining from the acidic chyme entering from the stomach.
c) Figure 38.13 ductal cells: Ductal cells are found in the liver and pancreas. In the liver, they help transport bile from the liver lobules to the bile ducts. In the pancreas, they assist in the secretion of pancreatic juices containing digestive enzymes into the pancreatic duct.
