BIO 203 Lecture Notes - Lecture 24: Gastrointestinal Tract, Gastric Pits, Small Intestine

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copperdolphin16

7 Aug 2018

School

Stony Brook University

Department

Biology

Course

BIO 203

Professor

William Collins

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Document Summary

Review of anatomy: so we"ve got all the organs and the alimentary canal, sphincters separates the oral cavity, esophagus, stomach, small intestine, large intestine. Pharynx / esophagus: upper part of esophagus called pharynx, conducts bolus of food to stomach. Digestion: gastrovascular cavities, but not alimentary canals, allow animals to devour larger prey than those using intracellular digestion alone: true b) false. Humans use alimentary canals: we ingest giant pieces of food, compared to an amoeba, the limit of food that an amoeba can digest is the size of themselves. The contents of your alimentary canal is outside of your body technically: allows us to devour giant pieces of food. Digestion: at room temperature, fats that are fully saturated with h tend to form solids, whereas fats that are not fully saturated with h tend to form liquids: true b) false.

Related Questions

1. Which organ is responsible for balancing the amount ofglucose floating around in the blood? (it stores excess glucosewhen there is too much and releases glucose into the bloodstreamwhen there isn't enough)

Select one:

a. liver

b. pancreas

c. spleen

d. stomach

2. The gastrointstinal tract has 4 basic layers. Which layer isthe one that comes in contact with the food that you eat?

Select one:

a. serosa

b. submucosa

c. muscularis

d. mucosa

3. Which digestive organ contains 3 layers of muscle tissue inthe muscularis?

Select one:

a. esophagus

b. large intestine

c. stomach

d. anus

The esophagus is the first organ in the digestive tract thatsecretes digestive enzymes to begin the chemical (molecular)breakdown of food.

Select one:

True

False

Gastric ulcers are often caused by bacterial infection.

Select one:

True

False

Lactose intolerance causes gas, bloating and stomach achesbecause undigested sugar molecules, called lactose, end up gettingdigested by bacteria in the intestines. When they digest it, theyproduce lots of gases.

Select one:

True

False

7. The lower esophageal sphincter prevents food in the stomachfrom backing up into the esophagus.

Since the esophagus is not equipped to handle the harsh acids inthe stomach, when food (mixed with stomach acids) does back up intothe esophagus, you get symptoms such as heart burn. This is calledgastroesophageal reflux (or "reflux").

When reflux is left untreated for many years, the person becomesa trisk for esophageal cancer. This is because the esophagus gets"burned" by the acids over and over again which can eventuallytrigger the development of cancerous cells.

Select one:

True

False

Peristalsis is defined as the rhythmic contractions of thedigestive system that pushes food along the digestive tract.

Select one:

True

False

tealgoat796

2. General questions about the digestive tract A. Mechanical digestion of all foods begins in the oral cavity. Describe how food is digested mechanically in the oral cavity. B. What is the scientific name for swallowing? Which portions of the pharynx does food pass through when swallowing? What is the function of the esophagus? C. Cells lining the stomach release hydrochloric acid (HCl). How does HCl assist in food digestion? How are the cells lining the stomach protected from being auto-digested by HCl? D. Carbohydrates, fats, and proteins must be broken down into their smallest subunits (AKA building blocks) in order to be absorbed through the epithelial lining of the small intestine. Name the building blocks of each of the major classes of nutrients: complex carbohydrates (AKA polysaccharides), fats, and proteins. E. About 99% of all nutrients are absorbed in the small intestine. Name the 3 portions of the small intestine. In which of these 3 portions does the greatest amount of nutrient absorption occur (think about the location and length of each segment)? Which type(s) of nutrient(s) is/are absorbed into blood capillaries? Which type(s) of nutrient(s) is/are absorbed into lymphatic capillaries? F. The last portions of the digestive tract are the rectum, anal canal and anus. Name the 2 muscular sphincters located at the anus. When the rectum fills, the defecation reflex is initiated. Describe the events that occur during the defecation reflex. Name the 2 sphincters located at the anus. Which sphincter undergoes involuntary relaxation during the defecation reflex? Which division of the autonomic nervous system causes this sphincter to relax and open? Name the sphincter that you control consciously to stop or initiate defecation.

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BIO 203 Lecture Notes - Lecture 24: Gastrointestinal Tract, Gastric Pits, Small Intestine

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