Anatomy & Physiology I, Digestive System, Module 3

List the 8 regions of the large intestine.

(1) Cecum, (2) appendix, (3) ascending colon, (4) transverse colon, (5) descending colon, (6) sigmoid colon, (7) rectum, (8) anal canal

What structures respectively form these parts of the mouth? 1. Opening 2. Floor 3. Walls 4. Roof

1.lips 2. tongue 3. cheeks 4. hard and soft palates

How many teeth are there in an adult human and what do they do?

32 teeth; used to tear and cut food of both a vegetable and meat diet, mechanically digest food

What is a stomach ulcer?

A stomach ulcer is an open sore in the wall of the stomach

Explain in detail how ammonia is removed from the body.

Ammonia is combined with carbon dioxide to make urea which is excreted in the urine.

Where is bile formed and stored?

Bile is formed in the liver which is stored in the gallbladder.

What are the 2 classes of carbohydrates and in what foods can each be found?

Carbohydrates are classified as starches and sugars. Milk and fruits such as apples or peaches contain sugar, while grains such as wheat and vegetables such as potatoes contain starches.

List 5 biochemical materials needed by the body that are found in food.

Carbohydrates, proteins, and lipids are the major biochemical substances found in food needed by the body in large amounts. Vitamins and minerals are also needed in a much smaller amount.

What are the three types of papillae on the tongue? Which ones contain taste buds?

Circumvillate, fungiform, filiform; only circumvallate and fungiform pappilae contain taste buds

Describe cellular respiration

During cellular respiration, glucose combines with oxygen to form carbon dioxide, water, and ATP.

Describe how fats, sugars and amino acids are absorbed by the small intestine

Each small intestinal villus contains blood vessels and a lacteal lymphatic vessel. Sugars and amino acids enter villi cells and then are absorbed into the bloodstream. Glycerol and fatty acids enter villi cells and are reassembled into fat molecules, which move into the lacteals.

List the content of feces.

Feces are about 75% water and 25% solid matter containing intestinal bacteria, undigested plant material, fats, bile pigments, inorganic material, mucus, and dead intestinal cells.

Describe the passage of food into and out of the stomach

Food enters the stomach from the esophagus via the cardioesophageal sphincter and exits the stomach via the pyloric sphincter into the small intestine.

What is the specific function of the salivary gland in the process of digestion?

Food is mixed and moistened with saliva and enzymes are released like amylase to break down starches in the food

List and describe the tissue layers of the esophagus.

Four layers from the inside: mucosa - secretes mucus into the interior GI tract submucosa - layer contains blood and lymph vessels, lymph nodes, nerves, and mucous glands muscularis externa - two layers of muscle (outer longitudinal fibers and inner cicumferential fibers) serosa - cells that secrete serous fluid

Explain two main hormones that are responsible for hunger and satiety

Ghrelin turns on the hunger center and originates from the stomach. Leptin comes from fat cells and produces feelings of satiety.; Leptin and Ghrelin. Leptin is produced by adipose tissue (fat cells). The role of leptin is to alert the brain to turn off the hunger center in the brain and activate the satiety center when consuming a meal. Ghrelin is produced by the stomach and has the opposite role. Ghrelin travels to the brain and stimulates the hunger center as it deactivates the satiety center. Ideally, leptin and ghrelin work together to balance hunger and satiety.

List the two bones and the membrane to which the tongue is attached.

Hyoid bone, the mandible, and the lingual frenulum

Describe glycolysis

In glycolysis glucose is broken down into two pyruvic acid molecules and two ATP molecules are formed.

Describe the TCA cycle

In the citric acid (TCA) cycle the pyruvic acid product of glycolysis is converted to carbon dioxide forming some additional ATP.

How is the energy released in the breakdown of glucose converted to a form usable by the cells?

In the electron transport chain hydrogen atoms formed during glycolysis and the TCA cycle are converted to water releasing energy which is used to add phosphate to ADP to form ATP.

What digestive system functions are carried out by the small intestine?

In the small intestine chemical digestion continues as enzymes from the pancreatic juices break down starches and proteins, and begin digestion of fat. Mechanical digestion continues as bile breaks down fat into smaller pieces. Absorption begins as digested food molecules, water and fat are absorbed into the bloodstream.

Explain which digestive system functions are carried out by the stomach.

In the stomach mechanical digestion continues as muscles churn and mix the food, breaking it into smaller pieces in the form of chime which is moved to the small intestine by peristalsis. Chemical digestion continues as pepsin digests proteins.

What is the source of the stomach enzyme pepsin and what is its function?

Inactive pepsinogen is secreted by the chief cells and converted into the active enzyme pepsin by HCl. Pepsin then begins the breakdown of proteins.

Describe the function of the tongue in the digestive process.

It repositions the food in the mouth compacting it into a bolus. Then it pushes the bolus back to the pharynx to begin the process of swallowing. It also contains many taste buds.

Describe the shape of the stomach and its location relative to the abdomen and diaphragm

It's shaped like a backward C with the lesser curvature medial to the liver and the greater more lateral. It is located at the left side of the abdomen and inferior to the diaphragm.

Name, tell the location of and explain in detail the first stage of lipid breakdown

Lipid metabolism occurs in the liver by a process known as beta-oxidation to form acetic acid which is further catabolized by the TCA cycle to carbon dioxide forming some ATP.

Name, tell the location of and explain in detail the first stage of lipid breakdown

Lipid metabolism yields twice the energy formed during glucose metabolism.

What are the three classes of lipid?

Lipids can be divided into three categories: saturated fat, unsaturated fat, and cholesterol.

List 2 ways in which minerals are different than carbohydrates, lipids and proteins. List the seven minerals needed in the human diet and four foods which are good sources of these.

Minerals are inorganic compounds (not organic like carbohydrates, lipids and proteins) and are not used as fuel in metabolic reactions. Humans need the following seven minerals in their diets: calcium, chloride, magnesium, phosphorus, potassium, sodium, and sulfur. Foods such as milk, some meats, legumes and vegetables are the best sources of minerals.

Through what sections of the pharynx does air travel? Through what sections of the pharynx does food travel?

Nasopharynx, oropharynx, Laryngopharynx;

Where are taste buds located?

On the tongue, surface of mouth, and pharynx wall

Describe in detail the 2 major functions of pancreatic juice.

Pancreatic juice contains sodium bicarbonate, which neutralizes the chyme and makes the pH of the small intestine slightly basic. Pancreatic juice also contains digestive enzymes that further digest every major component of food.

raised bumps on the tongue

Papillae

Why are proteins not usually used as a body energy source and when are they used?

Proteins are the building blocks for the cells and are therefore preserved by the body only being used to make ATP when carbohydrates and fats are unavailable to the body.

What are the 2 classes of protein and in what foods can they be found?

Proteins can be categorized as complete or incomplete proteins. Examples of complete proteins are meat, poultry, eggs, milk or dairy products, and soybeans; whereas, examples of incomplete proteins are grains, legumes, seeds, and nuts.

What are the three main divisions of a tooth?

Root, neck, crown

chemical receptors that are stimulated by the chemical composition of food.

Taste buds

The pH of stomach is 1.3 - 3.5. What is this due to and what is its source and function?

The 1.3-3.5 pH of stomach contents is due to hydrochloric acid secreted by the parietal cells. The high acidity level kills bacteria and converts the inactive pepsinogen into the active enzyme pepsin.

What are the 2 classes of vitamins? How is a vitamin different than a carbohydrate, lipid or protein? Why can ingestion of excessive amounts of one type of vitamin be dangerous?

The 2 classes of vitamins are water-soluble vitamins and fat-soluble vitamins. Vitamins are organic compounds that are not consumed in metabolic reaction but help enzymes carry out the metabolic reactions which convert nutrients to materials need by the body. Fat-soluble vitamins are stored in body fat and ingestion of excessive amounts can be problematic.

What are the 3 functions of the liver that are important in digestion?

The 3 functions of the liver important in digestion are (1) it produces bile, which is stored in the gallbladder before entering the small intestine, where it emulsifies fats, (2) it stores glucose as glycogen and breaks down glycogen to glucose between meals to maintain a constant glucose concentration (homeostasis) in the blood, and (3) it produces urea from amino groups that are removed from excess amino acids.

List the names of the 3 specialized structures in the wall of the small intestine

The 3 specialized structures in the small intestine are circular folds, villi and microvilli.

Name the main divisions of the digestive system organs.

The AL-CAN-AL or the Alimentary Canal and the Accessory Organs

What are the two sphincters of the anal canal?

The anal canal has an involuntary smooth muscle internal sphincter and a voluntary skeletal muscle external sphincter.

Describe how the muscular layers in the pharynx assist with food passage.

The circumferential outer layer and the inner longitudinal layer contract alternatively to cause peristalsis to squeeze food into the esophagus.

How is the energy released from the breakdown of glucose used by the body?

The energy is released during the breakdown of glucose is used by the body to add a phosphate to an adenosine diphosphate (ADP) molecule and make adenosine triphosphate (ATP).

How does the energy formed in fat catabolism compare to that formed in carbohydrate metabolism?

The energy released in the breakdown of glucose allows the body to add a phosphate to an adenosine diphosphate (ADP) molecule and make adenosine triphosphate (ATP) which is then used by cells as a source of energy to perform cellular activities.

What prevents food from entering the lungs and why is this necessary?

The epiglottis muscle. This prevents aspiration which can lead to life-threatening aspiration pneumonia.

List the 3 sections of the small intestine. Which section is the shortest?

The first and shortest section of the small intestine is the duodenum. Second section is the jejunum and third is the ileum.

List 4 functions of the large intestine.

The large intestine propel wastes, reabsorbs water, reabsorbs electrolytes and absorbs Vitamin K and certain B vitamins produced by intestinal bacteria.

Describe the lesser omentum and the greater omentum.

The lesser omentum is a serous membrane which attaches the lesser curvature of the stomach to the liver and the greater omentum is a serous membrane which attaches the greater curvature of the stomach to the posterior wall of the body

Explain in detail how the stomach contents enter the small intestine

The pyloric sphincter valve, located at the base of the stomach, relaxes causing a small quantity of chyme to pass through the opening into the first part of the small intestine. This initiates a reflex that causes the muscles of the sphincter to contract and close the opening temporarily. Then the sphincter relaxes again and allows more chyme to enter.

What are the names of the valves which are located at the beginning and end of the small intestine?

The small intestine runs from the pyloric sphincter at the end of the stomach to the ileocecal valve at the large intestine.

Describe the lesser curvature and the greater curvature.

The stomach has two curvatures: the concave lesser curvature which extends inward on the shorter side of the stomach and the convex greater curvature which extends outward on the longer side of the stomach.

List and describe the two functions of the stomach.

The stomach has two purposes. It is a temporary storage area for food, storing up to two liters of partially digested food. The muscular walls of the stomach contract vigorously and mix food with juices that are secreted whenever food enters the stomach, allowing food to be broken down into smaller pieces that are easier to digest.

What types of muscularis externa are along the GI tract? What is different about the stomach?

There are two muscles consistently throughout the GI tract - inner circumferential (circular) layer and outer longitudinal fibers; the stomach has another muscularis externa called the oblique layer

What is the definition of an essential amino acid, how many essential amino acids are there for adults and where can they be found?

They can only be ingested bc the body cannot make these. There are 9 essential amino acids. Complete proteins contain all 9 AAs.

What are the 2 major physiological problems caused by diarrhea?

When materials pass through the colon too quickly, excess water is not reabsorbed, and diarrhea will result, which can lead to serious dehydration and electrolyte loss.

What is the first step in the oxidation of an amino acid formed from a protein?

When proteins must be used to form ATP, the amino group is removed from the protein to form ammonia.

What enzyme is carried in the salivary glands? What does it do?

amylase that breaks down starches

Two types of skeletal muscle of the pharynx.

circumferential outer layer and inner longitudinal layer

What is a bolus?

compact mass of food

the visible portion of the tooth and lies above the gum line

crown

a bone-like substance composing most of each tooth.

dentin

very hard connective tissue which protects the surface of the crown of the tooth

enamel

Nervous innervation allows for sensations of _______, _______, an _________. The _________ cavity in the center of each tooth contains nerves and blood vessels

heat, cold, pain; pulp

What are the four types of teeth, how many of each type are there and what does each type do?

incisors - biting canines - tearing premolars - grinding molars - crushing

What digestive system functions are carried out by the mouth?

ingestion and digestion

Name the 4 main functions of the digestive system.

ingestion, digestion, absorption, defecation

Explain peristalsis.

it is the circular and longitudinal muscles contracting alternatively and pushing food down the esophagus.

What is the lower jaw called?

mandible

Th process by which food is chewed by the teeth in the mouth

mastication

What is the upper jaw called?

maxilla

List the 3 parts of the pharynx

nasopharynx, oropharynx, laryngopharynx

Part of the tooth located within the upper portion of the gums (gingiva)

neck

Name the seven parts of the gastrointestinal tract.

oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anus

largest portion of each tooth and is located within the alveolar process of the jaw bone

root

Name the six digestive system accessory organs.

salivary glands, gall bladder, pancreas, tongue, teeth, liver

the vertical mucous membrane by which the body of the tongue is attached to the floor of the mouth.

the lingual frenulum

Define anabolism

the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism.