Chapter 17 digestive system

Wall of alimentary canal is composed of 4 layers; inner most to outer most layer

- Mucosa: innermost layer, mucous membrane - Submucosa: nourishes cells, transports absorbed food molecules - Muscularis: muscle tissue, moves tube and food materials - Serosa: outermost layer; serous fluid eliminates friction

Which of the following are functions of lipids?

-storage of energy -membrane structure -signaling molecules (such as hormones or neurotransmitters)

The vitamin __________ is a coenzyme for reactions involving nitrogen-containing compounds, including proteins and amino acids. Therefore, the dietary need for this vitamin depends on protein intake.

B6

Secretions essential to stomach function are regulated in three phases: the _____________ phase, the ______________ phase, and the ______________ phase.

Blank 1: gastric Blank 2: cephalic Blank 3: intestinal

What stimulates goblet cells and intestinal glands to secrete their products?

Chyme provides both mechanical and chemical stimulation.

accessory organs

Consists of organs that empty secretions into the alimentary canal; food does not pass through them

What is the definition of digestion?

Digestion is the mechanical and chemical process of breaking down large food biomolecules into their individual monomeric units - molecules that are small enough to be transported into cells.

Cholesterol, a type of lipid, is abundant in plant-based foods.

False

Where haustra is found in ?

Large Intestine

Which hormone, if it were to be used clinically, could help in weight loss?

Leptin

While testing for an emulsifier, one of the test tubes showed a layer of oil sitting on top of the water. What property of lipids causes this to occur?

Lipids are nonpolar and so do not mix with polar water molecules.

What organ is responsible for the production of bile?

Liver

Where are sensory signals from the stomach and small intestine sent to trigger a vomiting reflex?

Medulla oblongata

What are mass movements?

Movements that generally follow a meal as a result of the gastrocolic reflex initiated in the small intestine. Movements that can be caused by irritation of the intestinal mucosa. Slow and strong movements that force intestinal contents toward the rectum. Peristaltic waves of the large intestine that happen only two or three times each day.

propelling movement

Moves materials in one direction - Peristalsis: ring of contraction progresses down tube; propels food particles down the trac

mixing movements

Muscle in small sections contracts rhythmically - Does not move materials in one direction - Example: segmentation

The enzyme __________ begins digestion of protein in the stomach.

Pepsin

Indicate the functions of cholesterol.

Precursor for some hormones. Precursor for bile salts. Structural component of cell membranes.

What occurs during the series of reactions called beta oxidation?

Removal of two-carbon segments from fatty acids

What is the correct order of vessels as blood flows through the liver?

Sinusoids, central vein, hepatic vein

Which of the following is an effect of secretin on the pancreas?

The pancreas releases more bicarbonate in the pancreatic juice.

Identify the correct structural differences between the small intestine and the colon.

The small intestine has two complete layers of muscle and the large intestine has one complete layer and one incomplete layer of muscle. The small intestine has villi and the large intestine does not.

Name the B vitamins

Thiamin (B1) Riboflavin (B2) Niacin (B3) Biotin Pantothenic acid Vitamin B6 Folate Vitamin B12

the body utilizes the absorbed nutrients to produce ATP.

True

The fat-soluble vitamin __________ can be produced by intestinal bacteria.

Vitamin K

What are the functions of the large intestine?

absorb water store feces

List the substances absorbed from the stomach.

alcohol small volumes of water lipid-soluble drugs

The pancreatic enzyme that digests starch is called pancreatic_________.

amylase

The hormone secretin stimulates the pancreas to secrete a solution high in ______.

bicarbonate ions

Hepatic cells produce a yellowish-green liquid called _________that assists with lipid digestion.

bile

chemical digestion

breaks down food particles by changing them into simpler chemicals

Which are functions of the liver in the metabolism of carbohydrates?

breaks down glycogen to glucose converts noncarbohydrates to glucose polymerizes glucose to glycogen

mechanical digestion

breaks down large pieces of food into smaller ones, but does not change chemical composition

Enzymes in saliva begin the chemical digestion of ______ in the mouth.

carbohydrates

Pancreatic amylase breaks ______ down into ______.

carbohydrates; disaccharides

What are the three phases of gastric activity?

cephalic, gastric, intestinal

What are the three phases of gastric secretion?

cephalic, gastric, intestinal

These triglycerides, along with other lipids, enter the lacteals as part of particles called ?

chylomicrons

Once food is mixed with gastric juice, it is called

chyme

The right and left hepatic ducts converge to form the

common hepatic duct

What part of the tooth is composed of cellular tissue similar to bone, but harder?

dentin

The pancreas secretes ______ by exocrine mechanisms, and ______ by endocrine mechanisms.

digestive enzymes insulin

alimentary canal

digestive tube that extends from the mouth to the anus; the food passage way

True or false: Most absorption of digestive products occurs in the stomach.

false

Which class of vitamin is more likely to be stored in the tissues of the body?

fat-soluble vitamins

Tubular glands that open into gastric pits of the fundus and body of the stomach are called ________________glands.

gastric glands

Openings at the ends of tubular gastric glands in the gastric mucosa, as indicated by the arrows are called gastric________?

gastric pit

After absorption from the digestive tract, all monosaccharides are converted by liver enzymes to what compound?

glucose

Hepatic cells responding to the hormone insulin lower the blood glucose level by polymerizing glucose to form_______

glycogen

What is the product of the process of glycogenesis? Multiple Choice

glycogen

The mucus-secreting cells in the epithelium of the intestine are called ______ cells.

goblet

What is the function of bile salts?

increases surface area of fatty substances, allowing better access for lipase enzymes

Which of the following is needed to digest fats?

lipase

The structures surrounding the mouth opening that contain skeletal muscles and sensory receptors useful in judging the temperature and texture of foods are the

lips

What molecules are absorbed into the lymph?

long chain fatty acids

The strong and infrequent peristaltic movements in the large intestine that occur only two to three times each day are called ______.

mass movements

Emulsifiers are

molecules with a polar end and a nonpolar end that can be used to disperse lipids into polar liquids such as water.

The large intestine's only significant secretion is

mucus

What do goblet cells secrete?

mucus

The insulin-secreting accessory organ of the digestive system that is both an endocrine and exocrine gland is the

pancreas

Which accessory organ is located posterior to the parietal peritoneum and closely associated with the small intestine?

pancreas

Distension of the intestinal wall stimulates ______ reflexes that trigger the release of small intestine secretions.

parasympathetic

Increased peristaltic activity in the small intestine is due to __________ nervous stimulation and distension of the __________ wall.

parasympathetic; stomach

Where is the pharynx located?

posterior to the oral cavity

The common hepatic duct is formed by the convergence of which two structures?

right and left hepatic ducts

examples of accessory organs

salivary glands, liver, gallbladder, pancreas

The hormone that stimulates the pancreas to secrete an abundant amount of fluid rich in bicarbonate ions when acidic chyme enters the duodenum is________.

secretin

In the small intestine, normal mixing movements are called ______ and normal propelling movements are ______.

segmentation; peristalsis

The organ that is most effective in absorbing digestive products, water, and electrolytes is the ______.

small intestine

Neuropeptide Y __________ appetite.

stimulates

The alimentary canal of the digestive system is controlled by which nervous system?

sympathetic and parasympathetic nervous systems

Describe the primary function of bile salts. They serve ______.

to emulsify fats

What structure is pulled upward during swallowing to close the opening between the nasal cavity and pharynx?

uvula

Small projections of the mucosa of the small intestine that increase the surface area of the intestinal lining are the intestinal_______

villi