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