Chapter 3
The absorptive process that requires the use of energy to transport nutrients is called_____.
active transport
Which of the following statements regarding enzymes is true? - Some enzymes require a coenzyme to be active. - Enzymes are specific to specific chemical reactions. - The shape of the enzyme's active site determines its activity. - All of these statements are true
all of these statements are true
____ is made in the liver, is stored in the gallbladder, and emulsifies fat for digestion
bile
when fat enters the duodenum, the gallbladder secretes____ to break up the large fat globules.
bile
When the lower esophageal sphincter contracts, food ___.
cannot reenter the esophagus from the stomach
The three structural features of the small intestine that increase its surface area are the _____ , the villi, and the microvilli
circular folds
The system that releases hormones that regulate cells' use of nutrients is the __________.
endocrine system
A fourth method is called ______, which involves a vesicle that forms from the enterocyte's cell membrane, engulfing the nutrient and then drawing the nutrient into the cell.
endocytosis
The process in which whole proteins are absorbed intact from the small intestine is called __________.
endocytosis
without the cartilage at the back of the tongue called the _____, food would enter the trachea during swallowing.
epiglottis
the bolus slides down this tube, called the ________, which connects the pharynx to the stomach.
esophagus
Nutrients are absorbed through the lining of the small intestine via a variety of mechanisms. Most nutrients require _______, where a specific carrier protein is utilized, but no energy is required.
facilitated diffusion
Bacteria in the colon produce ___.
Vitamin K
Celiac disease causes ______
damage to the villi
the first section of small intestine, receiving chyme from the stomach, is called the _____
duodenum
Small fat-soluble molecules, such as free fatty acids and fat-soluble vitamins, are absorbed through facilitated diffusion in the small intestine.
false
What nutrient must enter the lymphatic system before entering the bloodstream?
fat
Once absorbed, water-soluble nutrients like carbohydrates and amino acids enter capillaries and travel to the liver via the ______
hepatic portal vein
Most water is absorbed in the _____, and solid waste is then eliminated.
large intestine
this large gland, located near the stomach, releases digestive enzymes after a meal and also secretes insulin and glucagon to control blood glucose levels. This accessory organ is called the _____.
pancreas
what organ produces insulin?
pancreas
A process called ______ helps to propel first the bolus and then chyme forward through the esophagus, stomach, and small intestine.
peristalsis
Food is propelled forward by rhythmic contractions called _____, which moves down the esophagus and through the stomach.
peristalsis
the secretions called _____ saliva are produced in the glands located behind the tongue and contain the enzyme amylase to chemically digest carbohydrate.
saliva
The absorption of the majority of ingested nutrients takes place largely in the __________.
small intestine
The primary organ for digestion and absorption is the ___.
small intestine
Foods that leave the stomach the fastest are those that are high in ___.
sugar
Amino acids are absorbed through the process known as active transport.
true
Enzymes are proteins, which catalyze chemical reactions.
true
_____ are finger-like projections that cover the circular folds of the small intestine and contribute to its increased surface area
villi
The __ protects the trachea while swallowing.
epiglottis
The absorption mechanism that requires a specific carrier molecule, but no energy, to move digested nutrients across the cell membrane is called __________.
facilitated diffusion
The mixture that leaves the stomach for the small intestine is called __________
chyme
Some smaller molecules can cross via ______. Like with facilitated diffusion, no energy is required because the concentration of a nutrient is higher inside the GI tract than in the enterocyte. Unlike with facilitated diffusion, however, no ______ is needed.
-passive diffusion -carrier protein
Nutrients like glucose and amino acids are absorbed through ______, which requires both a carrier protein and energy in the form of ATP.
active transport
chyme passes through the _____ that connects the ileum with the ascending colon.
ileocecal sphincter
the last portion, or segment, of the small intestine is called the _______
ileum
the _____ is the middle portion of the small intestine.
jejunum
villi contain _____ and _____ blood vessels that absorb nutrients, which are then transported through the body.
lymph vessels and blood vessels
Fat-soluble nutrients initially travel via the ______ before entering the bloodstream.
lymphatic system
during _____, teeth cut and grind food into smaller pieces as the tongue mixes them with saliva.
mastication
the hair-like projections that cover the surface of an intestinal cell and contribute to the increased surface area of the small intestine called ____
microvilli