13: What Happens to the Food You Consume? Flashcards
Module 3, Lesson 2
The energy animals receive from food is in the form of…
Calories
A ____ is the energy needed to raise the temperature of 1 gram of water by 1 degree Celsius.
calorie
note lowercase “c”
A ____ is equal to 1,000 calories.
Calorie / kilocalorie
note uppercase “C”
The ____ is the minimum amount of energy consumed by the body under resting conditions.
Basal metabolic rate
(BMR)
People need to ingest about ____ more calories a day than the BMR.
50 - 100%
People need to consume a balanced ratio of…
(six)
- Proteins
- Carbohydrates
- Fats
- Vitamins
- Minerals
- Water
Once ingested, ____ are broken down into their component amino acids and used to build new, more complex proteins.
Proteins
Nine of the twenty amino acids used to build proteins are considered ____ and are obtained through the diet.
Essential
____ are used as the primary energy source in cellular respiration.
Carbohydrates
Energy can be extracted from carbohydrates by…
Breaking their chemical bonds
Energy contained in carbohydrates can be stored in the liver as ____ or in adipose cells as ____.
Glycogen ; fat
____ is an important energy storage molecule that can contain twice as much energy as other energy storage molecules.
Fat
____ fats are obtained through the diet.
Essential
Excess calories are converted to…
Fat
____ are organic compounds that are essential for metabolic reactions.
Vitamins
The primary role of vitamins is to…
Help catalyze metabolic reactions
True or false:
Vitamins can be produced by the body.
False
There are a total of ____ essential vitamins.
13
____ are inorganic compounds that help catalyze metabolic reactions.
Minerals
The digestive system is composed of…
(two)
- A tubular gastrointestinal tract (elementary canal)
- Accessory organs
In the digestive system, ____ produce enzymes that assist with digestion.
Accessory organs
List the four accessory organs associated with the digestive system.
- Liver
- Gallbladder
- Salivary glands
- Pancreas
Food is ingested through and mechanically broken down in the…
Mouth
The ____ is the opening of the oral and nasal cavities located between the mouth and the esophagus.
Pharynx
The ____ is a muscular tube leading to the stomach.
Esophagus
Food is chemically broken down in the…
Stomach
Digested nutrients are absorbed in the…
Small and large intestines
The waste products of digestion exit the body through the…
Anus
List the four main tissue layers of the digestive tract.
- Mucosa
- Submucosa
- Muscularis
- Serosa
The innermost layer of the digestive tract is the…
Mucosa
The mucosa is made up of ____ tissue.
Epithelia
List three functions of the mucosa.
- Secretes mucus
- Absorbs endproducts of digestion into the blood
- Protects underlying tissues from foreign objects
The submucosa is made up of ____ tissue.
Connective
The ____ is rich in blood, lymphatic vessels, and nerve fibers.
Submucosa
The muscularis is made up of…
Smooth muscle
What are the two orientations of smooth muscle in the muscularis layer?
Circular and longitudinal
like an earthworm :)
The primary function of the muscularis is to…
Move food through the gastrointestinal tract
The circular layers in the muscularis are responsible for…
Sphincter muscles
The serosa is made of ____ tissue.
Epithelial
The function of the serosa is to…
Protect the canal from abrasions as the walls flex and extend
The method of mechanical food breakdown in the mouth is called…
Mastication
(chewing)
Because birds do not have teeth, in order to mechanically break down their food they…
Ingest pebbles and store them in their gizzard
Chemical digestion of food begins in the…
Mouth
In the mouth, the tongue mixes chewed food with…
Saliva
Saliva is produced by…
Three pairs of salivary glands
List the four main components of saliva.
- Water
- Mucus
- Salivary amylase
- Antibacterial compounds
The role of water in saliva is to…
Dissolve hydrophilic substances
The role of mucus in saliva is to…
Bind food together
The role of salivary amylase in saliva is to…
Initiate starch breakdown
The tongue forms mechanically fractured food into a round structure called a ____, which is then swallowed.
Bolus
When food enters the back of the mouth, the ____ seals off the nasal cavity and temporarily pauses breathing.
Soft palate
The ____ is initiated once the bolus passes the soft palate.
Involuntary swallowing reflex
What happens during the involuntary swallowing reflex?
(two)
- The larynx is elevated
- The epiglottis folds
During swallowing, the epiglottis folds in order to…
Keep food out of the respiratory tract
After the bolus enters the ____, the larynx relaxes and breathing resumes.
Esophagus
The upper portion of the esophagus contains ____ muscle.
Skeletal
The majority of the esophagus contains ____ muscle.
Smooth
In the esophagus, longitudinal and circular muscle layers work together to…
Move food through the esophagus
____ is the process by which food is moved in one direction through the esophagus.
Peristalsis
True or false:
Food in the esophagus is always directed towards the stomach regardless of gravity.
True
The successive one-directional waves of muscle contraction in the esophagus are stimulated by…
The swallowing center in the brain
The circular opening that food must pass through to reach the stomach is called the…
Esophageal spincter
The inside of the ____ is highly convoluted to allow expansion.
Stomacg
Inside the stomach, the bolus is combined with highly acidic…
Gastric juice
List the three main components of gastric juice.
- Mucus
- Hydrochloric acid
- Pepsin
The inactive form of pepsin, ____ is converted to pepsin by acidity.
Pepsinogen
List the three muscle layers of the stomach lining.
- Oblique
- Circular
- Longitudinal
The muscles of the stomach lining churn food and mix it with gastric juice until it becomes…
Chyme
The stomach lining contains ____ which lead to glands that produce gastric juice.
Gastric pits
List the three types of cells involved in producing gastric juice.
- Chief cells
- Parietal cells
- Mucus-secreting cells
____ secrete pepsinogen.
Chief cells
____ secrete hydrochloric acid.
Parietal cells
Food exits the stomach through the…
Pyloric sphincter
The first region of the small intestine that food enters is the…
Duodenum
Most digestion and nearly all nutrient absorption occurs in the…
Small intestine
List the three regions of the small intestine.
- Duodenum
- Jejunum
- Ileum
Inside the ____, pancreas enzymes and gallbladder bile break down proteins and fats.
the answer is not “small intestine”, btw
Duodenum
The ____ is the region of the small intestine adapted to absorption of nutrients.
Jejunum
The ____ of the small intestine gives the intestine its massive surface area.
Folded epithelial lining
____ are folds in the mucosal lining of the small intestine.
Villi
The villi are covered with extensions of the plasma membrane called…
Microvilli
____ enzymes are digestive enzymes housed in the microvilli that aid in digestion of carbohydrates, proteins, and fatty acids.
“Brush border”
____ are broken down into amino acids by brush border enzymes, then transported through epithelial cells into the capillaries.
Proteins
____ are broken into monosaccharide monomers by brush border enzymes, then transported through epithelial cells into the capillaries.
Polysaccharides
Fats are broken down into fatty acids and monoglycerides by….
Bile salts
Fatty acids and monoglycerides are ____, so they easily diffuse across cell membranes.
Lipophilic
Inside cells, fatty acids and monoglycerides are assembled into triglycerides and packaged into…
Chylomicrons
Chylomicrons enter the lymphatic system via…
Lymphatic capillaries
Lymphatic capillaries join to form…
Lacteals
Absorbed nutrients are distributed to the body via the…
Circulatory system
Nutrients are transported to the liver via the…
Hepatic portal vein
The pancreas secretes ____ through the pancreatic duct.
Pancreatic juice
List five digestive enzymes/chemicals secreted by the pancreas.
- Trypsin
- Chymotrypsin
- Pancreatic amylase
- Lipase
- Bicarbonate
Trypsin and chymotropsin are ____ stored in an inactive form in the pancreas.
Proteases
Pancreatic amylase is used to help digest…
Carbohydrates
The pancreas secretes ____, which neutralizes the acidic chyme to make a suitable pH.
Bicarbonate
The ____ is the largest and most metabolically active internal organ.
Liver
List four major functions of the liver.
- Detoxification of harmful substances
- Synthesis of complex proteins
- Assembly and storage of glycogen
- Secretion of bile
The bile secreted by the liver is composed of…
Bile salts and bile pigments
Bile ____ are the waste products from broken-down red blood cells.
Pigments
Bile ____ help to emulsify clumped liquids.
Salts
The ____ stores and concentrates bile.
Gallbladder
The presence of fatty food in the duodenum stimulates…
Injection of bile into the duodenum
The small intestine empties into the large intestine at a junction where the ____ and ____ are located.
Cecum and appendix
True or false:
The colon is a vestigial structure.
False
The cecum and appendix are, but not the colon
List the four main functions of the colon.
- Absorbs any remaining water
- Absorbs electrolytes
- Absorbs vitamin K
- Compacts feces for expulion
Compacted feces enter the ____ to be expelled.
Rectum
Expulsion of feces is controlled by…
2 sets of sphincter muscles
True or false:
Both sets of sphincter muscles involved in feces expulsion are under voluntary control.
False
The second set is the only one under voluntary control
The first sphincter muscle involved in feces expulsion opens involuntarily in response to…
Pressure
Feces is composed of…
Parts of food that were not digested
True or false:
All animals lack the enzymes needed to digest cellulose.
True
In order to absorb cellulose, some animals have…
Bacteria and protists in their digestive tracts
____ have longer digestive tracts which allow more time for cellulose digestion.
Herbivores
Which three groups of animals are able to digest cellulose in their cecums?
- Herbivores
- Ruminants
- Rodents
____ have a four-chambered stomach that house bacteria and protists, enabling them to digest cellulose more effectively.
Ruminants
____ have no cecum and thus do not digest any cellulose.
Insectivores
____ have a small cecum but do not digest any cellulose.
Carnivores
____ is the process by which some animals eat their feces to absorb more nutrients on the second passage of food.
Coprophagy
List four hormones involved in controlling the digestive tract.
- Gastrin
- Cholecystokinin (CCK)
- Gastric inhibitory peptide (GIP)
- Secretin
____ is secreted by the stomach and targets chief and parietal cells to aid digestion of proteins.
Gastrin
____ is released by the duodenum in response to fatty chyme and targets the gallbladder and pancreas.
CCK
CCK stimulates the release of…
Bile and digestive enzymes
____ is released by the duodenum in response to fatty chyme and targets the stomach.
GIP
GIP inhibits…
The emptying of chyme into the duodenum
____ is released by the duodenum in response to acidic conditions and targets the pancreas.
Secretin
Secretin stimulates the pancreas to release…
Bicarbonate
CCP, GIP, and secretin are collectively referred to as…
Enterogastrones
Which two hormones are involved in long-term control of feeding behavior?
- Leptin
- Insulin
____ is released from fat cells and decreases appetite.
Leptin
Leptin targets cells in the…
Hypothalamus
A decrease in fat cells results in…
Decreased leptin release and increased appetite
Which three hormones are involved in short-term control of feeding behavior?
- CCK
- GIP
- Ghrelin
When involved in short-term control of feeding behavior, GIP, CCP, and ghrelin target cells in the…
Hypothalamus
CCK and GIP are released based on levels of food in the stomach and…
Inhibit appetite
____ levels rise just before feeding, which increases appetite.
Ghrelin
