The Digestive System
Stomach
"holding chamber" where food is stored; site of some mechanical and chemical digestion
stomach
"strechy" storage chamber where food is broken down mechanically and chemically; food becomes paste-like chyme
What are the two major components of the digestive system?
Alimentary canal, accessory organs
Pharynx
Another name for the throat; contains muscles that push food into the food tube
Is the process of swallowing voluntary, involuntary, or both?
Both voluntary and Involuntary
Oral cavity
Entrance point of food into the body; aids in moistening and breaking down food physically.
Duodenum
First and shortest region of the small intestine; where chyme (food paste) combines with digestive enzymes
Esophagus
Food tube that transports food from the oral cavity to the stomach
Pancreas
Gland that secretes enzymes for the digestion of proteins, lipids, and carbohydrates into the duodenum. Produces insulin needed for the proper uptake of glucose by cells.
Salivary Glands
Glandular secretions lubricate food; secretions contain the enzyme amylase which begins carbohydrate digestion
Where do stronger wave-like contractions occur?
In the body of the stomach
Rectum
Lower part of the colon that stores solid wastes
What are the two digestive processes?
Mechanical and Chemical Digestion
Anus
Opening through which solid wastes leave the body
Liver
Produces and secretes bile for lipid emulsification; converts glucose to glycogen.
Jejunum
Second section of the small intestine (8 ft in length); site of most digestion and absorption of nutrients.
Large intestine (colon)
Site of compaction of intestinal contents into feces; site of water and vitamin absorption.
Tongue
Skeletal muscle covered with epithelial tissue; used to manipulate food and assist in swallowing.
The component of the alimentary canal whose function is to break down food matter chemically through acid and enzymatic attack is the ?
Stomach
Gall Bladder
Stores bile and releases bile into the duodenum
Ileum
Third and final section of small intestine (about 12 ft long); additional site of some nutrient absorption
What moves bolus down the esophagus?
Wave-like contractions known as peristalis
mesentery
a double layered membrane that covers and holds abdominal organs in place
Haustral Churning process
a haustrum fills up with food remnants, contracts, and squeezes the contents into the next haustrum. While haustral churning occurs, peristalsis is also taking place.
an important function of the large intestine is to
absorb water
mastication
act of chewing food
deglutition
act of swallowing food
characteristics of large intestine
all choices are correct with the exception of c
what correctly describes the function of the liver?
all choices are correct. synthesizes bile, converts excess glucose to glycogen, filters and detoxifies blood
peristalsis
alterning contractions and reaxation of muscles in the wall of the digestive tract
What does the pancreas secrete in the small intestine?
amylase, lipase, trypsin
an enzyme found in saliva, secreted by the parotid, sublingual and submandibular glands
begins the digestion of carbohydrates
an enzyme found in saliva, secreted by parotid, sublingual, and submandibular glands..
beings the digestion of carbohydrates
Carbohydrate examples
breads, pasta, beans, rice, and fruits.
which of the following correctly describes digestion in the small intestine?
carbohydrate, protein, and lipid digestion are completed
regions of the large intestine in order from the small intestine to the anus
cecum, ascending, transverse, descending, rectum
Chief cells
cells-secrete pepsinogen will become pepsin and initiates digestion of proteins such as meat, fish and eggs.
Chemical digestion
consists of a series of reactions in which enzymes split large carbohydrate, lipid, and protein molecules into smaller molecules.
chemical digestion
digestion involving the breakdown of food particles into smaller molecules by acid/enzymes
mechanical digestion
digestion involving the physical breakdown of large food pieces into saller ones
amylase
digests carbohydrates
intestinal juice
digests carbohydrates and proteins
lipase
digests lipids
trypsin
digests proteins
which of the following organs is not an accessory structure of the digestive system? a. pancreas b. gall bladder c. salivary glands d.duodenum
duodenum
Bile directly assists in the
emulsification of lipids
salivary gland
exocrine glands that deliver secretions into the oral cavity; begin carbohydrate digestion
bile
fluid produced by the liver that functions to break down large fat globules
hard palate
forms the superior boundary of the oral cavity; made of fused maxillae
What occurs in the stomach in order to mix food with gastric juices and produce a paste-like substance called chyme?
gentle, rippling contractions
In the large intestine, undigested food will move along a series of ________________?
haustral pouches
the precursor substance, pepsinogen, is converted to pepsin
in the presence of HCI
What are the 5 major functions of the digestive system?
ingestion, movement, digestion, absorption, defecation
What are two hormones the pancreas produces?
insulin and glucagon
ingestion
intake of food in mouth
largest gland and internal organ of body
liver
synthesis and secretion of bile is a major digestive function of the a. liver b. gal bladder c.pancreas d.duodenum e. stomach
liver
large intestine
major site for the absorption of water and some vitamins; short, final segment of the alimentary canal
absorption
movement of small nutrient molecules to the circulatory system for transport to cells
esophagus
muscular tube that connects and delivers food from the oral cavity to the stomach.
teeth
needed to tear and grind food mechanically in the process of mastication
path food passes through while moving within and out of the digestive tract
oral cavity, pharynx, esophagus, stomach, small intestine, duodenum, jejunum, Ileum, large intestine, ascending, transverse colon, descending, sigmoid colon, rectum, anus
which of the following digestive juices contains enzymes that chemically digest carbohydrates, fats, and proteins?
pancreatic juice
chyme
paste-like stomach contents consisting of partially digested food and gastric juices
passage of a bolus of food down the food tube is assisted by
peristalsis and gravity
emulsification
physical breakdown of large fat globules into smaller ones
uvula
projection of the soft palate that extends downward; helps prevent the movement of food and water from the oral cavity up into the nasal cavity
which of the following correctly describes chemical digestion in the stomach?
protein digestion is initiated
digestive juice that contains enzymes that digest carbohydrates, but not fats and proteins
saliva
Parietal cells
secrete HCI
Mucous cells
secrete mucus which prevents pepsin from digesting the stomach lining
What occurs as chyme reaches the pyloric region of the stomach?
several mL of food will be forced through the pyloric sphincter.
which structure is the site of the most digestion and nutrient absorption?
small intestine
which structure is not a component or accessory structure of the digestive system?
spleen
which structure is not a component or accessory structure of the digestive system? a. liver b. gall bladder c. pancreas d. salivary glands e. spleen
spleen
the component of the alimentary canal whose function is to break down food matter chemically through acid and enzymatic attack is the
stomach
gall bladder
stores bile which is used to break down large fat globules into smaller droplets
Examples of Accessory organs
teeth, salivary glands, liver, pancreas, and gall bladder
hydrolosis
the addition of water to large food molecules to break binds and form smaller molecules
where do most digestion and nutrient absorption processes occur?
the duodenum and jejunum regions of the small intestine.
Mechanical digestion
the physical breakdown of food by teeth (mastication) and the churning of food by smooth muscles of the stomach and small intestine.
All of the following are functions of the oral cavity except
to absorb nutrients
all of the following are functions of the oral cavity except
to absorb nutrients
which chemical would you not expect to be actively involved in the digestion of fried potatoes?
trypsin
Alimentary Canal
tube that begins at the mouth (oral cavity) and extends to the anus. -measures approximately 30 feet (9m) in length
feces
undigested food products combined with water and bacteria that are discharged from the rectum
How does absorbed nutrients move to the liver?
via hepatic portal veins
When does the voluntary phase of swallowing occur?
when the ball of food known as a bolus is forced in the pharynx by the tongue.
When does the involuntary phase of swallowing occur?
when the pharyngeal muscles contract and force the bolus into the esophagus.