Chapter 9: Human Biology (Digestive System) Flashcards
mouth
the organ of the digestive tract where food is chewed and mixed with saliva
tongue
functions as a digestive organ by facilitating movement of food during mastication and assisting swallowing, other important functions include speech and taste
teeth
grinding and breaking up food
salivary glands
glands that produce saliva to keep the mouth moist and to begin the process of digesting starch
pharynx
a funnel-shaped passageway that connects the nasal and oral cavities to the larynx
epiglottis
a flap of tissue that prevents food from passing into the larynx
esophagus
a long muscular tube that is ordinarily collapsed, but opens and receives the bolus when swallowing occurs
cardiac sphincter
prevents acidic contents of the stomach from moving upward into the esophagus
stomach
an organ that receives food from the esophagus, starts the digestion of proteins, and moves food into the small intestine
pyloric sphincter
acts as a valve to controls the flow of partially digested food from the stomach to the small intestine
duodenum
the first part of the small intestine, where chyme enters from the stomach
liver
largest gland in the body, produces urea and bile, detoxifies blood, stores glycogen, and produces plasma proteins, among other functions
gall bladder
organ attached to liver that serves to store and concentrate bile
pancreas
-5 things it produces
digestive organ with with endocrine and exocrine functions; produces pancreatic juice containing sodium bicarbonate and digestive enzymes, secretes insulin, glucagon, and somatostatin
small intestine
- list 3 parts and give function (2)
consists of the duodenum, jejunum, and ileum; completes the process of food digestion and absorption of nutrients that will enter the blood capillaries or the lymphatic capillaries.
appendix
small projection from the cecum; plays a role in fighting infection
large intestine
includes cecum, colon, rectum, and anal cavity; absorbs water, salts, and some vitamins and store indigestible materials until it is eliminated as feces
rectum
temporary storehouse for feces
anus
opening of the rectum where the expulsion of feces occurs
salivary amylase
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- salivary glands
- mouth
- carbohydrates
- neutral
- starch + H2O –> maltose
pancreatic amylase
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- pancreas
- small intestine
- carbohydrates
- basic
- starch + H2O –> maltose
maltase
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- small intestine
- small intestine
- carbohydrates
- basic
- maltose + H2O –> glucose + glucose
pepsin
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- gastric glands
- stomach
- proteins
- acidic
- protein + H2O –> peptides
trypsin
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- pancreas
- small intestine
- proteins
- basic
- protein + H2O –> peptides
peptidases
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- small intestine
- small intestine
- proteins
- basic
- peptide + H2O –> amino acids
nuclease
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
-pancreas
-small intestine
-nucleic acids
-basic
RNA and DNA + H2O –> nucleotides
nucleosidases
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- small intestine
- small intestine
- nucleic acids
- basic
- nucleotide + H2O –> base + sugar + phosphate
lipase
- produced by
- site of action
- which macromolecule is broken down by it
- optimum pH
- digestion
- pancreas
- small intestine
- lipids
- basic
- fat droplet + H2O –> glycerol + fatty acids
swallowing
a process that occurs in the pharynx, is a reflex action performed automatically, without conscious thought. The soft palate moves back to close off the nasopharynx and the trachea moves up under the epiglottis to cover the glottis. During swallowing, food normally enters the esophagus because our air passages are blocked. We do not breathe when swallowing.
peristalsis
rhythmic muscular contractions that push food along the digestive tract. It begins in the esophagus and continues through all the organs of the digestive tract.
gastric juice
- contains what three things
- what gets converted when exposed to HCL
- ^ how and what does this breakdown?
- describe pH and benefits
- explain how it physically helps digestion
contains pepsinogen, hydrochloric acid (HCl), and mucus. Pepsinogen becomes the enzyme pepsin when exposed to HCl. Pepsin helps to break down proteins in peptides. The high acidity of the stomach (about pH 2) is also beneficial because it kills most of the bacteria or other microbes present in food. The juice helps break food into smaller pieces in the stomach as it churns.
pancreatic juice
- contains what two things
- where can it be found
contains sodium bicarbonate (NaHCO3) to help neutralize stomach acid, and digestive enzymes for all types of food. The juice moves into the duodenum and completes the process of food digestion.
intestinal juice
- contains what three enzymes
- function
contains maltase, peptidases, and nucleosidases. It is involved with the processes of the small intestine, including digestion of foods.
insulin
The pancreas secretes insulin from the beta endocrine cells of the pancreatic islets. Insulin is secreted when blood glucose level is high, which usually occurs just after eating. It stimulates uptake of glucose by cells, especially liver cells, muscle cells, and adipose tissue cells. In liver and muscle cells, glucose is then stored as glycogen. In the muscle cells, breakdown of glucose supplies energy for protein metabolism , and in fat cells, the breakdown of glucose supplies glycerol for the formation of fat. In all of these ways, insulin will lower the blood glucose level.
bile
Bile contains bile salts that are derived from cholesterol. These emulsify fats in the small intestine and break them down into smaller fat droplets. This provides a much larger surface area that can be acted on by pancreatic lipase.
functions of the liver (7)
(1) detoxifies blood by removing and metabolizing poisonous substances
(2) stores iron (Fe2+) and vitamins A, D, E, K, and B12
(3) makes many plasma proteins, such as albumins and fibrinogen, from amino acids
(4) stores glucose and glycogen after a meal, and breaks down glycogen to glucose to maintain glucose concentration of blood between eating periods
(5) produces urea after breaking down amino acids
(6) removes bilirubin, a breakdown product of hemoglobin, from the blood and excretes it in bile, a liver product
(7) helps regulate blood cholesterol level, converting some to bile salts
How is the small intestine specialized for digestion and absorption (2; expand on the second specialization)
The basic condition in the small intestine is optimal for digestive enzymes that are present from pancreatic juice or from secretions of the intestinal wall. These complete the process of food digestion. The surface area is especially large for effective absorption of nutrients. The walls contain fingerlike projections called villi. Each villus has an outer layer of columnar epithelial cells that have thousands of microscopic extensions called microvilli. Microvilli greatly increase the surface area of the villus for absorption of nutrients. Each villus also contains blood capillaries and small lymphatic capillary, called a lacteal. Nutrients are absorbed into these vessels.
describe the functions of E. Coli on the colon
E. Coli produces vitamin K and prevent pathogenic bacteria from colonizing the intestine.
