Chapter 3: Digestion and Absorption Flashcards
Absorption
The movement nutrients into or across tissues; particularly, the passage of nutrients and different substances into the walls of the GI tract then into the blood
Active Transport
The movement of compounds into or out of cells against their respective concentration gradient. This transport needs energy (ATP) and involves carrier (transport) proteins within the plasma membrane
Amylase
A secreted salivary catalyst that catalyzes the reaction of amylose, a starch. additionally referred to as ptyalin
Autonomic nervous system
division of the central system that regulates the automated responses of the body; consists of the sympathetic and parasympathetic systems
Bile
an alkalescent, yellow-green fluid that is made in the liver and stored long-term within the gallbladder. the first constituents of bile are bile salts, bile acids, phospholipids, cholesterol, and bicarbonate. bile efficiently emulsifies dietary fats, aiding fat digestion and absorption
Bolus
A chewed, moistened lump of food that’s able to be swallowed and digested
Catalyze
to speed up a chemical process
Cecum
blind pouch at the start of the large intestine into which the small intestine opens from one facet and that is continuous with the colon
Central nervous system (CNS)
The brain and the spinal cord. The central nervous system transmits signals that act to control muscular actions and glandular secretions along the entire GI tract
Cephalic phase Response
The responses of the parasympathetic nervous system to the sight, smell, thought, and sound of food. additionally referred to as preabsorptive phase responses
Cholecystokinin (CCK)
A hormone created by cells within the bowel that stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder
Chyme
A mass of partly digestible food and digestive juices moving from the stomach into the small intestine
Circular Muscle
Layers of smooth muscle that surround organs, together with the stomach and the small intestine
Colon
The portion of the large bowel extending from the caecum to the rectum. it’s made up of four parts- the ascending, transverse, descending, and sigmoid colons. though usually used interchangeably with the term large intestine, these terms aren’t synonymous
Concentration Gradients
between the solute concentrations of 2 substances
Constipation
occasional and troublesome bowel movements, followed by a sensation of incomplete evacuation
Diarrhea
Watery stools because of reduced absorption of water
Digestion
the process of transforming the foods we ingest into units for absorption
Duodenum
The portion of the small bowel closest to the stomach. The small bowel is ten to twelve inches long and wider than the rest of the small intestine
Emulsifiers
Agents that mix fatty and watery liquids by promoting the breakup of fat into little particles and stabilising their suspension in an aqueous solution
Endocytosis
The uptake of material by a cell be the indentation and pinching off of its membrane to make a vesicle that carries material into the cell
Enteric nervous system
A network of nerves located within the gastrointestinal wall
Enzymes
large proteins within the body that accelerate the speed of chemical reactions but aren’t altered in the chemical process
Esophageal sphincter
The gap between the esophagus and the stomach that relaxes and opens to permit the bolus to travel into the stomach, and so closes behind it. additionally acts as a barrier to stop the reflux of stomachal contents. normally known as the cardiac sphincter
Esophagus
The food pipe that extends from the pharynx to the stomach, about twenty five centimeters long
Facilitated Diffusion
A method by which carrier (transport) proteins within the cell wall transport substances into or out of cells down a chemical concentration gradient
Flatus
Lower intestinal gas that’s expelled through the rectum
Gallbladder
A pear-shaped sac that stores and concentrates digestive fluid from the liver