Vitamins and Minerals
What are the water soluble vitamins?
C & B vitamins
define Calories and kCal
Calorie (C) – measure of heat
1. One calorie is amount of heat required to raise temperature of one gram water by one
degree Celsius
C. Kilocalorie – actual unit of calorie used to measure human diet
1. One kilocalorie is amount of heat required to raise temperature of one kilogram of water
by one degree Celsius
what are the two types of salivary glands and what do they secrete?
Two main types of acinar cells in salivary glands:
1. Serous cells secrete a water-based fluid with enzymes and other solutes
a. Generally released just before or during eating
2. Mucous cells secrete mucus; primarily involved in keeping oral mucosa moist
a. Released continually
what is segmentation and peristalsis?
Peristalsis is accomplished by alternating contractions of longitudinal and circular
layers of smooth muscle in muscularis externa
a. Primary function is to propel chyme toward ileum and ultimately through
ileocecal valve to cecum
2. Segmentation, also known as intestinal churning, involves contractions of only
circular layer of smooth muscle
a. Produces a squeezing motion
b. Primary functions are mechanical digestion and mixing chyme with intestinal
and pancreatic enzymes as well as bile
What is the range of normal temperature?
5.8 to 38.2 °C (96–101°F) with an average of 37.5 °C (99.5 °F); reflects core body temperature
What are the fat soluble vitamins?
A,D,K,E
Define metabolism
What are the two factors in metabolism?
catabolism and anabolism
What substances are found in saliva? Function?
IgA, lysozyme
Consists primarily of water; electrolytes such as sodium, chloride, and potassium
ions; and variable amounts of mucus
Salivary amylase – first digestive enzyme that ingested food encounters;
catalyzes beginning of carbohydrate digestion
keeps the mouth moist and destroys bacteria
What is bile? Emulsification?
Bile: a liquid that contains multiple components, including water, electrolytes,
and organic compounds
2. Bile serves two critical functions
a. Required for digestion and absorption of lipids
b. Mechanism by which liver excretes wastes and other substances that kidneys cannot excrete
emulsification is used to take large fat droplets and convert them into smaller ones.
What factors have to be maintained to measure BMR (Basal Metabolic Rate)?
a. Person has not eaten for past 12 hours and has had a restful night of sleep
b. Person is not performing physical activity and has not performed strenuous
physical activity for at least 1 hour
c. Person is not under physical or emotional stress
d. Temperature surrounding person is constant and comfortable
Which vitamin is produced by the bacteria in the large intestine?
Vitamin K
What are the organs of the alimentary canal? What are the accessory organs?
Alimentary canal – continuous tube through which food passes directly
1. Consists of oral cavity (mouth), pharynx, esophagus, stomach, small intestine, and
large intestine
C. Accessory organs – not part of alimentary canal but assist in digestion in some way
1. Include teeth, tongue, salivary glands, liver, gallbladder, and pancreas
2. Food generally does not come into direct contact with accessory organs, although
teeth and tongue are exceptions
What are the two parts of the pharynx that is used in digestion and what are the three phases of swallowing?
Consists of three phases
1. Voluntary phase: tongue pushes bolus toward oropharynx
2. Pharyngeal phase: bolus enters oropharynx; soft palate and epiglottis seals off
nasopharynx and larynx
3. Esophageal phase: peristaltic waves move bolus down esophagus
What are fats coated with to keep them emulsified? How do lipids travel in the body?
micelles. Chylomicrons through a lacteal lymphatic vessel
Define BMR
minimal rate of metabolism for an awake individual
or “energy cost of living”
What are the four macromolecules that we get from the body?
carbs, nucleic acids, proteins, fats
define mastication, deglutition and bolus
chew, swallow, and food mixed with saliva
describe the four types of cells in the stomach
Four cell types in gastric glands
1. Enteroendocrine cells secrete hormones that influence digestion
a. Gastrin stimulates acid secretion
2. Chief cells secrete pepsinogen
a. When pepsinogen encounters an acidic pH, it becomes pepsin
1. Begins protein digestion in stomach
3. Parietal cells secrete hydrochloric acid (HCl)
a. Responsible for acidic pH of gastric juice
b. Acid activates pepsinogen, destroys many disease-causing organisms, and
stimulates parietal cell production of chemical intrinsic factor; required for
intestinal absorption of vitamin B12
4. Mucous neck cells secrete acidic mucus
a. Prevents neutralization of acid produced by parietal cells
What is ingestion?
Ingestion: bring food and water into digestive system
What hormones control satiety and hunger?
Hunger: Grehlin and glucagon (neuropeptide Y and orexin)
Satiety: leptin, insulin and CCK
These are the nutrients that we get from our diet and the body doesn't make them?
essential nutrients
What is the nervous system that controls the digestive system?
ENS (Enteric nervous system)
what are the three types of motility of the stomach?
Receptive function – when food or liquid is swallowed, gastroesophageal sphincter
and smooth muscle of fundus and body of stomach relax to allow stomach to fill, a
process known as receptive relaxation
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2. Churning function – after a meal, smooth muscle layers of stomach begin to produce
waves of peristalsis
a. Peristalsis propels bolus to pylorus, where small amounts of chyme are
propelled through pyloric sphincter into duodenum
b. Remainder of chyme is pushed backward into stomach where peristaltic
waves churn and mix chyme, and process repeats
3. Emptying function –control movement of chyme into duodenum; different materials
pass through pyloric sphincter at different rates
a. Liquids move rapidly from stomach to duodenum with essentially no delay
b. Solids must be converted to a nearly liquid state before they are able to enter
small intestine
c. Control of gastric emptying is critical because duodenum must mix incoming
chyme thoroughly before it moves to rest of small intestine; two reasons
1. Chyme is acidic, and duodenum must mix it with bicarbonate ions to
avoid damaging intestinal mucosa
2. Chyme is generally very concentrated and must be diluted with water
from pancreatic juice to prevent chyme from drawing water into
intestinal lumen by osmosis
What substances are secreted in the digestive system?
What is digestion?
Digestion: To breakdown
mucus, enzymes, saliva, acid and hormones
Compare the absorptive and postabsorptive states
absorptive:
Oxidation of nutrient molecules, primarily glucose, provides fuel to cells
2. Glyconeogenesis stores excess glucose in skeletal muscle and
hepatocytes
3. Lipogenesis stores triglycerides in adipocytes and hepatocytes
4. Protein synthesis provides structural materials for cells
c. Pancreatic hormone insulin orchestrates many of absorptive state processes
Post absorptive:
Breakdown of proteins in muscle cells releases glucogenic amino acids
into blood
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2. Ketogenesis in hepatocytes converts fatty acids to ketone bodies and
releases them into blood
3. Gluconeogenesis and glycogenolysis in hepatocytes release glucose into
blood
4. Lipolysis in adipocytes releases fatty acids into blood
5. Oxidation of molecules such as fatty acids provides most cells with fuel
a. Glucose sparing – phenomenon in which cells catabolized newly
delivered fatty acids preferentially in order to conserve glucose for
cells of nervous system
b. Non-nervous system cells can also use ketone bodies and amino acids for fuel (controlled by glucagon)