Nutrition Chapter 3

Active absorption (active transport)
requires energy and work; movement of molecules across a cell membrane from a region of their lower concentration to their higher concentration in the direction against some gradient; nutrients move from low to high concentrations with the help of the carrier protein, energy is required;energy input to move nutrients from lumen of the small intestine into the absorptive cells; makes it possible for cells to take up nutrients when they are consumed in low concentrations
Passive diffusion
does not require energy and work; diffusion across a cell membrane; nutrients move from high concentration to low concentration, no energy required; when the nutrient concentration is high in the lumen of the small intestine than in the absorptive cells, the difference in nutrient concentration drives the nutrient into the absorptive cells by diffusion. fats, water and some minerals are examples of nutrients that move down a concentration gradient to be absorbed by passive diffusion
Faciliated diffusion
passive transport that uses integral membrane proteins to help larger molecules cross the concentration gradient; nutrients move from high to low concentration with the help of a carrier protein; no energy required ; some compounds require a carrier protein to follow a concentration gradient into absorptive cells. this type of absorption is called facilitated diffusion. fructose is one example of a compound that makes use of such a carrier to allow for facilitated diffusion; some compounds require a carrier protein to follow a concentration gradient into absorptive cells. fructose is one example of a compound that makes use of such a carrier
Phagocytosis
process in which a cell forms an indentation, and particles or fluids enter the indentation and are engulfed by the cell; ex: infant absorbs immune substances from human milk
DNA
deoxyribonucleic acid: the site of hereditary information in cells; DNA directs the synthesis of cell proteins
Pepsin
chemical in stomach that breaks down food; enzyme that breaks down proteins into smaller peptides; produced in stomach and is one of the main digestive enzymes in the digestive systems that helps digest the proteins in food
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Mucus
A thick fluid secreted by many cells throughout the body. It contains a compound that has both carbohydrate and protein parts . It acts as a lubricant and means of protection for cells
Bicarbonate
produced in pancreas and small intestine; neutralizes stomach acid when it reaches the small intestine
Acid
produced in the stomach; promotes digestion of protein, destroys pathogens, solubilizes some minerals, activates some enzymes
Bile
A liver secretion stored in the gallbladder and released through the common bile duct into the first segment of the small intestine. It’s essential for the digestion and absorption of fat; produced in liver; aids fat digestion in the small intestine by suspending fat in water using bile acids, cholesterol, and lecithin
Sphincter
Ring of smooth muscle between stomach and small intestine
Chyme
A mixture of stomach secretions and partially digested food
Peristalsis
A coordinated muscular contraction used to propel food down the gastrointestinal tract
Villi
The finger like protrusions into the small intestine that participate in digestion and absorption of food
Intrinsic factor
A proteinlike compound produced by the stomach that enhances vitamin B-12 absorption; produced in stomach; facilitates absorption of vitamin B-12 in the small intestine
Digestion
process by which large ingested molecules are mechanically and chemically broken down to produce basic nutrients that can be absorbed across the wall of the GI tract
Absorption
the process by which substances are taken up from the GI tract and enter the bloodstream or the lymph
Hepatic Portal vein
blood leaves the small intestine and travels via a portal vein; the large vein leaving the intestine and stomach and connecting to the liver
Hepatic Portal circulation
the portion of the circulatory system that uses a large vein (portal vein) to carry nutrient-rich blood from capillaries in the intestines and portions of the stomach to the liver
Lymphatic system as it relates to digestion
a system of vessels and lymph that accepts fluid surrounding cells and large particles, such as products of fat absorption. Lymph eventually passes into the bloodstream from the lymphatic system (similar to blood); only white blood cells; its flow is driven by muscle contractions arising from normal body movements; these vessels pick up and transport the majority of products of fat digestion and fat absorption. they are emptied into the bloodstream only after passing through the lymphatic system (GI tract)
GI tract
gastrointestinal (GI) tract: the main sites in the body used for digestion and absorption of nutrients. it consists of the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. also called the digestive tract
Nutrigenomics/ nutrigenetics
Study of the effects of genes on nutritional health such as variations in nutrient requirements and responsiveness to dietary modifications
What are the parts of the cell and what do they do
organelles, cell (plasma) membrane, cytoplasm, mitochondria, cell nucleus, endoplasmic reticulum (ER), golgi complex, lysosomes, peroxisomes
organelles
compartments, particles, or filaments that perform specialised functions within a cell
cell (plasma) membrane
separates inside of cell to outside; it holds the cellular contents together and regulates the flow of substances into and out of the cell; cell to cell communication occurs by way of it; it’s a lipid bilayer of phospholipids; the cholesterol within the membrane is fat soluble and provides rigidity and stability for the membrane; the proteins within provide structural support and function as enzymes that affect chemical processes within the membrane
what are the 6 separate organs of the digestive system?
mouth and salivary glands; esophagus; stomach; liver; gallbladder; pancreas; small and large intestine
cytoplasm
combination of fluid material and organelles within the cell, not including the nucleus; provides small amounts of energy for the cell to use; it’s the sole source of energy production in red blood cells (energy: anaerobic metabolism: doesn’t require oxygen); metabolism of energy production begins in the cytoplasm with the initial anaerobic breakdown of glucose
Mitochondria
powerhouse of the cell; convert the food energy to a form of energy the cells can sue; aerobic process that uses the oxygen inhaled; all cells contain mitochondria except for red blood cells
Cell Nucleus
except red blood cells, all cells have one or more nuclei; contains genetic material responsible for controlling actions that occur in the cell; genetic material includes chromosomes, with genes (DNA); RNA: messenger molecule
Ribosomes
protein-synthesising sites (allow for gene expression)
Endoplasmic reticulum (ER)
an organelle composed of a network of canals running through the cytoplasm. part of the endoplasmic reticulum contains ribosomes: RNA code is translated into proteins during protein synthesis; involves lipid synthesis, detoxification of toxic substances, and calcium storage and release in the cell
Golgi complex
the cell organelle near the nucleus that processes newly synthesised protein for secretion or distribution to other organelles; ; packaging site (secretory vesicles) for proteins used in the cytoplasm or exported from the cell
Lysosomes
a cellular organelles that contains digestive enzymes for use inside the cell for turnover of cell parts; cell’s digestive system; sacs that contain enzymes for the digestion of foregone material
peroxisomes
a cell organelle that destroys toxic products within the cell
What are the types of nutrient absorption
passive diffusion; facilitated diffusion; active transport; phagocytosis, pinocytosis, endocytosis
Digestion (organs and their function including accessory organs, roles of various enzymes and where secrete from)
digestive system consists of the mouth, esophagus, stomach, intestines, GI tract and accessory structures/ organs (liver, gallbladder, and pancreas); it performs the mechanical and chemical processes of digestion of food, absorption of nutrients, and elimination of wastes; assists the immune system by destroying some pathogens and forming a barrier against foreign materials; first you chew food and have muscular contractions and move through the long GI tract; chemicals breakdown foods by acid and enzymes secrete it into the GI tract; as food moves along the GI tract, nutrients are absorbed and the waste products re at the large intestine. the bacteria that live in the large intestine produce some vitamins that can be absorbed . lastly waste is eliminated. under autonomic control: involuntary
Common digestive problems
chest pain: gastroesophagel reflux disease; gallstones; celiac disease; crohn’s disease;irritable bowel syndrome; haemorrhoids
What percentage of americans are overweight or obese?
68.8%
what is the body mass index for BMI 18.5-24.9
healthy weight
what is the body mass index for BMI 25-29.9
overweight
what is the body mass index for BMI >30
obese
what is the name of the study that looked at all aspects of children’s health, including weight and showed evidence that cardiovascular disease starts in childhood?
Bogalusa heart study
When obese children reach adulthood, they are ___ times more likely to develop high blood pressure than healthy weight children
8
what percent of obese children remain obese as adults
77%
what percent of normal weight children became obese as adults
7%
what fraction of americans maintain a healthy weight
1/3
what are 2 consequences as a result of obesity
diabetes and high blood pressure
subcutaneous fat
fat inside the abdominal wall and organs; which when in excess is no longer advantageous for health
Cells need building supplies; where does it get it from?
proteins and minerals
Cells need chemical regulators; where does it get it from?
vitamins
All cells are derived from?
preexisting cells
the cell membrane consists of?
double layers of lipid, cholesterol, carbohydrate, and protein
what is cholesterol’s role in the cell membrane
stability
what is protein’s role in the cell membrane?
structure, transport, enzymes; act as transport vehicles and function as enzymes that facilitate chemical processes
what is carbohydrate with fat or proteins role in the cell membrane?
signaling, identification markers and cell defence
what is the cell membranes main function?
to hold the cell together, regulate traffic, and cell to cell communication
what are the 4 types of tissues?
epithelial (cover surfaces and absorb and secrete important substances and excrete waste), connective (supports and protects body; stores fat, produces blood cells), muscle (movement), and nervous (bran, spinal cord, communication)
what are nutritional diseases with a genetic link?
cardiovascular disease, obesity, diabetes, cancer
predict how nutritional genomics will affect nutrition recommendations in the future
genetic testing for disease susceptibility will be more common in the future as genes that increase risk of developing various diseases are isolated and decoded