Nutrition 400 Module 2 Exam

Nutritional Sciences

Organization of the Human Body

Organization of the Human Body

1.) Chemical Level

2.) Cell Level

3.) Tissue Level

4.) Organ Level

5.) Organ system level

6.) Organism level

Atom (chemical level)

the smallest portion of which an element can be divided into and still retain properties

protons (+) and neutrons (neutral) make up the middle of the atom while electrons (-) are in the valence shell

Valence shell

first two orbit has 2 valence shells, then every other orbit trys to get 8 electrons to fill the valence shell

Molecule

two or more atoms joined by chemical bonds

example: H2O (water)

complex molecule

Large molecules made up of subunits

example: glycogen

Molucular formulas

# of atoms = small numbers after a atom

# of molecules = big number before the molecules

element

a pure substance made up of only one type of atom

periodic table of elements

6 elements that account for 99% of body weight in humans

• oxygen (O), 65% body weight, found in water

• carbon (C) 18% body weight, found in organic molecules

• hydrogen (H), 10% body weight, found in most molecules, including water

• nitrogen (N), 3% body weight, component of proteins

• calcium (Ca), 2% body weight, component of bones, teeth, and body fluids

• phosphorus (P), 1% body weight, found in cell membranes and bone matrix

Ions

atoms that have lost or gained an electron (NOT PROTONS)

Cation

net positive charge, due to LOSS of electrons

Anion

Net negative charge, due to GAIN of electrons

Formation of Cations

loss of electrons = cation formation

Formation of anion

gain of electron = anion formation

electron transfer

• atoms share electrons

• octet rule

  • most atoms prefer 8 electrons in valence shell

• losing/ gaining electrons stabilizes the valence shell

Oxidation reactions

when molecule A transfers its electrons to molecule B, molecule A is oxidized

Oxidation is loss of electrons

reduction reactions

when molecule B receives electrons from molecule A, Molecule B is reduced.

reduction is gain of electrons

free radicals

• free radicals molecules have unpaired electrons, making them unstable and reactive

• in a normal molecules, all electrons are paired

• the free radical steals an electron from another molecule to stabilize itself

• the molecule that lost its electrons has been oxidized creating a new free radical

• this creates a chain reaction; the newly formed free radical oxidizes another molecule by stealing an electron from it

Antioxidants

protective effect: can interrupt the free radical cascade

antioxidants can donate an electron without becoming unstable and reactive

Nutrients with antioxidant functions

• water-soluble vitamins

  • vitamin C, is an electron donor and functions as a water-soluble antioxidant

  • riboflavin, is part of an essential coenzyme that is required by an enzyme that has an antioxidant function and is particularly important in red blood cells

• fat-soluble vitamins

  • vitamin E, neutralizes free radicals by donating an electron

• trace minerals

  • copper, zinc, manganese, and selenium function as essential components of enzymes that are involved in important antioxidant defense mechanisms that neutralize free radicals

• phytochemical

  • beta-carotene and other phytochemical may provide health benefits by their ability to function as antioxidants in our body

chemical bonds

• the transfer or sharing of electrons

• atoms → molecules

• examples

  • ionic: cations and anions attract each other

  • covalent: sharing of electrons

  • hydrogen: weak

Ionic bond

cations (purple) and anions (green) attract each other like in salt (NaCl)

covalent bond

atoms share electrons like in water (H2O)

nonpolar covalent bonds

equal sharing

polar covalent bonds

unequal sharing (+ and - fighting)

Hydrophilic

• polar

• dissolves in water

hydrophobic

• nonpolar

• do not dissolve in water

• think phobic (phobia to water)

Condensation reactions

• MAKE REACTION

result in the formation of a chemical bond that joins molecules together. when a condensation reaction occurs, a molecule of water is released

Hydrolysis reaction

• BREAK REACTION

break chemical bonds by the addition of a molecule of water

pH scale

acidic: <7

neutral: = 7

basic/ alkaline: >7

buffering system

• buffer: resists changes in pH

• found in: blood, kidneys, lungs

• prevents acidosis/ alkalosis

  • acidosis: high acid

    • mild: headache, loss of appetite

    • starvation

    • diabetes

  • alkalosis: high base

    • excessive vomiting

    • overuse of diuretics/ laxatives

    • hyperventilating

Homostasis

• state of balance or equilibrium

• controlled by nervous & endocrine systems

• examples

  • regulation of blood glucose levels by two major hormones; insulin and glucagon

the cell organelles

cell membrane, smooth ER, rough ER, lysosome, cytoplasm, nucleus, mitochondria

cell membrane

cells are surrounded by a membrane that provides a protective boundary between intracellular and extracellular environments

smooth er

involved in lipid synthesis

do not have ribosomes therefore not involved in protein synthesis

rough er

contain ribosomes which build and process proteins

lysosome

contain digestive enzymes that breakdown proteins, lipids and nucleic acids

removes and recycles waste products

cytoplasm

gel-like substance inside cells that conatin the organelles, proteins, electrolytes, and other molecules

nucleus

contains the DNA which provided coded instructions for protein synthesis

mitochondria

produces most of the energy (ATP) of the cells

passive transport mechanisms

simple diffusion

facilitated diffusion

osmosis

active transport mechanisms

carrier-mediated active transport

exocytosis & endocytosis

exocytosis

cells move materials from within the cell into the extracellular fluid. Exocytosis occurs when a vesicle fuses with the plasma membrane, allowing its contents to be released outside the cell.

endocytosis

the process by which cells internalize substances from their external environment. It is how cells get the nutrients they need to grow and develop. Substances internalized by endocytosis include fluids, electrolytes, proteins, and other macromolecules.

humans 4 primary tissue types

epithelial tissue

connective tissue

neutral tissue

muscle tissue

epithelial tissue

covers and lines body surfaces, organs, and cavities

connective tissue

provided structure to the body by binding and anchoring body parts

neutral tissue

plays a role in communication by receiving and responding to stimuli

muscle tissue

contracts and shortens when stimulated, playing an important role in movement

Digestive system

• major organs and structures

  • mouth, esophagus, stomach, small intestine, large intestine, liver, gallbladder, pancreas, and salivary glands

• major function

  • governs the physical and chemical breakdown of food into a form that can be absorbed into the circulatory system. eliminates solid wastes

• includes organs of gastrointestinal tract, accessory organs

ingestion

food is taken into the body

digestion

food is mechanically and chemically broken down into absorbable units

absorption

substance are taken up from the gastrointestinal tract into the body

excretion

undigested material in our diet and other waste products are eliminated from the body

organs of the GI tract

mouth, esophagus, stomach, small intestine, and large intestine

mouth

in chewing mixes food with saliva and begins mechanical digestion

esophagus

carries food from the mouth to the stomach

stomach

adds acids, enzymes, and gastric juices to food, while grinding it into a semiliquid

• major site for mechanical digestion

small intestine

breaks down nutrients by using enzymes produced by the small intestine and pancreas; nutrients are absorbed into blood and lymph

• primary site for digestion of food and absorption of nutrients

large intestine

absorbs water and some minerals and vitamins and passes waste material to its lower portion, the rectum, for excretion

four tissue layers in the GI tract

• serosa

• muscularis

  • circular muscle

  • longitudinal muscle

• submucosa

• mucosa

• lumen

accessory organs and their functions

secrete fluids that aid in digestion

• salivary glands

  • secretes saliva that moistens and lubricates food and contains two digestive enzymes

• liver

  • produces bile that is required for lipid digestion and absorption

• gallbladder

  • stores bile produced in the liver until released into the small intestine

• pancreas

  • produces enzymes to digest energy-providing nutrients and released bicarbonate to neutralize stomach acid

Sphincters

regulate the flow of food

• the gastroesophageal sphincter, located between the esophagus and the stomach, relaxes briefly to allow food to enter the stomach

• after the food passes into the stomach, the gastroesophageal sphincter closes to prevent the stomach contents from re-entering the esophagus

where does food, bolus, chyme, waste take place

• food

  • in the mouth

• bolus

  • esophagus

• chyme

  • stomach, small intestine

• waste

  • large intestine

mechanical digestion

physical break down of food

• mastication

  • grinding of food into smaller pieces by the teeth

• peristalsis: propulsion

  • rhythmic waves of contractions that move the food particles through the various regions in which mechanical and chemical digestion take place

• segmentation: mixing

  • localized contractions of circular muscle of the GI tract

chemical digestion

breaks chemical bonds to cleave large molecules into smaller ones

involves enzymes and other substances

• enzymes chemically breakdown components of food

  • found throughout our GI tract

  • suffix -ase (usually used)

• saliva is part of chemical digestion

cephalic phase

early signaling prepares the GI tract for digestion

“wake up” call

gastroesophageal reflux disease (GERD)

happens when gastroesophageal sphincter weakens, the stomach contents flow back into the esophagus. the reflux of stomach contents into the esophagus is called gastro-esophageal reflux disease

peptic ulcers

occur when aicd in the digestive tract east away at the inner surface of the stomach or small intestine. the acid can create a painful open sore that may bleed

pancreas

• is an accessory organ

• pancreatic juice

  • is an alkaline solution that neutralizes the acidic chyme as it enters the duodenum.

  • also contains enzymes that aid in the digestion of carbohydrates, proteins ,and lipids

Liver and gallbladder

1.) once bile is made by the liver, some of its transported to the gallbladder where it can be stored for later release

2.) when the gallbladder contacts, bile is released into the cystic duct. the cystic duct joins the common bile duct

3.) bile acids in lipid digestion by enabling large lipid globules to disperse in the watery environment of the small intestine

4.) after aiding in lipid digestion, the bile constituents are reabsorbed from the ileum and returned to the liver via the hepatic portal vein

5.) the liver uses these constituents to resynthesizes bile

villi of the small intestine

increases the surface area for food absorption and adding digestive secretions

microvilli of the small intestine

absorbs nutrients and protects the body from intestinal bacteria

celiac disease

• autoimmune disease

• inflammatory response to gluten

  • wheat, rye, barley

• villi damaged; poor nutrient absorption

delivering nutrients to the body via circulatory and lymphatic system

• circulatory system (blood vessels)

  • carbohydrates

  • amino acids

  • minerals

  • water-soluble vitamins

• lymphatic system

  • mosts fats some vitamins

gut microbiome

• benefits

  • retrieves some energy from undigested carbohydrates

  • improves health of mucosa in the gut

  • promotes immune system health

  • enhances mineral absorption

  • synthesizes vitamin K, folate, biotin

  • displaces pathogenic (bad) bacteria

  • reduces cancer risk

• probiotics and prebiotics

inflammatory bowel disease (IBD)

• chronic autoimmune disease

• causes inflammation which can permanently harm the intestines

• examples

  • ulcerative colitis

  • chron’s disease

irritable bowel syndrome

• group of symptoms including abdominal pain, bloating, diarrhea, and other discomfort

• function disorder → does not lead to serious disease

• does not cause inflammation

• effects up to 20% of adults in the US

carbohydrates

main source of energy for the body (4 kcal/g)

• composition

  • carbon (C), hydrogen (H) and oxygen (O)

  • composed of one or more sugar (saccharide) units

• functions in food

  • source of fiber

  • adds sweetness and flavor

• found sources

  • starches and grains

  • fruit

  • dairy

  • sweets/ desserts

• functions in the body

  • source of energy for all cells in the body

  • indispensable source of energy for the brain, red blood cells, and muscles during intense exercise

  • important for intestinal health

  • reduces the use of protein for energy

simple carbohydrates

• Monosaccharides (1 sugar unit)

  • glucose

    • circulates in the blood stream. its found in fruits, vegetables, and honey

  • frutose

    • found in fruits vegetables, and honey

  • galactose

  • one of the monosaccharides that make up milk sugar

• disaccharides (2 sugar units)

  • lactose

    • often called “milk sugar” as it is found in onlu milk, yogurt, and other dairy products

  • sucrose

    • otherwise known as “table sugar” it is found in fruits and vegetables

  • maltose

    • formed in large amounts as a product of starch digestion; however very little is found in the foods we eat

complex carbohydrates

• oligosaccharides (3-10 sugar units)

  • raffinose

  • stachyose

• polysaccharides (>10 sugar units)

  • glycogen (digestible polysaccharides)

    • major storage form of carbohydrate in animals

    • found in liver, muscle

    • structure

      • highly branched

      • readily available sites for enzyme action

  • starch (digestible polysaccharides)

    • major storage form of carbohydrate in plants

    • 2 types of plant starch:

      • amylose: is a straight chain polymer

      • amylopectin: is branched

  • dietary fiber (indigestible polysaccharides)

    • diverse group of polysaccharides found in plants (within the cell wall)

    • may be straight chains of glucose or branched chains composed of a variety of sugars

    • abundant in legumes, nuts, whole grains, vegetables, and some berries

potential health benefits of dietary fiber (indigestible polysaccharides)

• soluble fiber

  • low CVD risk

  • promotes satiety and low obesity risk

  • slows BG rise following CHO ingestion

• insoluble fiber

  • low risk of Type 2 diabetes

  • low constipation occurrence

• high fiber intake may lower risk of some cancers

diverticular disease

• results when small, protruding pouches called diverticula form along the wall of the large intestine

• characterized by the formation of out pouching along ten wall of the large intestine

• high fiber diet and active lifestyle has protective effect

anatomy of a whole grain

• endosperm contains the highest amount of starch and protein and its all that remains when a grain is refined

• bran contains the majority of dietary fiber and a significant amount of B vitamins and minerals

• germ the embryo of the seed that germinates and grows and contains essential fatty acids and a number of B vitamins and minerals

• GERM AND BRAN

  • vast majority of vitamins and minerals and phytochemical are found in the germ and bran

  • germ and bran are removed when processing wheat to produce refined grains

fortification

• nutrients are:

  • absent originally

  • added to prevent deficiencies in a community

enriched

• nutrients are:

  • present originally

    • lost during processing

  • put back in! to maintain nutrient profile

• 5 nutrients in the U.S. requires to be added back in after processing is:

  • iron

  • thiamin

  • riboflavin

  • niacin

  • folate

how much carbohydrates do we need?

• 2020 dietary guidelines for Americans

  • consume at least half of all grains as whole grains. increase whole grain intake by replacing refined grains with whole grains

• health and medicine division recommendations (DRIs)

  • RDA: 130 g/day

  • AMDR: 45%-65% of total calories

    • 2,000 kcal/day diet: 225-325 g/day

    • 2,500 kcal/day diet: 281-406 g/day

added sugars in the diet

goal: <10am % total kcals

low carbohydrates diets

• < 100 g CHO/ day

• unlimited meats, high-fat foods

• low glycogen synthesis

  • water & body protein loss

• short-term vs long-term effects

carbohydrate digestion

dietary carbohydrates (salivary amylase) → polysaccharides, dextrins, sucrose, lactose, maltose (pancreatic amylase) → → monosaccharides: glucose, galactose, fructose (active transport) → monosaccharides in blood stream

digestion of carbs in the mouth

• mastication

• salivary amylase

  • acts on alpha -(1,4) linkages

activity in the stomach for carbohydrates

• salivary amylase in inactivated by gastric acid

• starch chemical digestion stops

digestion in the small intestine for carbohydrates

polysaccharides (pancreatic amylase) → disaccharides (disaccharidases) → monosaccharides

• the digestion of disaccharides takes place on the surface of the brush border of the small intestine

• intestinal disaccharidases hydrolyze disaccharides. the resulting monosaccharides are transported into enterocytes

absorption in the small intestine for carbohydrates

glucose absorption occurs in the small intestine by active transport via the sodium glucose co transporter. galactose, fructose and some glucose absorption is completed by the Glut5 transporter by facilitated diffusion

lactose intolerance

cause: lactose deficiency

symptoms: nausea, bloating, abnormal discomfort, diarrhea

treatment:

• lactose dairy products or lactase pills

• add calcium and vitamin D rich foods or supplements

3 fates of glucose

• immediate energy source for all cells

• concerted into glycogen (glycogenesis)

  • limited source of stored carbohydrate in the liver

• converted into fat

  • adipose tissue (unlimited storage capacity)

insulin

regulates glucose uptake from the blood

glucagon

regulates release of glucose into the blood

lipid basics

• supply energy (9 kcal/g)

• C, H, O

• oils vs fats

• water insoluble (non polar = hydrophic

• diverse function and structure

  • energy, insulation, fat soluble, vitamins, cell membranes, essential fatty acids, satiety & palatability

• types of lipids

  • fatty acids

  • triglycerides

  • sterols

  • phospholipids

fatty acids

• carbon chain with hydrogen atoms attached

• methyl (CH3) & carboxylic acid (COOH) groups

• differ in chain length and saturation

  • determines their function and role in health and disease

• chain length

  • short chain < 8 carbons

  • medium chain = 8-12 carbons

  • long chain > 12 carbons

• degree of saturation

  • no double bonds (saturated)

    • solid at room temp

  • one double bond (unsaturated)

    • liquid at room temp

  • 2 or more double bonds (unsaturated)

    • liquid at room temp

essential fatty acids

omega 3- fatty acids (Linoleic acid)

omega-6 fatty acid (Linoleic acid)