Nutrition Final Exam

What is night blindness?

A vitamin A deficiency disorder that results in loss of the ability to see in dim light

Is consuming too much beta carotene from the diet harmful?

Consuming large amounts of beta-carotene or other carotenoids in foods does not appear to cause toxic symptoms

Explain how free radicals form, why they are a health concern, and how antioxidants oppose them

Free radicals are a highly unstable atom with an unpaired electron in its outermost shell, or the molecule in which such an atom occurs. Free radicals commonly form during energy metabolism. As cells use oxygen and hydrogen to generate ATP, single electrons are sometimes released. Occasionally, oxygen accepts one of these single electrons. When it does so, the newly unstable oxygen atom becomes a free radical. Free radicals are also formed during other metabolic processes, such as when our immune system produces inflammation to fight allergens or infections. Other factors that cause free-radical formation include exposure to pollution, ultraviolet (UV) rays from the sun, other types of radiation, tobacco smoke, industrial chemicals, and asbestos. Continual exposure to these factors leads to uncontrollable free-radical formation, cell damage, and disease. Why are we concerned with formation of free radicals? Simply put, it is because of their destabilizing power. If you were to think of paired electrons as a married couple, a free radical would be extremely seductive outsider. Its unpaired electron exerts a powerful attraction toward all stale molecules around it. In an attempt to stabilize itself, a free radical will "steal" an electron from stable compounds, in turn generating more unstable free radicals. This is a dangerous chain reaction, because the free radicals generated can damage or destroy cells. One of the most significant sites of free-radical is the cell membrane. Free radicals that form within the phospholipid bilayer of cell membranes steal electrons from the stable lipid heads. When the lipid heads, which are hydrophobic, are destroyed, they no longer repel water. With the cell membrane's integrity lost, its ability to regulate the movements of fluids and nutrients into and out of the cell is also lost. This loss of cell integrity causes damage to the cell and to all systems affected by the cell. Other sites of free-radical damage include low-density lipoproteins (LDLs), cell proteins, and DNA. Damage to LDLs and cell proteins disrupts the transport of substances into and out of cells and alters cell function, whereas defective DNA results in faulty protein synthesis. Theses changes can also cause harmful changes (mutations) in cells or prompt cells to die prematurely. Free radicals also promote blood-vessel inflammation, which is an early step in the process of atherosclerosis, a risk for cardiovascular disease (CVD). In addition, they promote the formation of blood clots. When this occurs within arteries serving the heart or brain, the individual can experience a heart attack or stroke. Other diseases linked with free-radical production include cancer, type 2 diabetes, arthritis, cataracts, and Alzheimer's and Parkinson's diseases. How does the body fight free radicals and repair the damage they cause? 1. Antioxidant vitamins work independently by donating their electrons or hydrogen atoms to stabilize free radicals 2.Antioxidant minerals including selenium, copper, iron, zinc, and manganese, act as cofactors within complex antioxidant enzyme systems that convert free radicals to less damaging substances that are excreted by the body. They also work to break down fatty acids that have become oxidized, thereby destroying the free radicals associated with them. Antioxidant enzyme systems also make more vitamin antioxidants available to fight other free radicals. The following are examples of antioxidant enzyme systems: -Superoxide dismutase converts superoxide free radicals to less damaging substances such as hydrogen peroxide, which can then be degraded by other enzyme systems -Catalase promoted the elimination of hydrogen peroxide from the body by converting it to water and oxygen -Glutathione peroxidase also promotes the elimination of hydrogen peroxide from the body by reducing it to water and stops the production of free radicals in lipids 3. Phytochemicals such as bet-carotene help stabilize free radicals and prevent damage to cells and tissues In summary, free-radical formation is generally kept safely under control by certain vitamins, minerals working within antioxidant systems, and phytochemicals

Differentiate between heme and nonheme iron

Heme iron: Iron that is a part of hemoglobin and myoglobin; it is found only in animal-based foods, such as meat, fish, and poultry

What is carotenosis/ carotenodermia?

However, your skin can turn yellow or orange if you consume large amounts of foods that are high in beta-carotene. This condition is referred to as carotenosis or carotenodermia, and it appears to be both reversible and harmless

What mineral does vitamin C help enhance the absorption of?

Iron

Risk factors for Osteoporosis

Modifiable Risk Factors: -Smoking -Low body weight -Low calcium intake -Low sun exposure -Alcohol abuse -History of amenorrhea (failure to menstruate) in women with inadequate nutrition -Estrogen deficiency (females) -Testosterone deficiency (males) -Repeated falls -Sedentary lifestyle Non-Modifiable Risk Factors: -Older age (elderly) -Caucasian or Asian race -History of fractures as an adult -Gender (female) -History of amenorrhea (failure to menstruate) in women, with no recognizable cause

What may increase a person's need for vitamin C?

Smoking increases a person's need for vitamin C. Other high-stress situations that may increase the need for vitamin C include healing from a traumatic injury, surgery, or burns, and the use of oral contraceptives among women

Explain the significance of the T-score

T-score: A numerical score comparing an individual's bone density to the average peak bone density of a 30-year-old healthy adult, to determine the risk for osteoporosis -A T-score between +1 and -1 means that the individuals bone density is normal -A T-score between -1 and -2.5 indicates low bone mass and an increased risk for fractures -A T-score more negative than -2.5 indicates that the person has osteroporosis

What is the DASH Diet plan?

The Dietary Approaches to Stop Hypertension diet plan emphasizing fruits and vegetables, whole grains, low/no-fat milk and dairy, and lean meats

What is water intoxication or overhydration?

The dilution of body fluid. It results when water intake or retention is excessive

What happens with vitamin D deficiency?

The primary deficiency associated with inadequate vitamin D is loss of bone mass. Vitamin D deficiencies occur most often in individuals with diseases that cause intestinal malabsorption of fat and thus the fat-soluble vitamins. People with liver disease, kidney disease, Crohn's disease, celiac disease, cystic fibrosis, or Whipple's disease may suffer from vitamin D deficiency and require supplements. Vitamin D deficiency in children, called rickets, results in adequate mineralization (or demineralization) of the skeleton. The classic sign of rocket sis deformity of the skeleton, such as bowed legs and knocked knees. However, severe cases can be fatal. Rickets is not common in the United States because of fortification of milk products with vitamin D, but children with illness that cause fat malabsorption, or who drink no milk and get limited sun exposure, are at increased risk.

How is hypertension diagnosed?

There are no obvious symptoms of hypertension. For this reason, it is important that people get their blood pressure checked on a regular basis.

Map that illustrates the geographic location and impact on vitamin D synthesis

This map illustrates the geographic location of 37° latitude in the United States. In southern cities below 37° ;latitude, such as Los Angeles, Austin, and Miami, the sunlight is strong enough to allow for vitamin D synthesis through the year. In northern cities above 37° latitude, such as Seattle, Chicago, and Boston, the sunlight is too weak from about mid-october to mid-March to allow for adequate vitamin D synthesis

Collagen and vitamin C

Vitamin C is essential for healthy cross-linking of the chains that make up collagen strands

What vitamin does vitamin C help regenerate?

Vitamin E

Osmosis

(a) A filter that is freely permeable to water only is placed in a glass of dilute salt water (b) Additional salt is added to only one side of the glass (c) Drawn by the high concentration of electrolytes, water flows to the "concentrated salt water" side of the filter. This flow of water into the concentrated solution will continue until the concentration of electrolytes on both sides of the membrane is equal

A free radical

(a) Normally, an oxygen atom contains eight electrons (b) Occasionally, oxygen will accept an unpaired electron during the oxidation process. This acceptance of a single electron causes oxygen to become an unstable atom called a free radical

Bone remodeling involves resorption and formation

(a) Osteoclasts erode the bone surface by degrading its components, including calcium, other minerals, and collagen; these components are then transported to the bloodstream (b) Osteoblasts work to build new bone by filling the pit formed by the resorption process with new bone

Bioavailability depends on:

-Individual's age and calcium need -Dietary calcium and vitamin D -Binding factors (phytates, oxalates) in foods

Common food sources of calcium

-Yogurt, plain, nonfat - 8 oz: 450mg -Yogurt, fruit-flavored, low-fat - 8 oz: 330mg -Sardines, canned - 3 oz: 325mg -Milk, nonfat - 8 fl oz: 320mg -Cheese, ricotta, 2% fat - 4 oz: 315mg -Collard greens, cooked - 1 cup: 275mg -Cheese, Swiss - 1 oz: 225mg -Chinese cabbage, cooked - 1 cup: 160mg -Tofu, soft, fortified - 4 oz: 125mg -Kale, cooked - 1 cup: 90mg The RDA for calcium is 1,000 mg of calcium per day for men and women aged 19 to 50

What is hypertension?

A chronic condition characterized by blood pressure readings consistently above normal

What is the role of beta carotene and carotenoids in the body?

Although not a nutrient, beta-carotene is considered a provitamin, that is, an inactive form of vitamin that the body cannot use until it is converted to its active form. Our bodies convert beta-carotene to an active form of vitamin A, retinol; thus, beta-carotene is a precursor of retinol Beta-carotene and some other carotenoids are recognized to have antioxidant properties. Through their antioxidant action, carotenoids play other important roles in the body as well, such as -enhancing the immune system -protecting skin from the damage caused by the suns UV rays -protecting our eyes from damage, preventing or delaying age-related vision impairment

We can obtain vitamin K from the diet, but we can also absorb vitamin K from ________ that produce it in the colon.

Bacteria

Describe dehydration and its effects

Dehydration: The depletion of body fluid, which results when fluid excretion exceeds fluid intake -Effects: -Thirst (small fluid loss) -Discomfort (small fluid loss) -Loss of appetite (small fluid loss) -Sleepiness (severe fluid loss) -Nausea (severe fluid loss) -Flushed skin (severe fluid loss) -Problems with mental concentration (severe fluid loss) -Delirium (very severe fluid loss) -Coma (very severe fluid loss) -Cardiac arrest (very severe fluid loss) -Death (very severe fluid loss)

Identify the most accurate tool for assessing bone density

Dual-energy X-ray absorptiometry (DXA or DEXA) is considered the most accurate tool for measuring bone density. This method can measure the density of the bone mass over the entire body.

Differentiate between the actions of osteoclasts and osteoblasts

Osteoclasts: Cells that erode the surfaces of bones by secreting enzymes and acids that dig grooves into the bone matrix Osteoblasts: Cells that deposit bone matrix for bone formation

Three forms of vitamin A

Retinol (alcohol form) Retinal (aldehyde version) Retinoic acid (acid form)

Describe the function of selenium

The selenium in our bodies is contained in amino acids, primarily two amino acid derivatives: selenomethionine is the storage for selenium, and selenocysteine is the active form of selenium. Selenocysteine is a critical component of the glutathione peroxidase enzyme system. Glutathione peroxidase breaks down the peroxides that are formed by the body, so that they cannot form free radicals; this decrease in the number of free radicals spares vitamin E. This selenium helps spare vitamin E and prevents oxidative damage to the cells. Like vitamin C, selenium is needed for the production of Theroux hormone. By this action, selenium is involved in the maintenance of ball metabolism and body temperature. Selenium appears to play a role in immune function, and poor selenium states is associated with higher rates of some forms of cancer

Describe vitamin A's role in cell differentiation and other functions

Vitamin A contributes to cell differentiation, the process by which stem cells mature into highly specialized cells that perform unique functions. It begins when the retinoic acid form of vitamin A interacts with receptor sites on a cell's DNA. This interaction influences gene expression and the determination of the type of cells that the stem cells eventually become. This process is critical to the development of healthy tissues, organs, and body systems Vitamin A is also critical to the differentiation of specialized immune cells called T-lymphocytes, or t-cells, which fight infection. You can therefore see why vitamin A deficiency significantly increases the risk of infectious disease Vitamin A is also involved in reproduction. Although its exact role is unclear, it appears necessary for sperm production and for fertilization. It contributes to healthy bone growth by assisting in breaking down bone, so that new, longer, and stronger bone can develop. As a result of a vitamin A deficiency, children suffer from stunned growth and wasting

Formation of free radicals and vitamin E

(a) The formation of free radicals in the lipid portion of our cell membranes can cause a dangerous chain reaction that damages the integrity of the membrane and can cause cell death (b) Vitamin E is stored in the lipid portion of our cell membranes. By donating an electron to free radicals, it protects the lipid molecules in our cell membranes from being oxidized and stops the chain reaction of oxidative damage

Serving sizes and energy content to see different foods that can provide the same amount of calcium as an 8oz glass of milk

-9 cups lima beans (1,946 kcal) -5.2 oz plain, nonfat yogurt (83 kcal) -1.3 oz Swiss cheese (140 kcal) -2.8 oz canned sardines (165 kcal) -7 oz tofu, soft, with calcium (163 kcal) -1 1/8 cup cooked collard greens, from frozen (70 kcal)

Describe strategies for prevention or reducing the risk of developing hypertension

-Achieve and maintain a healthy weight. Losing 10 pounds cam often lower blood pressure alight, in general, the more excess weight you lose, the lower your blood pressure -Exercise regularly. The amount and intensity of exercise needed to improve blood pressure are easily achievable for most people. Regular activity, such as brisk walking, lasting at least 30 minutes per day most days of the week, can help lower blood pressure -Limit your alcohol intake. Because alcohol consumption can worsen hypertension, it is suggested that people with this disease abstain from drinking alcohol or limit their intake to no more than one (women) or two (men) drinks per day -Reduce your sodium intake, especially if you are salt sensitive. Some people who are not salt sensitive also benefit from eating low-sodium diets -Increase your potassium intake, emphasizing whole grains, fruits, vegetables, and low-fat dairy foods -Avoid all tobacco products. If you currently use tobacco, quit

Explain the role of each: ADH, renin, angiotensin II, aldosterone

-Antidiuretic Hormone (ADH): A hormone released from the pituitary gland in response to an increase in blood solute concentration. ADH stimulates the kidneys to reabsorb water and to reduce the production of urine -Renin: An enzyme secreted by the kidneys in response to a decrease in blood pressure. Renin converts the blood protein angiotensinogen to angiotensin I, which eventually results in an increase in sodium reabsorption -Angiotensin II: A potent vasoconstrictor that constricts the diameter of blood vessels and increases blood pressure; it also signals the release of the hormone aldosterone from the adrenal glands -Aldosterone: A hormone released from the adrenal glands that signals the kidneys to retain sodium and chloride, which in turn results in the retention of water

Describe tips to help increase calcium in your bone bank

-At the grocery store, stock up on calcium-fortified juices and milk alternatives. Look for single-serving portable "juice boxes" containing milk or calcium- fortified beverages -Purchase breakfast cereals and breads that are fortified with calcium -For quick snacks, purchase single-serving cups of yogurt, individually wrapped "cheese sticks" or calcium-fortified protein bars -Keep on hand shredded parmesan or any other hard cheese, and sprinkle it on hot soups, chili, salads, pasta, and other dishes -In any recipe, replace sour cream or mayonnaise with nonfat plain yogurt -Add nonfat day milk powder to hot cereals, soups, chili, recipes for baked goos, coffee, and hot cocoa. One-third of a cup of nonfat dry milk provides the same amount of calcium as a whole cup of nonfat milk -For a "guilt-free" dessert, try half a cup of plain nonfat Greek yogurt with fruit or a drizzle of maple syrup -Make a yogurt smoothie by blending nonfat plain or flavored yogurt with fresh or frozen fruit -At your favorite cafe, instead of black coffee, order a skim latte. Instead of black tea, order a cup of chai - spiced Indian tea brewed with milk -At home, brew a cup of strong coffee; then add a cup of warm skim milk for a cafe au lait -When eating out, order skim milk instead of a soft drink with your meal

Common food sources of vitamin A

-Beef, pan fried - 3 ounces: 6500 ug -Pumpkin, canned - 1 cup: 2000 ug -Carrots, cooked - 1 cup: 1400 ug -Sweet potato, canned - 1 cup: 1200 ug -Oatmeal, instant - 1 packet: 400 ug -Raisin bran cereal - 1 cup: 390 ug -Cheese, ricotta, whole milk - 1/2 cup: 150 ug -Broccoli, cooked - 1 cup: 150 ug -Asparagus, fresh - 10 spears: 50 ug The RDA for vitamin A is 900 ug per day for men and 700 ug per day for women

What are some tips for increasing vitamin E in your diet?

-Eat cereals high in vitamin E for breakfast or a snack -Add sunflower seeds to salads and trail mixes, or just have them as a snack -Add sliced almonds to salads, granola, and trail mixes to boost vitamin E intake -Pack a peanut butter sandwich for lunch -Eat veggies throughout the day - for snacks, for sides, and in main dishes -When dressing a salad, use vitamin E-rich oils, such as sunflower, safflower, or canola -Enjoy some fresh, homemade guacamole: mash a ripe avocado with a squeeze of lime juice and a sprinkle of garlic salt

What are the roles of ferritin, hemosiderin, and transferrin?

-Ferritin: A storage form of iron found primarily in the intestinal mucosa, spleen, bone marrow, and liver -Hemosiderin: A storage form of iron found primarily on the intestinal mucosa, spleen, bone marrow, and liver -Both of these storage forms of iron provide us with iron when our diet is inadequate or when our needs are high. Both can be mobilized if the body needs iron -Transferrin: The primary iron transport protein in the blood; transports iron to body cells -Transferrin receptors on the cells increase and decrease in number, depending on the cell's need for iron. In this way, cells can regulate the amount of iron they take in from the blood

Describe several tips for increasing your consumption of potassium

-For breakfast, look for whole-grain, unsweetened cereals containing bran and/or wheat germ, or sprinkle fruit and yogurt with wheat germ -Toss a banana, some dried apricots, or a bag of sunflower seeds into your backpack for a mid-morning snack -Instead of soft drinks, choose low-fat milk, kefir, soy milk, or low-sodium vegetable juice, or blend low-fat vanilla yogurt with ice cubes and a banana -Serve avocado of bean dip with veggie slices; use sliced avocado or marinated tofu for your sandwiched in place of processed meats -Make a tropical salad with avocado, papaya, banana, honeydew melon, mango, cantaloupe, and grapefruit -Make sweet potato fries (toss potato slices in olive oil and bake at 400 degrees for 15-20 minutes), or bake a wedge of acorn squash -Bake with fresh pr canned pumpkin or sweet potato: pumpkin/ sweet potato muffins, cookies, scones or even a home-baked pie

Different tissues contain different amounts of fluid. Which has more fluid lean tissue or fat tissue?

-Lean tissue: 70% fluid -Fat tissue: 10-20% fluid Since males have more lean tissue they have a higher percentage of body weight from fluid.

Describe some tips for increasing vitamin C in your diet

-Mix strawberries, kiwifruit, cantaloupe, and oranges for a tasty fruit salad loaded with vitamin C -Include tomatoes on salads, wraps, and sandwiches for more vitamin C -Make your own fresh-squeezed orange or grapefruit juice -Add your favorite vitamin C-rich fruits, such as strawberries, to smoothies -Buy ready-to-eat vegetables, such as baby carrots and cherry tomatoes, and toss some in a zip-lock bag to take to school or work -Put a few slices of romaine lettuce on your sandwich -Throw a small container of orange slices, fresh pineapple chunks, or berries into your backpack for an afternoon snack -Store 100% juice boxes in your freezer to pack with your lunch. They'll thaw slowly, keeping the rest of your lunch cool, and many brands contain a full day's supply of vitamin C in just 6 oz -Enjoy raw peppers with low-fat dip for a crunchy snack

Define the categories for consistent blood pressure measurements: normal blood pressure, elevated blood pressure, stage 1 hypertension, and stage 2 hypertension

-Normal blood pressure: systolic less than 120 mmHg and diastolic less then 80 mmHg -Elevated blood pressure: systolic between 120 and 129 mmHg and diastolic less than 80 mmHg -Stage 1 hypertension: systolic between 130-139 mmHg and diastolic between 80 and 89 mmHg -Stage 2 hypertension: systolic 140 mmHg or above and diastolic 90 mmHg or above

Common food sources of potassium

-Potato, whole, baked - 1 medium: 975 mg -Tomato juice - 1 cup: 550 mg -Halibut, cooked - 3 oz: 425 mg -Orange juice, from concentrate - 1 cup: 420 mg -Banana, raw - 1 medium: 415 mg -Cantaloupe, raw - 1 cup: 415 mg -Yogurt, nonfat, vanilla - 8 oz: 350 mg -Spinach, raw - 1 cup: 175 mg

Common food sources of beta-carotene

-Pumpkin, canned - 1 cup: 17.5mg -Sweet potato, baked, with skin - 1: 17mg -Spinach, frozen, cooked - 1 cup: 14mg -Kale, frozen, cooked - 1 cup: 12mg -Carrots, raw - 1 cup: 9.5mg -Cantaloupe, fresh - 1 cup: 3.5mg -Spinach, raw - 2 cups: 3.75mg -Broccoli, cooked - 2 cups: 3mg There is no RDA for beta-carotene

Common food sources of vitamin D

-Salmon, pink, canned - 3 oz: 500 IU -Mackerel, canned - 3 oz: 275 IU -Milk, 2% fat with added vitamin D - 8 fl oz: 125 IU -Milk, 1% fat with added vitamin D - 8 fl oz: 124 IU -Milk, nonfat with added vitamin D - 8 fl oz: 124 IU -Corn flakes cereal - 1 cup: 45 IU -Cheerios cereal - 1 cup: 45 IU For men and women aged 19 to 80 years, the RDA for vitamin D is 600 IU per day. The RDA increases to 800 IU for adults over the age of 70 years

Describe tips for increasing beta carotene in the diet

-Start your day with an orange, a grapefruit, a pear, a banana, an apple, or a slice of cantaloupe. All are good sources of beta-carotene -Pack a zip-lock bag of carrot slices or dried apricots in your lunch -Instead of french fries, think orange. Slice raw sweet potatoes, toss the slices in olive or canola oil, and bake -Add veggies to homemade pizza -Add shredded carrots to cake and muffin batters -Taking dessert to a potluck? Make pumpkin pie. It's easy if you used canned pumpkin and follow the recipe on the can -Go green, too. The next time you have a salad, go for the dark-green, leafy vegetables instead of iceberg lettuce -Add raw spinach or other green, leafy vegetables to wraps and sandwiches

Common food sources of vitamin C

-Strawberries, fresh - 1 cup: 89mg -Bell peppers, green, raw - 1 cup: 74mg -Grapefruit juice, unsweetened - 8 fl oz: 72mg -Orange - 1 medium: 70mg -Kiwi - 1 medium: 65mg -Broccoli, cooked - 1/2 cup: 50mg -Cauliflower, cooked - 1/2 cup: 28mg -Pineapple, fresh - 1 slice: 27mg -Sweet potato, baked, with skin - 1: 24mg -Tomatoes, fresh - 5 slices: 15mg The RDA for vitamin C is 90mg per day for men and 75mg per day for women

Common food sources of vitamin E

-Total cereal - 3/4 cup: 14mg -Sunflower seeds - 1/4 cup: 9mg -Almonds, dry roasted - 1/4 cup: 9mg -Marinara sause - 1 cup: 6mg -Canola Oil - 1 tbsp: 3.5mg -Avocado - 1 medium: 3.25mg -Peanuts, dry roasted - 1 oz: 2mg -Peanut butter, smooth - 1 tbsp: 1.75mg -Spinach, fresh - 2 cups: 1mg The RDA for vitamin E is 15mg a-tocopherol per day for men and women

Common food sources of vitamin K

-Turnip greens, boiled - 1/2 cup: 275 ug -Broccoli, boiled - 1 cup: 225 ug -Brussels sprouts, boiled - 1 cup: 224 ug -Spinach leaf, raw - 1 cup: 150 ug -Lettuce, green leaf, raw - 1 cup: 100 ug -Cabbage, raw - 1 cup: 55 ug -Soybeans, roasted - 1/2 cup: 50 ug -Soybean oil - 1 tbsp: 30 ug -Chicken thigh, roasted - 1: 25 ug -Canola oil - 1 tbsp: 10 ug -Cheese, cheddar, diced - 1/2 cup: 5 ug The Ads for adult men and women are 120 ug per day and 90 ug per day, respectively

Fluid and Electrolyte Balance (Teacher Info)

-When the concentration of solutes inside and outside the cell are equal the solution the cell is exposed to is isotonic and water moves into and out of the cell at the same rate so no change in cell shape. -When the concentration of solutes outside the cell is lower (hypotonic) than inside the cell then more water enters the cell than leaves causing cells to swell. -When the concentration of solutes is higher (hypertonic) outside the cell than inside it will cause water to leave the cell at a faster rate. -Keep in mind that water follows solutes so wherever there are more solutes that's where water will go

Describe the role of antioxidants in fighting free radicals

1. Antioxidant vitamins work independently by donating their electrons or hydrogen atoms to stabilize free radicals 2.Antioxidant minerals including selenium, copper, iron, zinc, and manganese, act as cofactors within complex antioxidant enzyme systems that convert free radicals to less damaging substances that are excreted by the body. They also work to break down fatty acids that have become oxidized, thereby destroying the free radicals associated with them. Antioxidant enzyme systems also make more vitamin antioxidants available to fight other free radicals. The following are examples of antioxidant enzyme systems: -Superoxide dismutase converts superoxide free radicals to less damaging substances such as hydrogen peroxide, which can then be degraded by other enzyme systems -Catalase promoted the elimination of hydrogen peroxide from the body by converting it to water and oxygen -Glutathione peroxidase also promotes the elimination of hydrogen peroxide from the body by reducing it to water and stops the production of free radicals in lipids 3. Phytochemicals such as bet-carotene help stabilize free radicals and prevent damage to cells and tissues In summary, free-radical formation is generally kept safely under control by certain vitamins, minerals working within antioxidant systems, and phytochemicals

Identify the three major systems that account for the body's ability to regulate acid-base balance.

1. Blood buffers: The blood transports many natural buffers. Proteins are excellent buffers, having the ability to take up excess hydrogen ions during acidosis and to release hydrogen ions when the blood becomes too basic. Another blood buffer is the bicarbonate-carbonic acid system. Carbon dioxide (CO2), one of the end products of energy metabolism, dissolves in the bloodstream to form carbonic acid (H2CO3), which itself dissociated into hydrogen (H+) and bicarbonate ions (HCO3-). Notice that this reaction is reversible: the bicarbonate ions are able to take up excess hydrogen ions or release hydrogen ions as needed in order to maintain acid-base balance 2. Respiratory compensation: Although, fast acting, blood buffers don't have enough buffering capacity to correct large or long-term acid-base imbalances. The second line of defense if the lungs. By increasing or decreasing the rate of respiration, the lungs regulate the amount of carbonic acid in the blood. High levels of carbonic acid (acidosis) trigger hyperventilation. Excess carbon dioxide is forced out, helping to increase blood pH. In a state of alkalosis, with high blood levels of bicarbonate, respiration slows, carbon dioxide is retained, and more carbonic acid is formed, decreasing blood pH 3. Renal compensation: Since there is a limit to how fast or slow a person can breathe, the ability of the lungs to regulate acid-base balance is so limited. The last line of defense is the kidneys. Healthy kidneys have the capacity to either secrete into blood or excrete into urine significant bicarbonate to correct acid-base imbalances. They can also use non bicarbonate buffers, such as ammonia or hydrogen phosphate, to excrete excess hydrogen ions

Urine color chart

A color chart used to assess hydration status based on the color of the urine Clear / Slightly Yellow: Adequate Hydration Yellow: Minor Dehydration Dark Yellow / Brown: Severe Dehydration

Describe how the bioavailability of calcium varies and identify dietary factors that enhance and impair calcium absorption

A nutrient's bioavailability is the degree to which the body can absorb and use any given nutrient. The bioavailability of calcium depends in part on a person's age and need for calcium. For example, infants, children, and adolescents can absorb more than 60% of the calcium they consume, as calcium needs are very high during these stages in life. In addition, pregnant and lactating women can absorb bout 50% of dietary calcium. In contrast, healthy long adults absorb only about 30% of the calcium consumed in the diet. When calcium needs are high, the body can generally increase its absorption. Although older adults have a high need for calcium, their ability to absorb calcium from the small intestine dimities with age and can be as low as 25%. These variations in bioavailability and absorption capacity were taken into account the calcium recommendations were determined. The bioavailability of calcium also depends on how much calcium is consumed throughout the day or at any one time. When diets are generally high on calcium, absorption of calcium is reduced. In addition, the body cannot absorb more than 500 mg of calcium at any one time, and as the amount of calcium in a single meal or supplement goes up, the fraction that is absorbed goes down. Dietary factors can also affect the absorption of calcium. Binding factors, such as phytates and oxalates, occur naturally in some calcium-rich seeds, nuts, grains, and vegetables, such as absorption from the small intestine. Additionally, consuming calcium with iron, zinc, magnesium, or phosphorous can interfere with the absorption and utilization of all these minerals. Despite these potential interaction, the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine (HMD) has concluded that there is not sufficient evidence to suggest that these interactions cause deficiencies of calcium or other minerals in healthy individuals. Finally, because vitamin D is necessary for the absorption of calcium, a lack of vitamin D severely limits the bioavailability of calcium.

Can you get vitamin D toxicity from too much sun exposure?

A person cannot get too much vitamin D from sun exposure, as the skin has the ability to limit is production

Define heat stroke

A potentially fatal illness characterized by hot, dry skin; rapid heart rate; vomiting; diarrhea; elevated body temperature; hallucinations; and coma

Night blindness

A vitamin A deficiency can result in night blindness. This condition results in: (a) poor night vision due to a darkening of one's visual field at night (b) difficulty in adjusting from bright light to dim light

Differentiate between acidosis and alkalosis

Acidosis: A disorder in which the blood becomes acidic; that is, the level of hydrogen in the blood is excessive. It can be caused by respiratory or metabolic problems Alkalosis: A disorder in which the blood becomes basic; that is, the level of hydrogen in the blood is deficient. It can be caused by respiratory or metabolic problems

Describe factors that enhance iron absorption and factors that impair iron absorption

All of the iron found in plant-based foods is nonhdme iron. Its absorption is influenced by the amount of heme in the diet. When foods containing heme iron are consumed with nonhdme iron, total iron absorption will increase. This is on part because meat, fish, and poultry contain a special meat, fish, poultry (MFP) factor, which enhances the absorption of nonhdme iron. Nonheme iron absorption is also influenced by an individual's level of stomach acid. When nonhdme iron-containing foods enter the stomach, gastric juices containing pepsin and hydrochloric acid reduce the ferric iron to ferrous iron, which is more soluble in the alkaline environment of the small intestine. Thus, adequate amounts of stomach acid are necessary nonheme iron absorption. People with low levels of stomach acid, including many older adults and individuals who use medications that reduce stomach acid, may experience reduces iron absorption. once iron enters the duodenum, it is taken up by enterocytes, with ferrous iron more rapidly absorbed than ferric iron. The solubility of nonheme iron in the small intestine is greatly modified by the presence of enhancing or inhibitory factors within the meal. Vitamin C enhances nonheme absorption by reducing dietary ferric to ferrous iron, which then forms a soluble iron-ascorbic acid complex in the stomach. Nonheme iron absorption from breakfast cereal, for example, is enhanced by having the cereal with a glass of orange juice. Conversely, iron absorption is impaired by phytates, polyphenols, and oxalic acid. Typically, these substances bind to the ferric iron and form complexes that cannot be digested. Phytates are found in legumes, rice, and whole grains; polyphenols are found in oregano, ed wine, and tannin derivatives found in tea and coffee; and oxalic acid is found in spinach, some whole grains, chard, and rhubarb. Because of the influence of these dietary factors on iron absorption, it is estimated that the bioavailability or iron from a vegan or vegetarian diet is approximately 5% to 10%, compared with the 14% to 18% absorption of the typical Western diet. Of course, the iron absorption rates from these diets will change depending on the iron status of the individual. Iron absorption can also be impaired by consumption of divalent cations such as zinc, manganese, and calcium. The mechanism whereby these minerals alter iron absorption varies based on the mineral, the amount consumed, and the presence of other iron inhibitors or enhancers in the diet. For example, calcium can inhibit iron absorption by changing the availability of the iron transport protein ferroportin in the enterocyte's basolateral membrane, thus depends in the amount and form of the mineral, with less interaction if both minerals are in foods, as opposed to supplements. Overall, high amounts of zinc, manganese, or calcium in supplements are more likely to impact iron absorption than the consumption of these minerals in food

Why is the content of selenium in foods highly variable?

As it is a trace mineral, we need only minute amounts to maintain health. The RDA for selenium is 55 ug per day for both men and women. The UL is 400 ug per day. Selenium is present in both plant and animal food sources but in variable amounts. Because it is stored in the tissues of animals, selenium is found in reliably consistent amounts in animal foods. Organ meats, such as liver and kidney, as well as pork and seafood, are particularly good sources

Amounts and categories of water sources and losses

Based on a woman expending 2,500 kcal per day Main Water Sources: -Beverages = 2,200 mL (9.3 cups) -Food = 500 mL (2.1 cups) -Metabolic water = 300 mL (1.3 cups) Total sources of water = 3,000 mL (12.7 cups) Main Water Losses: -Urine = 1,700 mL (7.2 cups) -Skin and lungs: 1,100 mL (4.7 cups) -Feces: 200 mL (0.8 cups) Total losses of water = 3,000 mL (12.7 cups)

What happens if we consume too much vitamin C?

Because vitamin C is water soluble, we usually excrete any excess. Consuming excess amounts in food does not lead to toxicity; only supplements can lead to toxic doses. Taking megadoses of vitamin C is not fatal; however, the side effects of doses exceeding 2,000mg per day for a prolonged period include nausea, diarrhea, nosebleeds, and abdominal cramps. There are rare instances in which consuming even moderately excessive doses of vitamin C can be harmful. Vitamin C enhances the absorption of iron. This action is beneficial to people who need to increase iron absorption. It can be harmful, however, to people with a disease called hemochromatosis, which causes an excess accumulation of iron in the body that can lead to tissue damage and a heart attack. In people who have preexisting kidney disease, taking excess vitamin C can lead to the formation of kidney stones. This does not appear to occur in healthy individuals.

Differentiate between systolic and diastolic blood pressure

Blood pressure is measured in two phases: systolic and diastolic. Systolic blood pressure represents the pressure exerted in the arteries at the moment the heart contracts, sending blood into the blood vessels. Diastolic blood pressure represents the pressure in the arteries between contractions, when the heart is relaxed

Bone growth, bone modeling, bone remodeling

Bone growth: -Determines bone size -Begins in the womb -Continues until early childhood Bone modeling: -Determines bone shape -Begins in the womb -Continues until early adulthood Bones remodeling: -Maintains integrity of bone -Replaces old bone with new bone to maintain mineral balance -Involves bone resorption and formation -Occurs predominately during adulthood

Overview of Nutrients Essential to Bone Health to identify what nutrients are needed for bone health. Identify the RDA for calcium only.

Calcium (major mineral) RDA: -Adults aged 19 to 50 years = 1,000 mg/day -Men aged 51-70 = 1,000 mg/day -Men aged >70 = 1,200 mg/day -Women aged >50 = 1,200 mg/day -UL (upper level) = 2,500 mg/day

The components of body fluid

Cell -Intracellular fluid (inside of the cell) -Extracellular fluid (outside of the cell) Liver -Intracellular fluid -Extracellular fluid (tissue fluid, or interstitial fluid) Capillary Network -Extracellular fluid (plasma) -Blood cell inside capillary -Intracellular fluid -Extracellular fluid (tissue fluid) -Intracellular fluid is contained within the cells that make up our body tissues -Extracellular fluid is external to cells -Interstitial fluid is external to tissue cells -Plasma is eternal to blood cells

Circumstances that affect iron status

Circumstances That Improve Iron Status: -Use of oral contraceptives: reduces menstrual blood loss in women -Breastfeeding: delays resumption of menstruation in new mothers and thereby reduces blood loss. It is therefore an important health measure, especially in developing nations -Consumption of iron-containing foods and supplements Circumstances That Diminish Iron Status: -Use of hormone replacement therapy: can cause uterine bleeding -Eating a vegetarian diet: reduces or eliminates sources of heme iron -Intestinal parasite infection: causes intestinal bleeding. Iron deficiency anemia is common in people with intestinal parasite infection -Blood donation: reduces iron stores; people who donate frequently, particularly premenopausal women, may require iron supplementation -Intense endurance exercise training: appears to increase the risk for poor iron status because of many factors, including inflammation, suboptimal iron intake, and increased iron loss due to rupture of red blood cells and increased fecal loses

Discuss the role of free radical damage in cardiovascular disease and the role of antioxidants in boosting heart health

Eating foods high in antioxidants is associated with lower rates of cardiovascular disease (CVD). Antioxidants may achieve this effect by reducing inflammation; acting as anticoagulants; and scavenging free radicals. Dietary fiber and folate are other compounds in fruits and vegetables that are though to reduce the risk for CVD

Evaporative cooling

Evaporative Collingwood occurs when heat is transported from the body core through the bloodstream to the surface of the skin The water evaporates into the air and carries away heat. This cools the blood, which circulates back to the body core, reducing body temperature Core heat -> Heat travels to skin -> Cooled blood flows back to the body core

Overview of Nutrients Essential to Blood Health

Folate (folic acid) RDA: -Men and women aged 19-50 years: 400 ug/day -UL: 1,000 mg/day Iron RDA: -Women aged 19 to 50 years = 18 mg/day -Men aged 19 to 50 years = 8 mg/day -UL = 45 mg/day

What are the causes and risk factors for hypertension?

For about 90% to 95% of people who have hypertension, the cause is unknown. This type is referred to as primary, or essential hypertension. For the other 5% to 10% of people with hypertension, the causes include kidney disease, sleep apnea, certain medications, illegal drugs, and chronic alcohol abuse. It is estimated that about two-thirds of all adults will hypertension have a condition known as salt sensitivity. These people respond to a high slat intake by experiencing an increase in blood pressure; they also experience a decrease in blood pressure when salts intake is low. People who dod not experience changes in blood pressure with changes in salt intake are referred to as salt resistant. Risk factor associated with hypertension include age, particularly over the age of 60 to 65 years, as well as overweight and obesity, as increased blood volume leads to increased pressure on blood vessel walls. A sedentary lifestyle also increases the risk. Tobacco use is a major risk factor, because it immediately raises blood pressure, and chronic use damages the lining of the blood vessels, increasing the likelihood of plaque deposition. Excessive alcohol intake is a strong predictor of hypertension and risk increases with the duration of abuse. In addition to the known risk of a diet high in sodium, low potassium intake is now recognized as an independent risk factor. Finally, genetic factors increase risk for those with a family history of hypertension

Functions of bone in the human body

Function Related to Structure and Support: -Bones provide physical support fo organs and body segments -Bones protect vital organs; for example, the rib cage protects the lungs, the skull protects the brain, and the vertebrae of the spine protect the spinal cord -Bones work with muscles and tendons to allow movement - muscles attach to bones via tendons, and their contraction produces movement in the body's joints Functions Related to Metabolic Process -Bone tissue acts as a storage reservoir for many minerals, including calcium, phosphorous, and fluoride. The body draws on such deposits when these minerals are needed for various body processes; however, this can reduce bone mass -Most blood cells are produced in the red bone marrow

Differentiate between hypercalcemia and hypocalcemia and what causes these conditions

Hypercalcemia: A condition characterized by an abnormally high concentration of calcium in the blood -Can be caused by cancer and by the overproduction of PTH Hypocalcemia: A condition characterized by an abnormally low concentration of calcium in the blood -Hypocalcemia does not result from consuming too little dietary calcium, but is caused by various diseases, including kidney disease, vitamin D deficiency, and diseases that inhibit the production of PTH

Differentiate between hyperkalemia and hypokalemia and explain what causes these conditions

Hyperkalemia: A condition in which blood potassium levels are dangerously high -Occurs when potassium us not efficiently excreted from the body Hypokalemia: A condition in which blood potassium levels are dangerously low -Can result from vomiting, diarrhea, adrenal gland disorders, or use of diuretics

Differentiate between hyponatremia and hypernatremia and explain what causes these conditions

Hyponatremia: A condition in which blood sodium levels are dangerously low -Can occur during periods of intense activity when people drink large volumes of water and fail to replace sodium -Such as a marathon run or all-day hike Hypernatremia: A condition in which blood sodium levels are dangerously high -Usually caused by a rapid intake of high amounts of sodium -Such as when a shipwrecked sailor drink seawater

Regulation of blood volume and blood pressure by the kidneys

Hypothalamus senses increased concentration of solutes in blood -> ADH release (from pituitary gland) -> Increase water reabsorption by kidneys -> Decrease urine output -> Normal blood solute concentration Blood volume -> Kidney receptors sense decreased blood pressure -> Kidneys secrete renin -> Renin catalyzes the conversion of angiotensinogen (from liver) -> Angiotensin I -> Angiotensin II -> [Vasoconstriction of blood vessels -> Blood pressure increase] or [Increased aldosterone (from adrenal glands) -> Increased reabsorption of sodium and chloride -> Increased water retention -> Decreased urine output]

Review the functions of iron

Iron helps form and oxygenate our blood cells and haemoglobin One of the most important functions of iron is in heme synthesis, which forms haemoglobin, a protein found in red blood cells. Haemoglobin's primary role is to transport oxygen from the lungs to body tissues to maintain basic life functions. Without healthy red blood cells, your body can't get enough oxygen, and this can result in you feeling increasingly tired or exhausted. Iron helps convert food to energy Iron plays a vital role in the process by which cells make energy. Human cells require iron in order to convert energy from food into ATP (Adenosine Triphosphate) and this is the body's primary energy source. Low iron means less ATP can be produced and this is often why people feel tired and fatigued. Iron helps maintain a normal immune system Iron is necessary for immune cell creation and growth, which help to keep us healthy. Lower iron levels may contribute to an increased risk of our immune systems being compromised and our bodies falling sick. Iron contributes to normal cognitive function Cognitive function includes brain functions such as memory, concentration, learning and problem solving. Maintaining good iron levels help us to ensure our brain is performing at its best without having to rely on that shot of caffeine in the morning!

Water content of different foods

Much of your daily water intake comes from the foods you eat Examples: -Lettuce, Iceberg: 96% water -Cucumbers, with peel, raw: 95% water -Peaches, raw: 89% water -Pineapple, raw: 86% water -Olives, ripe, canned: 80% water -Sweet potato, baked: 76% water -Pork chop, lean, broiled: 61% water -Almonds: 5% water

What happens if we consume too much vitamin E?

Nausea, intestinal distress, and diarrhea have been reported with vitamin E supplementation. Moreover, research has shown that vitamin E supplementation above the RDA can increase the risk of prostate cancer in men and risk for premature mortality in men and women Vitamin E is a mild anticoagulant, a substance that inhibits blood clotting. Thus, vitamin E supplements can augment the action of medications with coagulant effects. These include the prescription drug Coumadin, as well ad over-the-counter pain relievers such as aspirin and ibuprofen. Increased anticoagulant activity can lead to uncontrollable bleeding. In addition, evidence suggests that in some people, long-term use of standard vitamin E supplements may lead to hemorrhagic stroke

Describe the possible health effects of vitamin a deficiency

Night blindness and color blindness can result from vitamin A deficiency. Night blindness is a severe public concern in developing countries. According to the World Health Organization, approximately 250 million preschool children suffer from vitamin A deficiency. Of the children affected, 250,000 to 500,000 become permanently blinded every year. At least half of these children are likely to die within 1 year of losing their sight, typically from infections diseases such as measles and diarrhea, which are easily prevented and treated in more affluent countries. Vitamin A deficiency is also a tragedy for pregnant women in many developing countries. They often suffer from night blindness, and more likely to transmit HIV to their children if HIV-positive, and run a greater risk for maternal mortality. If Vitamin A deficiency progresses, it can result in irreversible blindness due to hardening of the cornea, a condition called xerophthalmia. Lack of vitamin A causes the epithelial cells of the cornea to lose their ability to produce mucus, causing the eye to become very dry. This leaves the cornea susceptible to damage, infection, and hardening. Once the cornea hardens in this way, the resulting blindness is irreversible. This is why it is critical to catch vitamin A deficiency in its early stages and treat it with either the regular consumption of fruits and vegetables that contain beta-carotene or with vitamin A supplementation. Vitamin A deficiency can also lead to follicular hyperkeratosis, a condition characterized by the excess accumulation of the protein keratin in the hair follicles. Keratin is usually found only on the outermost surface of the skin, hair, nails, and tooth enamel. With hyperkeratosis, keratin clogs hair follicles, makes skin rough and bumpy; prevents proper sweating through the sweat glands; and causes skin to become very dry and thick. Hyperkeratosis can also affect the epithelial cells of various tissues, including the mouth, urinary tract, vagina, and eyes, reducing the production of mucus by these tissues and leading to an increased risk of infection. Hyperkeratosis can be reversed with vitamin A supplementation. Other deficiency symptoms include unpaired immunity, increases risk for illness and infections, reproductive system disorders, and failure of normal Goth. Individuals who are at risk for vitamin A deficiency include elderly people with poor diets, newborns, premature infants, young children with inadequate vegetable and fruit intakes, and alcoholics. Conditions that result in fat malabsorption can also lead to vitamin A deficiency. These include cystic fibrosis, Crohn's disease, celiac disease, diseases of the liver, pancreas, or gallbladder, and consumption of large amounts of the fat substitute Olestra

Structure of bone

Notice the difference in density between the trabecular (spongy) bone and cortical (compact) bone Trabecular bone: A porous bone tissue that is found within the ends of the ling bones, inside the spinal vertebrae, inside the flat bones (sternum, ribs, and most bones of the skull), and inside the bones of the pelvis Cortical bone: A dense bone tissue that makes up the outer surface of all the bones, as well as the entirety of most small bones of the body

Overview of Nutrients Involved in Hydration and Neuromuscular Function

Nutrient Recommended Intake Sodium AI: Women and men = 1.5 g/day Potassium AI: Women and men = 4.7 g/day Chloride AI: Women and men = 2.3 g/day Phosphorous RDA: Women and men = 700 mg/day

Describe factors that may affect the ability to synthesize vitamin D from sunlight

Of the factors that affect vitamin D synthesis, latitude and time of year are most significant. People living in very sunny climates relatively close to the equator, such as the Southern United States and Mexico, may synthesize enough vitamin D from the sun to meet their needs throughout the year - as long as they spend time outdoors. However, vitamin D synthesis from the sun is not possible during most of the winter months for people living in places located at a latitude of more the 37°N or more than 37°S. At these latitude in winter, the sun never rises high enough in the sky to provide the amount of direct sunlight needed. The 37°N latitude runs like a belt across the United States from northern Virginia in the East to Northern California in the West. In addition, entire countries, such as Canada and the United Kingdom, are affected, as are countries and regions in the far Southern Hemisphere. Thus, many people around the world need to consume vitamin D in their diets, particularly during the winter months. Other factors influencing vitamin D synthesis include the time of day, skin color, age, and body weight status: -More vitamin D can be synthesized during the time of day when the sun's rays are strongest, generally between 10 AM and 3 PM. Vitamin D synthesis is severely limited or may be nonexistent on overcast days -Darker skin contains more melanin pigment, which reduces the penetration of sunlight. Thus, people with dark skin have a more difficult time synthesizing vitamin D from the sun than do light-skinned people -People 65 years of age or older experience a fourfold decrease in their capacity to synthesize vitamin D from the sun; they are also more likely to spend time indoors and may have inadequate dietary intake -Obesity has recently been associated with lower levels of circulating vitamin D. Although the exact mechanism for this finding is not clear, possible contributors include a lower bioavailability of cholecalciferol from adipose tissue, volumetric dilution of vitamin D in adipose tissue, decreased exposure to sunlight due to limited mobility or time spent outdoors with skin exposed, and alterations in vitamin D metabolism in the liver

Differentiate between oxidation and reduction

Oxidation: A chemical reaction in which an atom loses an electron, typically to an atom of oxygen Reduction: A chemical reaction in which an atom gains electrons

Describe the bone-supporting functions of phosphorus, magnesium, and fluoride, the best food sources, and the results of toxicity and deficiency of these minerals.

Phosphorous is the major negatively charged electrolyte inside the cell. It contributes to hydroxyapatite crystals, which provide the hardness of the bone. The RDA for phosphorous is 700 mg for adults. Foods high in protein are good sources. Phosphorous toxicity can lead to muscle spasms and convulsion, deficiencies are rare. Magnesium is a major mineral found in fresh foods, including spinach, nuts, seeds, whole grains, and some fish. Magnesium is important for bone health, energy production, and muscle function. The RDA for magnesium is 400 to 420 mg per day for men and 310 to 320 mg per day for women. Hypomagnesemia causes hypocalcemia, muscle cramps, spasms, and weakness. Magnesium deficiencies are also associated with osteoporosis and other disorders. The AI for fluoride is 4 mg and 3 mg per day for men and women, respectively. Primary sources of fluoride are fluoridated dental products and fluoride water. Fluoride toxicity causes fluorosis of the teeth and skeleton, and fluoride deficiency causes and increase in tooth decay

Functions of water

Regulates body temperature: -Water has a high capacity for heat: It takes a lot to raise its temperature. Because the body contains a lot of water, only sustained high heat can increase body temperature -Body fluids are our primary coolant. When heat needs to be released from the body, there is an increase in the flow of the blood from the warm body core to the vessels lying under the skin. This action transports heat out of the periphery, where it can be released from the skin. When we are hot, the sweat glands secrete more sweat from the skin. As this sweat evaporates off the skin's surface, heat is released into the environment. As a result, the skin and underlying blood are cooled Tissue protection and lubrication: -Water is a major part of the fluids that protect and lubricate the tissues. -The cerebrospinal fluid that surrounds the brain and spinal column protects these vital tissues from damage -A fetus in a mother's womb is protected by amniotic fluid -Synovial fluid lubricates joints -Tears cleanse and lubricate the eyes -Saliva moistens age food we eat -The water in the gastric juice dilutes the food to make chyme -The mucus lining the lumen of the intestine helps the chyme move smoothly along -The pleural fluid covering the lungs allows their friction-free expansion and retraction behind the chest wall Solubility and transport: -Water is an excellent solvent, which means it is capable of dissolving a wide variety of substances, including amino acids, glucose, the water-soluble vitamins, mineral salts, and some medications. The chemical reactions upon which life depends would not be possible without water -Water-soluble substances are readily transported via the bloodstream. In contrast, lipids do not dissolve in water. To overcome thus incompatibility, lipids and the fat-soluble vitamins are either attached to or surrounded by water-soluble proteins so that they, too, can be transported in the blood to the cells

Three active forms of vitamin A

Retinol -Vision -Sexual reproduction -Bone health -Immune function Retinal -Vision -Sexual reproduction -Bone health -Immune function Retinoic Acid -Cell differentiation -Bone health -Immune function Retinol and retinal can be converted interchangeably, retinoic acid is formed from retinol, and this process is irreversible. Each form of vitamin A contributes to many of our bodily processes

Differentiate between sensible fluid loss and insensible fluid loss

Sensible fluid loss: Body fluid loss is noticeable, such as through urine output is sweating Insensible fluid loss: The unperceived loss of fluid, such as through evaporation from the skin and exhalation from the lungs during breathing

How does the amount of body fluid as a percentage of total weight change as we age? Does it increase or decrease?

The amount of body fluid as a percentage of total weight decreases with age. About 75% of infant'd body weight is fluid, whereas the total body fluid of an elderly person is generally less than 50% of body weight. This decrease in total body fluid is, in part, a result of the loss of lean tissue that commonly occurs as people age

How does iron status affect iron absorption?

The body's ability to absorb dietary iron is influenced by a number of factors. The most important are the individual's iron status; the level of dietary iron consumption; the type of iron present in the foods consumed; the amount of stomach acid present to digest the foods; and the presence of the dietary factors that can either enhance or inhibit the absorption of iron. Although the iron absorbed from the typical western diet is to be 14% to 17%, the actual amount absorbed can vary widely depending on one's iron status (1% to 35%). Individuals with poor iron status, such as those with iron deficiency, pregnant women, and people who have recently experienced blood loss (including menstruation), may absorb as much as 35% of dietary iron. If iron status is good, iron absorption will drop to about 10% to 12% whereas if iron status is excellent, absorption can drop as low as 2% to 5%

Fluid and Electrolyte Balance

The health of our body's cells depends on maintaining the proper balance of fluids and electrolytes on both sides of the cell membrane, both at rest and during exercise. Let's examine how this balance can be altered under various conditions if exercise and fluid intake Moderate Exercise: -When you are appropriately hydrated, egged in moderate exercise, and not too hot, the concentration of electrolytes is likely to be the same on both sides of cell membranes. You will be in fluid balance Strenuous Exercise With Rapid and High Water Intake: -If a person drinks a great deal of water quickly during intense, prolonged exercise, the extracellular fluid become diluted. This results in the concentration of electrolytes being greater inside the cells, which causes water to enter the cells, making them swell. Drinking moderate amounts of water or sports drinks more slowly will replace lost fluids and restore fluid balance Strenuous Exercise With Inadequate Fluid Intake: -If a person does not consume adequate amounts of fluid during strenuous exercise of long duration, the concentration of electrolytes becomes greater outside the cells, drawing water away form the inside of the cells and making them shrink. Consuming sports drinks will replace lost fluids and electrolytes

Describe the function of vitamin E as an antioxidant

The primary function of vitamin E is an antioxidant: It donates an electron to free radicals, stabilizing them and preventing them from destabilizing other molecules. Once vitamin E is oxidized, it is either excreted from the body or recycled back into active vitamin E through the help of other antioxidant nutrients, such as vitamin C Because vitamin E is prevalent in adipose tissue and cell membranes, its action specifically protects polyunsaturated fatty acids and other fatty components of our cells and cell membranes from being oxidized, thereby lowering the risk of CVD. Vitamin E plays a critical role in protecting the membranes of red blood cells from oxidation and in protecting the cells of our lungs, which are constantly exposed to oxygen and the potentially damaging effects of oxidation. Vitamin E's role in protecting PUFAs and other fatty components also explains why it is added to many oil-based foods and skincare products - by preventing oxidation in these products, it reduces rancidity and spoilage Vitamin E serves many other roles essential to human health. It has anticoagulant properties, and thus exposes the excessive formation of blood clots that is promoted by free radicals. It is critical for normal fetal and early childhood development of nerves and muscles, as well as for maintenance of their functions. It protects white blood cells and other components of the immune system, thereby helping the body defend against acute infection and disease. It also improves the absorption of vitamin A if the dietary intake of vitamin A is low

What is erythrocyte hemolysis?

The rupturing or breakdown of red blood cells, or erythrocytes

What happens when calcium is deficient in the diet?

There are no short-term symptoms associated with consuming too little calcium. Even when a person does not consume enough dietary calcium, the body continues to tightly regulate blood calcium levels by taking calcium from bone. A long-term repercussion of inadequate calcium intake is osteoporosis. Hypocalcemia is the condition of having an abnormally low level of calcium in the blood. Hypocalcemia does not result from consuming too little dietary calcium, but is caused by various diseases, including kidney disease, vitamin D deficiency, and diseases that inhibit the production of PTH. Symptoms of hypocalcemia include muscle spasms and convulsions

What happens if we don't consume enough vitamin E

True vitamin E deficiencies are uncommon in humans. This is primarily because vitamin E is fat soluble, so we typically store adequate amounts in our fatty tissues, even when our current intake are low. Vitamin E deficiencies are usually a result of diseases that cause malabsorption of fat, such as those that affect the small intestine, liver, gallbladder, and pancreas. The liver makes bile, which is stores in the gallbladder until released into the small intestine, where it emulsifies fats. The pancreas makes fat-digesting enzymes. Thus, when the liver, gallbladder, or pancreas is not functioning properly, fat and the fat-soluble vitamins, including vitamin E, cannot be absorbed, leading to their deficiency Research suggests that the diets of most Americans do not provide the RDA for vitamin E. However, these intake estimates may be low, as the amounts and types of fat added during cooking are often not known and thus are not included in survey estimates Despite rarity of true vitamin E deficiencies, they do occur. One vitamin E deficiency symptom is erythrocyte hemolysis. This rupturing of red blood cells leads to anemia, a condition in which the red blood cells cannot carry and transport enough oxygen to the tissues, leading to fatigue, weakness, and a diminished ability to perform physical and mental work. Vitamin E deficiency can also cause loss of muscle coordination and reflexes, leading to impairments in vision, speech, and movement, and can reduce immune function, especially when body stores of the mineral selenium are low

Vitamin A's role in vision

Vitamin A is a component of two light-sensitive proteins, rhodopsin and iodopsin, that are essential for vision. Here we examine the rhodopsin's role in vision. Although the breakdown of iodopsin is similar, rhodopsin is more sensitive to light than iodopsin and is more likely to become bleached Eye Structure 1. After light enters your eye through the cornea, it travels to the back fo your eye to the macula, which is located in the retina. The macula allows you to see fine details and things that are straight in front of you 2.Inside the retina are too types of light-absorbing cells, rod, and cones. Rods contain the protein rhodopsin, while cones contain the protein iodopsin Effect of Light on Rhodopsin 1. As rhodopsin absorbs incoming light, the shape of vitamin A is altered, and it detaches from the rhodopsin 2. This process, called bleaching, causes a cascade of events that transmits visual messages through your optic nerve to your brain. After bleaching, some retinal is lost 3. Retinol from the blood is converted to retinal to replenish what is lost. The vitamin A returns to its original shape and becomes part of rhodopsin again, regenerating the eye's light-absorbing capabilities. This regeneration can take a few moments

What happens with vitamin A toxicity?

Vitamin A is highly toxic, and toxicity symptoms develop after consuming only three to four times the RDA. Toxicity rarely results from food sources, but vitamin A supplementation is known to have casques severe illness and even death. In pregnant women, it can cause serious birth defects and spontaneous abortion. Other toxicity symptoms include fatigue, loss of appetite, blurred vision, hair loss, skin disorders, bone and joint pain, abdominal pain, nausea, diarrhea, and damage to the liver and nervous system. If caught in time, many of these symptoms are reversible once vitamin A supplementation is stopped. However, permanent damage can occur to the liver, eyes, and other organs. Because liver contains such high amounts of vitamin A, children and pregnant women should not consume liver on a daily or weekly basis

What happens if we don't consume enough vitamin C?

Vitamin C deficiencies are rare in developed counties but can occur. Scurvy is the most common vitamin C deficiency disease. Because vitamin C assists absorption of iron, a key component of hemoglobin in red blood cells, anemia can result from vitamin C deficiency. People most at risk are those who eat few fruits and vegetables, including impoverished or homebound individuals, and people who abuse alcohol and drugs

Describe the functions of Vitamin C

Vitamin C is probably best known for its role in preventing scurvy, a disease that ravaged sailors on long sea voyages centuries ago. Scurvy was characterized by bleeding tissues, especially of the gums, and is thought to have caused more than half of the deaths that occurred at sea. One reason that vitamin C prevents scurvy is that it assists in the synthesis of collagen, a fibrous protein present in the matrix of connective tissues. The most abundant protein in the body, it provides structure to bone, teeth, skin, tendons, blood vessels, and many other tissues and organs. Collagen has a helical structure and acts like a scaffold, helloing to hold the tissue together and giving it strength and flexibly. It also helps prevent bruises, and it supports wound healing because it is a component of scar tissue and of the tissue that mends broken bones. Vitamin C prevents scurvy by acting as a coenzyme to specific enzymes that are required to convert collagen's precursor, pro collagen, to collagen. If a person is deficient in vitamin C, that necessary synthesis reactions cannot occur; as a result, the collagen chains that are produced cannot link and twist into thick strands and fibers. Instead, they are weak and quickly destroyed. Because the body cannot form collagen without adequate vitamin C, tissue hemorrhage, or bleeding, occurs. The symptoms of scurvy appear after about 1 month of vitamin C-deficient diet and include bleeding gums, loose teeth, wounds that fail to heal, swollen ankles and wrists, bone pain and fractures, diarrhea, weakness, and depression. Vitamin C may also be involved in the synthesis of other components of connective tissues, such as elastin and bone matrix. In addition to connective tissues, vitamin C assists in the synthesis of DNA, bile, neurotransmitters such as serotonin, and carnitine, which transports long-chain fatty acids from the cytosol into the mitochondria for energy production. In addition, many hormones are synthesized with assistance from vitamin C, including epinephrine, norepinephrine, thyroid hormones, and steroid hormones

The process of converting sunlight into vitamin D

When the ultraviolet (UV) rays of the sun hit the skin, they react with 7-dehydrocholesterol. This compound is converted to cholecalciferol, an inactive form of vitamin D. Cholecalciferol is then converted to calcidiol in the liver. Calcidiol travels to the kidney, where it is converted into calcitriol, which is considered the primary active form of the vitamin D in our bodies