Final Flashcards
(148 cards)
What is the definition of fluid?
- Molecules are far enough apart that they can slide past each other
- Conforms to shape of container
- Retains a nearly constant volume independent of pressure
How much fluid is in the human body?
- 60% fluid (decreases as we age) with electrolytes
- In blood (90% water), muscle (75%), bone (25%), fat (10%)
What are intra and extracellular fluids?
- Intracellular fluids: fluid within cells (eg. inside RBC, mucous membrane)
- Extracellular/interstitial/tissue fluid: fluid located outside of cells (eg. blood)
What are the functions of fluids?
- Dissolve and transport substances
- Carbohydrates, amino acids, water-soluble vitamins, minerals, medications
- Fat-soluble substances are transported with transport proteins (chylomicrons, lipoproteins, albumin) - Protect us
- Cerebrospinal fluid cushions brain from damage
- Amniotic fluid protects the developing fetus - Lubicant
- Saliva, tears, and mucus moistens us
- Synovial fluid in joints protect joints from going bone on bone - Maintain body temperature at 37 C
- Water keeps us from overheating and dying
- If hot, blood vessels bring up more blood (vasodilation) which evaporates as sweat - Involved in chemical reactions
- Hydrolysis: water breaks 2 molecules apart
- Condensation: water is released when 2 molecules are joined
What is water balance?
- State of equillibrium in which fluid intake from water/foods = fluid losses from GI tract, urine, sweat, and other secretions
Where does water intake and loss come from?
INTAKE:
- Mainly beverages, 1/4 from foods
- Some released during making triglycerides/peptide bonds + metabolism
LOSS:
Urine, feces, evaporation, sweat, breath, insensible losses (unaware)
How is water intake/loss regulated?
INTAKE:
- Hypothalamus receives signals to drink
- High solute concentrations in blood, low blood volume/pressure, dryness in mouth
- Low blood volume/increased solute = thirst centre in brain + saliva secretion is reduced = thirst = blood volume increases when drink
- May get confused with hunger message
LOSS:
- Blood becomes concentrated
- Antidiuretic hormone (ADH) is released
- Tells kidneys to retain water = no urination
What are the fluid recommendations?
AI (no RDA): women need 2.7 L, men 3.7 L
What is dehydration? How is it measured and who is susceptible?
- Excrete more water than take in
- Measured using change in body weight
- Susceptible: infants and children (increased body surface area and metabolic rate), older adults (decreased sensitivity for thirst), athletes (sweat losses)
What is mild, moderate and severe dehydration?
- 1-2% decrease in body weight
- Loss of appetite, crankiness, headaches, faintness, tiredness, dry eyes and mouth, dark urine - Moderate dehydration is loss of 3-5% of body weight
- Sleepiness, nausea, headache, decreased concentration, decreased cognitive functions - Severe dehydration is greater than 7%
- Delirium
- 10-20% loss of body weight can cause death
What is overhydration?
- Caused by too much fluid without enough sodium in diet
- Hyponatremia: low sodium per volume
- Swelling of tissues occurs (water moves out of blood vessels into interstitial spaces)
- Can lead to brain swelling, seizures, coma, death
- Rare, usually has kidney disfunction
What are electrolytes? Where are they found?
- Dissolved mineral ions with + or - charge
- Allows water to be drawn in (Na+) or out (K+) of cell/blood vessels
- Found in all foods (potassium, sodium, calcium)
What do electrolytes do? What are symptoms of not enough and how is it caused?
- Regulate fluid balance through osmosis
- Allows nerves to work
- Allows muscles to contract
- Imbalance = poor appetite, muscle cramps, confusion, irregular heartbeat
- Can occur due to kidney disease, vomiting, diarrhea, sweating, IV fed hospital patients
How are electrolyte levels in blood regulated?
- Controlled by kidneys
- Decrease in blood pressure due to low electrolytes = kidneys release enzyme renin = converts angiotensin I to II = secretion of aldosterone, increasing sodium retention + constriction of blood vessels = pull in water = reestablish blood pressure
What is sodium for? What are high sodium foods?
- Required for nerve signals, fluid balance, blood pressure (increase), nutrient transport
- High sodium foods: dill pickle, cured ham, tomato juice, canned cream-style corn, canned tomato soup, salted potato chips and saltine crackers
What are the recommendations for sodium? What are the risks and the process for this risk?
- Most Canadians consume more sodium (2400 mg/day) than UL (2300 mg/day)
- Increases risk of hypertension
- High sodium intake = increases blood sodium levels = fluid retention = increase in blood volume and pressure
Most individuals: kidneys excrete sodium, water follows = normal pressure
Salt-sensitive individuals: slow sodium excretion OR sodium prevents dilation of blood vessels = high blood pressure persists
What is hypertension? What are the process?
- 20% of Canadians have hypertension
- 70% of those over 80 (elasticity decreases with age)
- 20% of people with hypertension do not know
- Higher risk for heart attacks, stroke and kidney disease
- Causes include genetics, age, family history, lifestyle factors
What are vitamins and minerals?
- Vitamins: organic molecules (C) our body needs to function
- Minerals: inorganic molecules (metals) our body needs to function
- Do not provide us with energy, but necessary
What are water soluble vitamins? How are they absorbed and transported?
- B vitamins or vitamin C
- Some absorption in stomach
- Transported into intestinal cells using facilitated diffusion or active transport
- Transported in body bound to blood proteins
- If too much, excreted in urine
- In natural form, do not build up
What are fat soluble vitamins? How are they absorbed and transported?
- Vitamins A, D, E, and K
- Require dietary fat for absorption
- In stomach, digestion occurs and some niacin is absorbed
- Gallbladder releases bile to emulsify fat
- Absorbed into intestinal cells in small-intestine through simple diffusion (micelles) and packaged into active chylomicrons which enter lymph before passing through blood to liver
- Transported in body as lipoproteins or bound to transport proteins
- Stored in fat in body, accumulation can be dangerous
What is fortification and enrichment?
- Fortification: process of adding nutrients to food
- Examples: table salt with iodine (thyroid), milk with vitamin D (rickets), grains with thiamin, riboflavin, niacin, iron, and folic acid - Enrichment: adding nutrients back to foods that were lost in processing
- Flour, “white flour”, “enriched flour”, or “enriched white flour” is enriched (mandatory) with thiamin (B1), niacin (B3), folic acid (B9), and iron
What are the B vitamins? What do they do?
- B1 (thiamin), B2 (riboflavin), B3 (niacin), B5 (panththenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate or folic acid), B12 (cobalamin)
- Conenzyme vitamins that help enzymes function
- Involved in energy production (burning carbohydrates, fat protein)
- Involved in energy metabolism
- Vitamin combines with chemical group to form functional coenzyme
- Functional coenzyme combines with incomplete enzyme to form active enzyme
What is B1? What are its functions, sources and RDA?
- Needed to burn glucose for energy
- Needed for carbohydrate and protein metabolism (converts amino acid or glucose to acetyl CoA)
- Found in whole grains, pork, yeast extract, nuts, legumes, flaxseeds
- RDA: 1.1 mg/day for women and 1.2 mg/day for men
What is Beriberi? Why does it occur, what are the consequences?
- Profound weakness
- Lack of thiamin
- Most commonly occurs due to alcoholism (damages GI cells, decrease absorption)
- Causes lethargy, fatigue, depression, cardiovascular problems
- Nerve damage: dementia, confusion, memory loss
- Became common in Asia when white rice was introduced