Term
| Distinguish between intracellular fluid and extracellular fluid |
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Definition
Intracelluar Fluid:
Within the cell – 2/3 of body fluid
Extracellular Fluid:
Outside the cell – 1/3 of body fluid
Interstitial fluid
Intravascular fluid
Plasma transports blood cells within arteries, veins, and capillaries |
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Term
| What four major functions does water serve in the body? |
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Definition
Solvent
Dissolves a variety of substances for transport
Dissolved substances = Solutes
Water soluble substances:
Fat soluble substances attached to water soluble proteins
Maintenance of blood volume
Blood pressure increases when blood volume rises
Kidneys help to regulate blood volume and blood pressure
Kidneys control how much water is reabsorbed
Excess water is processed by the kidneys and excreted as urine
Temperature regulator
Water absorbs any excess heat
Cools body
Body secretes fluids via perspiration (sweating)
Lubrication and Protection
Cerebrospinal fluid protects the brain and spinal cord
Amniotic fluid protects the fetus
Synovial fluid lubricates joints
Saliva moistens food for ease of digestion |
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Term
| What does your average person lose in water per day and where do those losses come from? |
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Definition
Skin and Lungs = .9 L/day
Urine 1.5 L/day
Feces .1 L/day
This is made up for by drinking about 2.2 L/day and metabolizing .3L a day. |
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Term
| What activates the thirst mechanism? (2) |
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Definition
Increased concentration of salt and other dissolved substances in the blood
A reduction in blood volume and blood pressure |
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Term
| What hormone responds to increased water osmolarity or decreased blood volume, and what does it do to counteract this? |
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Definition
ADH or Vasopressin (same thing)
Released in hypothalamus
Increases water reabsorption in kidney in distal convoluted tubule
Increases Thrist |
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Term
| Describe the Renin-Angiotensin System (8) |
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Definition
Renin Produced by juxtaglomerular cells
Stimulated by decreased pressure
Hydrolyzes angiotensinogen, forming angiotensin I
Angiotensin converting enzyme forms angiotensin II
Vascular endothelial cells (lungs)
Angiotensin II Promotes release of aldosterone
Has potent vasoconstrictive properties
Increases thirst response |
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Term
| What is an ACE inhibitor? |
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Definition
| A pharmaceutical drug used primarily for the treatment of hypertension, however they have the side effect of reducing the thirst response. |
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Term
| What substance can inhibit ADH? |
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Definition
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Term
| What happens in a water overload? (4) |
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Definition
Increase in bv detected by barroreceptors
Atrial Natriuretic Peptide-promotes sodium losses which leads to water loss
Hyponatremia can occur, eventually leading to hemolysis
Firefighters & people who might sweat a lot can be in danger of hyponatremia |
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Term
| What % of sodium is absorbed and how is it's status in the body regulated? |
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Definition
| ~98% absorbed no matter how much sodium is in the body via na+ glucose transport system. It is regulated at the level of excretion in the kidneys. |
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Term
| Function of the basolateral sodium pump |
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Definition
| Creates and maintains a sodium gradient in enterocytes |
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Term
| Distribution of sodium and chloride |
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Definition
| ~60% in ECF, ~10% in cells, ~30% in skeleton |
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Term
| What are the obligatory losses of sodium? |
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Definition
Urine ~ 23 mg
Feces ~ 10-125 mg with diets of 500-4100 mg (average 25 mg)
Skin ~ 50 mg
Sweat - varies |
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Term
| Four main functions of sodium |
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Definition
Major determinant of osmotic pressure (as major extracellular cation)
Nerve transmission and impulse conduction
Muscle contraction
Absorption of glucose and active transport of molecules using sodium pumps |
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Term
| Four main functions of chloride |
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Definition
Important in electrolyte balance (with sodium)
Required for HCl formation in stomach
Immune function
Part of acid-base system (excretion of metabolic CO2 by lungs) |
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Term
| How does the acid-base system excretion of metabolic CO2 by lungs work? (3) |
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Definition
CO2 produced in tissues enters red cells, converted to HCO3- by carbonic anhydrase
HCO3- enters plasma after swapping for Cl-
CO2 breathed off in lungs |
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Term
| Symptoms of Hyponatremia (4) |
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Definition
Muscle cramps
Nausea and vomiting
Dizziness, shock, coma
Deficiency of chloride rare (efficiently reabsorbed in kidney), but may be seen with excessive vomiting |
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Term
| Symptoms of hypernatremia (13) |
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Definition
Ingestion of large amounts of salt may lead to nausea, vomiting, diarrhea, and cramps.
Symptoms: dizziness, low blood pressure, diminished urine production, severe edema, HTN, rapid heart rate, convulsions, coma, and death. |
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Term
| In what two ways are older people more salt sensitive? |
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Definition
o Have larger BP response to low sodium
o Have reduced renin response |
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Term
| What are the functions of K+? |
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Definition
Major intracellular cation (98% found in cells)
Regulation of osmotic pressure
Nerve impulses
Contractility of muscle |
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Term
| Absorption and Excretion of K+ (5) |
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Definition
Readily absorbed in small intestine and colon (~85-90% overall absorption)
Freely filtered in kidney. We reabsorb ~70-80%, ~10% enters distal tubule where it is regulated
Usually excrete 77-90% in urine (rest in feces)
Very little lost in sweat
Aldosterone causes excretion of K when Na is reabsorbed |
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Term
| K+ deficiency symptoms and causes (7) |
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Definition
Very rare
Hypokalemia – muscle weakness, heart problems
Can result from renal dysfunction, in diuretics, vomiting, diarrhea, overuse of laxatives |
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Term
| Symptoms of K+ toxicity (7) |
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Definition
Hyperkalemia – mainly associated with renal failure
No UL set
Insufficient aldosterone secretion
Symptoms: tingling of hands and feet, muscular weakness, temporary paralysis, cardiac arrhythmia, cardiac arrest. |
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Term
| Relationship between K+ and BP |
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Definition
| High K diet lowers BP – especially in those with a high sodium intake and those who are salt sensitive |
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Term
| What does carotene cleavage enzyme do? |
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Definition
splits b-carotene into to 2 retinal molecules which then must be reduced to retinol by retinaldehyde reductase
Its expression is most abundant in the jejunum, also expressed in liver, lung, kidneys, retina |
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Term
| What three carotenoids can be converted to vit a? |
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Definition
| α-carotene, β-carotene, and β-cryptoxanthin |
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Term
| What three carotenoids have known antioxidant functions in the body? |
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Definition
lycopene- general antioxidant
zeaxanthin & lutein- provide antioxidant activity to the eye |
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Term
| What is the function of retinaldehyde reductase? |
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Definition
| Reduces retinal to retinol |
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Term
| What 2 forms of vitamin a is found most often in foods? |
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Definition
| Retinyl esters and carotenoids |
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Term
| Digestion of vitamin A (4) |
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Definition
1 – hydrolyze protein
2 – free retinol is absorbed, so must unesterify RE
3 – retinol absorbed into enterocytes from micelles - 70-90% absorbed
More recently, carrier/transporter identified for retinol
4 – carotenoids appear to be absorbed via passive diffusion - |
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Term
| What does carotenoid absorption depend on? (3) |
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Definition
Isomerization – cooking increases # of cis isomers, therefore increases absorption
Dose – higher dose = lower absorption
Food matrix – compared with pure β-carotene dissolved in oil, availability from green leafies ~7%, carrots ~18-26%, fruit ~30% |
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Term
| What is CRBP and what is its function? |
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Definition
Cellular retinol binding protein
CRBP-2 (only in enterocytes-CRBP not 2 is in liver & other body parts)binds to retinol in cell; will get oxidized if not |
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Term
| What is LRAT and what is its function? |
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Definition
Lecithin-retinol acyl transferase;
catalyzes the esterification of all-trans-retinol into all-trans-retinyl ester during phototransduction, an essential reaction for the retinoid cycle in visual system and vitamin A status in liver. |
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Term
| What happens to retinol that is oxidized to retinoic acid in enterocytes? |
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Definition
| Enters portal vein bound to albumin |
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Term
| What is transthyretin and what is its function? |
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Definition
| TTR; essential blood carrier of retinol |
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Term
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Definition
Regulation of gene expression
Cell differentiation
Immunity
Hematopoiesis
Growth and development
Epithelium (trachea, skin, salivary gland, cornea, testis)
Embryogenesis – limb development, skin, lungs, CNS, eye, face, ear, heart, urogenital system |
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Term
| Describe retinol's role in vision (4) |
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Definition
11-cis-retinal binds to opsin in the photorecptor (rod) cell and makes rhodopsin which leads to neuronal signaling
this leaves opsin, and all-trans-retinal which is then reduced to all-trans-retinol, goes through the interphotoreceptor matrix
in the retinal pigment epithelium all-trans-retinol can either come from the photoreceptor or the blood
it is then made to all-trans-retinyl ester, then 11-cis-retinol, then finally back to 11-cis-retinal
This all takes several minutes so in a low vitamin A individual there is no retinol to draw from the blood and so night-blindness occurs. |
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Term
| Symptoms of Vit A deficiency (4) |
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Definition
Delayed dark adaptation (night blindness)
Xerophthalmia (dryness of eyes)
Dry roughened skin with hyperkeratotic eruptions
Increased susceptibility to infection
A nutritionally acquired immunodeficiency disease |
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Term
| Symptoms of Vitamin A toxicity and who's at risk |
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Definition
Acute - Nausea, headache, fatigue, decreased appetite, dizziness, dry skin
Chronic – above plus bone and joint pain, anoerexia, alopecia, ataxia, can lead to liver damage
Teratogenic – craniofacial abnormalities, heart abnormalities
At Risk: Elderly, chronic alcoholics |
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Term
| Assessment of Vitamin A (3) |
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Definition
Plasma retinol levels
Relative dose response
Percent increase over baseline plasma retinol levels after dose given
Assessment of dark adaptation |
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Term
| What % of zinc is absorbed? Where is it mainly absorbed? What protein is responsible for its absorption? |
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Definition
10-60%
Mainly absorbed in duodenum and jejunum
Utilizes ZIP transporter for entry into enterocytes ZIP 4 in particular |
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Term
| What two enzymes will zinc possibly bind to when entering an enterocyte? How is it subsequently absorbed? |
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Definition
CRIPs (Cysteine-rich intestinal protein) or metallothionein
Exits enterocyte using ZnT-1 (zinc transporter 1) on basolateral membrane |
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Term
| Enhancers of Zinc absorption (2) |
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Definition
Some amino acids
-Sulfur containing AAs specifically
Low zinc status |
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Term
| Inhibitors of zinc absorption (5) |
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Definition
High Zn stores
Phytate
Oxalate
Tannins
Copper |
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Term
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Definition
Find bound to albumin in circulation (~60%)
Also transferrin and IgGs and amino acids (~15-40%)
Completed with histidine and cysteine (~2-8))
Enters cells via specific transporters (ZIPs) and amino acid transporters
Stored as metallothinein (binds 7 zinc atoms) |
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Term
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Definition
A component of >200 different metalloenzymes
Catalytic – various proteases and phosphatases
Structural - Role in gene expression as component of “zinc fingers”; CuZn SOD; component of cell membranes and insulin
Regulatory – component of Zn-finger transcription factors, also DNA and RNA polymerases
Growth and development, immune response, neurological function, reproduction |
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Term
| Zinc Deficiency who's at risk (8) and signs & symptoms (6) |
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Definition
Acrodermatits enteropathica – genetic disorder; impaired zinc absorption (defective Zip4)
Signs and symptoms – growth retardation, skeletal abnormalities, delayed sexual maturation, impaired immune function, impaired taste sensation, night blindness
Mild deficiency –
At risk groups – infants (especially premature infants) and children, pregnant & lactating women, elderly, alcoholics, strict vegetarians, malabsorption syndromes, increased losses (trauma, surgery, burns, infection), chronic male masterbaters (lol, no seriously though, not kidding... don't ask me how I know this...) |
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Term
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Definition
Acute toxicity – 1-2 g zinc sulfate (225-450 mg zinc)
Metallic taste, nausea, vomiting cramps and diarrhea
Chronic toxicity – copper deficiency |
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Term
| Forms of selenium in foods |
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Definition
| sumed in foods as selenomethionine (plant foods) or selenocyteine (animal foods) |
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Term
| Absorption of selenium (4) |
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Definition
consumed in foods as selenomethionine (plant foods) or selenocyteine (animal foods)
Inhibited by heavy metals (mercury) and phytates
Enhanced by vitamins C, A, and E |
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Term
| Functions of selenium (6) |
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Definition
Pancreatic Immmune
DNA Repair
Antioxidant function
GSH peroxidase (GSH + H2O2 → GSSG + H2O)
Selenoproteins P and W
We make ~ 25 selenoproteins require selenium to function properly (as selenocysteine)
Thyroid hormone formation |
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Term
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Definition
Selenoprotein P
>50% of circulating selenium (as selenocysteine) |
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Term
Selenium deficiency causes and signs & symptoms (3)
Also, what is Keshan's Disease? (4 signs/symptoms) |
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Definition
Causes
Low intake due to low soil content
Consequences
Muscle pain
Muscle wasting
Cardiomyopathy
Keshan disease - Keshan disease is a congestive cardiomyopathy caused by a combination of dietary deficiency of selenium and the presence of a mutated strain of Coxsackievirus
Causes:
Heart disease in children
Accumulation of fatty acid peroxides in heart
Increase in blood clots
Irreversible |
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Term
| Signs & Symptoms of Selenium Toxicity (7) |
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Definition
Garlic breath
Changes in hair and nails (brittle)
Hair loss
Neurotoxicity
Nausea, vomiting
Weakness
Rashes |
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Term
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Definition
| CLIP THE NAILS AND ANALYZE THEM YA DUMMY! |
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Term
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Definition
Thyroid hormone synthesis (from iodide and tyrosine)
Metabolic rate
Growth
Development
T4-thyroxine-most abundant circulating TH
T3-active triiodothyronine – binds nuclear receptor, exerts action on gene expression |
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Term
| Signs & Symptoms of Iodine Deficiency (4) |
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Definition
| Mental retardation, hypothyroidism, growth and developmental abnormalities, goiter (early sign) |
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Term
| Explain the process of how goiter develops (3) |
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Definition
Insufficient T4 sensed by hypothalamus leads to continual release of TRH
TRH stimulates the anterior pituitary gland to continually release TSH.
TSH stimulates the thyroid gland to increase production of various enzymes and increases colloid matrix continually, resulting in goiter |
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Term
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Definition
Acute toxicity (gram quantities)
Burning of mouth, stomach, throat, fever, nausea, vomiting diarrhea, coma
Excess
When iodine sufficient – associated with elevated TSH, hypothyroidism and goiter
Increased incidence of thyroid cancer |
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Term
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Definition
| transcription factor that helps heterodimers transcribe DNA. |
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