Lesson 9: Water and Energy Flashcards
Where is about 2/3 of water from our body found?
Inside of cells
Where is the other 1/3 of water in our bodies found?
In the extracellular fluid compartment
What does the extracellular fluid compartment contain?
Cardiovascular system Interstitial fluid compartment Lymphatic system Sweat Tears Gastric juices Spinal fluid Fluid between joints
What is crucial to allow the body maintain the correct amount of water in each compartment?
The ability of water to move freely and accurately between compartments.
What is Chemistry Golden Rule #3?
Where ions go, water follows.
Where do water molecules move?
Toward compartments with the highest concentration of solutes.
What happens if you cut an eggplant, place salt over it and wait a few minutes?
Water leaves plant cells and moves to surface where salt is most concentrated.
What do we call the process of the diffusion of water through a selectively permeable membrane?
Osmosis
What happens when you have an equal number of solute particles on both sides of a semi permeable membrane, the concentrations are equal and the tendency of water to move in either direction is about the same?
The free moving water molecules pass from one side of membrane to the other. Other molecules that are H-bonded to solutes are not free.
What happens if additional solute is added to one side?
Solutes cannot flow across the divider (the membrane), which raises solute concentration. As water molecule cross over onto the side where solute was added, they become H bonded to solute molecules.
Where does water have a greater tendency to go?
To move to the side where there is a greater concentration of solute.
How do cells control the movement of water?
By directing the movement of major minerals
What are the major minerals involved in movement of water?
Sodium
Potassium
Magnesium
Which other minerals also play a role?
Chloride
Phosphorus
Sulfate
Sodium, potassium and magnesium are positively charged ions called ________.
Cations
Chloride, phosphorus and sulfate are negatively charged ions called _________.
Anions
What are electrolytes?
Salts that dissolve in water and dissociate into charged particles called ions
What is the most important function of water in the body?
Water transports nutrients and waste
What is blood plasma mostly composed of?
Water with suspended nutrients that are delivered to cells
What do we call the water generated during metabolism which is a produce of chemical reactions?
Metabolic Water
Why do we turn red when we exercise?
Blood rushes to the surface of the skin, carrying the heat generated by the metabolic reactions in your cells. The blood capillaries at the surface of your skin dilate, allowing more blood to flow through them.
How does sweat evaporate?
Evaporation of sweat occurs at the air-water interface of your sweat glands. For warm interstitial water to be continuously pulled up to the surface of your skin, water molecules reaching the surface must evaporate.
What happens if the air is too humid?
heated body water remains trapped in the body.
The body is 50-70% water. What are the two factors by which body water varies?
- Age
2. Sex and Body Composition
Who has more water weight, a newborn or the elderly?
Newborn
Who has more body water/water weight, men or women?
Men since they have more lean tissue than women
Where do kidneys receive about 21% of their cardiac output from?
The renal artery
What is cardiac output?
Volume of blood pumped into circulation per minute
How does waste removed from blood and clean blood leave the kidneys?
Via the renal vein
What do kidneys control?
blood volume
blood pressure
the solute concentration of body fluids
What are kidneys controlled by?
Secretions from the:
Posterior pituitary gland
Adrenal glands
What does the posterior pituitary gland secrete?
ADH - antidiuretic hormone
What do the adrenal glands secrete?
Aldosterone
When does the posterior pituitary gland secrete ADH?
When blood volume is low or when concentration of Na in the blood plasma is high
What does ADH do?
Either makes less urine or retains water (therefore, retains sodium & excretes potassium)
What does Aldosterone do?
Signals the kidney to reduce the elimination of sodium in urine. It retains sodium and excretes potassium (retains water)
What does excreting potassium encourage?
Water to be retained in extracellular compartment and not migrate into body cells.
What are ways to lower blood pressure?
Increase potassium intake
Increase magnesium intake
Reduce salt/sodium intake
What is a DASH diet?
Dietary Approaches to Stop Hypertension (a way to manage blood pressure)
How can fluid and electrolyte imbalances occur?
From water deficiency and toxicity
What are 2 conditions that could arise from water deficiency or toxicity?
Dehydration and Hyponatremia
What causes hyponatremia?
Water intoxification. Body water contents are too high in all body fluid compartments. It occurs when excessive amounts of plain water are consume in a short period of time or when kidneys have difficulty filtering water from blood.
What is metabolism?
The sum total of all the chemical reactions that go on in living cells
What is an anabolic chemical reaction?
A reaction that requires energy input in order to build stuff. Absorbs energy
What is a catabolic chemical reaction?
A reaction that releases stored chemical energy in order to break things down.
What is ATP?
Adenosine TriPhosphate. It is the energy currency of the cell.
What does the liver need to run its endless anabolic chemical reactions?
Constant supply of ATP
What is the mitochondrion?
ATP factory of every cell
The mitochondrion transfer energy that was once stored in energy-yielding nutrients into ATP. What is the end product of this catabolic reaction?
Metabolic water (H20)
CO2 (exhaled)
ATP
The number of mitochondria per cell vary as a function of their metabolic rate. Which cells are more saturated with mitochondria? Which cells are less saturated?
Muscle and liver cells are more saturated.
Fat cells are less saturated.
Why is ATP the energy currency of the cell?
- It is highly reactive due to cluster of negatively charged oxygen atoms in close proximity
- It is highly unstable, the last phosphate group of ATP is released & energy is liberated in the form of kinetic energy
What is motion caused by?
Contraction of muscle fibers that move the skeleton
What is ATP synthesized from?
ADP + Phosphate
Where does energy input come from?
carbs, lipids and proteins
What do energy outlets include?
energy in physical activity (30-50%)
energy used to digest and absorb food (10%)
energy used for basic metabolic needs (basal metabolism)(50-65%)
What is basal metabolism?
the energy needed to maintain life when the body is at rest
What is BMR?
basic metabolic rate (rate when your body is at rest or doing something like housekeeping)
How is BMR calculated?
measured after fasting and resting for 12 hours. Calculated as the energy spent for breathing, circulating blood, and maintaining organ functions.
Which organ consumes the most kcal per day?
The liver
What is TEF (thermal effect of food)?
The estimated amount of energy required to process food.
What does TEF include?
Digestion
Absorption
Transportation
Metabolizing the nutrients
When does weight remain stable?
When energy expenditure is balanced with energy intake
When does weight gain occur?
When energy intake exceeds energy expenditure
When does weight loss occur?
When energy expenditure exceeds energy intake
What are the factors that influence BMR?
Body Composition
Sex
Age
Body Surface Area
How does Body Composition affect BMR?
The muscle to fat tissue ratio is important. Muscle tissue being packed with mitochondria is more metabolically active than fat tissue.
The more muscle you have relative to fat, the higher your BMR
How does Body Surface Area affect BMR?
Tall people have a greater total body surface are. To maintain body temperature, the taller the individual, the more calories to burn to replace heat that is lost. Therefore, tall people have a higher BMR.
Do genes and environmental factors play a role in BMR?
Yes they both do. BMR is largely genetically determined & the environment plays a role in utero, as a neonate and in adulthood.
True or False: people with more functional sweat glands have less of a risk of dying from heat stress because they can cool down the body more efficiently.
True
How does the fetal environment affect BMR?
low birth weight babied had a statistically significant increase risk of becoming obese as adults
What is the Thrifty Gene Theory?
fetuses deprived of calories lower their BMRs because they predict an environment of food scarcity
What is epigenetics?
The study of how the environment can effect gene expression
What is nutritional genomics?
studies how good can influence gene expression
What is nutrigenetics?
studies how genes influence how nutrients are metabolized
