Chapter 4: Water Flashcards
Water
- explain structure
Polar nature gives it a v shape; positive hydrogen atoms and negative oxygen atoms
Describe the water content of the human body
- 60-70% of the body is water by weight
intracellular: 2/3 - A cell’s cytoplasm is 80% water; water in cytoplasm accounts for the majority of the body’s water
extracellular: 1/3 - blood, around joints, lining tissues around lungs, lymph, between cells
fill in the blank: blood is ___ water
90%
Explain how water is exchanged between the extracellular space and the blood (2)
- Osmosis: movement of water across semi permeable membranes to even out concentration differences
- blood pressure: force pushes water out of blood and into the extracellular space
List the functions of water (6)
- structure
- solvent
- hydrolysis
- defence from infection
- protection from injury
- temperature regulation
Explain how water provides structure
- Gives cells 3 dimensional shape to function properly with water pressure
- Synovial fluid in sacs between joints promote joint structure and allow bones to glide by each other more fluidly
- Fluid in eye gives it structure
Explain how water serves as a solvent
- Dissolves polar substances allowing them to be more easily transported around body through a medium into passageways (digestive tract or blood vessels)
- Compatible reactants dissolved in water have an increased chance of them colliding and undergoing a chemical reaction
Explain water’s role in hydrolysis
- Process of splitting larger molecules into smaller ones using water
- Example: maltose → 2 glucose molecules
Explain water’s role in defence from infection (2)
- Infectious agents are moved to the lymph where immune cells act on them
- Mucus traps and gathers pathogens for removal
Explain water’s role in injury protection
- Reduces the friction and damage from movement or trauma
- Water in synovial fluid prevents bones from scraping against each other
- Mucus protects tissues from injuries
- Cerebrospinal fluid protects brain from various forces
Explain water’s role in temperature regulation
- Internal temperature for proper function: 37degC
- Body opens blood vessels near skin to allow blood to shunt heat from the body’s core to the skins surface . This triggers the sweat response. Also contributes to the observable redness of our skin when exercising
- Sweating: released water on skins surface cools our bodies and skin as it evaporates
What are ways we lose water (3) and gain water (3)
lose: urine, feces, evaporation
gain: beverages, foods, metabolic processes (hydrolysis)
What 2 mechanisms come to play when blood volume decreases
- Thirst increases
- Kidneys gatekeep what stays in blood and is excreted in urine
(High blood volume → excess water is excreted in kidneys)
(Low blood volume + pressure → kidneys decrease urine production)
Dehydration
- symptoms
- what does chronic dehydration put you at risk for?
- symptoms: increased thirst, dry mouth, headaches, fatigue, dizziness, irritability, dark urine
- kidney disease, seizures, hypovolemic shock
Water intoxication
- what
- hyponatremia
- symptoms
- Content of water in body is too high with respect to the level of electrolytes
- Occurs when you consume too much water too fast or when you lose alot of water from sweating, diarrhea or vomiting and only replace it with more water (need electrolytes!)
- Hyponatremia: too much water in relation to sodium in the body
- Symptoms: headache, confusion, personality changes, irritability, drowsiness, malfunction of the CNS, increased risk for seizures, brain damage, coma, death
