MAB 3 Flashcards
Why is water needed by the body
- It is an important solvent and forms the basic medium of most bodily fluids
- It is a solvent for reactions to dissolve
- It is a transport medium to carry dissolved minerals, nutrients, wastes
- Allows for diffusing of substances to occur in and out of cells
- is a life chemistry
Why must the concentration of water be maintained within a narrow range for optimal functioning
- It is vital for efficient metabolism
- it allows correct concentration of substances to diffuse across and between cells as metabolic reactions only occur in solution - Cells can maintain a constant osmotic pressure so water loss through processes such as urination are compensated for
- If cells are not isotonic, they are vulnerable to losing or gaining too much water
What is a hypotonic and hypertonic solution
Hypotonic - there is less solutes outside the cell, so less water inside the cell. Therefore water moves into the cell causing it to burst
Hypertonic- there is more solutes outside the cell, and more water inside the cell so water will move outside the cell, causing it to shrivel
What are the 3 main forms of nitrogenous waste
Ammonia
Utica acid
Urea
What is ammonia
Secreted by fish and aquatic invertebrates. Soluble in water, very basic and very toxic
What is Uric acid
Secreted by birds, reptiles and insects. Very insoluble in water, very basic and least toxic of all nitrogenous wastes
What is urea
Excreted by mammals and amphibians. Soluble in water and diluted to reduce its toxicity
Why is the removal of wastes essential for continues metabolic activity
Chemical reactions of metabolism sometimes produces chemicals which are toxic to cells. Hence metabolic wastes must be constantly removed from cells in order to maintain normal metabolic functioning
Why must CO2 be removed and by what organ is it excreted by
CO2 is produced as a waste product of respiration. When it reacts with water in the cytoplasm of cells, it forms carbonic acid. This has the potential to lower the pH of the blood and other fluids affecting the body’s homeostatic balance, decreases metabolism and denatures enzyme functioning.
Excreted by lungs through exhalation
Why must nitrogenous waste be removed
Nitrogenous waste is the by product of protein breakdown. It is toxic to cells as it changed the pH of cells making it more alkaline which effect is enzyme activity causing it to denature and interferes with transport of substances across cell membrane. All in all, decreases metabolic functioning
Excreted by kidneys through urine
Why must excess salts and water be removed
Salts and water alters osmotic pressure and interferes with membrane functions (not isotonic). Cells could burst and create a less efficient metabolic process
Excreted by kidneys (urine) and sweat glands
What is osmoregulation
Process of maintaining an internal balance of salt and water
Role of the kidney
Responsible for filtering the blood and removing nitrogenous wastes.
Osmoregulation
Role of kidney in freshwater fish
Excrete excess water. The kidney produces copious amounts of very dilute. Ammonia is excreted in large amounts of dilute urine
Function of kidney in saltwater fish
Excreted salt
To avoid water loss, fish keep drinking water. They absorb both water and salts. Water is retained and salts are actively secreted some via gills/kidneys
Saltwater fish excrete very little urine
Function of kidney in terrestrial mammals
Water and solutes are easily lost due to evaporation from lung surfaces during respiration and through excretory processes. Hormones adjust water and salt levels of the urine and maintain homeostasis. Kidneys regulate the body’s water concentration by either exerting diluted or concentrated urine
What is the renal cortex
Filters blood and removed unwanted substances
With the help of nephrons and glomeruli
What does the renal medulla do
Maintains the balance of water and salt within the blood
What does the renal pelvis do
A reservoir that collects urine from the collecting ducts of the nephron system
What does the ureter do
Carried urine from the kidney to the bladder
What does the renal artery do
Carried oxygenated blood high in nitrogenous waste into kidney for filtration
What does the renal vein do
Removes filtered blood low in oxygen and wastes from the kidney
What do the kidney tubules do
Reabsorption and secretion
What is renal dialysis
An artificial process to replace damaged kidneys.
Dialysis is performed by a large machine attached to a variety of computers and other equipment. Performed under hospital conditions. Concentrations of substances in blood and dialysis fluid are monitored by a computer so that wastes are removed during treatment. Renal dialysis removed waste only by diffusion
Types of renal dialysis
Haemodialysis
Peritoneal dialysis
Problems with diffusion
- rate of movement is too slow
2. Not all wastes can be removed by diffusion
Problems with osmosis
- Too much water can be lost in urine
2. Movement of water can make wastes too dilute for excretion by diffusion
Define enantiostasis
The maintenance of metabolic and physiological functions in response to variations in the environment
