Homeostsasis definitions Flashcards
What is negative feedback?
A change in a system produces a second change, which reverses the first change
What is osmoregulation?
The control of the water content and solute composition of body fluids, e.g. blood, tissue fluid and lymph.
What is ultrafiltration?
Filtration under pressure that separates small soluble molecules from the blood plasma
What is selective reabsorption?
The process by which useful products, such as glucose and salts, are reabsorbed back into the blood as the filtrate flows along the nephron.
What is ADH?
A hormone that affects the permeability of the collecting duct walls through insertion of aquaporin proteins
What is dialysis?
A procedure to remove waste products and excess water from the blood if the kidneys stop working properly
What is the afferent arteriole?
-Brings blood into the glomerulus. -Lumen is wider than the efferent arteriole to generate high blood pressure
What is the efferent arteriole?
Removes blood from the glomerulus. Lumen is narrower than the afferent to generate high blood pressure.
What is the glomerulus?
site of ultrafiltration
What is the bowman’s capsule?
A structure called the basement membrane, and specialised cells called podocytes ensure that only water and small soluble molecules are filtered from the blood
What is the proximal convoluted tubule?
Site of selective reabsorption of important molecules such as glucose and sodium ions by active transport/co transport and water by osmosis
What is the descending limb of loop of henle?
Permeable to water. Water reabsorbed into the blood as filtrate passes down the descending limb
What is the ascending limb of loop of henle?
Impermeable to water. Nations actively transported into the medulla to create a water potential gradient for water
