Lab Midterm #2 Flashcards
urinary system
maintains homeostasis of the body -> specifically the composition and volume of blood by balancing the concentrations of ions and excreting wastes from the body
influences your RBC production and blood pressure
organs of the urinary system
two kidneys -> high on the posterior wall of the abdomen, protected by the 11th and 12th ribs
two ureters
urinary bladder
urethra
renal artery
carries 1200ml of blood to the kidneys per min
enters the kidney at the renal hilus
once it enters the kidneys it divides into smaller vessels that carry blood to each glomeruli
renal hilus
where the renal artery enters the kidney
where the renal vein and ureter connect
renal vein
filtered blood leaves the kidney via the renal vein
ureter
the collected wastes leave the kidney via the ureter and move to the bladder where they are stored before being excreted
kidney
composed of over 1 million nephrons which are the functional units of the kidney
is divided into the outer cortex and inner medulla
nephron
is the site of urine formation
has four regions
-> glomerular capsule
-> proximal convoluted tubule (PCT)
-> nephron loop
-> distal convoluted tubule (DCT)
the DCT empties into the collecting duct
cortex (outer layer)
in the cortex region there will be many circular glomeruli (glomerulus = singular) which is a tiny network of blood vessels within the glomerular capsule (aka bowman’s capsule)
-> these 2 structures are call a renal corpuscle
the glomerulus resembles a ball of yarn of capillaries -> this is the site of filtration
the remainder of the cortex is crowded with carious sections through proximal and distal convoluted tubules
medulla (middle layer)
consists of fan shaped renal pyramids
contain the nephron loops
renal columns
extensions of cortical (outer layer of organ tissue) tissue and house the blood vessels that supply nephrons
renal corpuscles
blood is filtered by them to produce filtrate in the glomerular capsule -> the thing that surrounds the glomerulus
filtrate
moves through the tubules and the nephron loop
as it travels through each section blood vessels reabsorb useful substances and secrete wastes
glomerulus
The glomerulus filters water and small solutes out of the bloodstream. The resulting filtrate contains waste, but also other substances the body needs: essential ions, glucose, amino acids, and smaller proteins.
urine formation
occurs in the nephron loops located in the medulla
minor and major calyces (calyx)
minor calyx surrounds the renal papillae of each pyramid and collects urine from that pyramid
several minor calyces converge to form of a major calyx
minor calyx -> major calyx -> renal pelvis -> collecting ducts
renal pelvis
large cavity in the centre of the kidney
is continuous with the ureter
ureter
transport urine to the bladder
leaves the kidney at the hilus
hilus
a depression or fissure where vessels or nerves or ducts enter a bodily organ.
the point of entry and exit of renal arteries, renal veins, lymphatic vessels, nerves, and ureters
nephrons
produce urine through three main processes -> filtration, reabsorption, secretion
filtration
high filtration pressure in the glomerulus forces substances through the filtration membrane (the wall of the glomerulus and the glomerular capsule)
size is a key factors -> water, glucose, nitrogenous wastes, and some ions can pass through
-> blood cells, proteins, and macromolecules cannot
separates materials on the basis of their size
glomerular filtration rate
the rate at which materials are filtered through the kidney during urine formation
in lab demonstration of filtration
colour of residue was black
colour of filtrate was blue
contents of mixture (table sugar, charcoal = black chunks, copper sulfate = blue in solution)
precipitate was formed in the filtrate to indicate presence of sugar
reabsorption
occurs as the filtrate flows through the nephron
substances that the body needs is reabsorbed back into the blood -> glucose and water
begins in the proximal convoluted tubule which majority of the tubular reabsorption occurs, but also occurs through the length of the nephron
peritubular capillaries
where reabsorbed substances enter after leaving the tubules
secretion
a process in which substances move from the blood to the peritubular capillaries into the filtrate
allows for additional wastes and other materials to leave the body in the urine
how the kidneys balance pH
excretes various levels of H+ and OH- ions to help regulate pH
active transport
cells lining the tubules of the nephron use active transport to pull molecules out of the filtrate against their concentration gradient
this is so that we can retain small molecules like glucose and amino acids in the blood and ensure they don’t get pulled into the urine
facilitated diffusion
Facilitated diffusion is the passive movement of molecules along the concentration gradient.
urea moves into the kidneys this way
osmosis
movement from a solution with high concentration of water molecules to a solution with a lower concentration of water molecules
the movement of water into or out of the kidneys depends of the concentration of solutes in the filtrate or blood
hormonal control
the amount of urine formed is under hormonal control
ADH
antidiuretic hormone is produced by the hypothalamus and secreted by the posterior pituitary gland
controls the reabsorption of water by the collecting ducts and prevents large swings in water balance, dehydration, and water overload
higher ADH levels = increased water reabsorption, reducing the volume of urine production but increasing its concentration
lower ADH levels = reduce reabsorption of water, large production of dilute urine
osmolarity
the release of ADH is regulated by the osmolarity of the blood
it is the concentration of solutes
high osmolarity indicates low availability of water -> leads to the release of ADH
low osmolarity indicates there is abundant water and leads to a decrease in ADH
factors the impact release of ADH
pain, low blood pressure, and certain drugs trigger ADH release
alcohol inhibits ADH release -> that is why you feel dehydrated after drinking
aldosterone
is produced by the cortex of the adrenal gland and helps to maintain correct concentration of sodium and potassium ions in extracellular fluids
targets the distal parts of the nephrons -> stimulates the reabsorption of sodium ions and thus water
promotes potassium secretion -> due to the function of the protein pump that actively transports sodium into the cell and potassium out
urochrome
a yellow pigment produced when hemoglobin is broken down
causes the yellow colour of urine
many disease states produce other pigments and may change the colour of urine
turbidity
cloudy urine
indicates alkaline urine, may be associated with a bacterial infection of the urinary tract
physical characteristics of urine
colour and transparency
specific gravity
pH
volume
specific gravity
weight of urine for a standard volume/ weight of water for a standard volume
water has a specific gravity of 1.000
normal urine has a specific gravity of 1.005 to 1.035
low specific gravity (dilute urine) may occur in patients with diabetes insipidus
high specific gravity (concentrate urine) is most commonly found in dehydration of excessive water loss
diabetes insipidus
disease caused by inadequate secretion of ADH or failure of the kidney tubules to respond to ADH