Lab 5 - Urinary Sys Flashcards
The urinary sys consists of:
- 2 kidneys
- 2 ureters
- urinary bladder
- urethra
Where are the kidneys located
the posterior wall of the abdomen and partially protected by the eleventh and twelfth pairs of ribs
What vessel carries blood to the kidneys
the renal artery
how much blood does the renal artery carry
~1200ml of blood/min
Where does the renal artery connect to the kidney
Renal Hilus
Renal Hilus
where the renal artery, renal vein, and ureter connect to the kidney
how much does the kidney filter
~180L/day
What do the kidneys do
- filter fluid from the bloodstream
- remove wastes
- recycle needed substances back to the body
Where does filtered blood exit the kidney?
Renal Vein
Where do the collected wastes leave the kidney
the ureter towards the muscular bladder
where are wastes from the kidneys stored before being exreted
the bladder
Through what are wastes from the kidneys excreted through?
the urethra
how much urine is produced in a day
~1-2L/day
Blood is filtered in the _____ __________ to produce ________ in the __________ _______
in the renal corpuscle
produce filtrate
in the glomerular capsule
What is blood filtered though to produce filtrate?
renal corpuscles
What is produced when blood is filtered through renal corpuscles and where is it
produces filtrate in the glomerular capsule
After being filtered through nephron loops, where is urine carried from and to?
- from the collecting ducts
- through the minor and major calyces
- to a large cavity in the centre of the kidney called the renal pelvis
- which continues into the ureter
- which leave the body at the hilus to the bladder
Renal Pelvis
the large cavity in center of kidney
What is the functional unit of the kidneys
the nephron
How does surface area tie in with kidney function?
Once the large renal artery enters the kidney, it divides into smaller vessels that carry blood to one of about a million glomeruli, one for each nephron of the kidney.
This generates a large surface area for the
process of urine formation
Nephrons produce urine through 3 main processes:
- filtration
- reabsorption
- secretion
where does filtration begin
when blood enters the glomerular capillaries
What can pass through the filtration membrane of the wall of the glomerulus
water
glucose
nitrogenous wastes (eg. urea)
some ions
other small substances
How does filtration work
high capillary pressures in the glomerular capillaries push small substances like water, glucose, nitrogenous wastes, etc. through the filtration membrane formed on the wall of the glomerulus.
What is retained during filtration under normal conditions
blood cells
proteins
macromolecules
Glomerular Filtration Rate:
- the rate at which materials are filtered through the kidney during urine formation.
- Altering the glomerular filtration rate alters the quantity of filtrate (and, ultimately, urine)
produced.
Reabsorption
is a process in which substances the body needs, such as glucose and water, re-enter the blood from the filtrate to prevent them from being eliminated in urine.
What types of things are reabsorbed?
glucose and water
Where does the process of filtration begin
in the proximal convoluted tubule, which is where majority of the tubular reabsorption occurs, but does occur throughout the length of the nephron
Where does majority of the tubular reabsorption occur?
in the proximal convoluted tubule
Reabsorbed substances enter the (to the back into blood)
Peritubular capillaries that surround the renal tubules
Secretion
- is a process by which substances move from the blood in the peritubular capillaries into the filtrate.
- This process allows additional wastes and other materials that were not passed into the filtrate during filtration, to leave the body in the urine
Kidneys and pH?
excretes varying amounts of **hydrogen (H+) and hydroxide (OH-) ions to help regulate pH of the blood
In order to retain most of the ions/small molecules, like glucose/amino acids, cells in the tubules of the nephron use ______ _______… why?
Active transport
- to pull the molecules out of the filtrate against their concentration gradient
Which process does urea use to move in and out of blood in the kidneys?
passive transport
facilitated diffusion
direction depends on concentration of solutes in filtrate and blood
Which process does water use to move in and out of blood in the kidneys?
passive transport
osmosis
direction depends on concentration of solutes in filtrate and blood
The amount of urine formed is controlled by
hormonal control
How is urine formation adjusted
hormonal control
according to body’s needs in order to maintain fluid/electrolyte homeostasis
ADH
Antidiuretic hormone
- produced in the hypothal
- secreted by posterior pituit gland
- controls the reabsorption of water by the collecting ducts and preventing large swins in water balance, dehydration, and water overload
What can ADH prevent
large swings in water balance, dehydration, water overload
High ADH causes
increase in the reabsorption of water reducing the volume of urine production but increasing concentration
What is the relationship between urine volume and urine concentraion?
they have an inverse relationship
higher ADH levels
- increase water reabsorption, leading to low urine vol but **high concentration
low ADH levels
- decrease water reabsorption, leading to high urine vol but low concentration
Low ADH causes
low reabsorption of water, leading to large amount of dilute urine
release of ADH is regulated by
osmolarity of blood
osmolarity of blood
concentration of solutes
High osmolarity reflects…
which leads to…
low available water, leading to release of ADH
Low osmolarity occurs when…
leading to…
water is abundant, leading to reduction of ADH release
What can trigger ADH release?
- pain
- low BP
- certain drugs (nicotine, morphine, barbiturates)
What can inhibit ADH release?
alcohol
Aldosterone
- produced by cortex of adrenal gland
- helps maintain correct concentrations of sodium/potassium ions in the extracellular fluids.
Aldosterone primary targets
the distal parts of the nephrons
- stimulates reabsorption of Na ions, and thus water
- promotes K excretion
3 categories of basic urinalysis
- physical characteristics
- chemical composition
- sediments
Physical Characteristics in Urinalysis
- color/transparency
- specific gravity
- pH
- volume
Where does urine get its color
Urochrome
- a yellow pigment produced when hemoglobin is broken down
Normal color of urine
yellow/amber color
comes from urochrome pigment
Turbidity
cloudiness/hazieness
Turbidity in urine indicates
alkaline urine
this may be associated with a bacterial infection of urinary tract
Normal specific gravity of urine
1.005-1.035
specific gravity expressed as numeric val and defined as
weight of urine for a standard vol / weight of water for a standard vol
low specific gravity (dilute urine) may occur in
patients with diabetes insipidus
in diseased that damage the renal tubules, thus interfere w/ kidneys ability to concentrate urine
Diabetes insipidus caused by
caused by inadequate ADH secretion or failure of kidney tubules to respond to ADH
high specific gravity (concentrated urine) most commonly found in
dehydration
excessive water loss (sweating, fever, vomiting, diarrhea)
if specific gravity is low, urine is
dilute
if specific gravity is high, urine is
concentrated
normal urine pH
slightly acidic ~6
varys from 4.5-8.0
what can alter urine pH
- diet
- medications
- pathological condition
volume of urine produced depends on factors such as…
- hydration
- activities
- environmental factors
- weight of individual
- drugs
- hormones
- individs health
average production of urine
1-2L/day
Polyuria
producing excessive urine (>2.5L/day)
oliguria
producing <400mL/day
not enough urine
Chemical Composition in Urinalysis
- glucose
- protein
- ketones
- bilirubin
- urobilinogen
- nitrite
- blood
glycosuria
excess glucose in urine
what can glycosuria indicate
diabetes mellitus
Proteinuria
protein in the urea
higher levels of protein in urine indicates
diseases such as renal disease or glomerulonephritis
OR non-kidney diseases such as HTN or HR
what causes proteinuria
increase permeability of the glomerular filter due to disease
Ketonuria
ketones in urine
ketones may appear in urine as the result of
carbohydrate deficient diets
what are Ketones and how produced?
when the body lack glucose to break down, it turns to its fat stores for energy
the metabolism of fats produces ketone bodies as a waste product
Ketonuria is an important signal of
body stress, as it occurs in uncontrolled diabetes mellitus, excessive insulin therapy, or carbohydrate metabolic malfunctions such as
- starvation
- increased body metabolism (eg. vomiting, diarrhea, fever, pregnancy, lactation, trauma)
Bilirubin in urine indicates
possible gallstone in bile duct, or cancerous growth in bowel or liver
- prevents bilirubin from being expelled
- blood lvls rise
may also be present in urine when
- liver is damaged by hepatitis or cirrhosis, and cannot produce bile
Bilirubin is formed when
hemoglobin is broken down by phagocytic cells in the liver and spleen
transported to liver and excreted via bile passages into intestine
Urine bilirubin measurement is particularly effective in monitoring
course of hepatitis
Urobilinogen is produced
in the intestine when bilirubin from bile is reduced to urobilinogen by action of intestinal bacteria
Urobilinogen in urine could indicate
liver disease
- hepatitis/cirrhosis
hemolysis
bile duct blockage
high lvls can indicated excessive RBC breakdown
Nitrite in Urine could indicate
urinary pathogens (bacteria) present in signif #’s
hemoturia
whole erythrocytes in urine
hemoglobinuria
hemoglobin from destroyed, hemolyzed RBCs in urine
Myoglobinuria
myoglobin from muscle tissue in urine
Sediments in Urinalysis
- cells
- crystals
- casts
- other components
Casts
roughly cylindrical structures made up of precipitated protein/other material
Hyaline casts
consisting entirely of protein, are common in healthy urine but are difficult to see
Cellular Casts
formed when cells present in the tubules become trapped in hardening protein
formed from RBCs, WBCs, or epithelial cells
- usually indicative of renal disease if present in large #s
Granular Casts
difficult to identify broken down cellular casts
Waxy Cast
fully disintegrated cellular casts
