Chapter 10: urinary system Flashcards
functions of urinary system:
-removes wastes from the blood
- helps regulate blood composition
- pH, volume, and pressure;
- maintains blood osmolarity
- and produces X
hormones
The urinary system consists of:
- Two Kidneys: regulate blood
volume and composition, produce
hormones and excrete wastes. - Two X: transport urine from
kidneys to urinary bladder. - One urinary bladder: stores urine
and expels it into urethra. - One urethra: discharges urine
from body.
ureters
Functions of the kidneys include the following:
1. Excretion of wastes
2. Regulation of blood ionic composition
3. Regulation of blood pH
4. Regulation of blood volume
5. Regulation of blood pressure (renin)
6. Maintenance of blood X
7. Production of hormones (calcitriol and erythropoietin)
8. Regulation of blood glucose level
osmolarity
What wastes do the kidneys excrete?
- …. wastes:
- urea and ammonia from the deamination of amino acids
- creatinine from the breakdown of creatine phosphate
- uric acid from the catabolism of nucleic acids
- urobilin from the breakdown of hemoglobin
- Other wastes: drugs and environmental toxins
Nitrogenous
Kidneys:
Regulation of blood pressure. The kidneys also help regulate blood pressure by
secreting the enzyme X, which activates the renin–angiotensin–aldosterone
pathway. Increased X causes an increase in blood pressure.
renin
The kidneys seperately regulate loss of water and loss of solutes in the urine
true/false
true (that way they maintain blood osmolarity)
Kidneys;
Production of hormones. The kidneys produce two hormones: X, the active
form of vitamin D, helps regulate calcium homeostasis, and erythropoietin stimulates
the production of X.
calcitriol
red blood cells
Renal medulla: deep, darker reddish-brown inner region. It consists of several
cone-shaped renal …..
pyramids
Together, the renal cortex and renal pyramids of the renal medulla constitute the
parenchyma or functional portion of the kidney.
- Within the parenchyma are the functional units of the kidney—about 1 million
microscopic structures called X - Filtrate (filtered fluid) formed by the nephrons drains into large X ducts, which
extend through the renal papillae of the pyramids.
nephrons
papillary
The papillary ducts drain into cuplike structures: X and X calyces. A X calyx
receives filtrate from the papillary ducts of one renal papilla and delivers it to a X
calyx. Once the filtrate enters the calyces it becomes urine because no further
reabsorption can occur.
- From the major calyces, urine drains into a single large cavity (renal pelvis) and then out
through the ureter to the urinary bladder.
minor and major
minor
major
Although the kidneys constitute less than 0.5% of total body mass, they receive 20–25%
of the resting cardiac output via the right and left X arteries.
renal
Finally, each nephron receives one e/afferent arteriole, which divides into a tangled, ballshaped capillary network called the X or glomerular capillaries.
- The glomerular capillaries then reunite to form the a/efferent arteriole that carries blood
out of the glomerulus.
afferent
glomerulus
efferent
Glomerular capillaries are unique among capillaries in the body because they are
positioned between two arterioles, rather than between an arteriole and a venule.
* Efferent arterioles divide to form the X capillaries.
peritubular
The peritubular capillaries eventually reunite to form X radiate veins, which also
receive blood from the vasa recta.
- Veins reunite and the blood finally leaves the kidney through a single X vein that
exits at the renal hilum and carries venous blood to the inferior vena cava
cortica
renal
Each nephron consists of two parts:
- Renal X: where blood plasma is filtered. It is composed by:
- Glomerulus: capillary network.
- Bowman’s capsule or glomerular capsule: a
double-walled epithelial cup that surrounds the
glomerular capillaries
- Renal X: into which the
filtered fluid (glomerular
filtrate) passes.
corpuscle
tubule
The glomerular (Bowman’s) capsule consists of two layers:
- Visceral layer: modified simple squamous epithelial cells called podocytes. The many
footlike projections of these cells (pedicels) wrap around the single layer of
endothelial cells of the glomerular capillaries and form the inner wall of the capsule. - Parietal layer: simple squamous epithelium and forms the outer wall of the capsule.
- Fluid filtered from the glomerular capillaries enters the X space, the space between
the two layers of the glomerular capsule, which is continuous with the lumen of the renal
tubule.
capsular
The renal tubule has three main sections:
- Proximal convoluted tubule
- Nephron loop (loop of X)
* Descending limb
* Ascending limb - Distal convoluted tubule
Henle
In each nephron, the final part of the ascending limb of the nephron loop
makes contact with the afferent arteriole serving that renal corpuscle.
* The columnar tubule cells in this region are: the macula X
densa.
Alongside the macula densa, the wall of the afferent arteriole (and
sometimes the efferent arteriole) contains modified X muscle
fibers: juxtaglomerular cells.
smooth
- Macula densa and juxtaglomerular cells constitute the juxtaglomerular
X (helps regulate blood pressure within the kidneys).
apparatus
To produce urine, nephrons and collecting ducts perform three basic processes:
- Glomerular filtration.
- Tubular X.
- Tubular secretion.
* By filtering, reabsorbing, and secreting, nephrons help maintain homeostasis of
the blood’s volume and composition.
reabsorption
Together, the glomerular capillaries and the
podocytes, form a leaky barrier known as the
filtration X: permits filtration of
water and small solutes but prevents filtration
of most plasma proteins and blood cells.
membrane
Substances filtered from the blood cross three
filtration barriers:
basement membrane (acellular)
glomerular endothelial cell
podocyte
put in right order
- First barrier: glomerular endothelial cell
- Second barrier: basement membrane
- Third barrier: podocyte
Located among the glomerular capillaries and in the cleft between afferent and
efferent arterioles are mesangial cells (contractile) cells: what do they do?
help regulate glomerular filtration?
The slit membrane is part of the …. (1st, 2nd or 3rd) barrier
3rd
Extending from each podocyte are thousands of footlike processes termed pedicels
that wrap around glomerular capillaries. The spaces between pedicels are the
filtration slits. A thin membrane, the slit membrane, extends across each filtration
slit; it permits the passage of small molecules: water, glucose, vitamins, amino acids,
very small plasma proteins, ammonia, urea, and ions. Albumin (the most plentiful
plasma protein) is too big to get through.
What is the glucose concentration of the primary urine?(= after going through the glomerulus)
blood glucose
- What is the sodium concentration of primary urine?
Blood concentration
What is the amino acid concentration of primary urine?
blood concentratino
How many red blood cells does primary urine have?
zeero
What is the albumin concentration of the primary urine?
zero
In conclusion: the primary urine is an ultrafiltrate of the plasma, that is to say… :
a protein-free plasma!
ok
the volume of fluid filtered by the renal corpuscle is much larger than in
other blood capillaries of the body for 3 reasons:
- large surface area for filtration (cappilaries are long and extensive)
- The filtration membrane is ….. (large fenestrations)
- Glomerular capillary BP is low/high
thin and porous
high
