Lesson plan 1 Flashcards
The urinary system consist of
- kidneys (2)
- Ureters (2)
- Urinary bladder
- Urethra
The functions of the urinary system are to:
- Kidneys regulate blood volume and composition; help regulate blood pressure, pH, and glucose levels; produce two hormones (calcitriol and erythropoietin); and excrete wastes inurine
- Ureters transport urine from kidneys to urinary bladder
- Urinary bladder stores urine and expels it into the urethra
- Urethra discharges urine from the body
8 functions of the Kidney are:
- Regulation of blood ionic composition (e.g. Na+, Cl-etc)
- Regulation of blood pH
- Regulation of blood volume
- Regulation of blood pressure
- Maintenance of blood osmolarity
- Production of hormones (calcitrol and erythropoietin)
- Regulation of blood glucose level
- Excretion of wastes from metabolic reactions and foreign substances (drugs or toxins)
•Pertaining to organs closely attached to the posterior abdominal wall and partly covered by peritoneum. The paired kidneys are reddish and bean shaped organs that are located just above the waist between the peritoneum and the posterior wall of the abdomen. Because their location is posterior to the peritoneum the kidneys are said to be __________
Retropertioneal
Height & Location of kidneys
•The kidneys are located between the levels of the last thoracic and third lumbar vertebrae, they are partially protected by the eleventh and twelfth pairs of ribs. The right kidney is slightly lower than the left because the liver occupies the space on the right side superior to the kidney
External anatomy of kidney
An adult kidney is 4-5 inches long, 2-3 inches wide and 1 inch thick (approximately the size of a bar of soap)
.•Renal hilum (or hilus)
Near the center of the concave borderof kidney
oAn indent where ureter emerges from kidney along with blood vessels, lymphatic vessels and nerve
Renal Hilum (or Hilus)
3 Tissue layers
- Renal capsule
- Adipose tissue
- Renal fascia
Deep layer
- Continuous with outer coat of ureter
- Barrier against trauma
- Maintains kidney shape
Renal capsule
- Middle layer
- Mass of fatty tissue surrounding the capsule
- Protects kidney from trauma and holds it in place
Adipose capsule
- Superficial layer
- Thin layer of connective tissue that anchors kidney to surrounding structures and abdominal wall
Renal fascia
- Superficial region of kidney
- Extending from renal capsule to the bases of the renal pyramid and into the spaces between them
- Divided into an outer cortical zone and inner juxtamedullary zone
Renal Cortex
- Inner region of kidney
- Consists of several pyramids
Renal Medulla
- Cone shaped
- Found in the medullaoBase points towards the cortex
- Apex (Papilla) points towards the renal hilu
Renal Pyramids
-The apex (narrow end) of renal pyramid which points towards the renal hilum
Renal Papilla
-The portions of the renal cortex that extend between the renal pyramids
Renal Columns
-Consists of a renal pyramid, its overlying area of renal cortex, and one-half of each adjacent renal column
Renal Lobe
- Functional portion of the kidney
- Made up of the renal cortex and renal pyramids
Parenchyma
- The functional units of the kidney
- Approximately 1 million microscopic structure
Nephrons
- Extend through the papillae of the pyramids
- Filtrate formed by the nephrons drain into these large ducts
Papillary ducts
- Cup-like structures that the papillary ducts drain into.
- Each kidney has 8-18 minor & 2-3 major calyces
Minor & Major Calyces
-Single large cavity that the major calyces drain into
Renal Pelvis
- A cavity within the kidneys that the hilum expands into.
- Contains part of the renal pelvis, the calyces and branches of the renal blood vessels and nerves
Renal Sinus
Urine that is formed by nephron drains into
Papillary ducts ↓ Minor calyces ↓ Major calyces ↓ Renal pelvis ↓ Ureter ↓ Urinary bladder
Blood supply
- Although kidneys constitute less than 0.5% of total body mass, they receive 20-25% of resting cardiac output via the right and left renal arteries
- In adults, renal blood flow, the blood flow through both kidneys, is about 1200 mL per minute
Blood flow of kindeys
- Left and right renal artery enters kidney and branches into segmental arteries which give off several branches of interlobar arteries. At the bases of the renal pyramids, the interlobar arteries arch and become arcuate arteries. Divisions of arcuate arteries produce interlobular arteries (they pass between renal lobules) then they enter the renal cortex and give off branches called afferent arterioles.
- Each nephron receives one afferent arteriole which divides into ball-shaped capillary network called the glomerulus. The glomerular capillaries reunites to form efferent arteriole that carries blood out of glomerulus. Unique capillariesbecause they are positioned between 2 arterioles…considered a part of the cardiovascular & urinary system. Efferent arterioles divide to form peritubular capillaries (in renal cortex) and some have vasa recta (in renal medulla)
- Peritubular capillaries reunite to form peritubular venules and interlobular veins which also receiveblood from vasa recta. Blood then drains through arcuate veins to interlobar veins which run between renal pyramids and then exit the kidneys via renal vein at the renal hilum and carries blood to the inferior vena cava.
Nephrons & its two pairs
-functional units of the kidney
-Consists of 2 parts
Renal corpuscle
Renal tubule
filters blood plasma
•Glomerulus -capillary network
•Glomerular (Bowman’s) capsule-double walled cup surrounding glomerulus
Renal corpuscle
receives filtered fluid
•Proximal convoluted tubule (PCT)
•loop of Henle (nephron loop)
•Distal convoluted tubule (DCT)
Renal tubule
oConnects the proximal and distal convoluted tubules
oThe first part of the loop dips into the renal medulla where it’s called descending limb of the loop of Henle. Then it makes a hairpin turn and returns to the renal cortex as the ascending limb of the loop of Henle
Loop of henle
–80-85% of nephrons oRenal corpuscle in outer portion of cortex and short loops of Henle extend only into outer region of medulla
Cortical nephrons
other 15-20%oRenal corpuscle deep in cortex and long loops of Henle extend deep into medulla
oReceive blood from peritubular capillaries and vasa recta
oAscending limb has thick and thin regions
oEnable kidney to secrete very dilute or very concentrated urine
Juxtamedullary nephrons
-Helps regulate blood pressure in kidney
-Consists of:
Macula densa
-Juxtaglomerular cells
Juxtaglomerular apparatus
Made up of columnar tubule cells
-Cells in final part of ascending loop of Henle o
Macula densa
- Made up of modified smooth muscle fibers
- Cells are found in afferent (sometimes efferent arterioles) alongside the macula densa of the ascending limb of loop of Henle
Juxtaglomerular cells
