The Urinary System
What are the 6 functions of the kidneys
*Regulation of blood ionic composition * Regulation of blood pH. *Regulation of blood volume. *Regulation of blood pressure. *Maintenance of blood osmolarity *Production of hormones *Regulation of blood glucose level *Excretion of wastes and foreign substances
What are the FUNCTIONS OF THE URINARY SYSTEM
1. Kidneys regulate blood volume and composition; help regulate blood pressure, pH, and glucose levels; produce two hormones (calcitriol and erythropoietin); and excrete wastes in urine. 2. Ureters transport urine from kidneys to urinary bladder. 3. Urinary bladder stores urine and expels it into urethra. 4. Urethra discharges urine from body.
How long is typical adult kidney?
10-12 cm (4-5 in.) long, 5-7 cm (2-3 in.) wide, and 3 cm (1 in.) thick—about the size of a bar of bath soap
How much plasma that passes through the glomeruli (180 liters) is filtered into the renal tubules daily
20%
What does Excretion of wastes and foreign substances consist of?
By forming urine, the kidneys help excrete wastes—substances that have no useful function in the body. Some wastes excreted in urine result from metabolic reactions in the body. These include ammonia and urea from the deamination of amino acids; bilirubin from the catabolism of hemoglobin; creatinine from the breakdown of creatine phosphate in muscle fibers; and uric acid from the catabolism of nucleic acids. Other wastes excreted in urine are foreign substances from the diet, such as drugs and environmental toxins.
What does Maintenance of blood osmolarity consist of?
By separately regulating loss of water and loss of solutes in the urine, the kidneys maintain a relatively constant blood osmolarity close to 300 milliosmoles per liter (mOsm/liter
What monitors the ECF solute (Na+) concentration
Chemoreceptors in the hypothalamus
3 Basic Renal Functions what are the 3 Basic Renal Functions
Glomerular filtration Tubular reabsorption Tubular secretion
What does Regulation of blood glucose level consist of?
Like the liver, the kidneys can use the amino acid glutamine in gluconeogenesis, the synthesis of new glucose molecules. They can then release glucose into the blood to help maintain a normal blood glucose level.
Describe the renal capsule?
The deep layer..is a smooth, transparent sheet of dense irregular connective tissue that is continuous with the outer coat of the ureter.
nephrons
The filtering unit of the kidney.
What part of the body is responsible for the major work of the urinary system
The kidneys
Why are kidney said to be retroperitoneal?
The kidneys are retroperitoneal because they are posterior to the peritoneum.
What does Regulation of blood pH consist of?
The kidneys excrete a variable amount of hydrogen ions (H+) into the urine and conserve bicarbonate ions (HCO3−), which are an important buffer of H+ in the blood. Both of these activities help regulate blood pH.
What does regulation of blood ionic composition consist of?
The kidneys help regulate the blood levels of several ions, most importantly sodium ions (Na+), potassium ions (K+), calcium ions (Ca2+), chloride ions (Cl−), and phosphate ions (HPO42−).
What does Production of hormones consist of?
The kidneys produce two hormones. Calcitriol, the active form of vitamin D, helps regulate calcium homeostasis (see Figure 18.14), and erythropoietin stimulates the production of red blood cells
Which organs constitute the urinary system?
The kidneys, ureters, urinary bladder, and urethra are the components of the urinary system.
Describe the adipose capsule?
The middle layer, is a mass of fatty tissue surrounding the renal capsule..also protects the kidney from trauma and holds it firmly in place within the abdominal cavity
Describe the renal fascia
The superficial layer. is another thin layer of dense irregular connective tissue that anchors the kidney to the surrounding structures and to the abdominal wall
How does the urinary system contributes to homeostasis
altering blood composition, pH, volume, and pressure; maintaining blood osmolarity; excreting wastes and foreign substances; and producing hormones.
What stimulates ADH secretion from the posterior pituitary gland
an increase in ECF osmolarity
What is Nephroptosis?
an inferior displacement or dropping of the kidney. It occurs when the kidney slips from its normal position because it is not securely held in place by adjacent organs or its covering of fat
Descrube the kidneys?
bean-shaped organs located just above the waist between the peritoneum and the posterior wall of the abdomen.
Where exactly are the kidneys located?
between the levels of the last thoracic and third lumbar vertebrae, a position where they are partially protected by the eleventh and twelfth pairs of ribs
How does blood flow into the kidneys?
by the renal arteries at the concave surface of the kidney that faces medially called the hilus
The distal tubule of up to 8 nephrons drains into a single larger tube called what?
collecting duct
What does Regulation of blood volume consist of?
conserving or eliminating water in the urine. An increase in blood volume increases blood pressure; a decrease in blood volume decreases blood pressure.
Describe the renal medulla?
deep, darker reddish‐brown inner region
Fluid from the ascending limb of the loop of Henle passes into what?
distal tubule
what is The function of the portal system
filter fluid out of the blood and into the lumen of the nephron (occurs at the glomerulus) then to reabsorb the fluid from the tubule back into the blood (occurs at the peritubular capillaries)
parenchyma
functional portion of the kidney
decrease in ECF osmolarity causes what
inhibits ADH secretion from the posterior pituitary gland
nephron twists and folds back on itself so that the final part of the ascending limb of Henle passes between the afferent and efferent arteriole. What is this region called
juxtaglomerular apparatus
what is Tubular reabsorption
moving substances in the filtrate from the lumen of the tubule back into the blood flowing through peritubular capillaries
What are the Three tissue layers of the kidneys?
renal capsule, adipose capsule, renal fascia
What are the two distinct regions of the internal kidneys?
renal cortex & renal medulla
What is the indentation near the center of the concave border called?
renal hilum
Collecting ducts pass from the cortex through the medulla and drain fluid into what?
renal pelvis
Reguarding the Atrial Natriuretic Hormone elevated blood pressure increases venous return which excessively stretches the wall of which atrium
right
Which kidney is lower?
right kidney is slightly lower than the left because the liver occupies considerable space on the right side superior to the kidney
What does Regulation of blood pressure consist of?
secreting the enzyme renin, which activates the renin-angiotensin-aldosterone pathway (see Figure 18.16). Increased renin causes an increase in blood pressure.
what is Tubular secretion
selectively removes molecules from the blood flowing through the peritubular capillaries and adds them to the filtrate in the tubule lumen
Describe the renal cortex?
superficial, light red area
The reabsorption of water and Na+ and the secretion of K+ at the DT and CD can be changed by certain hormones such as Antidiuretic Hormone (ADH), aldosterone, and Atrial Natriuretic Hormone
t
of the plasma that passes through the glomeruli (180 liters) is filtered into the renal tubules daily imbalances in these substances will impact blood pressure, membrane potentials, and cell volume
t
renal blood flow
the blood flow through both kidneys, is about 1200 mL per minute.
what is Glomerular filtration
the movement of fluid from blood into the lumen of the nephron (takes place at the renal corpuscle) the hydrostatic pressure NEVER falls below the osmotic pressure therefore fluid ONLY moves out of the glomerulus into Bowman's capsule (never the opposite
What are the forces governing fluid movement in the renal portal system are similar to?
to those that determine filtration of water and molecules out of systemic capillaries
The modified fluid (urine) leaves each kidney and passes into a hollow tube called what
ureter
The 2 ureters conduct urine from the kidneys to what
urinary bladder