Urinary system Flashcards
What is the function of the Urinary system
The urinary system’s function is to filter blood and create urine as a waste by-product.
7 Purposes of the Urinary System
- cleansing the blood and ridding the body of wastes
- regulation of pH
- regulation of blood pressure
- regulating the concentration of solutes in the blood
- determining the concentration of red blood cells
- perform the final synthesis step of vitamin D production
- providing the anatomical structures to store urine until the body is able to dispose.
Where does the Urinary systems ability to filter blood reside?
2 to 3 million tufts of specialized capillaries (the glomeruli) distributed equally between the two kidneys.
What is the first part of the nephron?
Bowman’s capsule – first part of the nephron where blood is initially filtered (to form filtrate).
Normal urine output volume:
1-2 litres/day
What does Oliguria mean?
Output of urine is below level may be caused by severe dehydration
What does Anuria mean?
The virtual absence of urine production.
What does Ployuria mean?
Excessive urine production, which may be due to diabetes mellitus or diabetes insipidus.
What is the minimum urine output volume?
500 mL/day
Location of the Kidneys:
kidneys lie on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall, well protected by muscle, fat, and ribs.
Describe the internal anatomy of the kidney:
- Outer region: renal cortex
- Inter region: medulla
- Renal columns: connective tissue extensions that radiate downward from the cortex through the medulla that divides the kidney into 6-8 lobes.
Describe the anatomy of the Ureters:
- ureters are approximately 30 cm long.
- inner mucosa is lined with transitional epithelium and scattered goblet cells that secrete protective mucus.
- longitudinal and circular smooth muscles that create the peristaltic contractions to move the urine into the bladder.
- loose adventitial layer composed of collagen and fat anchors the ureters between the parietal peritoneum and the posterior abdominal wall.
Describe the anatomy of the urinary bladder:
- partially retroperitoneal(outside the peritoneal cavity)
- peritoneal-covered “dome” projecting into the abdomen when the bladder is distended with urine
- interior surface is made of transitional cellular epithelium
- When empty, it resembles columnar epithelia, but when stretched, it “transitions” to a squamous appearance
Describe the anatomy of the urethra:
- transports urine from the bladder to the outside of the body.
- the proximal urethra is lined by transitional epithelium
- terminal portion is a non-keratinized, stratified squamous epithelium.
- In males there is pseudostratified columnar epithelium between two cell types.
Describe the anatomy of the nephron:
- functional unit of the kidney
- Afferent arteriole leads to renal corpuscle
- the afferent arterioles lead into a glomerulus
- Renal corpuscle consists of the glomerulus surrounded by Bowman’s capsule
- PCT
- loop od henle
- DCT
- Collecting duct
What tissue type lines the vasculature of the glomerulus and Bowman’s capsule?
Simple squamous epithelial
Where are all renal corpuscles, PCTs, and DCTs found?
Renal Cortex
Describe the microanatomy of Bowmans capsule:
- the parietal layer, is a simple squamous epithelium
- Visceral layer (over the glomerulus) consists of podocytes, which extend pedicels to cover the glomerular capillaries
Describe the anatomy and function of the PCT:
- Composed of simple cuboidal epithelial cells with microvilli.
- The microvilli increase surface area for reabsorption and secretion.
- these cells actively transport ions across their membranes.
Describe the anatomy and function of the loop of Henle:
- descending thick portion consists of simple cuboidal epithelium: permeable to water, impermeable to ions, hypertonic, therefore absorbs water.
- ascending thick portion consists of simple cuboidal epithelium: impermeable to water, permeable to ions
- descending and ascending thin portions consists of simple squamous epithelium
Describe the anatomy and function of the DCT:
- Formed by simple cuboidal epithelium
- fewer microvilli
- Cells pump against conc. gradient, although less mitochondria than PCT.
- Sensitive to endocrine hormones:
Anti-diuretic hormone
Aldosterone
Parathyroid hormone
What is anti-diuretic hormone?
Increase water absorption, therefore decreasing the volume of urine output
What is aldosterone?
- released when Sodium concentration is low, causes sodium reabsorption, which causes water reabsorption, and this increase of water volume increases blood pressure.
What is parathyroid hormone?
- Maintains and controls calcium concentration.
Describe the anatomy and function of the collecting ducts:
- sensitive to hormones
- each duct collects from several nephrons
- lined with simple squamous epithelium
What happens when collecting ducts are stimulated by ADH?
When ADH is present, the collecting duct becomes permeable to water.
What happens in the absence of ADH?
The apical surfaces of the principal cells of the collecting ducts are impermeable to water.
What is osmosis?
osmosis is the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell’s partially permeable membrane.
What happens when Osmolarity goes up?
Filtration and urine formation decreases and water is retained to decrease the concentration of solutes dissolved in the blood.
What happens when osmolarity goes down?
Filtration and urine formation increase, removing water from the system through the urine increase the concentration of solutes dissolved in the blood.
What is the regulation of osmolarity an example of?
Homeostasis
What is the GFR influenced by?
Hydrostatic and colloid osmotic pressure on either side of the capillary membrane of the glomerulus
Where does glomerular filtration occur?
When glomerular hydrostatic pressure exceeds the luminal hydrostatic pressure of bowman’s capsule
What is the Glomerular Filtration rate?
- the volume of filtrate formed by both kidneys per min.
How does decreased blood pressure affect GFR?
Decreases GFR
Where is the most water recovered?
Most water is recovered in the PCT, loop of Henle, and DCT. The collecting ducts, under the influence of ADH, can recover almost all of the water passing through them.
What does the filtrate produced by the renal corpuscle resemble?
Similar to blood plasma without the proteins, and at this point not at all like urine.
Describe reabsorption and secretion in the loop of Henle:
The liquid entering the loop of Henle is the solution of salt, urea, and other substances passed along by the proximal convoluted tubule, from which most of the dissolved components needed by the body—particularly glucose, amino acids, and sodium bicarbonate—have been reabsorbed into the blood.
What is the vasa recta?
Straight capillaries coming off from arcades in the mesentery of the jejunum and ileum, and heading toward the intestines
What does Aldosterone increase in the basal membrane of the DCT and collecting duct?
Aldosterone increases the amount of Na+/K+ ATPase in the basal membrane of the DCT and collecting duct.
What are the results of the movement of Sodium out of the lumen of the collecting duct?
Movement of Na+ out of the lumen of the collecting duct creates a negative charge that promotes the movement of Cl– out of the lumen into the interstitial space by a paracellular route across tight junctions.
What is ARF?
Acute renal failure
What is BUN?
Blood urea nitrogen
What is CAPD?
continuous ambulatory peritoneal dialysis
What is GFR?
Glomerular filtration rate
What is HD?
Hemodialysis
What is UA?
Urinalysis
What is UTI?
Urinary tract infection
Urinary bladder combining form
Cyst/o
Vesic/o
Kidney combining form
nephr/o
ren/o
Renal pelvis combining form
pyel/o
Ureter combining form
ureter/o
Urethra combining form
urethr/o
What type of Epithelium is in the kidneys and what is its functions?
Non-keratinized simple squamous epithelium and its function is Diffusion and Filtration.
What type of Epithelium is in the Renal Corpuscle and what is its functions?
Non-keratinized simple squamous epithelium and its function is Diffusion and Filtration.
What type of Epithelium is in the Urinary bladder and what is its functions?
Transitional epithelium and its function is to expand
and stretch.
.
What type of Epithelium is in the Collecting ducts and what is its functions?
Non-keratinized simple cuboidal epithelium and its function is Secretion and absorption.
Albuminuria meaning:
Abnormal condition of protein in urine
Anuria meaning:
Abnormal condition of no urine production.
Dysuria meaning:
Painful urination
Glycosuria meaning:
Abnormal condition of glucose in urine
Hematuria meaning:
Abnormal condition of blood in urine.
Nephrolithiasis meaning:
Abnormal condition of stones in the kidney
Renal failure meaning:
Condition in which the kidneys stop functioning and producing urine.
Uremia meaning:
Condition of high levels of urea in the blood.
What is the blood urea nitrogen lab test for?
Measures the amount of urea in the blood.
What is the Cystoscopy lab test for?
Visual examination of the urinary bladder with a cystoscope.
