How do we get rid of toxic waste? Flashcards
Where do the kidneys lie and why does the right kidney lie lower than the left?
- The kidneys lie behind the parietal peritoneum on the posterior abdominal wall on either side of vertebral column.
- Right kidney slightly lower than left (due to liver).
- Lumbar vertebrae and rib cage partially protect the kidneys.
- Bean shaped and about the size of a fist (~130g).
What is the renal capsule, adipose tissue and renal fascia?
- Renal capsule: fibrous connective tissue surrounding each kidney.
- Adipose tissue: engulfs renal capsule and acts as cushioning.
- Renal fascia: thin layer loose connective tissue, which anchors kidneys to posterior abdominal wall.
What is the Hilum, Ureter, Cortex & Renal columns?
- Hilum: Renal artery and nerves enter and renal vein and ureter exit.
- Hilum opens into renal sinus: cavity filled with fat and loose connective tissue.
- Ureter: exits at the hilum; connects to urinary bladder.
- Cortex: outer area.
- Renal columns: part of cortical tissue that extends into medulla.
What is the Medulla, Renal Pyramids, Minor Calyces, Major Calyces & Pelvis?
- Medulla: inner area, surrounds renal sinus.
- Renal pyramids: cone shaped. Base is boundary between cortex and medulla.
- Apex of pyramid is renal papilla, points toward sinus.
- Minor Calyces: funnel shaped chambers into which papillae extend.
- Major Calyces: converge to form the renal pelvis.
- Pelvis: enlarged chamber formed by major calyces.
What is the Nephron, what are the parts and why does the blood enter the nephron?
- Functional unit of the kidney
- Parts of the nephron: renal corpuscle, proximal tubule, loop of Henle, distal tubule.
- Blood enters the nephron for filtration. Filtrate/urine produced.
- Urine continues from the nephron to papillary ducts, minor calyces, major calyces, renal pelvis and ureter.
What are the types of neurons?
-1.3 million nephrons in each kidney and range from 50-55mm in length.
o Juxtamedullary nephrons: The renal corpuscle located near the medulla. Long Loops of Henle which extend deep into the medulla (15%).
o Cortical nephrons: Renal corpuscle located nearer to the periphery of the cortex. Loops of Henle do not extend deep into the medulla (85%).
What is the Bowmans capsule, What is the glomerulus & what does blood/fluid enter
- Bowman’s capsule: enlarged end of the nephron, double walled chamber. Filters the blood/fluid which then enters the proximal convoluted tubule.
- Glomerulus: network/ball of capillaries.
- Blood/fluid enters the glomerulus through afferent arteriole, exits through efferent arteriole.
- Note the size difference Afferent is bigger than efferent = PRESSURE
What is a parietal & visceral layer in bowmans capsule?
- Parietal layer: Outer layer. Simple squamous epithelium – becomes cuboidal in PCT.
- Visceral layer: Inner layer. Specialised podocytes that wrap around the glomerular capillaries.
What is fenestrae, filtration slips, basement membrane & what occurs here?
- Fenestrae: window-like openings in the endothelial cells of the glomerular capillaries.
- Filtrations slits: gaps between podocytes.
- Basement membrane: sandwiched between the endothelial cells of the glomerular capillaries and the podocytes.
- Filtration occurs here.
What is proximal convoluted tubule, loop of henle, distal convoluted tubule & collecting duct?
- Proximal convoluted tubule: filtrate drains from the Bowman’s capsule into the PCT.
- Loop of Henle (nephron loop): each loop has a descending and ascending limb.
- Distal convoluted tubule: shorter than PCT
- Collecting ducts: large diameter. Extend through medulla towards renal papilla → ureter.
In terms of the histology what is the proximal tubule, loop of henle, distal tubule & collecting ducts?
- Proximal tubule: Simple cuboidal epithelium with many microvilli. Active reabsorption of Na+2, K+ & Cl
- Loop of Henle: Thick parts - simple cuboidal. Thin parts - simple squamous epithelium – for osmosis/diffusion.
- Distal tubule: Simple cuboidal, and very few microvilli. Numerous mitochondria.
- Collecting ducts: Larger in diameter, simple cuboidal epithelium.
In urine movement what forces urine through the nephron?
-Pressure forces urine through nephron
What moves urine from renal pelvis to kidneys, through what and what do the ureters enter the bladder through?
- Smooth muscle in ureters: Peristalsis moves urine from the renal pelvis in the kidneys through the ureters to the urinary bladder.
- Ureters enter bladder obliquely through trigone. Pressure in bladder compresses ureter and prevents backflow
What do the ureters do and what are they lined with?
-Bring urine from renal pelvis to urinary bladder. Lined by transitional epithelium
What is the urinary bladder & trigone?
- Urinary bladder: hollow muscular container. Located in pelvic cavity posterior to symphysis pubis.
- Trigone: interior of urinary bladder. Triangular area between the entry of the two ureters and the exit of the urethra.
What is the urethra and what is it lined with?
- Urethra: transports urine from the bladder to the outside of the body. Internal urinary sphincter - Elastic connective tissue and smooth muscle prevent urine continuously flowing out of the bladder.
- Lined with transitional epithelium (top) stratified columnar epithelium (external opening).
What is the external urinary sphincter, what does it act as? Describe the male & female urethras
- External urinary sphincter: skeletal muscle surrounds urethra as it extends through pelvic floor. Acts as a valve that controls the flow of urine
- Male urethra: extends from the inferior part of the urinary bladder through to the tip of the penis.
- Female urethra: shorter; opens into vestibule anterior to vaginal opening