Genitourinary System Flashcards
Name the four sections of the Renal tubule
Proximal Convoluted Tubule
Loop of Henle
Distal Convoluted Tubule
Collecting Duct
Explain the function of the PCT
Involved primarily in the reabsorption of nutrients like glucose or amino acids, 2/3 of filtrate is reabsorbed here. it has a brush border too.
Explain the occurrences in the Loop of Henle
there is no net reabsorption here. the thicker ascending wall pushes out solutes which diffuse back into the thinner descending wall. this creates a recirculation of solutes which creates high osmolarity at the tip of the loop.
What happens in the DCT
The DCT has most of the same function as the PCT, but there is less intense reabsorption and it doesn’t have a brush border.
What happens in the collecting tubule
Urine is passed onto to the minor calyx. The concentration of urine can depend on the permeability of luminal membrane. If there is less water in the body, ADH will be secreted, which instructs Aquaporins to insert into the wall, allowing for more permeability. Water can move out due to the high osmolarity from the nearby tip of the Loop of Henle. This concentrates the urine. The opposite can happen and less ADH (anti-diuretic hormone) is released and therefore less water reuptake and more dilute urine.
How does the Juxtaglomerular apparatus regulate blood pressure?
The JGA is a mass of cells where the DCT passes up close to the glomerulus of the nephron. if there is low ions moving through the DCT then the JGA will read this as low filtration and therefore low blood pressure. It will secrete Renin, an enzyme that activates the precursor Angiotensinogen which in its active form is Angiotensin 1. this is converted to Angiotensin 2, a powerful vasoconstrictor.
How are salt levels controlled?
If concentrations of electrolytes are low e.g. Na+ or Cl- then aldosterone is secreted from the adrenal cortex in higher amounts. This increases reuptake in the renal tubules and from the gut, sweat and tears,
Describe the nephron
Functional unit of the kidney. Made of the renal tubules (DCT, PCT and Loop of Henle), and the renal corpuscle (glomerulus and Bowman’s capsule).
Blood supply to the kidney?
Blood is supplied via the right and left renal arteries which rise from the abdominal aorta. the renal arteries enter at the hilum and split into the interlobar blood vessels which supply the lobes. these further split into the cortical arteries which supply the cortex. the renal vein exits the hilum and is drained by the inferior vena cava.
What are the main principles of early disease detection as per Wilson and Jungner?
- condition should be a relevant problem for individual and community
- accepted treatment for patients with disease
- facilities for diagnosis and treatment need to exist
- recognisable dormant/early stage
- suitable test
- the test should also then be accepted by the general population
- the history of the condition from development to disease should be known
- should be policies to agree on who to treat
- economics should be viable
- screening must be continuous
give an example of how a screening programme like bowel screening works.
Most common cancer in Scotland. men and women between 50-74 invited to take part. A sample of shit is collected in a tube at home, and sent back to a lab. The sample of jobby is tested for haemoglobin as advanced bowel cancers cause bleeding. If a high enough level is detected then patients are referred for colonoscopy.
Give a value for the maximum and minimum rate for urine production
Minimum- 1ml/min
Maximum-20ml/min
What is the structure of the urinary bladder?
there are four layers to the bladder, the smooth muscle Detrusor, then the submucosa, the lamina propria and then the transitional epithelium. Ureters enter at the ureteral orifice. the internal sphincter at the neck of the bladder is involuntarily controlled whilst the external sphincter on the urethra is voluntarily controlled. the urethra has 3 sections in men, the prostatic, membranous and pendulous. There is a mucosal lining on the transitional epithelium to stop leakage of urine out the bladder and to protect the epithelium lining.
Describe the storage phase in peeing.
As the bladder starts to fill there’s still low pressure, bladder wall and external sphincter are relaxed. there’s no flow from the urethra as the pressure is higher in the urethra than the bladder.
First sensations develop, so the sphincter contracts retaining continence. a second sensation follows (UM) the urge to micturate.
Describe the voiding phase in peeing
The UM is followed by voluntary voiding
The bladder wall contracts, raising pressure in the bladder above the pressure in the urethra. the sphincters relax leading to a flow from the urethra.
Voiding is then stopped by the sphincter activities, creating a build up of pressure in the bladder.
secondary voiding then follows.
