renal system Flashcards
layers of the kidney
Cortex – outer zone, granular
Medulla – inner zone made of renal pyramids, divided into lobes
Renal pelvis – funnel-shaped, continuous with ureter
Cortical nephrons
which lie predominantly in the renal cortex and their Loop of Henle dips into the renal medulla.
Juxtamedullary nephrons
lie at the cortex-medulla junction and have long nephron loops that are located deep in the medulla.
vascular components
Abdominal aorta
Renal artery
Afferent arteriole
Glomerulus (capillaries)
Efferent arteriole
Peritubular capillaries
Renal vein
Inferior vena cava
tubular components
Renal corpuscle (Glomerulus and Bowman’s capsule)
Proximal convoluted tubule (PCT)
Loop of Henle (nephron loop)
Distal convoluted tubule (DCT)
Collecting duct
urine flow
urine drains out of pyrimids
minor claycles
major claycles
renal pelvis
ureter
urinary bladder
urethra
ureters
Muscular tubes that transport urine from renal pelvis to urinary bladder by peristalsis.
urethra
In the female, the urethra serves as a passage for urine.
In the male, there are three parts: prostatic, membranous and penile. It serves for the passage of semen and urine.
In both female and male it has a voluntary external sphincter (striatal muscles).
urinary bladder
Hollow, muscular organ that stores urine before voiding.
It is a powerful detrusor muscle (smooth muscle).
Has internal urethral sphincter (smooth muscle).
primary functions of the renal system
Excretion (metabolic waste and foreign substances such as drugs)
Acid-base balance (regulate concentration of ions e.g. Hydrogen ions)
Osmoregulation (regulate total volume of water and total concentration of solutes in that water).
secondary functions of the urinary system
Blood pressure maintenance (regulate water and solute concentration)
Anaemia correction (produce erythropoietin, regulating red blood cell production)
Calcium regulation
Protein catabolism – urea
Detoxification (removes toxins and waste).
glomerular filtration rate
(urine concentration) x (urine flow rate) / (serum creatine concetration)
glomerular hydrostatic pressure
pressure exerted on the walls of the capillaries by fluid
this forces fluid out of capilaries into the bowemens capsule
colloid osmotic pressure
is exerted by plasma proteins remained in the blood
pulling fluid back towards the capillaries
capsular hydrostatic pressure
pressure exerted by fluids from bowemans capsule into the blood vessels
autoregulation of blood pressure
decreased blood pressure
decrease in GFR
afferent vessels vasodilate
increase glomerular hydrostatic pressure
increase GFR
hormones that have an affect on blood pressure here
angiostein- vasoconstriction// stimulates aldosterone and ADH
ADH- increase water reabsorption- increase blood volume and pressure
aldosterone- retains more Na+ ions so water is reabsorbed
ANP/ BNP= stop ADH AND ALDONSTERONE
Urine formation steps
glomerular filtration
tubular reabsorption
tubular secretion
glomerular filtraton
water and blood solutes move from blood capillaries/ glomerulus into bowemans capsule
pressure pushes these materials
ions/ water/ glucose
non selective
tubular reabsorption
proximal convuluted tubular
selective process
filtrate of water/ glucose/ ions move back into blood
tubular secretion
selective process
wastes Hplus drugs
glycosuria
glucose in urine
if not fully reabsorbed
water reabsorption
obligatory- solutes go then water goes too= osmosis
factulative- hormone reabsorption
micturition reflex
Filling of the bladder is enabled by:
Contraction of internal urethral sphincter
Inhibition of detrusor (bladder) muscle activity.
Emptying of the bladder is enabled by:
contraction of the detrusor (bladder) muscle
relaxation of the internal and external sphincters
ageing and renal system
Sphincter loses muscle tone which leads to incontinence
Urinary retention if prostate enlarged.
Decreased number of functional nephrons:
↓ GFR due to fewer glomeruli
Deterioration in filtration, reabsorption and endocrine functions
Nephrons become less sensitive to ADH.
