The Urinary System Flashcards
What are the 4 structures of the Urinary System:
1) 2 Kidneys (with adrenal glands)
2) 2 Ureters
3) 1 Bladder
4) 1 Urethra
What it the location and function of the kidney?
Location = Posterior to the abdominal wall and underneath the diaphragm Function = To secrete urine
What is the function of the 2 ureters?
To transport the urine from the kidneys to the bladder by peristalsic contractions (intothe 2 orifices in the trgone of the bladder)
What is the function of the bladder?
To temporarily store urine and MICTURITION
How much urine is normally stored in the bladder?
250 - 300ml.
500ml = painful.
What are the 3 layers of the bladder called?
(inside - out)
1) Mucous layer
2) Muscular
3) Serosa
What is the ‘TRGONE’ in the bladder?
3 orifices that made a triangle.
2 open up to the ureters and 1 opens up to the urethra
What is the function of the urethra?
To transport the urine to the outside world.
Why is the urethra different in the male and female?
Male is longer and female’s is shorter. The males has both a urinary and reproductive function, whereas the female’s only has a urinary function.
Describe the process of micturition?
1) 200ml of urine in the bladder stimulate the stretch receptors.
2) Impulses are sent via the afferent pelvic nerve to the sacral region of the spinal cord.
3) An interneurone, sends information to the thalamus and then to the cerebral cortex.
4) Information is then send down the efferent pelvic nerve to the DETRUSOR MUSCLE.
5) The detrusor muscle is stimulated to contract.
6) Elimination of urine (micturition) will only occur when the external urethral sphincter relaxes.
Describe the Gross Structure of the Kidney?
1) Renal Capsule (Fibrous Outer Layer)
2) Renal Cortex
3) Renal Medulla (organised in striations to form the renal pyramids - that contain the nephrons)
4) Renal Papilla
5) Minor Calyx
6) Major Calyx
7) Renal Pelvis that is continuous with the ureter (thin smooth muscle wall)
How will the smooth muscle in the renal pelvis contract?
Pacemaker cells in the calyces (minor and major calux) will initiate the impulses for the smooth muscle to contract.
What is the functional unit of the kidney and where is it contained?
The nephron - in the renal pyramids (of the renal medulla).
Describe the components of the nephron:
1) Glomerular capsule/Bowman’s Capsule (contains the glomerulous - network of arterial capillaries)
2) Proximal convoluted tubule
3) Loop of Henle
4) Distal convoluted tubule
5) Collecting duct
What happens at the end of each collecting duct?
Collecting ducts from other nephrons will join together in order to form larger ducts and urine is taken from these ducts, down the minor/major calyces and into the renal pelvis (that is continuous with the ureter)
What are the 4 functions of the kidney?
1) Simple Glomerular Filtration = Blood is filtered from the glomerulus in the glomerular capsule and a plasma-like filtrate is formed.
2) Selective tubular absorption = useful substances are absorbed back into the blood.
3) Tubular secretion = Unwanted substances are taken into the tubules.
4) Water conservation = Water is absorbed back into the blood.
Describe the blood supply to and from the kidney:
1) Aorta
2) Renal artery
3) Afferent renal arteriole
4) Glomerulous
5) Efferent renal arteriole
6) 2nd cappilary bed (supplies the nephron with O2 and nutrients)
7) Renal Venule
8) Renal Vein
9) INFERIOR vena cava
What nerve supply controls the kidneys?
Autonomic Nervous System
What occurs in simple glomerular filtration?
The blood in the glomerulous is filtered and taken in to the glomerular capsule - forming a PLASMA-LIKE FILTRATE.
What 2 things aids glomerular filtration?
1) The walls of both the glomerulus and glomerular capsule are thin and semi-permeable.
2) Pressure differences between the plasma in the glomerulus and the plasma-like fluid in the glomerular capsule.
What substances can NOT pass though into thee filtrate, during simple glomerular filtration?
1) Plasma proteins
2) Thrombocytes
3) WBC’s
4) RBC’s
5) Some drugs
Describe the filtration membrane of glomerulous (What the blood needs to be filtered through before going into the glomerular capsule)
(inside - out)
1) Cappillary endothelium (with fenestrations)
2) Basal Lamina
3) Podocyte cell body
4) Pedicels (produced by the podocyte cells)
5) Filtration slits (inbetween the pedicels)
What does the GFR tell us?
How much filtrate is being produced by BOTH of the kidneys in simple glomerular filtration/ per min