Renal and Urinary Physiology 1 Flashcards
What makes up the urinary system?
4
The kidneys
The ureters
The urinary bladder
The urethra
What is the main function of the kidneys?
Produce urine
What are the units of the kidney?
The nephrons
What is the main function of the bladder?
Storage of urine
What are the two main functions of the renal system?
Excretion
Elimination
What is excretion?
The removal of organic waste products from body fluids
What is elimination?
The discharge of waste products into the environment
List the functions of the renal system.
8
Homeostatic regulation of blood plasma
Regulating blood volume and pressure
Regulating plasma ion
concentrations
Stabilizing blood pH
Conserving nutrients
Metabolism of vitamin D.
Production of Renin.
Production of EPO
List some products of the renal system.
2
Renin
EPO
What is the renal system responsible for regulating?
4
Blood plasma
Blood volume and pressure
Plasma ion concentrations
Blood pH
What is the renal system responsible for metabolising?
Vitamin D
What does the renal system conserve?
Nutrients
What does renin stimulate?
Angiotensin
What are ureters and urethra?
Flexible tubes
What is EPO?
Erythropoietin
Which kidney is higher than the other?
Left is higher than right
What is the entry/exit point of the kidney?
The hilum of kidney
What enters the kidney at the hilum?
2
Renal artery
Renal nerves
What exits the kidney at the hilum?
2
Renal veins
Ureter
What are the three distinct regions of the kidney?
Cortex
Medulla
Pelvis
How do you identify the cortex?
The outermost pale region
What begins in the cortex?
All nephrons begin in the cortex
What area is damaged first in kidney disease?
The cortex
How do you identify the medulla?
2
Middle part of kidney
Contains renal pyramids
How many renal pyramids are in each kidney?
6-8 depending on size of kidney
How do you identify the renal pelvis?
White inner region of kidney
Why is the renal pelvis white?
Contains collagen
What is the function of the renal pelvis?
Collects urine
What surrounds the kidney?
A smooth capsule
What does it mean if the capsule is bumpy?
Kidney is diseased
What is the renal pelvis also called?
Calyces
List the pieces of the nephron
6
Renal corpuscle
Renal tubule
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Collecting system
What is the function of the proximal convoluted tubule?
Reabsorption
List the two parts of the loop of Henle.
Descending limb
Ascending limb
What are the two functions of the distal convoluted tubule?
Actively secretes ions, toxins, drugs
Reabsorbs sodium ions from tubular fluid
What does the DCT secrete?
3
Ions
Toxins
Drugs
What is the function of the collecting system?
Reabsorption
What are the two types of nephrons?
Cortical nephrons
Juxta-medullary nephrons
What are the cortical nephrons?
2
85% of all nephrons
Located in the cortex
Where are the juxta-medullary nephrons found?
Closer to renal medulla
Where do the loops of Henle extend?
Deep into renal pyramids
How many nephrons are found in each kidney?
About a million
What happens in the nephrons?
Blood is filtered
Where in the nephrons is the blood filtered?
In capillaries known as glomeruli
What happens to the filtrate as it moves through the nephrons?
The filtrate is modified and turned into urine
What runs alongside the peri-tubular capillaries?
Renal tubules
Why do renal tubules run alongside peri-tubular capillaries?
So exchange may take place between the two
Where does the renal tubule begin?
It begins at the renal corpuscle
What does the renal corpuscle include?
2
Bowman’s capsule
Glomerulus
How does blood leave the nephron?
Via the efferent arteriole
What does the filtration membrane consist of?
3
Glomerular capillary endothelium
Visceral layer of Bowman’s capsule
The loose connective tissue between the two
What are the cells of the visceral layer of the Bowman’s capsule called?
Podocytes
What is not filtered from the filtration membrane?
2
Formed elements
Plasma proteins larger than albumin
From where do the glomerular capillaries receive blood?
An afferent arteriole
To where do the glomerular capillaries empty?
An efferent arteriole
What are the sites of filtration?
The glomerular capillaries
When exactly does filtration occur?
Filtration occurs as fluid move across the glomerulus
List the things that happen to blood in order.
4
Blood is filtered in glomerulus
Blood enters the nephron
Blood becomes filtrate
60% of filtrate is reabsorbed by PCT
What happens when the glomerular filtration rate is distrurbed?
The Renin-Angiotensin system is activated
Give two reasons why glomerular filtration rate would decrease.
Drop in blood pressure
Drop in blood flow to the kidney
What happens when the renin-angiotensin system is activated?
This restores blood flow to the kidney and restores filtration
What is the renin-angiotensin pathway? (4)
Decreased filtration ->
renin produced by juxtaglomerular apparatus ->
Angiotensin I formed ->
Activation to form angiotensin II ->
What six things happen when angiotensin II is formed?
Efferent arterioles are constricted
Adrenal glands increase aldosterone secretion
Increased vasoconstriction
CNS increases ADH production, sympathetic motor tone and stimulation of thirst centres
What three things does the CNS increase when angiotensin II is formed?
ADH production
Sympathetic motor tone
Stimulation of thirst centres
What are the two end results of the renin angiotensin pathway?
Blood pressure is raised
Increased fluid volume and therefore blood flow
Where is the filtrate produced?
The glomerulus
Where does the vast bulk of reabsorption occur?
Proximal convoluted tubule
Describe the filtrate produced by the glomerulus.
Similar to plasma without the proteins
What three things are mainly absorbed by the PCT?
Organic nutrients
Sodium
Water
Other than absorption, what happens in the PCT?
Secretion
What is the primary chemical that drives most reabsorption?
Sodium
Describe the sodium concentration gradient
3
Normally high in the lumen of the PCT
Low inside the cells lining the PCT
=> sodium diffuses out of the lumen and into the cytoplasm of the cells
