L101: Kidney 1 Flashcards
What type of organ are the kidneys?
Excretory
What are the two main functions of the kidneys?
- Filter blood and produce urine;
- Maintain internal homeostasis*.
- fluid, BP, acid/ base, erythropoietin, Ca, Vit D, electrolytes
What is the function of the ureters?
Convey urine
What is the function of the bladder?
Store urine
What is the function of the urethra?
Void urine
What supplies blood to the kidneys?
Abdominal aorta (via renal arteries)
What drains the blood from the kidneys?
Inferior vena cava (via renal veins)
At what anatomical feature do arteries and veins join to the kidneys?
The hilum of the kidneys
What is the peritoneum?
A serous membrane forming the lining of the abdominal cavity
What is the name of the structure that supports and protects the kidneys?
Renal fat pad
In the macroscopic structure of the kidney, what are the three main parts?
- Pelvis;
- Medulla;
- Cortex.
Which part of the kidney contains the majority of nephrons?
Cortex - 85%
Where is urine concentrated, to prevent excess water loss, in the kidneys?
Medulla
What happens in the pelvis of the kidney?
Collection of urine which is then funnelled into the ureter
How much blood is processed by the kidneys per minute?
1.2L
The kidneys are highly vascular organs, what is the main sequence of blood flow from the renal artery?
- Afferent arterioles -
- Glomerular capillaries -
- Efferent arterioles -
- Peritubular capillaries.
How are the peritubular capillaries adapted for their function?
Vasa recta are U-shaped for greater absorbance
What are the two types of nephron?
- Cortical (short, LofH, 85%);
- Juxtamedullary (long, 15%).
In the kidneys, where does filtration occur?
In the renal corpuscle
What are the major components of the renal corpuscle?
- Bowman’s capsule;
- Glomerulus.
In the kidneys, where does reabsorption and secretion occur?
In the renal tubule
What are the major components of the renal tubule?
- PCT;
- L of H;
- DCT.
What is a glomerulus?
A network of fine capillaries within the Bowman’s capsule
How does the structure of the capillaries of the glomerulus assist ultrafiltration?
- Surrounded by a single layer of endothelial cells (fenestrated - pores);
- Basement layer;
- Podocytes with pedicels
What cannot pass through the ultrafiltration barrier?
- Large cells inc. rbc;
- Negatively charged molecules;
- Large proteins;
- Serum albumin.
What is the Bowman’s capsule?
- Cuplike structure surrounding the glomerulus;
- Bowman’s space allows for filtered components to be captured;
- Visceral (inner) layer;
- Pareital (outer) layer.
How is the visceral layer of the Bowman’s capsule specialised?
Podocytes, with pedicel projections that wrap around the glomerular capillaries
What are the major components of the filtration barrier?
- Fenestrated glomerular endothelium;
- Basement membrane;
- Pedicels of podocytes.
What can pass through the ultrafiltration barrier?
- Water;
- Glucose;
- Amino acids;
- Urea;
- Creatinine;
- Ions: Ca2+, Cl-, HCO3-, K+, PO4, Na+.
What constitutes to hydrostatic pressure within the glomerulus?
Wider afferent arteriole to efferent arteriole
What is glomerular filtration rate (GFR)?
The rate at which blood is filtered through the glomerulus into the Bowman’s capsule
What forces favour glomerular hydrostatic pressure?
i.e. push fluid out of the glomerulus
- Glomerular hydrostatic pressure;
- Capsular osmotic pressure.
What forces counteract glomerular hydrostatic pressure?
i.e. push fluid into the glomerulus
- Glomerular osmotic pressure;
- Capsular hydrostatic pressure.
What primarily drives GFR?
Glomerular hydrostatic pressure
What primarily counteracts GFR?
Capsular hydrostatic pressure
What counteracts capsular hydrostatic pressure?
Glomerular osmotic pressure
What is normal, healthy GFR?
125mL/ min, 180L/ day.
How does CKD effect GFR?
CKD decreases GFR - insufficient blood clearance and waste removal - accumulation of waste in the blood
What blood component can be measured as an estimate of kidney function?
Creatinine
How does the level of creatinine change in the blood of a patient with CKD?
Creatinine levels increase as CKD progresses (lower blood clearance)
