Renal system Flashcards
what are the kidneys?
a pair of high pressure filtration organs
where are the kidneys found?
in the retroperitoneum close to the dorsal body wall
what are kidneys protected by?
the long transverse processes of the lumbar vertebrae
what is a hilus and where is it found?
indentations on the medial border of the kidney
what are the kidneys surrounded by?
a tightly adherent fibrous capsule
what are the three main parts of the kidney?
- outer cortex - vascular
- inner medulla - less vascular
- renal pelvis - structure in the centre of the kidney
what is in the renal pelvis?
a collection space for urine before passed to ureters
what is the renal artery?
- supplies the kidneys
- branches off the aorta
- forms capillaries which form the glomerulus
what is a nephron and what is it formed by?
- functional unit of the kidney
- formed by blood vessels and glomerulus
what is formed by the capillaries in the renal artery?
glomerulus
what is the glomerulus?
tuft of capillaries within. the bowman’s capsule
how does blood enter the glomerulus?
via the afferent arteriole
how does blood leave the glomerulus?
via the efferent arteriole
what is ultrafiltration?
when high blood pressure forces water and electrolytes, through holes in the wall of the glomerulus which are large enough to allow molecules such as urea and haemoglobin through but small enough to retain larger molecules like albumin, RBC, WBC
what is the Bowman’s capsule?
a cup where the glonerulus sits
what is the bowmans capsule made up of?
simple squamous epithelial cells
what are podocytes?
- specialised epithelial cells in the kidney
- neighbour the bowmans capsule cells
what is the proximal convoluted tubule?
drains the bowmans capsule and runs alongside the blood capillaries
what is reabsorbed in the proximal convoluted tubule?
salt, sodium, glucose, and water
what does the loop of henle carry?
- carries the filtrate into the medulla of the kidney
what is the loop of henle made up of?
two parts
- ascending
- descending
what is reabsorbed in the loop of henle?
water, sodium and chloride
what does the descending aspect of the loop of henle carry?
filtrate to medulla
what leaves the loop of henle?
distal convoluted tubule
what is reabsorbed in the distal convoluted tubule?
sodium
what is excreted in the distal convoluted tubule?
potassium and hydrogen
why is hydrogen being excreted by the distal convoluted tubule important?
maintains acid-base balance
what regulates sodium absorption and potassium excretion in the distal convoluted tubule?
aldosterone
where is aldosterone produced?
renin-angiotension aldosterone pathway
what hormones influence calcium ion reabsorption in the distal convoluted tubule?
- calcitonin (decreases reabsorption)
- parathyroid (increases reabsorption)
what does the distal convoluted tubule pass into?
collecting duct
what does the collecting duct pass into?
the medulla of kidney and opens into renal pelvis
what is the permeability of the walls of the collecting duct controlled by?
anti-diuretic hormone
what happens if more water is absorbed in the walls of the collecting duct?
urine output will be reduced
what is the fluid surrounding the collecting ducts called?
hypertonic
what causes water to be drawn out of the filtrate in the collecting duct?
osmosis
where does urine move to after the collecting ducts?
renal pelvis
what is the vasa rectae?
capillaries that form a net like arrangement from blood vessels
what are some functions of the renal system?
- filtration
- conversion of vit D
- produces erythropoietin
- production of renin
what are the juxtaglomerular apparatus?
specialised cells that are responsible for the secretion of renin and erythropoietin
what is renin?
- produced by the liver
- has two effects (vasocontriction) and (stimulating the release of aldosterone from adrenal cortex)
what converts angiotensin 1 in to angiotensin 2?
ACE
what stimulates red bone marrow to make red blood cells?
Erythropoietin
what is the normal pH of bodily fluids?
7.4
where can the kidneys regulate pH through?
cells in the distal convoluted tubule
what are the three processes to do with drug excretion?
- glomerular filtration
- tubular secretion
- tubule reabsorption
where do secretions enter kidney tubule from?
- tubular secretion
- involves 2 carrier systems (basic carriers for basic drugs (acidic carriers for acidic drugs)
systemic clearance =
rate of elimination / serum concentration
what is renal clearance?
the total amount of drug excreted over a specific time
what do the kidneys do regarding homeostasis?
control amount of water, ions, substances by excreting them in urine
what is secreted to help maintain homeostasis?
hormones
