Urinary Anatomy
How plentiful are nephrons?
There are millions of them
What do the the collecting ducts connect to?
Rena pelvis
The proximal tubule mainly uses which kind of transport? What does that mean?
Active transport, meaning it requires energy
What is the purpose of secretion?
To do one final 'balancing act' to correct the levels of solutes in the blood, ridding the body of the right amount of solutes and substances
How does one treat diabetes mellitus?
Insulin shots
Describe the cross-section of a kidney
Outside layer: renal cortex
Inner layer: medulla
Connected to ureter through: renal pelvis
Why are they called convoluted tubules? For what purpose?
They're wiggly! Winding path for more surface area for reabsorption and secretion
The proximal tubule absorbs 100% of two kinds of monomers. Which two?
Glucose and amino acids
Which three parts of the nephron are involved in secretion?
Proximal and distal convoluted tubules and collecting duct
What are two reasons you might find blood in your urine?
1. Kidney stones
2. Damaged glomerulus
Describe the movement of urine through the body
After the collecting duct. Renal pelvis, ureter, bladder, urethra
Which parts of the nephron are in the medulla?
The proximal and distal straight tubules and Loop of Henle
What is required for the distal tubule to absorb the remaining water and salt?
ADH and aldosterone
How does secretion regulate pH?
Secretes extra H+ ions, reducing acidity
What are the functions of aldosterone and ADH?
Aldosterone increases permeability to salt
ADH increases permeability to water
Which three specifically named kinds of blood vessels connect directly to the kidneys?
Renal artery, renal vein, peritubular capillaries
The glomerulus allows which solutes to pass into the Bowman's capsule? (6 possible answers, 100 points each up to 500)
Water, salts, glucose, amino acids, hydrogen ions and urea
What part of the nephron is particularly efficient at water reabsorption? Why?
The descending limb of the Loop of Henle because it dips into the salty medulla. The salt outside of the nephron draws the water out of the nephron and into the bloodstream
What are three examples of secreted substances?
Ammonia, H+ ions, minerals (in general)
Describe the cause of diabetes insipidus
Hyposecretion of antidiuretic hormone (ADH) causes the nephron to become less permeable to water, reducing reabsorption and resulting in dehydration, high thirst and frequent urination
How is urea formed?
Excess proteins are broken down by the liver, producing ammonia which combines with carbon dioxide to form urea.
Describe the movement of fluid (blood, filtrate) through the nephron
Blood = in through afferent arteriole, into glomerulus, then out through efferent arteriole
Filtrate = Bowman's capsule, proximal convoluted tubule, proximal straight tubule, descending and then ascending limb of the Loop of Henle, distal straight tubule, distal convoluted tubule then collecting duct
Describe how to absorption of water and salt changes throughout the Loop of Henle
In the descending limb, the osmotic gradient causes water to passively flow out of the nephron towards the salty environment. As the filtrate moves through, the filtrate becomes more concentrated with solutes and begins to require active transport on the way up the ascending limb.
What might happen to the body if a disease prevented secretion? Give three reasonable ideas.
Answers may vary: High blood pressure, fluid retention and swelling, blood acidity or general pH dysregulation, high solute concentration in blood, blood toxicity
Describe the cause of diabetes mellitus
Hyposecretion of insulin by the islet cells of the pancreas causes reduced cell uptake of glucose. This causes high blood sugar, resulting in high glucose content in urine, dehydration, high thirst and frequent urination