Kidney and Excretory System Midterm Review

peritubular capillary

one of the tiny blood vessels that form a network surrounding the proximal and distal tubules in the kidney

What is least likely to be present in the glomerular filtrate of a healthy adult nephron?

proteins

proximal convoluted tubule

where osmoregulation takes place; organic solutes like glucose and amino acids are absorbed; helps recapture sodium, potassium, and water.

Kidney Anatomy

- Medulla (most salty region) - Renal Artery (dirty blood) - Renal Vein (clean blood)

kidney filtrate

- The filtrate is composed of water, ions (sodium, potassium, chloride), glucose and small proteins - makes urine at the end

kidney dialysis

- a machine removes blood from your body, filters it through a dialyzer (artificial kidney) and returns the cleaned blood to your body

tubular reabsorption

- selectively returns 99% of substances from filtrate to blood in renal tubules and collecting ducts - Sodium/potassium ATPase, a sodium pump takes care of this by moving 3 Na+ out of the cell for reabsorption into the bloodstream, and pumping 2 K+ into the cell . - Glucose, amino acids and other substances diffuse out on passive transporters and are then reabsorbed by the blood - Loop of Henle Reabsorption in the ascending limb: 25% of the sodium and potassium is reabsorbed

Loop of Henle

- where most reabsorption happens - pumps needed salts - makes the medulla hypertonic (very salty) and it draws out water

How does the kidney regulate blood?

1. Filtration - Bowman's Capsule - Glomerulus 2. Secretion - PCT - DCT - Loop of Henle 3. Reabsorption - PCT - DCT - Loop of Henle - Collecting Duct (sometimes)

Presence of which of the following in the urine, even in small amounts, is indicative of a possible problem in the renal system of a patient? A: Glucose B: Creatinine C: Urea D: Sodium

A

Which of the following choices correctly traces the route of glomerular filtrate on its path to the collecting duct of a nephron? A: Bowman's capsule, proximal tubule, descending loop of Henle, ascending loop of Henle, distal tubule B: proximal tubule, Bowman's capsule, descending loop of Henle, ascending loop of Henle, distal tubule C: Bowman's capsule, proximal tubule, ascending loop of Henle, descending loop of Henle, distal tubule D: Bowman's capsule, distal tubule, descending loop of Henle, ascending loop of Henle, proximal tubule

A

Urine is formed in a three-step process: which of the following gives the correct order in which these steps take place in the nephron? A: Tubular secretion, tubular reabsorption, glomerular filtration B: Tubular reabsorption, tubular secretion, glomerular filtration C: Glomerular filtration, tubular reabsorption, tubular secretion D: Glomerular filtration, tubular secretion, tubular reabsorption

C

Which of the following is least likely to be present in the glomerular filtrate (the filtrate produced by the nephron before it enters the loop of Henle) of a healthy adult nephron? A: Electrolytes B: Amino acids C: Glucose D: Large molecular weight protein

D

ADH

Diabetes insipidus is a rare disorder that causes you to feel very thirsty (despite drinking a lot), and to produce large amounts of urine. It is usually caused by a malfunction in the production of antidiuretic hormone (ADH), a hormone that prevents the production of dilute urine (i.e., retains water in the body).

As glomerular filtrate moves through the ascending loop of Henle, the filtrate becomes more dilute: why?

The ascending loop of Henle is permeable to ions but impermeable to water

Excretion in African Lungfish

When it aestivates in mucus cocoon on land, ammonia is detoxified to urea. During the maintenance phase of aestivation, urea accumulates in the body, which is subsequently excreted upon arousal.

excretion in birds

While mammals excrete nitrogenous wastes mostly in the form of urea, birds convert it to uric acid or guanine, which reduces water loss in comparison.

collecting duct

creates the urine and leads it to the ureter, bladder, and urethra in excretion

Excretion in humans

elimination of waste through the urethra in the form of urine

nephron

functional unit of the kidney

distal convoluted tubule

pumps and hormones regulate calcium, potassium, and sodium leaving water, urea, and other metabolic waste

Osmoregulation

the control of solute concentrations and water balance, hydration

glomerulus

the pressure squeezes fluid out of the blood

Bowman's capsule

what was excreted from the blood is now called the filtrate (water, urea, ions, etc.), blood cells and proteins don't get filtered