Download BIOL 204 Homework Week 10 Name ________Answer

BIOL 204 Homework Week 10
1.
Name ________Answer Key___________
What is glomerulus? What is the function of glomerulus?
Glomerulus is a network of capillaries.
Function is to produce filtrate containing solutes except protein. (alternate acceptable answer –
function is to filter blood)
2. What is a nephron? Briefly describe the different parts of the nephron.
Nephron is functional unit of kidney that produces urine.
Structures incl: renal corpuscle (glomerulus & capsule), PCT, Ascending limb/Descending limb of loop
of Henle (Nephron loop), DCT ( alternate acceptable version : nephron consists of renal corpuscle
and renal tubule. Students should then elaborate on what makes up the renal corpuscle and the
parts of the tubule as stated in Rhonda’s answer)
3. Name the three processes in the mechanism of urine formation.
Glomerular filtration
Tubular Reabsorption
Tubular Secretion
4. Describe filtration, reabsorption, and secretion. ( alternate acceptable answer: filtration- materials
from blood are filtered except for proteins, blood cells; Reabsorption - 99% of the filtered
substances are reclaimed into the blood; Secretion –substances that were not filtered initially,
unwanted substances from the body, and substances that were initially reabsorbed but needed to
be removed are secreted from blood back into the filtrate)
Filtration: Hydrostatic pressure regulate passive movement of Water & small solutes across filtration
membrane
Reabsorption: Selective process returns all organic nutrients to system.
PCT: Glucose, Amino Acids, vitamins, 65% of water & NA+
Descending limb: permeable to water
Ascending limb: impermeable to water, active & passive transport of ions
DCT: Na+ and H2O permeable regulated by ADH, Aldosterone, Atrial natriuretic peptide
Secretion: Eliminate waste (solutes, excess K+), maintains blood pH between 7.35-7.45. Mostly in
PCT, some in DCT and Collecting Duct
5. What is filtrate?
Plasma-like (no proteins) fluid produced by nephron in the process of making urine (filtrate contains
all components of plasma except proteins)
6. Is filtrate the same as urine? Why or why not?
Filtrate is not the same as urine. Filtrate contains all components found in blood plasma except
proteins. Urine contains metabolic and other waste ie excess salts.
7. Name three hormones that act on the distal convoluted tubules and collecting duct.
Antidiuretic hormone (ADH)
Aldosterone
Atrial natriuretic peptide (source cardiac atrial cells) decease Na+ uptake, decrease blood volume,
decrease BP, increase Urine volume)
8. What is the mechanism of action of aldosterone? How will blood volume, blood pressure, and urine
volume be affected?
Aldosterone (source: adrenal cortex) increases reabsorption of Na+
Macula densa cells detect low NaCl stimulates JG cells to release renin enzyme convert
angiotensinogen to angiotensin I. Angiotnsinogen Converting Enzyme (ACE) transform angiotensin I
to angiotensin II stimulates adrenal cortex to release aldosterone.
Aldosterone increase blood volume bec increase in water reabsorption due to increase of Na+
reabsorption.
Increase volume causes increase in Blood Pressure.
Urine volume decreases
9. What is the action of antidiuretic hormone? How will blood volume, blood pressure, and urine
volume be affected?
ADH (source Posterior Pituitary) increase water reabsorption.
Blood volume increase
Blood Pressure increase
Urine volume decrease
10. Name the variables that will be tested on in the urinalysis lab activity. (independent / dependent
variable)
Independent variables
Dependent variables: Volume
Salty chips and other
NaCl
Specific Gravity