The document discusses the process of excretion in the human body. Medications are eliminated from the body through excretion, which primarily occurs through the kidneys. The kidneys filter waste from the blood through glomerular filtration and either reabsorb or actively secrete drugs and other molecules into the urine through tubular transport processes for excretion from the body.

1. Susan Ross, Lindsay Leiter, Bonnie Schlicker

2. What is excretion?
The elimination of waste products by an organism.

3. Humans
 Humans excrete waste products through:
 Urine
 Feces
 Expired air (CO2)
 Sweat
 Saliva
 Breast milk

4. What about medicine?
Think of the last time you were sick.
You most likely took some sort of medication that
eventually helped you feel well again.
But what happened to the medicine once it completed
its task?
It must be excreted!!!

5. Pharmacology- study of drugs and their
interactions with living systems.
Pharmacokinetics- drug movement
1. Absorption
 Route from administration site
to the bloodstream
 IV, Injection, Oral, or Topical
2. Distribution
 Bloodstream to the site of action
Fig. 1-Pharmacokinetics: Absorption,
distribution, metabolism, and elimination.

6. Pharmacokinetics
3. Metabolism
 The breakdown of chemical
structure by the liver
4. Excretion
 The elimination of a
medication from the
body primarily through
the kidneys.
Fig. 2-Absorption, distribution, metabolism, and
excretion in the human body.

7. Kidney Anatomy
Fig. 4 A single nephron unit.Fig. 3 Longitudinal section of the kidney

8. Glomerular Filtration
 Begins at the glomerulus
 Consists of a capillary
network surrounded by
Bowman's capsule
 Small pores perforate the
capillary walls
 Drugs are forced
through these pores
 This process moves
drugs from the blood
into the tubular urine. Fig. 5-Renal corpuscle

9. Passive Tubular Reabsorption
 Blood vessels to the
glomerulus meet up with
the renal distal tubule.
 Here, concentration of
drugs in the blood are lower
than drugs in the tubule.
 This concentration gradient
acts as a driving force to
move drugs from the tubule
back into the blood
(reabsorption).
Fig. 6-Glomerular capsule.
http://kvhs.nbed.nb.ca/gallant/biology/nephron_structu
re.html

10. Active Tubular Secretion
 Drugs are pumped from the
blood to tubular urine via active
transport systems.
 An area of lower concentration
toward an area of higher
concentration.
 Requires energy
 Tubular cells contain P-
glycoprotein in their
membranes, which pump drugs
into urine.
Fig. 7-Renal drug xcretion.

11. The End (of Drug Movement)

12. References
 Lehne, R. A. (2013). Pharmacology for nursing care. 8th Ed. St.
Louis, Mo: Elsevier/Saunders.
 Lewis, Sharon. Medical-Surgical Nursing: Assessment and
Management of Clinical Problems, 8th Edition. Mosby, 2011.
<vbk:9780323065801>.
 Urinary System. (n.d.). Retrieved August 30, 2013, from
http://legacy.owensboro.kctcs.edu/gcaplan/anat2/notes/A
PII Notes3%20urinary%20system.htm
 Wissman, J., Knippa, A., Lawler, K. M., Stacy, B. L., & Assessment
Technologies Institute. (2008). Pharmacology for nursing.
Overland Park, KS: Assessment Technologies Institute.