The Biology II Course was developed through the Ohio Department of Higher Education OER Innovation Grant. The course is part of the Ohio Transfer Assurance Guides and is also named OSC004. This work was completed and the course was posted in October 2019. For more information about credit transfer between Ohio colleges and universities, please visit: www.ohiohighered.org/transfer.Team LeadCathy Sistilli                                         Eastern Gateway Community CollegeContent ContributorsLisa Aschemeier                                 Northwest State Community CollegeShaun Blevins                                     Rhodes State CollegeRachel Detraz                                     Edison State Community College                                     Sara Finch                                          Sinclair Community CollegeWendy Gagliano                                 Clark State Community College AJ Snow                                             University of Akron Wayne CollegeLibrarianAmanda Rinehart                               Ohio State UniversityReview TeamJessica Hall                                        Ohio Dominican UniversitySanhita Gupta                                    Kent State UniversityErica Mersfelder                                 Sinclair Community College

Solute concentrations across semi-permeable membranes influence the movement of water and solutes across the membrane. Osmoregulation and osmotic balance are important bodily functions, resulting in water and salt balance. Osmolarity is measured in units of milliequivalents or milliosmoles, both of which take into consideration the number of solute particles and the charge on them. Some organisms are osmoconformers in that they are isotonic with their environment. The kidneys are the main osmoregulatory organs in mammalian systems; they function to filter blood and maintain the osmolarity of body fluids. Many systems have evolved for excreting wastes that are simpler than the kidney and urinary systems of vertebrate animals. The simplest system is that of contractile vacuoles present in microorganisms. Flame cells and nephridia in worms perform excretory functions and maintain osmotic balance. Some insects have evolved Malpighian tubules to excrete wastes and maintain osmotic balance.

By the end of this section, you will be able to do the following:

Explain how vacuoles, present in microorganisms, work to excrete waste
Describe the way in which flame cells and nephridia in worms perform excretory functions and maintain osmotic balance
Explain how insects use Malpighian tubules to excrete wastes and maintain osmotic balance

By the end of this section, you will be able to do the following:

Explain how hormonal cues help the kidneys synchronize the osmotic needs of the body
Describe how hormones like epinephrine, norepinephrine, renin-angiotensin, aldosterone, anti-diuretic hormone, and atrial natriuretic peptide help regulate waste elimination, maintain correct osmolarity, and perform other osmoregulatory functions

By the end of this section, you will be able to do the following:

Compare and contrast the way in which aquatic animals and terrestrial animals can eliminate toxic ammonia from their systems
Compare the major byproduct of ammonia metabolism in vertebrate animals to that of birds, insects, and reptiles

By the end of this section, you will be able to do the following:

Define osmosis and explain its role within molecules
Explain why osmoregulation and osmotic balance are important body functions
Describe active transport mechanisms
Explain osmolarity and the way in which it is measured
Describe osmoregulators or osmoconformers and how these tools allow animals to adapt to different environments

By the end of this section, you will be able to do the following:

Explain how the kidneys serve as the main osmoregulatory organs in mammalian systems
Describe the structure of the kidneys and the functions of the parts of the kidney
Describe how the nephron is the functional unit of the kidney and explain how it actively filters blood and generates urine
Detail the three steps in the formation of urine: glomerular filtration, tubular reabsorption, and tubular secretion