Urination
Description

Micturition (peeing) starts with urine flowing from the kidneys to the bladder via ureters. The bladder expands using transitional epithelium. Urine exits through the urethra, controlled by internal and external urethral sphincters. Ureters prevent backflow, thereby reducing infection risk

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Raja Narayan
Skeletal structure and function
Description

Skeletons support and protect our bodies. Bugs have exoskeletons outside their bodies, while humans have endoskeletons inside. Our bones are in axial (skull, ribcage, spine) and appendicular (arms, legs) groups. Bone marrow makes blood cells; more specifically, red marrow makes blood and yellow marrow stores fat. 

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Tracy Kim Kovach
Biodiversity and natural selection
Description

Patterns and processes of evolution. How evolution and natural selection are reflected in the similarities and differences of organisms. 

Language
English
Resource Type
Publisher
California Academy of Sciences
Publication Date
Creator/Author
California Academy of Sciences