Heart Rate: Alteration by Nervous System Although the heart muscle maintains a base heart rate via?myogenic?stimulation, there are several circumstances that can cause an individual's heart rate to...
Introduction to the Heart Mammalian heart structure The heart is a hollow,?muscular organ?located in the chest cavity The heart is divided into?four chambers The two top chambers are?atria The bott...
Double Circulation The need for a circulatory system All organisms need to?transport?materials to where they are needed inside their tissues Small organisms?(or relatively inactive animals like jel...
Arteries Introduction to blood vessels The?circulatory system?of the human body contains several different types of?blood vessel: Arteries Arterioles Capillaries Venules Veins Each type of blood ve...
Discovery of the Circulation of Blood NOS: Theories are regarded as uncertain; William Harvey overturned theories developed by the ancient Greek philosopher Galen on movement of blood in the body A...
Digestive System Diagram Human Digestive System The human digestive system includes the following: Glands?- the salivary glands, and glands in the pancreas that produce digestive juices The?stomach...
Methods of Absorption Digestion breaks down food into?smaller, soluble molecules These products of digestion then pass from the?lumen?of the intestine into the?blood They pass through the microvill...
Villi: Increasing the Surface Area The?ileum?(the second section of the small intestine) is adapted for?absorption It is?very long It has a?highly folded surface It has?millions of villi?(singular ...
Introduction to Digestion The digestive system is an example of an?organ system?in which several organs work together to digest and absorb food Digestion is a process in which relatively?large, ins...
