Nitrogenous Wastes
Of the four major macromolecules in biological systems, both proteins and nucleic acids contain nitrogen. During the catabolism, or breakdown, of nitrogen-containing macromolecules, carbon, hydrogen, and oxygen are extracted and…
Excretion Systems
Microorganisms and invertebrate animals use more primitive and simple mechanisms to get rid of their metabolic wastes than the mammalian system of kidney and urinary function. Three excretory systems evolved…
The Kidneys and Osmoregulatory Organs
Although the kidneys are the major osmoregulatory organ, the skin and lungs also play a role in the process. Water and electrolytes are lost through sweat glands in the skin,…
Osmotic Regulation and Excretion
Figure 22.1. Just as humans recycle what we can and dump the remains into landfills, our bodies use and recycle what they can and excrete the remaining waste products. Our…
Blood Flow and Blood Pressure Regulation
Blood pressure (BP) is the pressure exerted by blood on the walls of a blood vessel that helps to push blood through the body. Systolic blood pressure measures the amount of…
Arteries, Veins, and Capillaries
The blood from the heart is carried through the body by a complex network of blood vessels (Figure 21.15). Arteries take blood away from the heart. The main artery is the aorta…
Mammalian Heart and Blood Vessels
The heart is a complex muscle that pumps blood through the three divisions of the circulatory system: the coronary (vessels that serve the heart), pulmonary (heart and lungs), and systemic…
Components of the Blood
Hemoglobin is responsible for distributing oxygen, and to a lesser extent, carbon dioxide, throughout the circulatory systems of humans, vertebrates, and many invertebrates. The blood is more than the proteins,…
The Circulatory System
Figure 21.1. Just as highway systems transport people and goods through a complex network, the circulatory system transports nutrients, gases, and wastes throughout the animal body. Introduction Most animals are…
Transport of Gases in Human Bodily Fluids
Once the oxygen diffuses across the alveoli, it enters the bloodstream and is transported to the tissues where it is unloaded, and carbon dioxide diffuses out of the blood and…
