Human Reproductive Anatomy and Gametogenesis
As animals became more complex, specific organs and organ systems developed to support specific functions for the organism. The reproductive structures that evolved in land animals allow males and females…
Animal Reproduction and Development
Figure 24.1. Female seahorses produce eggs for reproduction that are then fertilized by the male. Unlike almost all other animals, the male seahorse then gestates the young until birth. (credit:…
Disruptions in the Immune System
A functioning immune system is essential for survival, but even the sophisticated cellular and molecular defenses of the mammalian immune response can be defeated by pathogens at virtually every step.…
Antibodies
An antibody, also known as an immunoglobulin (Ig), is a protein that is produced by plasma cells after stimulation by an antigen. Antibodies are the functional basis of humoral immunity. Antibodies…
Primary Centers of the Immune System
Although the immune system is characterized by circulating cells throughout the body, the regulation, maturation, and intercommunication of immune factors occur at specific sites. The blood circulates immune cells, proteins,…
Mucosal Surfaces and Immune Tolerance
The innate and adaptive immune responses discussed thus far comprise the systemic immune system (affecting the whole body), which is distinct from the mucosal immune system. Mucosal immunity is formed…
Adaptive Immune Response
The adaptive, or acquired, immune response takes days or even weeks to become established—much longer than the innate response; however, adaptive immunity is more specific to pathogens and has memory. Adaptive…
Phagocytosis and Inflammation
The first cytokines to be produced are pro-inflammatory; that is, they encourage inflammation, the localized redness, swelling, heat, and pain that result from the movement of leukocytes and fluid through increasingly…
The Immune System
Figure 23.1. In this compound light micrograph purple-stained neutrophil (upper left) and eosinophil (lower right) are white blood cells that float among red blood cells in this blood smear. Neutrophils…
Hormonal Control of Osmoregulatory Functions
While the kidneys operate to maintain osmotic balance and blood pressure in the body, they also act in concert with hormones. Hormones are small molecules that act as messengers within…
