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Human physiology

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The cover illustration by William B. Westwood
Depicts a battle waged on multiple fronts in response to an invasion. A splinter has pierced the skin and allowed bacteria to enter the underlying tissue.This has enlisted numerous defense mechanisms to plug the torn tissue and blood vessels and combat the bacteria.

When the physiological events are viewed, the common experience of getting a splinter becomes rightly appreciated as high drama.

The splinter has pierced the epidermis and dermis of the skin, as well as blood vessels in the dermis. This has initiated a cascade of reactions involving blood platelets (small tan spheres) and clotting factors that produce a web of fibrin proteins forming a clot in the wound. Bacteria (staphylococcus are shown as purple grape-like clusters, streptococcus as short chains of orange-brown ovals) invade the body through this breach in the epidermal barrier. Neutrophils (the numerous large purple cells covered with bumps representing microvilli) leave small blood vessels and enter the surrounding tissues along with fluid, which causes swelling in the area. Neutrophils can "eat" bacteria by phagocytosis, as shown in this illustration by two neutrophils engulfing staphylococci bacteria. Neutrophils also trap bacteria in secreted web-like NETS (neutrophil extracellular traps) and release enzymes and other molecules that kill bacteria.

Macrophages (green cells) are also phagocytic and catch bacteria in their filamentous pseudopod extensions. Lymphocytes (another type of white blood cell here colored blue-green; one is shown in the 12:00 o'clock position) secrete antibodies, which are depicted as yellow Y-shaped protein molecules. Antibodies initiate events that activate complement proteins (small turquoise spheres) and that stimulate mast cells (gray cells) to release histamine (small gray eggs) and other mediators of inflammation. Antibodies promote phagocytosis by neutrophils and macrophages, and complement proteins help antibodies destroy bacterial cells.

All this is but a snapshot of ongoing events that normally result in eradication of the bacteria and healing of the wound. The common experience of getting a splinter and recovering from it presents a fine example of homeostasis, of how physiological mechanisms act to re-establish a healthy state after normal conditions are perturbed.

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Ketersediaan

Informasi Detail

Judul Seri

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No. Panggil

612 Fox h

Penerbit

New York : Mc Graw-Hill., 2013

Deskripsi Fisik

xxii, 810 hal. : il. ; 29 cm.

Bahasa

English

ISBN/ISSN

9780073403625

Klasifikasi

612

Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

Ed. XIII

Subjek

Fisiologi Manusia

Info Detail Spesifik

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Pernyataan Tanggungjawab

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Versi lain/terkait

Lampiran Berkas

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