Stephen E. Fish, Ph.D. Mitchell L. Berk, Ph.D.

Stephen E. Fish, Ph.D. Mitchell L. Berk, Ph.D. Marshall University J. C. E. School of Medicine

Note to instructors: I use these PowerPoint slides in histology lectures that I give to first year medical students. Copy the slides, or just the images into your own teaching media. We all know that teaching science often requires compromises and simplification for specific student populations, or the requirements of a specific course. Please feel free to offer suggestions for improvements, corrections, or additional illustrations. I would be pleased to hear from anyone who finds my work useful, and am always willing to make it better. Also, the images have been compressed to screen resolution to keep PowerPoint file size down, and I can provide them at any resolution. Contact me about the illustrations and Mitchell L. Berk about the photomicrographs. Stephen E. Fish, Ph.D. [email protected] [email protected]

Blood & lymph vessels

Vessels have a common plan of layers

A little about elastin in the media It is made by the smooth muscle cells Elastin fibers predominate in small arteries Elastic laminae predominate in large arteries They are like inner tubes, one inside another But they are perforated to allow access to O2 & nutrients They appear wrinkled in most slides because the smooth muscle often contracts in death

Intima Media Adventitia Vasa vasorum Artifactual crack Very large arteries- aorta

Media Aorta detail This is so dark because it is stained for elastin (Intima is missing on many slides) Internal elastic lamina hard to see, look for others in the media Intima Endothelium

Aorta detail Dense irregular CT of adventitia with elastic stain Media Crack External elastic lamina Vasa vasorum

Muscular arteries (medium size) Media- elastic lamina faint or nonexistent, mostly elastin fibers Internal elastic lamina Intima very thin Adventitia

Arterioles Minimal intima & 1- 3 muscle layers In media a few elastin fibers & no laminae Normal constriction (vasomotor response) is important for regulating capillary blood flow

Capillaries supplying sweat glands with water & proteins Capillaries consist of endothelial cells & their basement membrane The only layer is the intima

Type 1 Capillary

Type 2 (for type 3, covered in kidney lectures, just imagine there are no diaphragms)

One example of a sinusoid

Capillary bed

Low flow (pressure) in a capillary bed

High flow in a capillary bed

Lymphatic vessels

Medium artery & vein compared

How veins look on slides

Vena cava