JК
Английский язык :: Беликова Елена
Страница: 28 из 68Muscular distributing arteries are medium-sized vessels that are characterized by their predominance of circularly arranged smooth muscle cells in the media interspersed with a few elastin components. Up to 40 layers of smooth muscle may occur. Both internal and external elastic limiting membranes are clearly demonstrated. The intima is thinner than that of the large arteries.
Arterioles are the smallest components of the arterial tree. Generally, any artery less than 0,5 mm in diameter is considered to be a small artery or arteriole. A suben-dothelial layer and the inter nal elastic membrane may be present in the largest of these vessels but are absent in the smaller ones. The media is composed of several smooth muscle cell layers, and the adventitia is poorly devel oped. An external elastic membrane is absent.
New words
endothelium – эндотелий
media – средняя
arteries – артерии
to be classified – классифицированный
according – соответственно
their – их
size – размер
appearance – вид
tunica – оболочка
major – главный
elastic – эластичный
conducting – проведение
arteries – артерии
to include – включать
aorta – аорта
branches – ветви
up to – до
layers – слои
smooth – гладкий
may – может
infima – внутренняя полость артерии
24. Capillaries
Capillaries are thin-walled, narrow-diameter, low-pressure vessels that generally permit easy diffusion across their walls. Most capillar ies have a cross-sectional diameter of 7 – 12 mm. They are composed of a simple layer of endothelium, which is the lining of the entire vas cular system, and an underlying basal lamina. They are attached to the surrounding tissues by a delicate reticulum of collagen. Associated with these vessels at various points along their length are specialized cells called pericytes. These cells, enclosed within their own basal lamina, which is continuous with that of the endothelium, contain contractile proteins and thus may be involved in the control of capillary dynamics. They may also serve as stem cells at times of vascular repair.
Arterioles are the smallest components of the arterial tree. Generally, any artery less than 0,5 mm in diameter is considered to be a small artery or arteriole. A suben-dothelial layer and the inter nal elastic membrane may be present in the largest of these vessels but are absent in the smaller ones. The media is composed of several smooth muscle cell layers, and the adventitia is poorly devel oped. An external elastic membrane is absent.
New words
endothelium – эндотелий
media – средняя
arteries – артерии
to be classified – классифицированный
according – соответственно
their – их
size – размер
appearance – вид
tunica – оболочка
major – главный
elastic – эластичный
conducting – проведение
arteries – артерии
to include – включать
aorta – аорта
branches – ветви
up to – до
layers – слои
smooth – гладкий
may – может
infima – внутренняя полость артерии
24. Capillaries
Capillaries are thin-walled, narrow-diameter, low-pressure vessels that generally permit easy diffusion across their walls. Most capillar ies have a cross-sectional diameter of 7 – 12 mm. They are composed of a simple layer of endothelium, which is the lining of the entire vas cular system, and an underlying basal lamina. They are attached to the surrounding tissues by a delicate reticulum of collagen. Associated with these vessels at various points along their length are specialized cells called pericytes. These cells, enclosed within their own basal lamina, which is continuous with that of the endothelium, contain contractile proteins and thus may be involved in the control of capillary dynamics. They may also serve as stem cells at times of vascular repair.