Ebook Inderbir singh human histology (7/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Inderbir singh human histology (7/E): Part 2
Ebook Inderbir singh human histology (7/E): Part 2
Chapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heart Ebook Inderbir singh human histology (7/E): Part 2t to various tissues are called arteries. T e smallest arteries are called arterioles. Arterioles open into a network of capillaries that pervade the tissues. Exchanges of various substances between the blood and the tissuestake place through the walls ofcapillaries. In some situations, capillaries Ebook Inderbir singh human histology (7/E): Part 2are replaced by slightly different vessels called sinusoids. Blood from capillaries (or from sinusoids) is collected by small venules that join to forEbook Inderbir singh human histology (7/E): Part 2
m veins. T e veins return blood to the heart.Blood vessels deliver nutrients, oxygen and hormones to the cells of the body and remove metabolic base pChapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heart Ebook Inderbir singh human histology (7/E): Part 2o called endotheliocytes). On surface view the cells are polygonal, and elongated along the length of the vessel. Cytoplasm is sparse.Te cytoplasm contains endoplasmic reticulum and mitochondria. Micro flaments and intermediate flaments are also present, and these provide mechanical support to the c Ebook Inderbir singh human histology (7/E): Part 2ell. Many endothelial cells show invaginations of cell membrane (on both internal and external surfaces). Sometimes the inner and outer invaginationsEbook Inderbir singh human histology (7/E): Part 2
meet to form channels passing right across the cell (seen typically in small arterioles). T ese features are seen in situations where vessels are highChapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heart Ebook Inderbir singh human histology (7/E): Part 2nctions of EndotheliumApart from providing a smooth internal lining to blood vessels and to the heart, endothelial cells perform a number of other functions as follows:□Endothelial cells are sensitive to alterations in blood pressure, blood fow, and in oxygen tension in blood.□T ey secrete various s Ebook Inderbir singh human histology (7/E): Part 2ubstances that can produce vasodilation by infuencing the tone of muscle in the vessel wall.□T ey produce factors that control coagulation of blood. UEbook Inderbir singh human histology (7/E): Part 2
nder normal conditions clotting is inhibited. When required, coagulation can be facilitated.https://khothuvien.cori!Chapter 13 The Cardiovascular SystChapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heart Ebook Inderbir singh human histology (7/E): Part 2ssel wall. In acute in fammation. endothelium allows neutrophils to pass from blood into surrounding tissues.□Under the in fuence of histamine (produced in allergic states) endothelium becomes highly permeable, allowing proteins and fuid to difi'use from blood into tissues. T e resultant accumulatio Ebook Inderbir singh human histology (7/E): Part 2n of fuid in tissues is called oedema.Note: Changes in properties of endothelium described above take place rapidly (within minutes).ARTERIESBasic StrEbook Inderbir singh human histology (7/E): Part 2
ucture of ArteriesT e histological structure of an artery varies considerably with its diameter. However, all arteries have some features in common whChapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heart Ebook Inderbir singh human histology (7/E): Part 2consists of:•An endothelial lining•A thin layer of glycoprotein which lines the external aspect of the endothelium and is called the basal laminaFig. 13.1: Layers in the wall of a typical artery (Schematic representation)211Textbook of Human Histology•A delicate layer of subendothelial connective ti Ebook Inderbir singh human histology (7/E): Part 2ssue•A membrane formed by elastic fbres called the internal elastic lamina.□ Outside the tunica intima there is the tunica media or middle layer. T eEbook Inderbir singh human histology (7/E): Part 2
media may consist predominantly of elastic tissue or of smooth muscle. Some connective tissue is usually present. On the outside the media is limited Chapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heart Ebook Inderbir singh human histology (7/E): Part 2f connective tissue in which collagen fbres are prominent. T is layer prevents undue stretching or distension of the artery.T e fbrous elements in the intima and the adventitia (mainly collagen) run longitudinally (i.e., along the length of the vessel), whereas those in the media (elastic tissue or Ebook Inderbir singh human histology (7/E): Part 2muscle) run circularly. Elastic fbres. including those of the internal and external elastic laminae are often in the form of fenestrated sheets (fenesEbook Inderbir singh human histology (7/E): Part 2
trated = having holes in it).Elastic and Muscular ArteriesOn the basis of the kind of tissue that predominates in the tunica media, arteries are oftenChapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heartChapter 13The Cardiovascular SystemT e cardiovascular system consists of the heart and blood vessels. T e blood vessels that take blood from the heartGọi ngay
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