.

Michael J Davis1, Scott D Zawieja1, Ying Yang2

  • 1Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, United States.

概括

淋巴 (LVs) 在四个阶段发展. 研究人员发现,LVs变得功能性,并防止在第3阶段和第4阶段之间的回流,挑战了关于其发展的先前假设.

相关概念视频

Development of the Lymphatic System01:15

Development of the Lymphatic System

The development of lymphatic tissues and vessels in embryonic life begins around the fifth week. These structures originate from the mesoderm layer, with lymph sacs emerging from developing veins.
The first lymph sacs to form are the paired jugular lymph sacs located at the junction of the internal jugular and subclavian veins. From these sacs, lymphatic capillary plexuses extend to the thorax, upper limbs, neck, and head, eventually forming lymphatic vessels. Each jugular lymph sac maintains a...
702
Lymphatic Vessels and Lymph Transport01:16

Lymphatic Vessels and Lymph Transport

Lymphatic vessels, known as lymphatics, are crucial in transporting lymph from peripheral tissues to our venous system. This process begins with lymph entering through tiny capillaries that branch through tissues. These capillaries have unique features such as larger diameters, thinner walls, and a distinctive one-way valve system formed by overlapping endothelial cells.
This one-way system allows fluids, solutes, and even pathogens to enter but prevents their return to the intercellular...
3.1K
Detailed Structure and Function of Lymph Nodes01:23

Detailed Structure and Function of Lymph Nodes

Lymph nodes are bean-shaped structures that cluster along the lymphatic vessels in the inguinal, axillary, and cervical regions. Each node is divided into compartments by a capsule that extends trabeculae inward.
From a histological perspective, lymph nodes can be split into two main areas: the superficial cortex and the deep medulla. The outer cortex is populated by dendritic cells, macrophages, and B lymphocytes, which are densely packed into follicles. When these B-lymphocytes are presented...
1.6K
Heart Valves01:16

Heart Valves

The human heart is a complex organ with an intricate system of valves that regulate blood flow. There are two main types of valves: atrioventricular (AV) valves and semilunar valves.
The AV valves prevent the backflow of blood from the ventricles to the atria during ventricular contraction. These valves function with the assistance of the chordae tendineae and papillary muscles. When the ventricles are relaxed, the chordae tendineae are slack, allowing blood to flow from the atria into the...
4.6K
Development of the Heart01:27

Development of the Heart

The development of the human heart, a crucial organ, commences from the mesoderm on the 18th or 19th day after fertilization. This process initiates in the cardiogenic area, a group of mesodermal cells at the embryo's head end, which evolves into elongated strands known as cardiogenic cords. These cords undergo a transformation to form hollow-centered endocardial tubes.
As the embryo undergoes lateral folding, these paired tubes approach each other, merging into a single primitive heart...
936
Functions of the Lymphatic and Immune System01:28

Functions of the Lymphatic and Immune System

The lymphatic system plays a crucial role in bolstering our immune system. It consists of a network of lymphoid organs, lymph, and lymphatic vessels that provide structural and functional support in safeguarding the body against pathogens such as viruses and bacteria.
The primary lymphoid organs, including the bone marrow and the thymus, serve as the maturation sites for lymphocytes. Secondary lymphoid organs, like the mucosa-associated lymphoid tissue, activate these lymphocytes and serve as...
3.1K