c h a p t e r 23 the lymphoid system powerpoint ® lecture slides prepared by jason lapres north...
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C h a p t e r
23
The Lymphoid System
PowerPoint® Lecture Slides prepared by Jason LaPres
North Harris CollegeHouston, Texas
Copyright © 2009 Pearson Education, Inc.,publishing as Pearson Benjamin Cummings
Introduction
The lymphoid system Lymphatic vessels Lymph (fluid connective tissue) Lymphoid tissues Lymphoid organs
Plays central role in body’s defenses against viruses, bacteria, and other microorganisms
Lymphatic vessels originate in peripheral tissues and deliver lymph to the venous system.
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An Overview of the Lymphoid System
Lymph consists of: Interstitial fluid, which resembles blood plasma,
but with a lower concentration of proteins Lymphocytes, cells responsible for the immune
response Macrophages of various types
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An Overview of the Lymphoid System
Primary functions of the lymphoid system: Produce, maintain, and distribute lymphocytes Maintain normal blood volume and eliminate local
variations in the chemical composition of the interstitial fluid
Provide an alternative route for the transport of hormones, nutrients, and waste products
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An Overview of the Lymphoid System
Figure 23.1 Lymphoid System
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Structure of Lymphatic Vessels
Lymphatic capillaries Lymphatic vessels (or lymphatics) carry lymph
from peripheral tissues to the venous system. Lymphatic capillaries (or terminal lymphatics)
form a complex network within peripheral tissues. Lymphatics contain internal valves that prevent
backflow of lymph/
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Structure of Lymphatic Vessels
Two sets of lymphatic vessels: Superficial lymphatic vessels travel with superficial veins
The subcutaneous layer next to the skin The loose connective tissues of the mucous membranes The loose connective tissues of the serous membranes
Deep lymphatic vessels are large lymphatic vessels that accompany the deep arteries and veins. Collect lymph from skeletal muscles and other organs of the neck,
limbs, and trunk, as well as visceral organs in the thoracic and abdominopelvic cavities
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Structure of Lymphatic Vessels
Figure 23.2a Lymphatic Capillaries: (a) Association of Blood Capillaries, Tissue, and Lymphatic Capillaries
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Structure of Lymphatic Vessels
Figure 23.2b Lymphatic Capillaries: (b) Sectional View
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Structure of Lymphatic Vessels
Figure 23.3 Lymphatic Vessels and Valves
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Structure of Lymphatic Vessels
Figure 23.4 Lymphatic Ducts and Lymphatic Drainage
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Structure of Lymphatic Vessels
Figure 23.5 Major Lymphatic Vessels of the Trunk
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Lymphocytes
Lymphocytes are the primary cells of the Lymphoid system, and they are responsible for specific immunity.
They respond to the presence of Invading organisms, such as bacteria and viruses Abnormal body cells, such as virus-infected cells
or cancer cells Foreign proteins, such as the toxins released by
some bacteria
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Lymphocytes
Three different classes of lymphocytes in the blood:
T cells (thymus dependent) Cytotoxic T cells Helper T cells Suppressor T cells Memory T cells
B cells (bone marrow derived) Plasma cells Memory B cells
NK cells (natural killer)
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Lymphocytes
Figure 23.6 Lymphocytes and the Immune Response
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Lymphocytes
Figure 23.7 Derivation and Distribution of Lymphocytes
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Lymphoid Tissues
Any tissue containing an abundance of lymphocytes
Diffuse lymphoid tissues—loosely packed lymphocytes within connective tissue
Lymphoid nodules—densely packed lymphocytes within loose connective tissue Tonsils Aggregated lymphoid nodules (Peyer’s patches)
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Lymphoid Tissues
Figure 23.8a Histology of Lymphoid Tissues: (a) Aggregated Lymphoid Nodule (Intestinal Tract)
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Lymphoid Tissues
Figure 23.8b Histology of Lymphoid: (b) Pharyngeal Tonsil (Respiratory Tract)
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Lymphoid Organs
Lymphoid tissues that are separated from surrounding tissues by a capsule
Lymph nodes Thymus Spleen
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Lymphoid Organs
Figure 23.9 Structure of a Lymph Node
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Lymphoid Organs
Figure 23.10 Lymphatic Drainage of the Head and Neck
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Lymphoid Organs
Figure 23.11a Lymphatic Drainage of the Upper Limb: (a) Male, Anterior View
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Lymphoid Organs
Figure 23.11b Lymphatic Drainage of the Upper Limb: (b) Female, Anterior View
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Lymphoid Organs
Figure 23.12 Lymphatic Drainage of the Lower Limb
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Lymphoid Organs
Figure 23.13 A Pelvic Lymphangiogram
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Lymphoid Organs
Figure 23.14a, b Lymphatic Drainage of the Inguinal Region: (a) Dissection of the Upper Right Inguinal Region in a Male (b) Inguinal Lymph Nodes and Vessels
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Lymphoid Organs
Figure 23.15 Lymph Nodes in the Large Intestine and Associated Mesenteries
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Lymphoid Organs
Figure 23.16 Anatomy and Histological Organization of the Thymus
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Lymphoid Organs
Figure 23.17 Anatomy and Histological Organization of the Spleen
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Lymphoid Organs
Figure 23.18 Jan’s X-Ray
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Aging and the Lymphoid System
With advancing age, the lymphoid system becomes less effective at combating disease.
T cells become less responsive to antigens. The number of helper T cells is reduced. B cells are less responsive. Antibody levels do not rise as quickly after antigen
exposure.
The net result is an increased susceptibility to viral and bacterial infection, and cancer.
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