Class Notes (1,100,000)
CA (630,000)
UTSC (30,000)
BIOB32H3 (100)

BIOB32H3 Lecture Notes - Immunoglobulin A, Immunoglobulin D, Integumentary System

Biological Sciences
Course Code
Kenneth Welch

This preview shows pages 1-2. to view the full 7 pages of the document.
The Lymphatic System and Immunity
An Overview of the Lymphatic System and Immunity
lymphatic system
•The lymphatic system
•Contains cells, tissues, and organs responsible for defending the body
•Lymphocytes resist infection and disease by responding to
•Invading pathogens such as bacteria or viruses
•Abnormal body cells such as cancer cells
•Foreign proteins such as toxins
Organization of the Lymphatic System
The lymphatic system consists of
•Lymphatic vessels
•Lymphoid tissues and organs
•Lymphocytes and supporting phagocytic cells
Functions of lymphatic system
•Primary function is production, maintenance, and distribution of lymphocytes
•Lymphocytes must:
•Detect where problems exist
•Be able to reach the site of injury or infection
Lymphatic vessels include
•Lymphatic capillaries
•Small lymphatic vessels
•Major lymph-collecting vessels
Major lymph-collecting vessels
•Superficial and deep lymphatics
•Thoracic duct
•Cisterna chyli
•Right lymphatic duct
•Three classes of lymphocytes
•T (thymus dependent) cells
•B (bone marrow-derived) cells
•NK (natural killer) cells
Lymphocyte production (lymphopoiesis)
•Involves bone marrow, thymus, and peripheral lymphoid tissue
•B cells and NK cells mature in bone marrow
•T cells mature in the thymus

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Lymphoid tissue
•Connective tissue dominated by lymphocytes
•Lymphoid nodules
•Lymphocytes densely packed in areolar tissue
•Found in the respiratory, digestive, and urinary tracts
•MALT (mucosa-associated lymphoid tissue)
•Collection of lymphoid tissues linked with the digestive system
Lymphoid organs
•Lymph nodes – function in the purification of lymph
•Afferent lymphatics carry lymph to nodes
•Efferent lymphatics carry lymph from nodes
•Deep cortex dominated by T cells
•Outer cortex and medulla contains B cells
The Lymphatic System and Immunity
The Thymus
•Located behind sternum in anterior mediastinum
•Two lobes
•Divided into lobules, each with a cortex and medulla
•Cortical lymphocytes surrounded by reticular endothelial cells
•Maintain blood–thymus barrier
•Secretes thymic hormones: thymosins, thymopoietins, and thymulin
The Spleen
•Largest mass of lymphoid tissue
•Cellular components form pulp
•Red pulp contains RBC
•White pulp similar to lymphoid nodules
Spleen functions include
•Removal of abnormal blood cells and other blood components
•Storage of iron
•Initiation of the specific immune response
Lymphatic system and body defenses
•Nonspecific defenses
•Do not distinguish one type of threat from another
•7 types
•Specific defenses
•Protect against particular threats
•Depend upon the activation of lymphocytes
Nonspecific Defenses
Nonspecific Defenses, Physical barriers
•Keep hazardous organisms outside the body
You're Reading a Preview

Unlock to view full version