The document outlines the components and functions of the lymphatic system, including lymph, lymph vessels, and lymphoid organs such as lymph nodes, spleen, and thymus, where lymphocytes mature. It describes immunity, distinguishing between innate immunity—which is nonspecific and does not create memory—and adaptive immunity that responds to foreign antigens including bacteria, viruses, and malignant cells. The text also details various barriers and defensive cells involved in innate immunity, highlighting their roles in protecting the body from infections.

1. Lymphatic System:
Antibodies and Immune cells:
Dr Rafaqat Ishaq
(Zool-402)
Human Physiology
27-05-2024

2. Parts of the Lymphatic System
1. Lymph and lymph vessels.
2. Lymphatic tissue: lymph nodes and nodules,
spleen, and thymus; lymphocytes mature and proliferate
Antibodies and Immune cells

23. Immunity
—the ability to destroy foreign antigens and
prevent future cases of certain infectious
diseases
1. Antigens are chemical markers that identify
cells.
Human cells have “self” antigens—the HLA types.
2. Foreign antigens stimulate antibody production
or other immune responses, and include bacteria,
viruses, fungi, protozoa, and malignant cells.

27. Innate Immunity
1. Nonspecific
responses are always the same, do not create memory, and does not become more efficient. Consists of barriers,
defensive cells, and chemical defenses.
2. Barriers
• Unbroken stratum corneum and sebum; living epidermal cells secrete defensins
• Subcutaneous tissue with WBCs
• Mucous membranes , upper respiratory epithelium is ciliated
• HCl in gastric juice
• Lysozyme in saliva and tears
3. Defensive cells
• Phagocytes—macrophages, neutrophils, eosinophils; macrophages also activate the lymphocytes
of adaptive immunity
• Langerhans cells and other dendritic cells—activate lymphocytes
• Natural killer cells—destroy foreign cells by rupturing their cell membranes
• Basophils and mast cells—produce histamine and leukotrienes (inflammation)

41. THE END