Transcript Nerve activates contraction

12
PART A
The Lymphatic System
and Body Defenses
PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University
ESSENTIALS
OF HUMAN
ANATOMY
& PHYSIOLOGY
EIGHTH EDITION
ELAINE N. MARIEB
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Lymphatic System
 Lymphatic system functions
 Transport fluids back to the blood
 Role in body defense, disease resistance
 Lymph: excess tissue fluid
 Lymphatic vessels: carry lymph toward heart
 Lymph materials returned to the blood Water, blood cells, proteins
 Harmful materials that enter lymph vessels
 Bacteria, Viruses, Cancer cells, Cell debris
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Lymph Nodes
 Lymph Nodes:
 Filter lymph before it is returned to the
blood
 Defense cells within lymph nodes
 Macrophages – engulf and destroy
foreign substances
 Lymphocytes – provide immune response
to antigens
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Lymph Nodes
Figure 12.3
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Other Lymphoid Organs
 Spleen: filters blood, destroys old
RBCs.
 Thymus: Located in throat, over
heart. Programs lymphocytes.
 Tonsils: lymph tissue of pharynx,
traps & removes bacteria.
Tonsillitis: bacteria congestion
 Peyer’s patches: Capture and
destroy bacteria in the intestine
 Appendix: help produce
antibodies
Figure 12.5
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Body Defenses
 The body is constantly in contact with bacteria,
fungi, and viruses. Body secretes chemicals like
lysozyme, acid, and enzymes to kill invaders;
mucous to trap invaders.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Defensive Cells
 Phagocytes
(neutrophils and
macrophages)
 Engulfs foreign
material
 Lysosome enzymes
digest material
 Interferon
 Bind to healthy cell
surfaces to inhibit
viruses binding
Figure 12.7a
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Inflammation- Second Line of Defense
 Inflammation: Triggered when body tissues are
injured.
 Signs- Redness, Heat, Swelling, Pain
 Results in a chain of events leading to protection
and healing of tissue
 Fever: Abnormally high body temperature.
 High temperatures inhibit the release of iron and
zinc from liver and spleen needed by bacteria.
Fever also increases the speed of tissue repair.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Antigens (Nonself)
 Antigen: any foreign substance capable of
triggering immune system
 Examples of common antigens:
 Foreign proteins, pollen grains, microorganisms
 Our immune cells attack specific antigens
 Has memory – recognizes and mounts a stronger
attack on previously encountered pathogens
 Allergies: molecules that immune system interprets
as foreign, end up attacking our own cells
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Cells of the Immune System
 Lymphocytes (B and T lymphocytes)
 B lymphocytes: bind to a specific antigen,
Produce antibodies (immunoglobulins Igs) to
destroy antigens. Some become memory cells.
 T lymphocytes: Antigens must be presented by
macrophages to T cell. Killer T cells destroy it.
 Macrophages
 Arise from monocytes
 Become widely distributed in lymphoid organs
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular (Cell-Mediated) Immune
Response
Figure 12.17
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders of Immunity:
Immunodeficiencies
 Immunodeficiency: immune cells abnormal,
not enough. Includes AIDS- Acquired
Immune Deficiency Syndrome
 Autoimmune Disease: cells cannot tell self
and non-self apart and attacks own cells.
Includes Multiple Sclerosis (MS), arthritis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings