The Lymphatic Systemand Immunity Chapter 13

Lymph and Lymph Vessels Lymph

a specialized fluid formed in the tissue spaces that is transported by of specialized lymphatic vessels to eventually reenter the circulatory system.

Movement of lymph is one way Have one way valves

(like veins)

Lymph and Lymph Vessels

Lymphatic capillaries permit excess tissue fluid and some other substances

such as dissolved protein molecules to the leave the tissue spaces.

Lymph Nodes

Filter lymph before reentering blood

2 jobs – defense and white blood cell formation

Filter out bacteria and other abnormal cells by phagocytosis

Lymph Nodes Prevents local infections from spreading

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Lymph Nodes Afferent lymph vessels

Carry lymph to the node

Efferent lymph vessels

Carry lymph out of the node

Thymus

Click icon to add pictureComposed of lymphocytes – largest at puberty

Source of lymphocytes before birth

Especially important in the maturation or development, of specialized T lymphocytes (T cells).

Thymus completes most of its work early in childhood and is replaced largely by fat and connective tissue – involution

Tonsils

Masses of lymphoid tissue

Located in the mouth and back of the throat

First line of defense from exterior

Spleen

Located in the upper left quadrant of the abdomen – protected by the lower ribs

Filters blood, destroys worn out RBC’s, and salvages iron found in hemoglobin

Serves as a reservoir for blood – very rich blood supply (1 pint)

IMMMUNE SYSTEM

The body’s defense mechanisms protect us from disease-causing microorganisms, from foreign tissue cells that may have been transplanted into our bodies, and from our own cell when they have turned malignant or cancerous.

Nonspecific Immunity

Is maintained by mechanisms that attack any irritant or abnormal substance that threatens the internal environment. In other words, general protection

Often called innate immunity

Ex: skin, tears, mucous membranes, etc….

Inflammatory response – a set of nonspecific responses that often occurs in the body.

Inflam

mato

ry R

esp

on

se

Tissue Damage Occurs

Mediators are

released

WBCs

BloodFlow

Vascular Permeability

Increased # of

leukocytes &

mediators

ContainedDestroyedPhagocytized

Nonspecific Immunity

Includes protective mechanisms that confer very specific protection against certain types of invaders.

Involves the memory and ability to recognize and respond to certain harmful substances or bacteria – called adaptive immunity

Specific Immunity

Can be either natural or artificial

Natural – is not deliberate and occurs in everyday living

Artificial – is called immunization and is deliberate exposure of the body to a potentially harmful agent.

Specific Immunity

Active When an individuals own

immune system responds to a harmful agent, regardless of whether that agent was naturally or artificially encountered.

Passive When immunity to a

disease that has developed in another individual or animal is transferred to an individual who was not previously immune.

IMMUNE SYSTEM MOLECULES

Antibodies – protein compounds that are normally present in the body. Have combining sites and combine with antigens Antigens are often protein molecules imbedded in the

surface membranes of invading or diseased cells. In general, antibodies produce immunity by changing the

antigens so that they cannot harm the body.

IMMUNE SYSTEM MOLECULES

Complement Proteins Complement is that name used to describe a group of

protein enzymes normally present in an inactive state in the blood.

Complement cascade – basically drill holes in foreign cells causing them to die

IMMUNE SYSTEM CELLS

Phagocytes – Neutrophils, Monocytes, and Macrophages

Lymphocytes – T-lymphocytes and B-lymphocytes