bio final

Immunity

The body's ability to defend itself against infectious agents, foreign cells and even abnormal body cells

Lymphatic system primary organs

tonsils, right lymphatic duct, thymus gland, thoracic duct, spleen, some lymph vessels, some lymph nodes, bone marrow.

Tonsils

Defense against bacteria and other foreign agents.

Right Lymphatic Duct

Drains right upper portion of the body.

Thymus Gland

Site where certain white blood cells acquire means to chemically recognize specific foreign invaders.

Where Lymphocytes mature

Thoracic Duct

Drains most of the body

Spleen

Major site of antibody production; disposal site for old red blood cells and foreign debris; site of red blood cell formation in the embryo.

Site where B lymphocytes go to produce antibodies

Some Lymph Vessels

Return excess interstitial fluid and reclaimable solutes to the blood.

Some Lymph Nodes

Filter bacteria and many other agents of disease from lymph

Bone Marrow

Marrow in some bones is production site for infection fighting blood cells (as well as red blood cells and platelets)

Physical and chemical barriers (non-specific)

Skin and mucous membranes

tears, skin, large intestine, saliva, respiratory tract, stomach, bladder

Tears

Wash away irritating substances and microbes

Lysozyme kills many bacteria

Skin

Provides a physical barrier to the entrance of microbes

acidpH discourages the growth of organisms

Swear, oil, and fatty acid secretions kill many bacteria.

Large Intestine

Normal bacterial inhabitants keep invaders in check.

Saliva

Washes microbes from the teeth and mucous membranes of the mouth.

Respiratory tract

Mucus traps organisms, Cilia sweeps away trapped organisms

Stomach

Acid kills organisms

Bladder

Urine washes microbes from urethra

General Defenses

Second Line of Defense

Fever, inflammatory response, phagocytes, defensive cells and proteins

Complement System

Fever, Inflammatory response

Fever

Pyrogens raise body's set point; makes internal environment less hospitable to pathogen

Inflammatory response

Pain, redness, swelling as more blood goes to these regions; attracts phagocytes and promotes tissue healing

Phagocytes

Neutrophils and Macrophages; engulf and digest foreign cells; eosinophils bombard large parasites with digestive enzymes and phagocytize foreign proteins

Specific Defense

If a pathogen elicits a very specific response by the body it is called an antigen

Two ways to produce antigens; produce antibodies, kill the pathogens outright.

Each method uses a different type of lymphocyte

specific immunity

Acquired or adaptive immunity: recognize specific agents, adapt/respond and target these agent

Immune System

A system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response

a self (MHC) marker labels the body's cells as self or friend; an antigen is a molecule often on the surface of a pathogen that the immune system recognizes as nonself or foe.

Nonspecific Immunity

General defense mechanisms that provide protection from infection and disease but are not targeted at a particular pathogen

Helps body respond to generalized tissue damage, common/obvious pathogens, most bacteria and some viruses

B Lymphocytes

produce antibodies; secrete antibodies to neutralize the antigen

Mature in the bone

marrow (B for bone)

Memory B cells (long term immunity)

How antibodies work

When antibodies encounter a pathogen with the right surface antigen they bind to it forming an antigen-antibody complex

Some antibodies cause pathogens to agglutinate (clump together)

The formation of an antibody-antigen complex marks the pathogen for attack by phagocytes or complement proteins.

T Lymphocytes

Mature in the Thymus; do not secrete antibodies (attack directly); Activated by some macrophages and B cells called antigen-presenting cells (APCs), helps T-cells identify pathogens

Helper T cells

Enhance the response of other immune cells

Cytotoxic T cells

Attack and destroy

Neutrophils

Granular Leukocytes; most abundant WBC

First to fight infection from bacteria and some fungi

Eosinophils

Granular Leukocytes; 2-4% of WBC

Defense against parasites, release chemicals to reduce allergic reaction

Basophils

Granular Leukocytes; Rarest of WBC

Defense against parasites; Secrete histamine in response to allergic reaction

Lymphocyte

Agranular Leukocytes

30% of WBC

Work in lymphatic system; reside in tonsils, spleen, lymph nodes, thymus, and bloodstream

Monocyte

Agranular Leukocytes

5% of WBC, largest WBC

Turn into macrophages for destroying pathogens

Stimulate other WBC to defend body

Not specific - will destroy any pathogen they recognize

Male gamete

sperm

Female gamete

egg (ovum)

Male gonads

testes

Female gonads

ovaries

Reproductive system functions

produce, protect, and nourish gametes, trigger puberty, maintain reproductive ability, stimulate secondary sex characteristics, produce hormones involved in sexual maturation and general homeostasis.

Reproductive system structures

Gonads, ducts, accessory glands, supporting structures

Gonads

Produce gametes

Ducts

transport gametes and fertilized eggs

Accessory glands

facilitate gamete production and survival

Supporting structures

Help deliver and support the gametes

Male Reproductive System

Function: produce, store and deliver sperm to the female reproductive system.

Testes

produce sperm and testosterone

Scrotum

regulates temperature of testes

epididymis

stores sperm while maturing

Ductus (vas) deferens

stores and transports sperm

Ejaculatory duct

transports sperm and secretions

Penis

Delivers sperm

Male reproductive system: accessory glands

seminal vesicles, prostate gland, bulbourethral gland

Seminal vesicle

secretes fructose and most of the seminal fluid