A&P II Chapter 21 lymphatic system Q&A

Immunity

Ability to resist damage or disease

Susceptibility

Lack of resistance to disease

Innate immunity

Defenses present at birth

Adaptive immunity

Specific defenses developed after antigen exposure

Pathogen

A disease-producing microbe

What type of immunity responds rapidly to many threats?

Innate immunity

What type of immunity remembers previous pathogens?

Adaptive immunity

Lymph

Fluid flowing through lymphatic vessels

What are lymphatic tissues made primarily of?

Reticular tissue with B and T cells

What does the lymphatic system return to the bloodstream?

Excess interstitial fluid and proteins

What nutrients does the lymphatic system transport?

Dietary lipids

What major protective function does the lymphatic system perform?

Immune responses

Lymphatic capillary

A closed-ended vessel that collects interstitial fluid

Why does fluid move only into lymphatic capillaries?

Their structure creates one-way flow

Lacteal

A lymphatic capillary that absorbs dietary lipids

Where are lacteals located?

Small intestine

What structures prevent lymph from flowing backward?

Valves

What do merged lymphatic capillaries form?

Lymphatic vessels

What structures filter lymph along lymphatic vessels?

Lymph nodes

Lymphatic trunk

A vessel formed by lymph vessels leaving a group of nodes

What are the five lymphatic trunks?

Lumbar intestinal bronchomediastinal subclavian and jugular

What is the main lymphatic duct?

Thoracic duct

Cisterna chyli

Abdominal enlargement at the start of the thoracic duct

What region drains into the right lymphatic duct?

Right head neck and chest

What forms lymph?

Excess interstitial fluid

What pump moves lymph during body movement?

Skeletal muscle pump

What pump moves lymph during breathing?

Respiratory pump

Where does lymph reenter the bloodstream?

Near the internal jugular and subclavian veins

Primary lymphatic organ

A site where lymphocytes develop and mature

What are the primary lymphatic organs?

Red bone marrow and thymus

Secondary lymphatic organ

A site where most immune responses occur

What are the major secondary lymphatic structures?

Lymph nodes spleen and lymphatic follicles

Where is red bone marrow found in adults?

Flat bones and long-bone epiphyses

Where do B cells mature?

Red bone marrow

Where do T cells mature?

Thymus

Thymus

A bilobed organ where T cells mature

What happens to the thymus with age?

It atrophies

What thymic cells provide a framework for T cells?

Epithelial cells

What thymic cells remove debris and dead cells?

Macrophages

Where are lymph nodes located?

Along lymphatic vessels

Which vessels carry lymph into a lymph node?

Afferent vessels

Which vessel carries lymph out of a lymph node?

Efferent vessel

Hilum

A depression where the efferent lymphatic vessel exits

Trabeculae

Extensions of a lymph node capsule

What is the main function of lymph nodes?

Filtering foreign substances from lymph

Why does slow lymph flow improve immune defense?

It provides time for an immune response

How do macrophages destroy material in lymph nodes?

Phagocytosis

What is the largest mass of lymphatic tissue?

Spleen

White pulp

Splenic tissue where immune responses occur

Red pulp

Splenic tissue that removes defective blood cells

What does the spleen store?

Platelets

What blood-forming function does the fetal spleen perform?

Hemopoiesis

Lymphatic follicle

An unencapsulated concentration of lymphatic tissue

MALT

Lymphatic tissue within mucous membranes

What structures contain large groups of lymphatic follicles?

Appendix and tonsils

What is the first line of innate defense?

Skin and mucous membranes

How does the epidermis block microbes?

It forms a physical barrier

How does mucus protect the body?

It traps microbes

How do respiratory cilia protect the body?

They sweep away trapped microbes

How do tears protect the eyes?

They dilute and wash away microbes

How does saliva protect the mouth?

It washes microbes from oral surfaces

How does urine protect the urinary tract?

It washes microbes from the urethra

How do defecation and vomiting defend the body?

They expel microbes

Sebum

An oily secretion that creates an acidic skin barrier

Lysozyme

An enzyme that destroys microbes

Where is lysozyme commonly found?

Tears saliva perspiration and secretions

How does gastric juice protect the body?

It destroys bacteria and many toxins

How do vaginal secretions limit bacterial growth?

Their slight acidity

What is the second line of innate defense?

Internal defenses

Natural killer cell

A lymphocyte that destroys abnormal body cells

What process do natural killer cells trigger in targets?

Apoptosis

Perforin

A protein that forms channels in target membranes

Granzyme

A protein that triggers target-cell apoptosis

Phagocyte

A cell that engulfs foreign material

What are the two major phagocyte types?

Neutrophils and macrophages

What do monocytes become after entering infected tissue?

Macrophages

Chemotaxis

Movement toward chemicals released at an injury

Adherence

Attachment of a phagocyte to foreign material

Ingestion

Engulfment of material into a phagosome

What happens during phagocytic digestion?

Lysosomes fuse with the phagosome

Where does undigested material remain after phagocytosis?

Residual bodies

Inflammation

A response that removes threats and begins tissue repair

What are the four signs of inflammation?

Redness heat swelling and pain

What vascular change occurs during inflammation?

Vasodilation

What allows defensive cells to leave blood vessels during inflammation?

Increased vessel permeability

Diapedesis

Movement of phagocytes through blood vessel walls

Which chemicals contribute to inflammation?

Histamine prostaglandins and leukotrienes

Fever

An abnormally elevated systemic temperature

Which organ raises the body's temperature during fever?

Hypothalamus

How can fever slow an infection?

It inhibits microbial growth

Interferon

An antimicrobial protein released by virus-infected cells

What is the main action of interferons?

Blocking viral replication

Complement system

A group of inactive proteins that enhance immune reactions

Opsonization

Coating a pathogen to improve phagocytosis

Cytolysis

Destruction caused by cell-membrane rupture

Membrane attack complex

A complement structure that creates membrane openings

Antigen

A foreign substance that produces an immune response

What two features distinguish adaptive immunity?

Specificity and memory

What does immune specificity allow?

Recognition of a particular antigen

What does immunological memory produce after later exposure?

A faster and stronger response