Biology Chapter 12: Lymphatic System

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Questions and Answers

The lymphatic system lacks two of these structures: the _ and _.

pump, arteries

Like the _ of the cardiovascular system, the vessels of the lymphatic system are equipped with _.

veins, valves

The lymphatic vessels pick up leaked fluid, now called _, and return it to the bloodstream. About _ of fluid is returned every 24 hours.

lymph, 3 liters

What is the largest lymphatic organ?

spleen Signup and view all the answers

What is the function of lymph nodes?

to filter lymph Signup and view all the answers

What organ produces hormones that help to program the immune system?

thymus Signup and view all the answers

What are the largest collections of lymph nodes found in?

cervical, axillary, inguinal Signup and view all the answers

What is the general function of lymph nodes?

to protect against bacteria Signup and view all the answers

The three major elements of the body's nonspecific defense system are: The _, consisting of the skin and _; defensive cells, such as _ and phagocytes; and a whole deluge of _.

surface membrane barriers, mucosae, natural killer cells, chemicals (inflammatory & antimicrobial) Signup and view all the answers

Lysozyme is found in the body secretions called _ and _.

tears, saliva Signup and view all the answers

Fluids with an acid pH are found in the _ and _.

stomach, female reproductive tract Signup and view all the answers

Sebum is a product of the _ glands and acts at the surface of the _.

sebaceous, skin Signup and view all the answers

Mucus is produced by mucus-secreting glands found in the respiratory and ___ system mucosae.

digestive Signup and view all the answers

Which of the following have antimicrobial activity?

Both A and B Signup and view all the answers

Provide mechanical barriers.

mucosae and skin Signup and view all the answers

What structure entraps microorganisms entering the respiratory passages?

mucus Signup and view all the answers

Describe the protective role of cilia in the respiratory tract.

They propel mucus laden with trapped debris superior away from the lungs to the throat. Signup and view all the answers

Define phagocytosis.

ingestion and destruction of particulate material by certain cells. Signup and view all the answers

What is chemotaxis?

cellular migration directed by a chemical gradient. Signup and view all the answers

What is diapedesis?

leukocytes pass through the wall of a capillary. Signup and view all the answers

What is edema?

results from accumulation of fluid leaked from the blood stream. Signup and view all the answers

What is the function of fibrin mesh?

walls off the area of injury. Signup and view all the answers

What is histamine?

inflammatory chemical released by injured cells. Signup and view all the answers

What accounts for redness and heat in an inflamed area?

increased blood flow to an area. Signup and view all the answers

What do inflammatory chemicals promote?

release of white blood cells from the bone marrow. Signup and view all the answers

What are macrophages?

phagocytic offspring of monocytes. Signup and view all the answers

What is a neutrophil?

first phagocytes to migrate into the injured area. Signup and view all the answers

Study Notes

Lymphatic System Overview

The lymphatic system is distinct from the cardiovascular system, lacking a pump and arteries.
Lymphatic vessels function similarly to veins, featuring valves to prevent backflow.
They collect leaked fluid known as lymph and return about 3 liters daily to the bloodstream.

Lymphatic Organs and Their Functions

Spleen: The largest lymphatic organ, serves as a blood reservoir and removes aged red blood cells.
Lymph Nodes: Act as filters for lymph, housing immune cells.
Thymus: Crucial in youth, it produces hormones programming the immune system.
Tonsils: Important components of MALT, protecting against pathogens.
Peyer’s Patches: Guard against bacteria breaching the intestinal wall.

Immune Cells in the Lymphatic System

B Lymphocytes: Predominant in germinal centers, their daughter cells (plasma cells) produce antibodies.
T Lymphocytes: Major cell type in cortical areas of lymph nodes, crucial for immune response.
Macrophages: Surround medullary sinuses of lymph nodes, acting as phagocytes to engulf pathogens.

Lymphatic Flow Dynamics

Fewer efferent lymphatics than afferent lymphatics in lymph nodes slow lymph flow, allowing immune cells more time to react.
Valves in both afferent and efferent lymphatic vessels ensure one-way flow.
Major lymph node collections are located in cervical, axillary, and inguinal regions.

Nonspecific Defense Mechanisms

The body's nonspecific defense includes:
- Surface Membrane Barriers: Skin and mucosae.
- Defensive Cells: Natural killer cells and phagocytes.
- Chemical Defenses: Inflammatory and antimicrobial chemicals.

Chemical Barriers and Their Functions

Lysozyme: Antimicrobial found in tears and saliva.
Acidic Fluids: Present in the stomach and female reproductive tract, inhibiting pathogen growth.
Sebum: Produced by sebaceous glands, provides surface protection on skin.
Mucus: Traps microorganisms in the respiratory and digestive systems.

Phagocytosis and Cell Migration

Phagocytosis: Process of ingestion and destruction of pathogens by immune cells; rough particles are more easily phagocytosed.
Chemotaxis: Directed cellular migration towards a chemical gradient.
Diapedesis: Movement of leukocytes through capillary walls.

Inflammatory Response

Edema: Accumulation of fluid leakage from blood vessels, often observed in injury sites.
Fibrin Mesh: Forms to wall off areas of injury, aiding in healing.
Histamine: Released by injured cells, initiating an inflammatory response.
Increased blood flow causes redness and heat at inflammation sites, promoting white blood cell release from bone marrow.

Key Immune Cells in Inflammation

Macrophages: Derived from monocytes, serve as key phagocytes in inflamed areas.
Neutrophils: The first immune cells to migrate to injured tissues, initiating the phagocytic response.

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Description

Test your knowledge of Chapter 12 focusing on the lymphatic system and body defenses. This quiz will cover key terms and concepts related to the vessels and functionalities of the lymphatic system, including its structure and role in immunity.