Human Anatomy and Physiology

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Questions and Answers

What is the primary function of the spleen in the immune system?

The spleen stores and filters blood, and makes white blood cells that protect the body from infection.

What is the difference between red and yellow bone marrow?

Red bone marrow contains blood stem cells that can become red blood cells, white blood cells, or platelets, while yellow bone marrow is made mostly of fat and contains stem cells that can become cartilage, fat, or bone cells.

What is the role of thymosins in the immune system?

Thymosins are hormones produced by the thymus that cause T lymphocytes to become immunocompetent.

What is MALT, and what is its function in the immune system?

MALT (mucosa-associated lymphatic tissue) is a type of lymphoid tissue found in the mucous membrane lining of various organs, and it prevents pathogens from penetrating the mucous membrane. Signup and view all the answers

What is the difference between nonspecific and specific defense systems?

The nonspecific defense system responds immediately to protect the body from all foreign substances, whereas the specific defense system is the immune system, which responds to specific pathogens. Signup and view all the answers

How does the acid pH of the skin secretions inhibit bacterial growth?

The acid pH of the skin secretions inhibits bacterial growth by creating an environment that is not conducive to bacterial growth. Signup and view all the answers

What is the role of lysozyme in the immune system?

Lysozyme is an enzyme that destroys bacteria, and is found in saliva and lacrimal fluid. Signup and view all the answers

What is the function of sticky mucus in the immune system?

Sticky mucus traps many microorganisms that enter the gastrointestinal and respiratory passages. Signup and view all the answers

What type of cells are the chief phagocytic cells that wander throughout a region in search of cellular debris?

Macrophages Signup and view all the answers

What is the function of natural killer cells in the immune system?

To lyse and kill cancer cells and virus-infected cells Signup and view all the answers

What is the role of histamine in the inflammatory response?

Damaged tissue releases histamine, which causes capillaries to become 'leaky' and increases blood flow to the area Signup and view all the answers

What is the function of interferon in the immune system?

To stimulate neighboring cells to activate an antiviral protein, which blocks viral reproduction Signup and view all the answers

What is the role of complement proteins in the immune system?

To provide a major mechanism for destroying foreign substances in the body and enhancing the inflammatory response Signup and view all the answers

What is the adaptive immune system?

An antigen-specific, systemic, and memory-based immune response Signup and view all the answers

What is the difference between active and passive immunity?

Active immunity involves the activation of immune cells, while passive immunity involves the transfer of pre-formed antibodies Signup and view all the answers

What are the five classes of antibodies?

IgD, IgM, IgG, IgA, and IgE Signup and view all the answers

What is the function of IgE antibodies?

To bind to mast cells and basophils, causing histamine release when activated Signup and view all the answers

What is the role of chemotactic factors in the inflammatory response?

To attract phagocytic cells, such as neutrophils and monocytes, to the site of infection Signup and view all the answers

What is the outcome of the combined action of immune cells, including T cells and other cells, in the immune response?

The outcome is an amplification of the local inflammatory reaction with recruitment of circulating cells of the immune system. Signup and view all the answers

What is the key difference between cytotoxic T cells and natural killer (NK) cells in terms of antigen recognition?

Cytotoxic T cells need to recognize a specific antigen, whereas natural killer cells do not. Signup and view all the answers

How do cytotoxic T cells deliver lethal chemicals to target cells?

They attach directly to the target cell via specific receptors, release the lethal chemicals, and then detach and move on to kill additional targets. Signup and view all the answers

What is the primary function of helper T cells in the immune response?

Helper T cells sense the presence of an infection and activate other immune cells to fight the infection. Signup and view all the answers

Where are helper T cells produced in the body?

Helper T cells are produced by the thymus gland. Signup and view all the answers

What is the significance of the adaptive immune response, which involves helper T cells, in the body's defense against infection?

The adaptive immune response, involving helper T cells, is an important part of the body's defense against infection, allowing for specific recognition and elimination of pathogens. Signup and view all the answers

What is the primary function of the lymphatic system in the body?

To protect the body from infection and maintain a healthy balance of fluid throughout the body. Signup and view all the answers

What type of fluid flows through the lymphatic vessels, and what is its direction of flow?

Lymph fluid flows through the lymphatic vessels, and it flows only towards the heart. Signup and view all the answers

What prevents backflow in the lymphatic vessels, and what maintains the flow of lymphatic fluid?

Valves prevent backflow, and the flow of lymphatic fluid is maintained by skeletal muscle contraction, pressure changes in the thorax, and contractions of the lymphatic vessels. Signup and view all the answers

What types of cells are found in lymphoid tissues, and what are their functions?

Lymphocytes (immunocompetent cells), plasma cells (antibody-producing B cells), macrophages and dendritic cells (phagocytes and cells that initiate an immune response), and reticular cells (form the lymphoid tissue stroma) are found in lymphoid tissues. Signup and view all the answers

What are the components of a lymph node, and what is their function?

Lymph nodes are made up of reticular connective tissue, house macrophages and lymphocytes, and filter lymph to help activate the immune system. Signup and view all the answers

What is the structure of a lymph node, and what are the functions of its cortex and medulla?

A lymph node has a fibrous capsule, a cortex containing lymphocytes that act in immune responses, and a medulla containing macrophages that engulf and destroy foreign debris, as well as lymphocytes and plasma cells. Signup and view all the answers

What is the function of the spleen in the lymphatic system, and how does it differ from lymph nodes?

The spleen does not filter lymph, but rather plays a role in the immune response and red blood cell production. It differs from lymph nodes in that it does not filter lymph. Signup and view all the answers

What is the function of bone marrow in the body, and what types of cells does it produce?

Bone marrow produces red blood cells, platelets, and white blood cells. Signup and view all the answers

What is the role of the right lymphatic duct and thoracic duct in the lymphatic system?

The right lymphatic duct drains lymph from the right arm and right side of the upper body, and the thoracic duct receives lymph from the rest of the body. Signup and view all the answers

What is the significance of lymph nodes in the immune response, and how do they facilitate the activation of the immune system?

Lymph nodes filter lymph and help activate the immune system by housing macrophages and lymphocytes that facilitate the immune response. Signup and view all the answers

Study Notes

Lymphatic System

The lymphatic system is a group of organs, vessels, and tissues that protect the body from infection and maintain a healthy balance of fluid throughout the body.
The lymphatic system includes organs such as bone marrow, thymus, spleen, and lymph nodes.
It is composed of lymphatic vessels, which form a one-way network, and lymphatic capillaries, collecting vessels, trunks, and ducts, in which fluid flows only towards the heart.

Lymphatic Vessels

Lymphatic vessels have a slow flow of fluid, which is maintained by skeletal muscle contraction, pressure changes in the thorax, and contractions of the lymphatic vessels.
Backflow is prevented by valves.

Lymph Nodes

Lymph nodes are made up of reticular connective tissue and house macrophages and a continuously changing population of lymphocytes.
They may be diffuse or packaged into dense follicles, which often display germinal centers (areas where B cells are proliferating).
Lymph nodes filter lymph and help activate the immune system.

Bone Marrow

Bone marrow produces red blood cells, platelets, and white blood cells, including lymphocytes, which play an important part in the body's immune system.
There are two types of bone marrow: red and yellow.

Spleen

The spleen is a small organ inside the left rib cage, just above the stomach, which stores and filters blood and makes white blood cells that protect the body from infection.
It provides a site for lymphocyte proliferation and immune function and destroys aged or defective red blood cells and blood-borne pathogens.

Thymus

The thymus is most functional during youth and produces hormones that cause T lymphocytes to become immunocompetent.

MALT (Mucosa-Associated Lymphatic Tissue)

MALT is found in the intestinal wall, lymphoid follicles of the appendix, tonsils of the pharynx and oral cavity, and follicles in the genitourinary and respiratory tract mucosae.
It prevents pathogens from penetrating the mucous membrane lining.

Nonspecific Defense System

The nonspecific defense system responds immediately to protect the body from all foreign substances.
It is provided by the intact skin and mucous membrane, inflammatory responses, and proteins produced by body cells.

Specific Defense System

The specific defense system is the immune system, which is antigen-specific, systemic, and has memory.

Cells of the Nonspecific Defense System

Phagocytes (e.g., macrophages, neutrophils, eosinophils, mast cells) engulf and destroy foreign substances.
Natural killer cells (NK cells) lyse and kill cancer cells and virus-infected cells.

Inflammatory Response

Damaged tissue releases histamine, which causes capillaries to become "leaky," increasing blood flow to the area.
Clotting factors and phagocytes are released into the wound, and phagocytes engulf bacteria, cellular debris, and dead cells.

Antimicrobial Proteins

Interferon and complement proteins are important antimicrobial proteins that enhance the innate defenses by attacking microorganisms directly and hindering their ability to reproduce.

Adaptive Immune System

The adaptive immune system is antigen-specific, systemic, and has memory.
It has two separate but overlapping arms: humoral, or antibody-mediated (B Cell) immunity, and cellular, or cell-mediated (T Cell) immunity.

Lymphocytes

There are two types of lymphocytes: B lymphocytes, which oversee humoral immunity, and T lymphocytes, which constitute the cell-mediated arm of immunity.

B Cells

B cells mature in the bone marrow and encounter antigens, producing antibodies against them.

T Cells

T cells mature in the thymus and constitute the cell-mediated arm of immunity.
There are several types of T cells, including CD4+ T cells (helper T cells) and CD8+ T cells (cytotoxic T cells, or killer T cells).

Helper T Cells

Helper T cells sense infections and activate other immune cells to fight the infection.

Cytotoxic T Cells

Cytotoxic T cells attach directly to the target cell, recognize a specific antigen, and kill on contact.

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Description

This quiz assesses students' understanding of human anatomy and physiology, including the structure and function of different systems, organ interactions, and maintenance of homeostasis.