Human Anatomy & Physiology II - Topic 4

Pneumocystis Jirovecii

this is a fungus causing a form of pneumonia, particularly dangerous to individuals with weakened immune systems

Kaposi's Sarcoma

a type of cancer often associated with HIV/AIDS and characterized by the development of multiple tumors in the skin, mucous membranes, and other organs

Capillary Filtration

the process by which fluids, including plasma, move out of capillaries and into the interstitial space

Viscera

refers to the internal organs within the body's cavities, like the heart, lungs, liver, and intestines

Lumbar Trunks

major lymphatic vessels that collect lymph from the lower back, pelvis, and lower limbs, playing a key role in the lymphatic drainage system

Bone marrow

tissue found inside bones; the site of all blood cell differentiation and maturation of B lymphocytes

Thymus

primary lymphoid organ; where T lymphocytes proliferate and mature

Spleen

secondary lymphoid organ that filters pathogens from the blood (white pulp) and removes degenerating or damaged blood cells (red pulp)

Lymph Nodes

function to remove debris and pathogens from the lymph and are thus sometimes referred to as the "filters of the lymph"

Lymphoid nodules

unencapsulated patches of lymphoid tissue found throughout the body

Tonsils

lymphoid nodules associated with the nasopharynx

Mucosa-associated lymphoid tissue (MALT)

lymphoid nodule associated with the mucosa

Bronchus-associated lymphoid tissue (BALT)

lymphoid nodule associated with the respiratory tract

Hematopoiesis

the process of blood cell formation, which primarily occurs in the red bone marrow

Marginal Zone

the region between the red pulp and white pulp of the spleen, which sequesters particulate antigens and presents them to lymphocytes

Dendritic Cells

specialized immune cells that capture, process, and present antigens to activate other immune cells, playing a crucial role in initiating immune response

B cells

lymphocytes that act by differentiating into an antibody-secreting plasma cell

T Cells

originate from the bone marrow; after their initial development, they migrate to the thymus gland where they further mature

Plasma Cells

a B cell that has differentiated in response to antigen binding and has thereby gained the ability to secrete soluble antibodies

Natural Killer Cells

a circulating blood cell that contains cytotoxic (cell-killing) granules in its extensive cytoplasm

Innate Immune Response

the body's rapid, nonspecific defense mechanism against pathogens that it encounters, such as bacteria and viruses

Phagocytic Cells

immune cells that engulf and digest pathogens, such as bacteria and viruses, as part of the body's defense against infections

Red Bone Marrow

a tissue found in the cavities of certain bones, primarily in the spongy or cancellous bone, where blood cells, including red blood cells, white blood cells, and platelets, are produced through a process called hematopoiesis

Adaptive immune response

relatively slow but very specific and effective immune response controlled by lymphocytes

Phagocytosis

movement of material from the outside to the inside of the cells via vesicles made from invaginations of the plasma membrane

Macrophage

phagocytic cell of the myeloid lineage; a mature monocyte

Neutrophils

granulocytes that stain with a neutral dye and are the most numerous of the leukocytes; especially active against bacteria

Monocytes

an agranular leukocyte that is able to migrate into tissues and transform into a macrophage

Langerhans Cells

specialized immune cells in the skin's epidermis that capture and process antigens, playing a key role in activating the immune response

Mycobacteria Tuberculosis

a species of bacteria responsible for causing tuberculosis (TB), a highly contagious and potentially deadly infectious disease that primarily affects the lungs but can also affect the other parts of the body

Phagosome

where ingested particles, such as bacteria or cellular debris, are enclosed and processed for digestion and destruction

Histamine

a naturally occurring compound in the body; it plays a key role in the body's immune response, inflammation, and regulating stomach acid (symptoms such as itching and sneezing)

Cytokines

class of proteins that act as autocrine or paracrine signaling molecules; in the cardiovascular system, they stimulate the proliferation of progenitor cells and help to stimulate both nonspecific and specific resistance to disease

Chemokine

soluble, long-range, cell-to-cell communication molecule

Interferons

early induced proteins made in virally infected cells that cause nearby cells to make antiviral proteins

Inflammation

basic innate immune response characterized by heat, redness, pain, and swelling

Acute inflammation

inflammation occurring for a limited time period; rapidly developing

Chronic inflammation

inflammation occurs for long periods of time

Vasodilation

relaxation of the smooth muscle in the wall of a blood vessel, resulting in an increased vascular diameter

Mannose-Binding Protein

an early-induced protein produced by the liver, which recognizes and binds to specific polysaccharide components on the surface of bacterial cells

C-Reactive Protein

an early-induced protein produced by the liver, helps to mark pathogens for phagocytosis by immune cells and is often used as a clinical marker for inflammation and infection

Rheumatoid Arthritis

a chronic autoimmune disease characterized by inflammation in the joints, leading to pain, swelling, stiffness, and potential joint damage; occurs when the immune system mistakenly attacks healthy joint tissues, causing long-term joint problems

Osmotic Balance

refers to the equilibrium of solute concentrations on both sides of a semipermeable membrane

Immunological memory

ability of the adaptive immune response to mount a stronger and faster immune response upon re-exposure to a pathogen

Antibodies

are proteins produced by B cells; they recognize and bind to specific antigens, helping to neutralize pathogens or mark them for destruction by other immune cells

Self-Antigens

are molecules or structures present in the body's own tissues, and the immune system has mechanisms to distinguish them from foreign antigens to prevent autoimmunity

Antigen processing

internalization and digestion of antigen in an antigen-presenting cell

Antigen presentation

binding of processed antigen to the protein-binding cleft of a major histocompatibility complex molecule

MHC class I

found on most cells of the body, it binds to the CD8 molecule on T cells

MHC class II

found on macrophages, dendritic cells, and B cells, it binds to CD4 molecules on T cell

Peptide-Binding Clefts

small indentations in major histocompatibility complex (MHC) molecules, specifically in MHC class I and MHC class II, where processed antigen fragments (peptides) sit

Nasopharynx

the upper part of the throat that connects the nose to the back of the mouth and plays a role in breathing and sound production

CD4 Molecules

primarily found on helper T cells and interacts with MHC class II molecules

CD8 Molecules

found on cytotoxic T cells and interacts with MHC class I molecules

Self-Antigen

molecules or proteins naturally present in an individual's body

Apoptosis

a natural process of programmed cell death, crucial in maintaining health; it allows cells to self-destruct in a controlled manner, often as part of normal development, immune response, or to remove damaged or unnecessary cells

NK Cells

a type of white blood cell in the innate immune system. They play a vital role in detecting and destroying infected or abnormal cells, such as cancer cells, without the need for prior exposure or specific recognition

Macrophages

large white blood cells that play a key role in the immune system by engulfing and digesting foreign invaders, cellular debris, and pathogens, helping to initiate and coordinate immune responses

Antibody

are proteins produced by the immune system to identify and neutralize foreign invaders like bacteria and viruses

Agglutination

clustering of cells into masses linked by antibodies

Peripheral tolerance

mature B cell made tolerant by lack of T cell help

Serum

the clear cell-free portion of blood that remains after blood clots

Clonal Expansion

refers to the process in which specific immune cells, such as B cells and T cells, reproduce and multiply after encountering an antigen

Naïve B Cell

an immature B cell that has not yet encountered its specific antigen; capable of recognizing antigens, but they have not yet been activated

IgM

antibody whose monomer is a surface receptor of naive B cells; the pentamer is the first antibody made of blood plasma during primary responses

Class switching

ability of B cells to change the class of antibody they produce without altering the specificity for antigen

IgG

main blood antibody of late primary and early secondary responses; passed from carrier to unborn child via placenta

IgA

antibody whose dimer is secreted by exocrine glands, is especially effective against digestive and respiratory pathogens, and can pass immunity to an infant through breastfeeding

IgE

antibody that binds to mast cells and causes antigen-specific degranulation during an allergic response

Antigen-Binding Sites

these are regions on the antibody molecule that specifically bind to antigens (pathogen molecules)

Colostrum

the first milk produced by mammals immediately following the birth of their young; source of antibodies for newborns.

Mast Cells

these are immune cells involved in allergic reactions, activated by binding of allergen-specific IgE antibodies

Anaphylaxis

a severe rapid allergic reaction that can be life-threatening, often triggered by allergens like food, insect stings, or medications, leading to symptoms like swelling and difficulty in breathing

Passive immunity

transfer of immunity to a pathogen to an individual that lacks immunity to this pathogen usually by the injection of antibodies

Active immunity

immunity developed from an individual's own immune system

T cell-independent antigen

binds to B cells, which do not require signals from T cells to make antibody

T cell-dependent antigen

antigen that binds to B cells, which requires signals from T cells to make antibody

Smallpox

a contagious viral disease characterized by severe skin rashes and flu-like symptoms

Placenta

a temporary organ that develops during pregnancy and attaches to the uterine wall, providing a vital connection between the mother and the developing fetus

Polio

primarily affects the nervous system, leading to paralysis, muscle weakness, and sometimes death

Seroconversion

clearance of pathogen in the serum and the simultaneous rise of serum antibody

Neutralization

inactivation of a virus by the binding of specific antibodies

AIDS

a late stage of HIV (human immunodeficiency virus) infection; it is characterized by a severely weakened immune system, leaving the individual susceptible to various infections and diseases

Peyer's Patches

small regions of lymphoid tissue found in the small intestine, which play a significant role in the immune system's response to pathogens and antigens encountered in the gut

Leprosy

primarily affects the skin and nerves, leading to skin lesions and nerve damage

Immediate hypersensitivity

(Type I) IgE-mediated mast cell degranulation caused by crosslinking of surface IgE by antigen

Type II hypersensitivity

cell damage caused by the binding of antibody and the activation of complement, usually against red blood cells

Type III hypersensitivity

damage to tissues caused by the deposition of antibody-antigen (immune) complexes followed by the activation of complement

Erythroblastosis fetalis

disease of Rh factor-positive newborns in Rh-negative mothers with multiple Rh-positive children; resulting from the action of maternal antibodies against fetal blood

Delayed hypersensitivity

(Type IV) T cell-mediated immune response against pathogens infiltrating interstitial tissues, causing cellular infiltration

Eczema

a common skin condition characterized by inflammation, redness, and itchy rashes; it can vary in severity and often includes dry or scaly patches on the skin

Penicillin

one of the first antibiotics discovered and remains an essential and widely used medication; works by inhibiting the growth of bacteria