AP EXAM 2

Components of Blood (by percentage)

Plasma (55%) and Formed Elements (45%)

Three Main Functions of Blood

Transportation, Protection, and Homeostasis (Regulation)

Most abundant plasma protein

Albumin (maintains osmotic pressure)

Advantage of RBC biconcave shape

Provides a massive surface-area-to-volume ratio for rapid gas diffusion.

Why RBCs generate ATP anaerobically

They lack mitochondria, which ensures they do not consume the oxygen they are transporting.

Part of hemoglobin that binds Oxygen ($O_2$)

The Iron ($Fe^{2+}$) atom within the heme group.

Part of hemoglobin that binds Carbon Dioxide ($CO_2$)

The amino acids of the globin chains (forming carbaminohemoglobin).

Hormone that regulates erythropoiesis

Erythropoietin (EPO), released primarily by the kidneys.

Stimulus for EPO release

Hypoxia (low blood oxygen levels).

What a reticulocyte count measures

The rate of RBC production (measures immature RBCs in the blood).

Organ known as the 'RBC graveyard'

The Spleen (macrophages here break down old RBCs).

Term for the percentage of blood volume occupied by RBCs

Hematocrit

Most numerous leukocyte (WBC)

Neutrophil (50-70%)

Leukocyte that produces antibodies

Lymphocyte (specifically, B cells)

Leukocyte that targets parasitic worms

Eosinophil

Leukocyte that releases histamine and heparin

Basophil

Leukocyte that matures into a macrophage

Monocyte

Antigens and Antibodies in Type A Blood

Antigens: A; Antibodies: Anti-B

Antigens and Antibodies in Type O Blood

Antigens: None; Antibodies: Anti-A and Anti-B

Universal Donor Blood Type

Type O negative (has no A, B, or Rh antigens).

Universal Recipient Blood Type

Type AB positive (has A, B, and Rh antigens; no antibodies).

The 3 steps of Hemostasis (in order)

1. Vascular Spasm, 2. Platelet Plug Formation, 3. Coagulation

Final product of the coagulation cascade (the 'mesh')

Fibrin (converted from fibrinogen by thrombin).

The 'clot buster' enzyme that dissolves clots

Plasmin (formed from plasminogen)

Condition in an Rh- mother pregnant with an Rh+ fetus

Hemolytic Disease of the Newborn (HDN)

Major functions of the lymphatic system

1. Return leaked fluid from interstitial space back to the blood. 2. House immune cells (lymphocytes). 3. Absorb digested fats (lacteals) from the intestine.

Compare Lymphatic vs. Blood Vessel flow direction

Blood vessels: Circular flow (pumped by heart). Lymphatic vessels: One-way flow, towards the heart.

How do lymphatic capillaries maintain one-way flow?

They have overlapping endothelial cells that form minivalves. High interstitial pressure opens them (fluid in); high capillary pressure closes them (fluid can't get out).

The 5 major lymphatic trunks

Lumbar, Bronchomediastinal, Subclavian, Jugular, and (unpaired) Intestinal Trunk.

The 2 main lymphatic ducts

1. Right Lymphatic Duct (drains right arm/head/thorax) 2. Thoracic Duct (drains the rest of the body)

Veins that the lymph ducts empty into

The junction of the internal jugular vein and the subclavian vein (on their respective sides of the body).

Mechanisms that help move lymph (no heart pump)

1. Skeletal muscle 'milking' 2. Pressure changes from breathing (respiratory pump) 3. Smooth muscle contractions in lymphatic vessel walls 4. Pulsing of nearby arteries

Function of T and B lymphocytes

B cells: Produce plasma cells, which secrete antibodies (humoral immunity).

T cells

Manage the immune response, directly attack and destroy infected cells (cellular immunity).

Function of a lymph node

1. Filter lymph (macrophages destroy debris/pathogens) 2. Activate the immune system (lymphocytes encounter antigens).

Why do lymph nodes have more afferent than efferent vessels?

Having more inlets (afferent) than outlets (efferent) slows down the flow of lymph, giving macrophages and lymphocytes more time to 'filter' and 'inspect' it.

Inflamed vs. Cancerous lymph nodes

Inflamed: Swollen, painful to the touch. Cancerous: Swollen, but not painful (firm, non-tender).

Function of the Spleen

Filters blood (not lymph). Removes old RBCs, stores platelets and iron, and is a site for immune response.

Function of the Thymus

Site of T-lymphocyte (T cell) maturation. Most active in childhood, atrophies in adults.

Function of Tonsils

Gather and remove pathogens from inhaled air and food. They have 'crypts' that trap pathogens to be presented to immune cells.

Innate vs. Adaptive Defenses

Innate: Non-specific, born with it. (e.g., skin, fever, inflammation). Adaptive: Specific, develops over time. (e.g., antibodies, T cells).

First Line of Defense (Innate)

Surface Barriers: Skin (keratin, acid mantle) and Mucous Membranes (mucus, cilia, acidic stomach).

Second Line of Defense (Innate)

Internal Defenses: Phagocytes, Natural Killer (NK) cells, Inflammation, Antimicrobial Proteins, and Fever.

The 4 Cardinal Signs of Inflammation

Redness, Heat, Swelling, and Pain (sometimes Impairment of function).

Antimicrobial Proteins: Interferons

Released by virus-infected cells. They 'interfere' with viral replication in nearby healthy cells, protecting them.

Antimicrobial Proteins: Complements

A group of >20 plasma proteins that, when activated, amplify the inflammatory response, opsonize (coat) pathogens, and can form a MAC (Membrane Attack Complex) to lyse cells.

Physiological role of a fever

Systemic response to infection. High body temp increases metabolic rate of immune cells and causes liver/spleen to sequester iron and zinc (needed by bacteria).

The 3 Hallmarks of Adaptive Immunity

1. Specific (targets one specific antigen) 2. Systemic (acts throughout the body) 3. Memory (mounts a stronger attack on subsequent encounters).

Primary vs. Secondary Immune Response

Primary: First exposure. Slow (3-6 day lag), lower antibody peak. Secondary: Re-exposure. Fast (2-3 days), higher antibody peak, lasts longer. (Due to memory cells).

Humoral vs. Cellular Immunity

Humoral: B cells & antibodies. Targets pathogens in 'humors' (fluids) like blood/lymph. Cellular: T cells. Targets infected cells, cancer cells, or transplanted tissue.

Example: Active, Naturally Acquired Immunity

Getting sick with an infection (e.g., catching the flu). Your body actively makes its own antibodies and memory cells.

Example: Active, Artificially Acquired Immunity

Getting a vaccine. Your body is 'tricked' into actively making antibodies and memory cells.

Example: Passive, Naturally Acquired Immunity

Antibodies passed from mother to baby via the placenta or breast milk.

Example: Passive, Artificially Acquired Immunity

Injection of an antiserum or gamma globulin (e.g., anti-venom for a snake bite, rabies shot). You are given pre-made antibodies.

What is an autoimmune disease?

The immune system loses its ability to distinguish 'self' from 'non-self' and attacks the body's own tissues (e.g., Rheumatoid arthritis, Type 1 diabetes).

What is AIDS?

Acquired Immune Deficiency Syndrome. Caused by HIV, which targets and destroys Helper T cells, crippling the adaptive immune system.