Science 30 UA T CDE

What are the two main blood circulation pathways?

Pulmonary circulation (heart → lungs → heart) and systemic circulation (heart → body → heart).

Function of pulmonary circulation?

Carry deoxygenated blood to lungs, release CO2, pick up O2, return oxygenated blood to left atrium.

Function of systemic circulation?

Carry oxygenated blood to body tissues, return deoxygenated blood to right atrium.

Three special systemic circulations?

Coronary (heart), Renal (kidneys), Portal (digestive organs + liver).

What is plasma?

Liquid portion of blood (92% water) with ions, proteins (antibodies, fibrinogen), nutrients, wastes.

What are erythrocytes (RBCs)?

Biconcave cells without a nucleus, filled with hemoglobin for O2 and CO2 transport.

What protein gives blood its red colour?

Hemoglobin (iron-containing, binds O2 loosely).

What does “oxygenated” mean?

RBCs carry O2, bright red.

What does “deoxygenated” mean?

RBCs release O2, carry some CO2, dark red.

Average lifespan of an RBC?

~120 days; broken down in liver and spleen.

What happens if iron is low?

Iron-deficiency anemia → low hemoglobin, reduced oxygen transport, fatigue.

What is sickle cell anemia?

Abnormal RBC shape blocks flow, causes low O2, organ damage, can be fatal.

What are leukocytes (WBCs)?

Larger, less numerous, nucleated cells for defense against infection.

Two main WBC defense methods?

Phagocytosis of microbes; enzyme production to detoxify harmful substances.

What is pus?

Dead/dying leukocytes, bacteria, and tissue cells at infection site.

What is leukemia?

Cancer of WBCs; uncontrolled production of abnormal cells, prone to infection.

What are platelets (thrombocytes)?

Cell fragments with thromboplastin, clot blood at injury sites.

Steps of blood clotting?

1. Platelets release thromboplastin → 2. Converts fibrinogen to fibrin → 3. Fibrin forms net trapping RBCs → 4. Clot contracts → wound sealed.

Why can clots be dangerous?

Traveling clot may block brain (stroke) or heart (heart attack).

What is cholesterol?

Waxy fat-like substance in membranes, hormones, vitamin D; high levels cause plaque buildup.

What is plaque?

Semi-hardened deposits of cholesterol, fats, and cells inside artery walls.

What are lipoproteins?

Proteins that transport cholesterol and fats in blood.

LDL (“bad cholesterol”)?

Carries cholesterol to body cells; deposits in arteries → plaque.

HDL (“good cholesterol”)?

Carries cholesterol from cells back to liver for excretion.

What is atherosclerosis?

Hardening/narrowing of arteries due to fatty deposits; increases BP, reduces elasticity.

What is angina?

Chest pain from reduced blood flow/oxygen to heart tissue.

What causes a heart attack?

Blockage of coronary artery → death of heart tissue.

What causes a stroke?

Blockage of brain artery → death of brain tissue.

What is an aneurysm?

Weak bulging in artery wall, risk of rupture → internal bleeding, stroke, death.

What is a septal defect?

Hole in heart septum → mixing of oxygenated and deoxygenated blood.

What is valvular heart disease?

Faulty valve doesn’t close properly → backflow, heart works harder.

Pros/cons of artificial valves?

Long-lasting but risk clots.

Pros/cons of tissue valves?

Less clot risk but shorter lifespan.

What is a pathogen?

Disease-causing agent (bacteria, virus, parasite).

How can pathogens enter the body?

Cuts, digestive tract, respiratory tract, reproductive tract, insect vectors (e.g. malaria).

First line of defense (barriers)?

Skin, tears, mucous, cilia, saliva, stomach acid, urine flow.

Second line of defense (non-specific)?

Phagocytic WBCs (neutrophils, monocytes, macrophages), inflammation, fever.

What is phagocytosis?

Process where WBCs engulf and digest microbes.

What causes fever?

Chemicals from WBCs act on hypothalamus; slows microbes, speeds immune response.

Third line of defense (specific)?

Antibody-mediated immunity: antibodies target specific antigens.

What is an antigen?

Foreign molecule on pathogen that triggers immune response.

What is an antibody?

Y-shaped protein made by B cells that binds antigens and neutralizes them.

Roles of antibodies?

Block pathogens, clump antigens, attract phagocytes, stimulate T cells and granulocytes.

What are lymphocytes?

White blood cells (T cells and B cells) involved in specific immunity.

Function of B cells?

Produce antibodies; create memory B cells for long-term immunity.

Function of T cells?

Identify antigens, activate B cells, activate killer T cells, suppress immune response after infection.

Types of T cells?

Helper T cells (activate others), Killer T cells (destroy infected cells), Suppressor T cells (stop response), Memory T cells (long-term memory).

What is HIV?

Virus that infects T cells, hides in DNA, eventually destroys immune system → AIDS.

What are autoimmune diseases?

Immune system attacks body’s own cells (misdirected response).

What are vaccines?

Dead/inactive pathogens trigger immune response, form memory B cells, long-term protection.

What are antibiotics?

Chemicals (often from fungi/bacteria) that kill bacteria, e.g. penicillin.

How does penicillin work?

Prevents bacterial cell wall formation → bacteria burst and die.

Three dangers of antibiotic misuse?

Side effects/allergies, ineffective against viruses, antibiotic resistance.

What is antibiotic resistance?

Surviving bacteria adapt to resist drugs, creating new resistant strains.