System Physiology Ch 9

Anemia (LOW RBC function)

Mechanism:

• ↓ RBC count OR ↓ hemoglobin

• Effect:

• ↓ oxygen delivery → tissue hypoxia

• Symptoms:

• Fatigue

• Pallor

• Dyspnea

• Chills

Polycythemia (HIGH RBC count)

Mechanism:

Too many RBCs → ↑ blood viscosity

Effect:

Sluggish blood flow

↑ risk of clotting

Types:

1. Polycythemia vera

Cause: bone marrow cancer

Hematocrit > 80%

2. Secondary polycythemia

Cause: low O₂ (high altitude, lung disease)

↑ erythropoietin (EPO)

Treatment:

Therapeutic phlebotomy (remove blood)

Erythropoietin (EPO) Clinical Issues

Normal Role:

Hormone that ↑ RBC production

When Increased:

Hypoxia → ↑ EPO → ↑ RBCs

Abuse (Athletes):

Artificial EPO → ↑ hematocrit

Danger:

Blood becomes too thick

Leads to:

Clots

Stroke

Heart failure

Leukocytosis (HIGH WBCs) white blood cells

Cause:

Infection

Meaning:

Normal immune response

Leukemia (CANCER) white blood cells

Mechanism:

Overproduction of immature, nonfunctional WBCs

Effects:

Crowds bone marrow

↓ RBCs → anemia

↓ platelets → bleeding

Key detail:

WBC count can be extremely high (>150,000)

Thrombus

Definition:

Clot that forms in place

Effect:

Blocks blood flow → tissue death

Embolus

Definition:

Clot that travels

Examples:

Pulmonary embolism

Cerebral embolism (stroke)

Risk Factors:

Atherosclerosis

Immobility (blood stasis)

RBC Breakdown & Clinical Relevance

Key Process:

RBCs broken down → bilirubin formed

Oxygen-Related Clinical Causes of Hypoxia

↑ bilirubin → jaundice (yellowing)

Oxygen-Related Clinical Causes of Hypoxia

↓ RBCs (hemorrhage)

↓ hemoglobin (iron deficiency)

↓ oxygen availability (lung disease, altitude)

Platelet / Bleeding Clue

Petechiae

Small red/purple spots on skin

Indicates bleeding/clotting issue

Fate and destruction of Erythrocytes

RBC Problems:

Anemia → too little O₂

Polycythemia → too thick blood

Hormonal:

EPO ↑ → more RBCs

Too much → dangerous clotting

WBC Problems:

↑ WBC → infection

↓ WBC → weak immunity

Leukemia → cancer, nonfunctional cells

Clotting:

Thrombus = stuck clot

Embolus = traveling clot → stroke/PE

Big Danger Themes:

Hypoxia

Hyperviscosity

Clot formation

Immune dysfunction