Chapters 18 - 20: Cardiovascular System
P
Exam
I
Exam
II
Today:
A. Leukocytes
B. Platelets
Blood
C. Hemostatis
D. Heart Anatomy
Mariners
Tigers
3
4
Blood Components - Erythrocytes:
• Balance of RBCs important:
• Low = tissue hypoxia
• High = viscous blood
• Iron and B-complex vitamins crucial for RBC development
• Vitamin B12 and folic acid = Proper DNA synthesis
• Iron = Hemoglobin synthesis
• Stored as ferritin and hemosiderin
• Transported in blood via transferrins
• Reserves = hemoglobin (80%), cells (20%), blood (<1%)
• Controlled hormonally by erythropoietin
• Produced by kidney (~ 85%) and liver (~ 15%)
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Blood Components - Erythrocytes:
Blood Components - Erythrocytes:
Hypoxia
Lo
wB
loo
d OOxygen Level
Normal Blood
xyg
en
Le
vel
Increased O2
Level in Blood
1) RBC loss
2) Low O2
3) Exercise
Normal Blood Oxygen Level
Reduced O2
Level in Blood
Erythropoietin
Stimulates
Bone Marrow
RBCs Mature
More Rapidly
Kidney Releases
Erythropoietin
Chapters 18 - 20: Cardiovascular System
Increased O2
Level in Blood
RBCs Mature
More Rapidly
Reduced O2
Level in Blood
Erythropoietin
Stimulates
Bone Marrow
Kidney Releases
Erythropoietin
Chapters 18 - 20: Cardiovascular System
Lifecycle of RBCs:
Blood Components - Erythrocytes:
Erythrocyte Disorders:
1) Anemias (↓ oxygen carrying capacity)
• Decreased RBCs (e.g. blood loss, marrow destruction)
• Decreased Hemoglobin (e.g. iron / B12 deficiency)
• Abnormal Hemoglobin (e.g. Thalassemia; Sickle-cell anemia)
2) Polycythemia (↑ RBCs)
• Bone marrow cancer
• High altitude living
• Blood doping (artificial)
(Figure 18.7)
Whole Blood
EPO
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Blood Components - Leukocytes:
Granulocytes (contain granules):
Blood Components:
3) Leukocytes (White Blood Cells - WBCs)
• Complete cell
• Function in defense against disease
• Utilize blood for transport
• Perform most functions in tissue (exit = diapedesis)
• Produced in bone marrow
• Produced/mobilize quickly
• Generally < 1 day in circulation
1) Neutrophils (55-65%)
• Small granules (hydrolytic enzymes/defensins)
• Multi-lobed nuclei
• Engulf bacteria/fungi (respiratory burst)
2) Eosinophils (1-4%)
• Large granules (lysosomes)
• Bi-lobed nuclei
• Attack parasitic worms (e.g. tapeworms)
3) Basophils (< 1%)
• Large granules (histamines)
• U-shaped nuclei
• Vasodilate vessels/attract WBCs
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Blood Components - Leukocytes
Leukopoiesis (Figure 18.11):
Blood Components - Leukoocytes:
Agranulocytes (lack granules):
proerythroblast
1) Lymphocytes (25-35%)
• Large nuclei
• Few in blood (lymph nodes/spleen)
• Immunity function (Life span = years)
• T lymphocytes (virus-infected/tumor cells)
• B lymphocytes (antibodies)
Hemocytoblast
Myeloid stem cell
Hormones:
Interleukins
Colony-stimulating factors
(+)
Lymphoid stem cell
Myeloblast
Monoblast
Lymphoblast
Eosinophils
Basophils
Neutrophils
Monocytes
Lymphocytes
2) Monocytes (3-7%)
• Largest of WBCs
• Large U-shaped nuclei
• Macrophages (phagocytosis)
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Blood Components - Leukocytes:
Leukocyte Disorders:
1) Overproduction of WBCs
• Leukemias (cancers of WBCs)
Lymphocytic leukemia
• Mononucleosis (Epstein-Barr virus - high agranulocyte counts)
2) Underproduction of WBCs (Leukopenia)
• Induced by drugs (glucocorticoids / anticancer)
Blood Components:
4) Platelets (thrombocytes)
• Cytoplasmic fragments (anucleate)
• Function in blood clotting
• Granules → clotting chemicals
• Short-lived (~ 10 days)
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Blood Components - Platelets:
Thrombopoietin
Platelet Production:
Megakaryocyte
Megakaryoblast
proerythroblast
Hemocytoblast
Platelets
(+)
(+)
Myeloid stem cell
Lymphoid stem cell
Myeloblast
Monoblast
Lymphoblast
Eosinophils
Basophils
Neutrophils
Monocytes
Lymphocytes
(Figure 18.12)
Chapters 18 - 20: Cardiovascular System
Hemostasis (“Stoppage of blood flow”):
• Series of fast, localized reactions to halt blood loss
Phases:
1) Vascular Spasms (Vasoconstriction of damaged vessel)
• Significantly reduces blood loss
• Activated by:
(a) Direct injury to smooth muscle
(b) Chemical release
(c) Nociceptors
2) Formation of Platelet Plug
• Temporarily seals vessel break (Positive feedback loop)
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Hemostasis - Platelet Plug Formation:
Hemostasis (“Stoppage of blood flow”):
Rupture of vessel
Phases:
3) Coagulation (Blood clotting)
• Blood converted from liquid to gel (3-6 minutes)
Collagen exposed
Attracts more
platelets
Step 1: Formation of prothrombin activator
(+)
Platelets stick to site
Vascular
spasms
• Intrinsic pathway → outside of body (minutes)
• Extrinsic pathway → in tissues (seconds)
Step 2:
Platelets release contents
Prothrombin (protein)
Adenosine
Diphosphate
(ADP)
Prothrombin
activator
Thrombin (enzyme)
Aspirin
Thromboxane
A2
Serotonin
Step 3:
Thrombin
Fibrinogen (protein)
Fibrin mesh (seals hole)
Events in
coagulation:
Chapters 18 - 20: Cardiovascular System
• Produced in liver
• Most require vitamin K
(Figure 18.13)
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Hemostasis (“Stoppage of blood flow”):
Hemostasis (“Stoppage of blood flow”):
Clot Retraction and Removal:
1) Platelets draw wound together (Actin/myosin fibers)
Factors preventing undesirable clotting:
1) Endothelium → smooth walls
2) Prostacyclin (PGI2) and Heparin (anticoagulants)
• Inhibit platelet aggregation (produced by endothelial wall)
Thromboembolytic Disorders (Undesirable clot formation):
• Thrombus: Clot develops in unbroken vessel
• Embolus: Clot floats freely in vessels
2) Platelet-derived Growth Factor (PDGF - Platelets)
• Stimulates vessel to rebuild (smooth muscle/fibroblasts)
3) Plasminogen converted to Plasmin
• Dissolves clot (fibrinlysis)
• Plasmin activated by tPA (tissue plasminogen activator)
• Drug treatment = Aspirin, heparin, warfarin
Bleeding Disorders (e.g. Hemophilia - coagulation factor deficiency)
Chapters 18 - 20: Cardiovascular System
Chapters 18 - 20: Cardiovascular System
Transfusion and Blood Replacement:
Transfusion and Blood Replacement:
1) ABO Blood Groups
2) Rh Blood Groups
• Presence / absence of 1 glycoprotein
• Presence / absence of 2 glycoproteins (antigens)
Type Rh+
Type A
Type B
Type AB
• Blood has pre-formed antibodies opposite blood type
• Type O blood = Universal Donor
• Type AB blood = Universal Recipient
Type Rh-
Type O
• Antibodies formed after initial contact with antigen
Ø Hemolytic disease of the newborn
Chapters 18 - 20: Cardiovascular System
Transfusion Reactions:
1) Clumping of foreign RBCs:
2) RBCs rupture/are destroyed:
Hemoglobin
Treatment = Alkaline fluids (dilute/dissolve hemoglobin)
Diuretics
Kidneys