The Circulatory system is a "closed circulation” Systemic Circuit Pulmonary Circuit Systemic Circuit

Blood

Blood = Plasma + Formed (Cellular) Elements ~ 55% blood volume ~ 92% of plasma is water High dissolved O2 content Dissolved proteins Cells ~ 45% blood volume RBCs (~ 99% of cells) WBCs (~ 1% of cells)

Proteins in Plasma Albumins 60% of plasma proteins (forms lipoproteins). Globulins 35% of plasma proteins – mostly immunoglobulins. Fibrinogen For clotting reaction, forms fibrin. * serum = plasma without clotting proteins

Cellular Components RBCs (erythrocytes) ~ 99% of all cells. Hematocrit = % of blood occupied by cellular components. (packed RBC volume) Lacks: nuclei, ribosomes, and mitochondria. Anaerobic metabolism (glycolysis) Life span = ~120 days

Scanning Electron Micrograph (SEM) of Erythrocytes or Red Blood Cells (RBCs) on the tip of a hypodermic needle.

Millions of Hb inside each RBC

Normal Red Blood Cells Anemia – reduction in O2 carrying capacity of blood. Sickle Cells - Sickle Cell Anemia

White Blood Cells Neutrophils 70% of circulating leukocytes Highly mobile phagocytes. Eosinophils much less common Attracted to foreign compounds reacted with antibodies. Basophils relatively rare Migrate to damaged tissue, releases histamine.

Lymphocytes primary cell of lymphatic system T-cells attack foreign cells directly. B-cells produce antibodies. Monocytes Migrate into tissues and differentiate into Macrophages - highly mobile phagocytes. Platelet cells (Thrombocytes) Fragments of cells (Megakaryocytes) for clotting.

Never Let Monkeys Eat Bananas

Blood Vessels

Blood Vessels

MAP Type of Blood Vessel

Blood flows down a pressure gradient (P) Highest at the heart (driving P), decreases over distance. Flow  P / R

Resistance Opposes Flow 3 Factors Influence Resistance of fluid flow in Tube: 1) Length of tube (vessel):  length =  Resistance  viscosity =  Resistance 2) Viscosity of fluid (blood): 3) Diameter (radius) of tube (vessel):  radius =  Resistance

3 Types of Capillary Beds 1. Continuous Capillary Bed - most common type in the body. - have tight junctions - ‘leaky’ capillaries

2. Fenestrated Capillary Bed - have ‘pores’ or fenestrations. - more ‘leaky’ than continuous. - specific locations in body: e.g., kidney and synovial joints.

3. Sinusoidal Capillary Bed - open ‘flaps’ in adjacent endothelial cells. - ‘leakiest’ capillary bed. - high degree of exchange. - highly convoluted (twisting). - least common in body: e.g., liver and spleen.

Capillaries Venule Ateriole

Anemia Hemolytic anemia Hemorrhagic anemia Inadequate erythropoiesis Sickle cell anemia Hemorrhagic anemia Hemophilia, trauma, ruptured aneurysm Inadequate erythropoiesis Inadequate nutrition (e.g., iron deficiency)