Blood - Overview, Composition

Blood
Presentation lecture by:Melody Holmes, MT,
Collin County Community College District

Overview of Blood Circulation

Composition of Blood

* Tissue type
* Composition
* Formed elements
o Erythrocytes
o Leukocytes
o Platelets
* Hematocrit

Components of Whole Blood
Physical Characteristics and Volume
* Characteristics
* Color
* pH
* Temperature
* Percentage of body weight
* Average volume

Functions of Blood
* Distribution
* Regulation
* Protection

Distribution
* Transportation
o Gases
o Nutrients
o Metabolic wastes
o Hormones
* System Maintenance
o Body temperature
o pH
o Fluid volume

Protection
* Blood loss
o Plasma proteins and platelets
o Clot formation
* Infection
o Antibodies
o Complement proteins
o WBCs

Blood Plasma
* Solutes
o Proteins
+ Albumin, globulins, clotting proteins
o Lactic acid, urea, creatinine
o Organic nutrients
+ Glucose, carbohydrates, amino acids
o Electrolytes
+ Sodium, potassium, calcium, chloride, bicarbonate
o Respiratory gases
+ Oxygen and carbon dioxide
Formed Elements

* Erythrocytes, leukocytes, and platelets
o WBCs
o RBCs
* Life span
* Production

Erythrocytes

* Physical characteristics
o Shape
o Nucleation
o Organelles
* Hemaglobin
o Function
* Spectrin
o Function

Erythrocytes Gas Transport
* Structural characteristics
o Surface area
o Hemoglobin
o ATP generation
Erythrocyte Function
* RBCs are dedicated to respiratory gas transport
* Hemaglobin (Hb)
o Affinity for oxygen
o Composition
o Heme group
o Capacity

Structure of Hemoglobin
Hemoglobin (Hb)
* Oxyhemoglobin
* Deoxyhemoglobin
* Carbaminohemoglobin

Production of Erythrocytes
* Hematopoiesis
* Red bone marrow
o Axial skeleton and girdles
o Epiphyses of the humerus and femur
* Hemocytoblasts

Production of Erythrocytes: Erythropoiesis
* Hemocytoblast → Proerythroblast
* Proerythroblasts → Early Erythroblasts
* Developmental pathway
o 1 – ribosome synthesis in early erythroblasts
o 2 – Hb accumulation in late erythroblasts and normoblasts
o 3 – ejection of the nucleus from normoblasts and formation of reticulocytes
* Reticulocytes → Mature Erythrocytes

Erythropoiesis: Regulation and Requirements
* Circulating erythrocyte number
o Too few RBCs
o Too many RBCs
* Erythropoiesis control
o Iron, amino acids, and B vitamins

Erythropoiesis: Hormonal Control
* Erythropoietin (EPO)
o Triggers
+ Hypoxia
+ Decreased oxygen availability
+ Tissue demand for oxygen
* Enhanced erythropoiesis
o Outcome
+ RBC count
+ Oxygen carrying ability
Homeostasis: Normal blood oxygen levels
Erythropoietin Mechanism
Homeostasis: Normal blood oxygen levels
Erythropoiesis: Dietary Requirements
Erythrocytes: Fate and Destruction
* Life span
* Degenerate
* Dying RBCs
o Macrophages
* Heme and globin
* Iron
Erythrocytes: Fate and Destruction
* Heme → Bilirubin
* Bilirubin → Bile
* Bile → Urobilinogen
* Stercobilin
* Globin
* Hb
Erythrocyte Disorders
Anemia: Insufficient Erythrocytes
* Hemorrhagic anemia
* Hemolytic anemia
* Aplastic anemia
* Iron-deficiency anemia
o Secondary result
o Iron-containing foods
o Iron absorption
* Pernicious anemia
o Vitamin B12
o Intrinsic factor
* Treatment
o B12
o Nascobal
Anemia: Decreased Hemoglobin Content
Anemia: Abnormal Hemoglobin
* Sickle-cell anemia
o HbS
+ Amino acid substitution
o Result

Polycythemia

* Polycythemia
* Three main polycythemias
o Polycythemia vera
o Secondary polycythemia
o Blood doping

Blood.ppt