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B L O O D P A R T 1
Cardiovascular System
Homework
Lab this week
Endocrine presentations
No PreLab this week
Due Monday 2/25/13
HW 13-14: Endocrine System HW 1
HW 17: Endocrine System HW 3
Introduction
Circulation
Blood vascular
Blood
Heart
Blood vessels
Lymphatic system
Lymph
Lymph vessels
Lymph nodes
Blood
Formed Elements
Cellular portion
Fluid portion
Arterial versus venous
Blood
~8% of body weight
Average volume
Males : 5–6 L
Females: 4–5 L
Blood
Viscosity
Color
pH
7.35–7.45
Temperature
38C (99 F)
Functions of Blood
1. Transport
O2 and carbon dioxide
Nutrients
Metabolic wastes
Hormones and enzymes
Functions of Blood
2. Regulation
Body temperature
pH
Water content of cells
Functions of Blood
3. Protection against Blood loss
Plasma proteins and platelets initiate clot formation
Infection (immune response)
Antibodies
WBC’s
Structure of Blood
Formed elements 45%
Plasma 55%
Copyright © 2010 Pearson Education, Inc. Figure 17.1
1 Withdraw
blood and place
in tube.
2 Centrifuge the
blood sample.
Plasma • 55% of whole blood • Least dense component Buffy coat • Leukocytes and platelets • <1% of whole blood Erythrocytes • 45% of whole blood • Most dense component
Formed
elements
Plasma
Water 90%
Proteins 7-9%
Albumin
Viscosity and osmolarity
Globulins
Transport and immunity
Fibrinogen
Clotting
Plasma
Electrolytes
Na+, K+, Ca2+, Cl–, HCO3–
Nutrients
Glucose, carbohydrates, amino acids, lipids
Gases
O2 and CO2
Wastes
Lactic acid, urea, ketones, uric acid
Formed Elements
Erythrocytes
No nuclei or organelles
Leukocytes
5 types
Granular
Agranular
Thrombocytes
Cell fragments
Formed Elements
General
Most survive in the bloodstream for only a few days
RBC’s = 120 days
Most blood cells do not divide and originate in bone marrow
Figure 17.2
Platelets
Neutrophils Lymphocyte
Erythrocytes Monocyte
Erythrocytes
Appearance Biconcave discs
Non-nucleated
8 nm in diameter
Figure 17.3
2.5 µm
7.5 µm
Side view (cut)
Top view
Erythrocytes
Properties Filled with hemoglobin (Hb) for gas transport
Major factor contributing to blood viscosity
Survive 120 days
Hematocrit Males 47%
Females 42%
Erythrocytes
Gas transport Biconcave shape
Hemoglobin 33% of weight
No mitochondria
ATP production is anaerobic (no O2 is used in generation of ATP)
Erythrocytes
Hemoglobin structure
Globin: protein
Heme: iron
Each Hb molecule can transport 4 O2
Each RBC has about 250 million Hb molecules!
Erythrocytes
Hemoglobin roles
O2 loading in the lungs
O2 unloading in the tissues
CO2 loading in the tissues
Hematopoiesis
Blood cell formation
Red bone marrow of axial skeleton, girdles and proximal epiphyses of humerus and femur
Erythropoiesis
Spongy bone
Sternum, ribs, cranium
Epiphyses
Femur and humerus
Vertebral bodies
Figure 17.5
Stem cell
Hemocytoblast Proerythro- blast
Early erythroblast
Late erythroblast Normoblast
Phase 1
Ribosome synthesis
Phase 2
Hemoglobin accumulation
Phase 3
Ejection of nucleus
Reticulo- cyte
Erythro- cyte
Committed
cell
Developmental pathway
Erythropoiesis
Erythropoiesis
Regulation
Too few RBCs leads to tissue hypoxia
Too many RBCs increases blood viscosity
Balance between RBC production and destruction depends on
Hormonal controls (renal erythropoietic factor)
Adequate supplies of iron, amino acids and B vitamins
Erythropoiesis
Hormonal control
Hypoxemia kidney’s release REF plasma protein converted to EPO RBC production stimulated
Erythropoiesis
Effects of EPO
More rapid maturation of committed bone marrow cells
Increased circulating reticulocyte count in 1–2 days
Figure 17.6
Kidney (and liver to a smaller extent) releases erythropoietin. Erythropoietin
stimulates red bone marrow.
Enhanced erythropoiesis increases RBC count.
O2- carrying ability of blood increases.
Homeostasis: Normal blood oxygen levels
Stimulus:
Hypoxia (low blood
O2- carrying ability)
due to
• Decreased RBC count
• Decreased amount of hemoglobin
• Decreased availability of O2
1
2
3
4
5
Erythrocytes
Fate
Life span
Old RBCs become fragile and Hb begins to degenerate
Macrophages engulf dying RBCs in the spleen