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Chapter 18: Blood - Coggle Diagram
Chapter 18: Blood
Blood Circulation
- Powered by pumping action of the heart
- Oxygen & nutrients diffuse across capillary walls to body tissues
- Transports hormones from endocrine glands
- Conveys cells of immune system
- Regulates body temperature
Circulatory System
- Divided into:
- Cardiovascular system
- Lymphatic system
Blood
- Transport medium for
- Nutrients
- Signaling molecules
- Respiratory gases
- Waste products
Composition of Blood
Blood Volume
- Males: 5-6L
- Females: 4-5L
Cellular & Liquid Components of Blood
- Is a specialized connective tissue
- Blood cells: formed elements
- Plasma: liquid portion of blood
Blood Plasma
- Straw-colored, sticky fluid portion of blood
- Approx. 90% water
- Contains more than 100 kinds of molecules
- Ions: Na+ & Cl-
- Nutrients: sugars, amino acids, lipids
- Wastes: CO2, urea & ammonia
- Proteins
3 Main Proteins
Albumin
- Prevents water from diffusing out of blood vessels
Globulins
- Include antibodies & blood proteins that transport lipids, iron & copper
Fibrinogen
- One of the molecules involved in chemical reactions for blood clotting
Formed Elements
- Blood cells:
- Erythrocytes
- Leukocytes
- Platelets
Erythrocytes
Red Blood Cells (RBCs)
- Oxygen-transporting cells
- Most numerous of the formed elements
- Have no organelles or nuclei
- Are the ideal measuring tool for estimating sizes of nearby structures
- Packed with O2-carrying hemoglobin
- Pick up O2 at lung capillaries
- Release O2 across other tissue capillaries
Hemoglobin
- Hemoglobin molecule bears 4 chains of amino acids
- Each amino acid chain bears an iron atom
- Oxidation of iron atoms of hemoglobin molecules gives blood its red color
- There are the binding sites for oxygen molecules
Structural Characteristics
- Structural characteristics contribute to respiratory function
- Biconcave shape: 30% more surface area
- 97% hemoglobin
- Lack mitochondria
Leukocytes
White Blood Cells (WBCs)
- Protect the body from infectious microorganisms
- Function outside the bloodstream in loose connective tissue
- Diapedesis: circulating leukocytes leave the capillaries
- Originate in bone marrow
- 2 types of leukocytes
Granulocytes
- Neutrophils
- Eosinophils
- Basophils
Neutrophils
- Most numerous WBC
- Granules pick up acidic & basic stains
- Nucleus has 2-6 lobes
- Attracted by bacterial products and are first line of defense in inflammatory response
- Die in the process
- Become puss as they accumulate
- Phagocytize & destroy bacteria
- Also release enzymes into extracellular matrix of infected tissue
Eosinophils
- Represent 1-4% of all WBCs
- Granules are large & stain red
- Granules contain enzymes active during allergic reactions and parasitic infections
- Play a role in ending allergic reactions by phagocytizing allergens
- Secrete enzymes that degrade histamines
Basophils
- ~0.5% of all leukocytes
- Nucleus is usually 2 lobes
- Granules secrete histamines
- Vasodilation, capillary permeability, allergic reaction
- Function in inflammation mediation
- Similar in function to mast cells
- Direct later stages of inflammation in allergies and parasitic infections
Lymphocytes
- Comprise 20-45% of WBCs
- The most important cells of the immune system
- Nucleus stains dark purple
- Effective in fighting infectious organisms
- Act against a specific foreign molecule (antigen)
- 2 main classes of lymphocyte
T-cells
- Attack foreign cells directly
- Produced in bone marrow
- Mature in thymus
B-cells
- Differentiate & produce antibodies
- Mark the foreign cell for destruction by macrophages
- Produced in bone marrow
- Mature in bone marrow
Monocytes
- Compose 4-8% of WBCs
- Largest leukocytes
- Nucleus is kidney-shaped
- Transform into macrophages after diapedesis
Mnemonic
Never Let Monkeys Eat Bananas
- Neutrophils, lymphocytes, monocytes, eosinophils, basophils
- Most abundant to least abundant leukocytes
- Neutrophils are most abundant
- Basophils are least abundant
Platelets
Thrombocytes
- Cell fragments
- Break off from megakaryocytes
- Function in clotting of blood
Hematocrit
- The percentage of the blood volume that consists of red blood cells (RBCs)
- RBCs are also called erythrocytes
Buffy Coat
- Portion of blood composed of leukocytes & platelets
- Present at junction of plasma and RBCs
- Leukocytes are white blood cells
Blood Cell Formation
- Hematopoiesis: process by which blood cells are formed
- 100 billion new blood cells formed each day
Bone Marrow as the Site for Hematopoiesis
- Bone marrow is located within all bones
- When young, all bone marrow is red marrow
Red Marrow
- Actively generates new blood cells
- Contains immature erythrocytes
- In adults, red marrow is located:
- Between trabecular of spongy bone of axial skeleton
- Girdles
- In proximal epiphyses of humerus & femur
Yellow Marrow
- Dormant
- Contains many fat cells
- Located in the long bones of adults
- Makes blood cells only in emergencies
Tissue Framework of Bone Marrow
- Composed of reticular connective tissue
- Fibroblasts covering & secreting the fiber network are reticular cells
- Blood sinusoids run throughout the reticular tissue
- Mature blood cells enter the blood stream through endothelial cells of sinusoids
- Contains macrophages that extend pseudopods to capture antigens
- Some cells of the reticular network are mesenchymal stem cells
- Can give rise to:
- Fat cells, osteoblasts, chondrocytes, fibroblasts & muscle cells
Disorders of the Blood
-
Disorders of Leukocytes
Leukemia
- A form of cancer
- Classified as:
- Lymphoblastic
- Affects development of B or T cells
- Myeloblastic
- Affects development of RBCs, platelets & the other WBCs
Disorders of Platelets
Thrombocytopenia
- Abnormally low concentration of platelets
- Easy bruising, petechiae, nose bleeds