Chapter 14 Blood. Structure & Function Blood is a type of connective tissue (consists of cells in a...
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Transcript of Chapter 14 Blood. Structure & Function Blood is a type of connective tissue (consists of cells in a...
Structure & Function
• Blood is a type of connective tissue (consists of cells in a matrix)
• Function –
• pH –• Volume – 5L (in avg. adult male)• Temp. – 100.4 º F.• Accounts for 8% of body weight• Color varies from scarlet (O2 rich) to dark red (O2
poor)
Structure
• Composition – • composed of 3
types of cells (called solid portion):
• 1. RBCs –
• 2. WBCs –• 3. platelets -
Structure
• The solid portion makes up 45% of a blood sample
• Called the hematocrit (HCT) or packed cell volume (PCV)
• Matrix (liquid portion) –
• Makes up remaining 55% of
sample; mostly H2O, nutrients, etc.
Erythrocytes (RBCs)
• Structure:
• 1. biconcave disks
• three advantages:
A.
B. no point within the cytoplasm is far from the surface; ideal for gas exchange
C.
Erythrocytes
• Structure:• 2.
• 3. Mature RBCs lack nuclei; allows more room for Hb (each RBC is 1/3 Hb by volume)
• Normal RBC count: 4-6 million/mm³ of blood (in avg. adult) (slight incr. after meals or exercise; decr. from anemia, leukemia, or hemorrhage)
Hemoglobin
• Hb consists of the protein globin→ • Each has 4 polypeptide chains
& 4 heme groups (pigment)
where O2 binds
• Hb combines easily w/O2 –
•
• When O2 is released from the RBC, deoxyhemoglobin is produced; makes blood dark bluish-red
Hemoglobin
• Normal Hb levels – 14-18 gm/100 ml of blood (in avg. adult male)
• Cyanosis –
• Symptoms – bluish lips &
nail beds, dizziness, fainting,
fatigue, muscle weakness
Dietary Factors for RBC Production
• Two B-complex vitamins (B12 & Folic acid) are imp. for normal RBC production
• Both are needed for DNA synthesis• Lack of B12 –
• Iron (Fe) – needed for production of Hb (Vit C increases absorption of Fe in the digestive tract)
• Anemia –
Destruction RBC
• RBC break down from wear and become ruptured when travelling through the kidney and spleen.
•
• Hemoglobin breaks down into 4 globin groups and heme groups
•