HB101 Lecture Notes - Lecture 1: Erythropoiesis, Myocyte, Vagus Nerve
HPE110: Lecture 1
The Heart and Circulation
Learning objectives
• Describe the composition and purpose of blood
• Describe the basic anatomy and functioning of the heart related to cardiac output
and blood flow, cardiac pathways of nerve conduction, and electrical activity.
• Describe the acute cardiovascular response to exercise of increasing intensity
The Blood
• Cardiovascular system = Blood heart and the blood vessels
Blood Properties
• Compared to water blood is:
– slightly denser (1.06x)
– 4.5-5.5x more viscous
– pH range 7.35-7.45 (7.0 during exercise)
• Sodium concentration 140mM (135-145mM, 0.85-0.9%)
• Approx 8% of body weight
Blood Functions
• Transport
• Regulation
• Protection
Blood Functions
• Transport of:
– O2
– CO2
– Nutrients
– Waste
• From cells to kidneys, lungs and sweat glands.
– Enzymes
– Heat Energy
• Regulation of:
– pH via
• Bicarbonates, amino acids and Hb
– Water content of cells
• Through dissolved Na+ ions
• Protects against
– Fluid loss -through clotting
– Toxins and foreign microbes
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Physical Characteristics of blood
• Made up of Plasma and Blood cells
• Hematocrit (Hct) -% of blood that is composed of cells.
– Complete in Lab 1
– Normal Hct
• Males ~42%
• Females ~38%.
Plasma
• Consists of 55% of blood volume
• ~91% water
• ~9% plasma proteins (made up of)
– Serum albumin 60%
– Serum globulin 36%
– Fibrinogen 4%
• Minerals, ions, hormones
Blood Cells
• Approx 45% of blood volume.
• Formed elements
– Red blood cells (Erythrocytes)
– White blood cells (Leucocytes)
– Platelets (Thrombocytes)
Red Blood Cells
• >99% of blood ells are ‘BCs
• Contains Hemoglobin (Hb)
• Fx – carry O2 from the lungs to tissues
• Bioconcave discs
– Mean diameter 8 μm, 2 μ thik at eds, ≤1 μm in the
centre
• Pliable and can change shape to squeeze through capillaries
Haemoglobin
The hemoglobin molecule is composed of:
• A protein centre
• globin, and
• four iron-containing groups called heme to which oxygen bind
• Carbon dioxide is carried by globin
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Hemoglobin
• Concentration in blood
– Males ~14-18g/dL ( =16g/dL)
– Females ~11.5-16g/dL ( =14g/dL)
– Children =12g/dL
– At birth ~17g/dL
• 1g Hb combines with 1.34ml of O2, therefore
– Male carries 1.34 x 16 = 21.4ml O2 /dL blood
– Female carries 1.34 x 14 = 18.8ml O2 /dL blood
Red Blood Cells
• Hemoglobin
– Important Buffer
– Accounts for ~50% of buffering capacity in blood
• Contains carbonic anhydrase
• Increases rate of breakdown of H2CO3
Erythropoiesis
• Production of RBCs
• 0-5 yrs all bones but especially long bones
• 5-20yrs Long bones
• >20yrs marrow of vertebrae, sternum, ribs, ilia
• Marrow becomes less productive as age increases
• Stress can stimulate marrow to produce large quantities of RBCs if required
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The blood: cardiovascular system = blood heart and the blood vessels. Blood properties: compared to water blood is: Ph range 7. 35-7. 45 (7. 0 during exercise: sodium concentration 140mm (135-145mm, 0. 85-0. 9%, approx 8% of body weight. Heat energy: from cells to kidneys, lungs and sweat glands, regulation of: Ph via: bicarbonates, amino acids and hb. Water content of cells: through dissolved na+ ions, protects against. Physical characteristics of blood: made up of plasma and blood cells, hematocrit (hct) -% of blood that is composed of cells. Normal hct: males ~42, females ~38%. Plasma: consists of 55% of blood volume, ~91% water, ~9% plasma proteins (made up of) Blood cells: approx 45% of blood volume, formed elements. Red blood cells: >99% of blood (cid:272)ells are bc(cid:859)s, contains hemoglobin (hb, fx carry o2 from the lungs to tissues, bioconcave discs. Mean diameter 8 m, 2 (cid:373) thi(cid:272)k at e(cid:374)ds, 1 m in the centre: pliable and can change shape to squeeze through capillaries.
