physiology of the blood i. the plasma and fluid compartments
TRANSCRIPT
Physiology of the Blood I. Fluid compartments and the plasma
Prof. Szabolcs Kéri
University of Szeged, Faculty of Medicine, Department of Physiology
2021
Introductory case vignette
• Young male patient
• Pale skin
• Fatigue, dizziness, shortness of breath
• Poor attention and concentration
• Recurrent infections, fever
• Sensitive gingiva (bleeding)
• Small suffusions under the skin
Blood sample
Increased number of undifferentiated white blood cells
(accelerated division, poor differentiation – lymphoblasts)
Lymphoblasts destroy the bone marrow:
- Red blood cell ↓ → pale skin, fatigue
- Mature white blood cells ↓ → infections
- Platelets ↓ → bleeding
Diagnosis: acute leukaemia
• Blood and the fluid compartments of the body
• Functions of the blood in general
• Components of the blood: plasma and cells
• Anorganic and organic components of the plasma
• Special emphasis: proteins of the plasma
Topics to be discussed:
Intracellular Extracellular
Cell membrane Capillary
wall
Interstitial
fulid Pla
sm
a
Principles of:
- Isotonicty
- Isovolemia
EDEMA: fluid movement and accumulation through the cell membrane and/or capillary wall
Inside the cell
Organization of the fluid spaces: the three-compartment model
Blood and the fluid compartments of the body
Total water: 0.6 x body weight (kg)
1. INTRACELLULAR COMPARTMENT: 0.4 x body weight
2. EXTRACELLULAR COMPARTMENT: 0.2 x body weight
2.1. Interstitial (0.75 x extracellular)
2.2. Intravasal = BLOOD PLASMA (0.25 x extracellular)
2.3. Transcellular (liquor, eye, inner ear, pleura)
Volume = amount of indicator / concentration after equilibrium
- Intravasal: Evans-blue or 131I bound to albumin
- Extracellular: inulin
- Total: tritiated water, antipyrine
When the continuity of fluid compartments is disrupted:thrombosis
Thrombus in the blood vessel
Ahead the thrombus: insufficient/ceased flowBeyond the thrombus: congestion and
edema
Ultrasound diagnosis of deep vein thrombosis
Excessive fluid in the chest: hydrothorax
Chest X-ray:
pleural effusion
(accumulation of fluid around the lungs)
Blood components after centrifugation
PLASMA (55%)
WHITE BLOOD CELLS AND PLATELETS (<1%) (buffy coat)
RED BLOOD CELLS (45%)
HEMATOCRIT: the proportion of cells in the blood (~ 0.44-0.46 male, 0.41-0.43 female)
Sera = plasma without protein fibrinogen (after blood coagulation)
~ 5 liters
Components of the plasma
1. ANORGANIC ELECTROLITES: sodium, potassium, calcium, magnesium,
chloride, bicarbonate, phosphate
2. ORGANIC SUBSTANCES:
- proteins
- glucose
- amino acids
- urea (blood urea nitrogen [BUN]), creatinine, uric acid
- lipids (triglyceride, cholesterol)
- organic acid (lactate, pyruvate, citrate, bilirubin)
Proteins of the plasma
- Synthesis: liver, gut, white blood cells, endothelium (60-80 g/l)
- Function: oncotic pressure, transport, acid-base buffer, inhibition of renal filter and
receptor effect
1. Albumin (35-45 g/l): oncotic pressure, bilirubin transport, binding of drugs
2. α1-globulin: thyroxine, cortisol, vitamin D transport
3. α2-globulin: ceruloplasmin (copper), haptoglobin
4. β-globulin: transferrin (iron)
5. γ-globulin: antibodies
6. Fibrinogen: blood coagulation
Normal Liver cirrhosis
Nephrosis Multiple myeloma
Lipoproteins of the plasma
Hydrophobic core: triglycerides (T), cholesterol (C)
Hydrophilic periphery: phospholipids, apolipoproteins (Apo)
Chylomicron, VLDL (Very Low Density Lipoprotein), IDL (intermediary),
LDL (low), HDL (high): increased density and protein content in this order
Chylo: absorbed from instestines
HDL („good” cholesterol): synthesis in liver, taking up cholesterol in vessels
Peroxisome proliferator
- activated receptors
(PPARs): nuclear receptors,
Apo-expression
Ligand: e.g. fatty acids