Blood Flashcards
Plasma
- Consists of organic and inorganic substances dissolved in water
- Proteins:
- Albumin
- Globulins
- Fibrinogen
- Electrolytes & nutrients:
- Glucose
- Amino acids
- Vitamins
- Waste:
- Urea
- Bilirubin
- Creatine
- Oxygen and carbon dioxide
- Hormones
- Increase secretion of Na and H2O
- Decrease cardiac output
Diuretics
Reduce cardiac output
Beta-adrenergic receptor blockers
Reduce entry of Ca in vascular smooth muscle = weaker contractions = lower peripheral resistance
Calcium channel blockers
Prevents formation of vasoconstrictor, allowing vasodilation, lowering peripheral resistance
Angiotensin-converting enzyme (ACE) inhibitor
Renin-Angiotensin System
- Renin reacts with angiotensinogen to form angiotensin I
- ACE converts angiotensin I into angiotensin II
Affects of angiotensin:
- Vasoconstriction
- Na+ and H2O retention
Stimulates Na+ reabsorption by kidney tubules
Aldosterone
- Produced by cardiac cells
- Inhibit sodium reabsorption
- Acts on renal blood vessels to increase filtration rate causing sodium excretion
- Inhibits action of aldosterone
Atrial Natriuretic Peptide (ANP)
- EPO - erythrocytes
- Colony-stimulating factor (CSF) - granulocytes, monocytes
- Stem cell factor - various
Haematopoietic Growth Factors (HGF)
Within hours of blood loss
- Interstitial fluid into capillaries to increase plasma volume
- Increase in thirst
- Decrease in salt and water excretion
- Mediated by:
* Renin
* Angiotensin
* Aldosterone
Within days of blood loss
- Replacement of cells
* Erythropoiesis
* Haematopoiesis
Decrease in ability of blood to carry oxygen
- Decrease in number of RBCs
- Low haemoglobin
Anaemia
Causes of anaemia
- Dietary
- Bone marrow failure
- Blood loss
- Inadequate EPO
- Excessive destruction
Haemostasis
- When a blood vessel is severed, the response is to constrict:
- Slow blood flow to the area
- Presses endothelial surfaces together, inducing a ‘stickiness’
