Lecture 4/5: Hemodynamics & Blood Flashcards
Blood pressure is defined as what?
Pressure/force exerted by the blood on the walls of a vessel. It is mostly generated by ventricular contraction
What are two ways blood pressure can be altered?
- If blood volume decreases by >10%, BP drops.
- Water retention increases BP.
What is pulse pressure?
The difference/space between systolic and diastolic pressure.
What is mean arterial blood pressure?
Average pressure during entire cardiac cycle
Name six pulse points on the body.
Common carotid, brachial, radial/ulnar, femoral, popliteal, dorsalis pedis
Name three factors that affect BP.
Cardiac output (HR,SV). Blood volume (loss, water retention), peripheral vascular resistance
What is vascular resistance?
Friction between blood and the vessel walls
Give examples of the two forces that regulate BP.
Neural: baroreceptor reflexes, chemoreceptor reflexes.
Hormonal: Epi/norep, ADH
How does ADH (vasopressin) regulate BP?
Released from post. pituitary in response to dehydration. It causes renal water retention and systemic vasoconstriction.
How does ANP (atrial natriuretic peptide) regulate BP?
Released from cells in right atrium in response to atrial distension/stretch. Causes renal loss of salt and water and systemic vasodilation.
What are the 5 factors that determine oxygen delivery?
BP, systemic vascular resistance, cardiac output, stroke volume, oxygen content
What 5 factors increase oxygen demand?
Increased BMR, infection/fever, increased work of organs, agitation/pain, increased workload
What is the definition of shock?
Failure of cardiovascular system to deliver enough oxygen & nutrients. Lactic acid builds up, cells/tissues die.
What are the 4 types of shock? Describe briefly.
Cardiogenic = inability of heart to pump effectively.
Obstructive = impaired blood flow.
Hypovolemic = reduction in blood volume
Distributive = profound vasodilation
What are the three compensation mechanisms of shock?
Neural response, hormonal response, chemical response
What does “maintain MABP” mean?
Maintain mean arterial blood pressure
What are the three short-term effects of hormonal regulation of BP by catecholamines?
Increases HR/contraction, vasoconstriction of skin and abdominal organs, vasodilation of cardiac & skeletal muscle
What does angiotensin II do?
Constricts vessels, causes aldosterone secretion
Which hormones/peptides work agonistically?
ANP and ADH.
What are parts of a Complete Blood Count (CBC) blood test?
RBC count, hemoglobin, hematocrit (packed cell volume), WBC count, platelets, morphology
What are the three different types of a blood sample?
Venipuncture, finger/heel stick, arterial stick
What 3 structures do erythrocytes lack?
Nucleus, DNA, mitochondria
The hemoglobin molecule is comprised of ___ and ____ chains, and an ___-_____ _______ ____. What does it carry?
Alpha, beta, iron-containing heme group. Carries oxygen.
Where are RBCs produced? Where are they broken down?
Produced in red bone marrow, live for 120 days, broken down in spleen and liver.
