MODULE 1 - BLOOD, ETC. Flashcards
What is the composition of blood
- plasma (55%)
* formed elements (45%)
What is the composition of plasma
- water (90%)
* proteins (10%)
Identify the formed elements of blood
- Red blood cells (RBCs; erythrocytes)
- White blood cells (WBCs; leukocytes)
- Platelets
Which is the most abundant formed element
erythrocytes
State the main function of each of the formed elements
- RBCs - transport oxygen
- WBCs - immunity
- Platelets - clotting
Explain in general terms the production of formed elements (hematopoeisis)
through a sequence of divisions and differentiations stem cells produce the various formed elements in the red bone marrow
Describe clotting process and explain why clots are red
Step 1: platelets clump at the site of the punctured vessel and partially seal the hole
Step 2: proteins are produced which form long threads of fibrin
Step 3: fibrin threads wind around the clump of platelets completing the seal
Trapped red blood cells give clots their red colour
What is the myocardium
- middle layer of the heart
* the heart’s muscle
Identify and distinguish between the 2 chambers of the heart
- atria
- receiving chambers - receive blood from veins
- thinner walls - ventricles
- lower set
- pumping chambers
- ventricular myocardium is thicker than that of the atria because of the force required to pump blood a larger distance
Around which of those pairs is the myocardium thicker?
ventricles
Which of the ventricles has the thickest wall?
left ventricle because it pumps blood throughout the whole body
Trace the flow of blood and list all the vessels involved
Vena cava Right atrium Right ventricle Pulmonary arteries Lungs Pulmonary veins Left atrium Left ventricle Aorta
Identify the 3 categories of blood vessels and their function.
- arteries - carry blood away from the heart
- veins - carry blood towards the heart
- capillaries - sites of material exchange
Distinguish between the 3 categories of blood vessels
- Arteries: composed of 3 layers, middle layer is smooth muscle
- Veins: same 3 layers as arteries but with less smooth muscle
- Capillaries: simple epithelium, single layer of cells
List the 4 major structures of the conduction system of the heart:
- sinoatrial (SA) node, or pacemaker
- atrioventricula (AV) node
- AV bundle
- Purkinje system
Which structure of the heart’s conduction system initiates the signal
SA node or pacemaker
Identify the 5 phases of the heart phase/cardiac cycle.
- Atrial systole
- Isovolumetric ventricular contraction
- Ejection
- Isovolumentric ventricular relaxation
- Passive ventricular filling
What is a normal resting adult heart rate?
60 - 80 bpm
What is an electrocardiogram?
records hearts electrical activity
Which phase of the cardiac cycle does the first heart beat appear?
Isovolumetric Ventricular Contraction
What is believed to be responsible for the sound of the heartbeat?
2 sets of valves closing
What does the Primary Principle of Circulation state?
Blood flows in response to pressure gradients
What are the 2 factors that affect arterial blood pressure?
- blood volume
2. resistance to flow/peripheral resistance
What is the average person’s blood volume?
5 L
