Lab exam 1 Flashcards
labs 2 to 5
What are the components of whole blood?
Plasma (55%)
Buffy coat (<1%)
Erythrocytes (45%)
What is considered formed elements in whole blood composition?
The buffy coat and erythrocytes
How is the composition of whole blood found?
Blood is withdrawn and placed in a tube
It is centrifuged and then analyzed
What is hematocrit?
The percentage of red blood cell out of the total blood volume
What type of tube is used in blood centrifugation?
Capillary tube (microhematocrit tube)
What does PCV stand for?
Packed cell volume
How is hematocrit calculated?
Volume of packed red blood cells (PCV) divided by total volume of the blood sample
What is the hematocrit normal value for men and women?
Male: 41-53%
Female 36-46%
What are the normal hemoglobin values for men and women?
Men: 13.5 to 16.5 g/dl
Women:15.1 to 21.2 g/dl
What are the five types of leukocytes?
Neutrophils, eosinophils, basophils, lymphocytes, monocytes
What are platelets, and how do they function?
Fragments of megakaryocytes, they function by forming temporary plug to help seal blood vessel breaks
A blood group type AB has what antigen and plasma antibodies?
Antigens: A and B
Antibodies: none
A blood group type B has what antigen and plasma antibodies?
Antigen: B
Antibodies: A
A blood group type A has what antigen and plasma antibodies?
Antigen: A
Antibodies: B
A blood group type O has what antigen and plasma antibodies?
Antigen: none
Antibodies: A and B
In blood typing, if the addition of Anti-A indicated agglutination, what does that signify?
In a positive result, the blood type is A
What is an Rh factor?
A type of protein on the outside of a red blood cell
What does the presence of D Rh antigen mean?
They are Rh D positive or Rh-positive
Why do men have higher packed cell volume than women?
Because their body mass is heavier and they produce more testosterone
What is the schematic that relates hypoxia and the EPO production?
Exercise
Decrease in oxygen levels
Decrease in ATP
Increase in lactic acid
Kidneys
Medulla and Cortex
Peritubular Fibroblasts
Hypoxia
Inducible Factor
EPO Gene
EPO
Bone Marrow
Increase in Erythropoiesis
Negative feedback
Explain the coagulation pathway
Prothrombin
- needed for:
Prothrombin = Thrombin
Thrombin is needed for
Fibrinogen = Fibrin
Why can tumors cause anemia?
They interfere with the body’s ability to absorb nutrients and fats
They increase tissue metabolic demands, tumors demand a high metabolic rate which affects nutrient levels
What does “pro” and “ogen” mean in the coagulation pathway?
“Pro” means the protein is its inactive precursor form (ex: thrombin and prothrombin)
“ogen” means to form or produce active form (fibrin and fibrinogen)
How can we tell someone has leukemia?
There would be an increase in immature/abnormal white blood cells
What are three things that could be deciphered by looking at a tube of centrifuged blood?
Plasma, Buffy Coat and Erythrocytes
How does the body respond to squatting down?
The venous return increases = stroke volume increases = pressure increases
How does the body respond to standing up?
The venous return decreases (gravity) = stroke volume decreases = pressure decreases
Define blood pressure
The force exerted by circulating blood on the walls of blood vessels
Define cardiac output (CO)
The volume of blood the heart pumps per minute
Define Systemic Vascular Resistance (SVR)
The resistance offered by the systemic blood vessels to blood flow
Define heart rate (HR)
The number of heart beats per minute
Define stroke volume (SV)
The amount of blood pumped by the left ventricle of the heart in one contraction (pumps to the whole body)
Why does the venous return increase when squatting down?
There is less of an effect from gravity, the position causes the vein to be compressed
How does the HR usually respond to the squatting down?
It will decrease a little to keep BP stable. Since a lot of things are in play, it does not necessarily go up
What determines blood pressure?
The heart rate
The amount of blood pumped per beat (stroke volume)
The resistance of the arterial system
What are baroreceptors?
They are special sensors in tissues in the aortic arch and carotid arteries. They influence the heart rate
What is orthostatic hypotension?
A type of low blood pressure when happens when standing up
If someone takes meds to impair the ability of the heart to increase its rate, what activities could cause dizziness?
Standing up quickly or coughing (since the heart rate can’t increase)
How to evaluate someone for blood loss?
The heart rate will increase
Blood loss = stroke volume decreases = cardiac output decreases = heart rate increases to keep BP stable
What happens when coughing?
Increase of intrathoracic pressure
right side of the heart has some resistance
compression of heart and vessels
resistance causes decrease in CO
Body increases HR to keep BP stable
Why do astronauts experience orthostatic hypotension and dizziness on return to Earth?
In space, the effects of gravity are diminished. BP is affected, HR and SVR decreases
Their body adjusts by reducing the amount of water retained in the vessels, reducing the BP
Would a heart recipient heart rate change with coughing or severe fright?
Since the sympathetic and parasympathetic pathways are severed, the heart does not have autonomic nervous control. The endocrine system is not disturbed, so stress hormones (cortisol or adrenaline) will still cause an increase in HR
How could such medication be used to determine which of these systems is responsible for heart rate?
If HR decreases (sympathetic blocker) then the SNS (makes HR increase) was responsible for the increased HR
If HR increases (parasympathetic blockers) then PSN (make HR decrease) was responsible for the decrease of HR
What happens when the hand is submerged in cold water?
Activation of skin thermoreceptors
Sensory signals to central nervous system
Sympathetic nervous system activated
Release chemicals (noradrenaline)
Peripheral vasoconstriction
Increase peripheral vascular resistance
Blood pressure increases
What are some derived consequences of the hand in cold water?
Cold stimulus = increased catecholamines
Direct stimulation of the heart (SA node)
Increased heart rate
Increased blood pressure sensed by baroreceptors = usually slow HR but sympathetic effect overrides
When is the physiological response faster?
When putting the hand in the cold water:
The HR rises due to the immediate sympathetic reaction
Why is the physiological response time of the recovery longer?
It is more gradual because it involves the removal of the stressor, clearance of catecholamines and re-balancing of the autonomic nervous system
What happens when you dive?
Rapid decrease in heart rate (conserve oxygen)
Peripheral vasoconstriction is stimulated via SNS = increases peripheral resistance = rise in blood pressure
What is vasovagal syncope?
A condition where the body’s nervous system responds to a trigger by activating PNS instead of the SNS.
Causes sudden drop in BP and HR, reduced blood flow to brain = fainting
Lub is caused by which event?
Closure of atrioventricular valves at the start of ventricular systole
Dub is caused by which event?
Closure of semilunar valves at the beginning of ventricular diastole
During which 2 periods are all the valves closed?
Isovolumetric contraction and isovolumetric relaxation
Most of the blood going to the ventricles are due to passive filling, how can that be?
During ventricular diastole, pressure in the atria is slightly higher than the pressure in the ventricle, so blood flows from atria to ventricle
Where in the graph does passive filling occur?
Between rapid inflow and diastasis
What does a third heart sound indicate?
Heart failure
When does the aortic valve open?
When the pressure in the ventricle is higher than the pressure in the aorta
When does the AV valve open?
When the pressure in the atria is higher than the pressure in the ventricle
Does the atria provide a lot of blood to the ventricles during atrial systole
No
Why would an ECG have a negative deflection?
Because the electrical vector travels away from the exploring electrode (when the exploring electrode is placed on the right)
How would a BRADYCARDIA EKG look like?
Long intervals between each beat
TACHYCARDIA
More than 100 beats per minute, the P wave is hiding in the T wave
JUNCTIONAL RHYTHM
P-wave is weird (missing, upside down, after QRS complex)
PREMATURE VENTRICULAR COMPLEX (PVC)
QRS complex: wide and unusual looking
P-Wave : not there before PVC
+ pause after the PVC
2ND DEGREE BLOC TYPE 1 (MOBITTZ 1 OR WENCKEBACH)
PR interval : gets longer until QRS is skipped
P-Wave: present no matter what
2ND DEGREE BLOCK TYPE 2 (MOBITZ 2)
PR interval: stays the same until QRS is skipped
P-Wave: present no matter what
QRS Complex: wider
3RD DEGREE BLOCK (COMPLETE HEART BLOCK)
Atrial and Ventricular Rate: separate from each other
P-wave: present no matter what
QRS Complex: narrow or wide
ATRIAL FIBRILLATION
Rhythm is irregular
P-Wave is absent instead fibrillatory waves
QRS Complex: normal but irregular timing
