Muscles And The Heart Flashcards
What constrictors do endothelial cells release ?
Endothelin
Thromboxane
What are the functions of endothelial cells ?
Blood vessel control
Prevent platelet aggregation and blood clot formation
Angiogenesis and vessel remodelling
Permeable barrier for nutrients and fluid between plasma and interstitial fluid
What dilators do endothelial cells release ?
Nitric oxide
Prostacyclin
What is normal blood pressure ?
120/80 ( systole / diastole )
How do you work out mean arterial pressure ?
Diastolic bp + 1/3 pulse pressure
What is cardiac output equal to ?
Stroke volume * heart rate
In an ecg : what does the p wave equal ?
Atrial depolarisation
What does the QRS complex equal ?
Ventricular depolarisation
What does the t wave equal ?
Ventricular re polarisation
What does the p-r interval represent ?
Delay through the av node
What does the s-t interval represent
Plateau phase of a.p
What is positive inotrophy
Increases force of contraction
What is positive choronotrophy
Increases heart rate
Positive lusitrophy ?
Increase speed of relaxation
What is positive dromotrophy
Increases speed of conduction
What is MABP ?
Mean arterial blood pressure - cardiac output * total peripheral resistance
Where are baroreceptors
What do they respond to ?
Carotid sinus and aortic arch
Respond to stretching pressure change
When do the lungs develop ?
32 weeks
In foetus what diverts blood away from the lungs via the pulmonary vein
To aorta via ductus arteriosus
What does the ductus venousus do ?
Diverted umbilical vein blood from the vena cava
What does the foramen ovale do ?
What does it become after birth
Hole between atria prevents blood going to lungs
Becomes fossa ovalis
What can cause infective endocarditis
Strep. Viridans
Staph. Aureus
What factors control blood flow ?
Length of tube
Viscosity of liquid
Pressure gradient
Cross sectional area of the tube
What is the poiseuille equation ?
Blood flow (q) = (
What do we have to assume when using the equation
- flow is laminar
- flow is non pulsated
- flow is straight through uniformed tube
What percentage of blood plasma is albumins ?
60%
What percentage is globulins ?
35%
What percentage is fibrinogen ?
4% (key component of blood clot)
What percentage are regulatory proteins ?
1%
What percentage of blood is cells ?
55%
What percentage of blood is plasma ?
45%
Where is red bone marrow found ?
Skull (vault)
Top/bottom ends of long bones e.g femur
Pelvis
What is the life span of a red blood cell ?
120 days
What are old red blood cells removed by ?
MP system
Mononuclearphagocyte system
What are rbc broken down into ?
Protein - amino acid pool
Haem - iron - biliverdin - bilirubin - excreted as bile pigment
What is required for erythropoiesis to occur successfully ?
Folic acid and vitamin b 12 iron
What regulates rbc formation?
Erythropoietin
What is the rbc on day 1
Proerythroblast
Day 2 ?
Basophillic erythroblast
Day 3
Polychromatophillic erythroblast
Day 4?
Normoblast - ejection of nucleus
Day 5-7 ?
Reticulocyte
Enters circulation
What percentage of wbc are neutrophils ?
What are they associated with ?
What do they look like ?
50-70%
Acute inflammation, phagocytic non specific defense
Multi-nucleated 2x rbc size
What percentage are basophils ?
What are they associated with ?
What do they look like ?
1%
Circulating masts cells produce histamine / heparin
Dark mass 3x rbc
What percentage are eosinophils ?
What are they associated with ?
What do they look like ?
2-4%
Involved in allergic reactions and defence against parasites
Bilobed nucleus
3x size
Which cells are granulocytes?
Neutrophils
Basophils
Eosinophils
Which cells are agranulocytes?
Monocytes
Lymphocytes
What percentage of cells are monocytes ?
What are they associated with?
What do they look like ?
2-8%
Become macrophages, antigen presenting cells
Dark bilobed nucleus
Much bigger
What percentage are lymphocytes ?
What are they associated with ?
What do they look like ?
25-30%
Cell mediated immunity (t)
Humoural immunity ( antibody producing B cells )
Large dark nucleus - fills most of space
What are platelets derived from ?
Megakarocytes
What are the roles of platelets
Involved in haemostasis Release vasoconstrictors Form platelet plug Source of phospholipid for coagulation Normal amount is 150-400x10^9 per litre
Which blood groups are most common ?
Which is the rarest
A and O
AB
Which is the most common rhesus
RH +
Which blood group is the universal donor ?
Blood group O-
Which blood group is universal recipient ?
Group AB
What vessels form the superior vena cava
L and R Brachiocephalic veins
Why may bp increase in lungs
May be a superior vena cava obstruction
How many valvules in aortic valves
3
Where are the aortic sinuses
What arises close to them
Just above aortic valve
Coronary arteries
Where does blood enter right atria
Via superior and inferior vena cava
Deoxygenated
Where does blood enter the left atria
Left and right pulmonary veins
Oxygenated
