Heart Stuff Flashcards
Pressure in the right atrium during the cardiac cycle
0-4mmHg
Pressure in the right ventricle during the cardiac cycle
25 Systolic and 4 Diastolic
Pressure in the Pulmonary Artery during the cardiac cycle
25 Systolic and 10 Diastolic
Pressure in the left atrium during the cardiac cycle
8-10 mmHg
Pressure in the left ventricle during the cardiac cycle
120 systolic and 10 diastolic
Pressure in the aorta during the cardiac cycle
120 systolic and 80 diastolic
Chronotropic effects
Heart Rate
Inotropic Effects
Strength of contraction
Dromotropic
Conduction Velocity
Parasymapthetic and blood vessels
Causes vasodilation ; acetylcholine
Frank starling law
More blood in , more blood out. More blood in ventricles stronger contraction
Sympathetic and blood vessels
Vasoconstriction ; epi and Norepinephrine
Baroreceptors
Carotid sinus, aortic sinus, right atrium
What is a baroreceptor?
Receptors relay info from blood pressure
What are the three phases of blood clotting?
Vascular spasm, platelet plug, coagulation phase
In the first phase of blood clotting what does smooth muscle do to limit bleeding
Vasoconstriction
What fibres are exposed when the blood vessel wall is damaged
Collagen fibres
What happens to collagen fibres when they are exposed
Platelets stick to them within 30-60 seconds. These platelets then release a prothrombin activator then prothrombin activates then thrombin then fibrinogen then fibrin
What does thrombin do
It’s like a molecular scissor that cuts fibrinogen into fibrin
What’s fibrins job
To reinforce the clot as the remodelling occurs to heal the damaged wall
Where are platelets formed ? Where are prothrombin formed?
Platelets = bone marrow prothrombin=liver
What part of the second phase requires vitamin k for its production
Prothrombin
How many litres of blood in the typical human
5 liters
Red blood cells
45% of blood , erythrocytes, derived from stem cells in bone marrow. Travels far in body until being replaced 120 days later.
White blood cells
Leukocytes, primary role defense
Platelets
Contain enzymes important in clotting. Clump together and stick to damaged walls. Continuously replaced circulates 9-12 days until being removed by the spleen
Hemostasis
- Vascular spasm 2. Platelet plug formation 3. Coagulation (blood clotting)
Von willebrand factor (vwf)
Helps platelets adhere to damaged blood vessels. Carries clotting protein VIII
Serotonin
Enhances vascular spasm
Adenosine diphosphate (ADP)
Attracts more platelets to the site
Thromboxane A2
ASA works here. Enhances spasm and attracts more platelets to the site
Platelet plug formation
Takes 60 seconds. Very lose build up until fibrin arrives to reinforce
Two pathways to prothrombin activator
Intrinsic (slower) and extrinsic (faster). Both pathways lead to Factor X
Fibrinolysis
Removes uneeded clots when healing has occurred
Drugs that effect blood clotting mechanisms
- Anti coagulants , 2. Platelet inhibitors , 3. Thrombolytics
% of red blood cells vs plasma
55% plasma , 45% red blood cells
Lub Dub
Lub = S1 AV valves close Dub= S2 semi lunar valves close
Ejection Fraction
% of blood pumped out of each ventricle with contraction
How long is systole and diastolic
Systole = 0.1 second Diastolic = 0.7 sec
EDV end diastolic volume
Amount of blood in ventricle during diastole
ESV End systolic volume
Amount of blood remaining in ventricle after contraction
ESV End systolic volume
Amount of blood remaining in ventricle after contraction
