what does blood pressure represent? what do the numbers mean?
Blood pressure is the pressure exerted by circulating blood on the walls of blood vessels (arteries).
Systolic BP represents the pressure as your heart beats and pushes blood through the blood vessels (contraction)
Diastolic BP is the pressure when the vessels are relaxed when the heart rests between beats.
Lack of blood supply to the brain results in a ______.
what happens to the heart muscle upon "myocardial infraction"?
During a myocardial infraction the blood supply and O2 supply to a part of the heart is interrupted. Usually caused by an occlusion (blockage) of a coronary artery which can by caused by an atherosclerotic plaque detachment which will result in Ischemia (restriction of blood supply) and eventually the shortage of O2 will cause death of myocites.
What is normal blood pressure? What is hypotension and hypertension?
Normal BP= 120/80
Hypotension= low blood pressure = < 90/60
Hypertension= high blood pressure= > 140/90
How can one lower BP ??
- stop smoking
- reduce weight
- lower salt
- sufficient rest
- low protein
- no cafeine
what is arteriosclerosis? what can it cause?
Arteriosclerosis is the hardening of arteries which can be caused by hypertension (high blood pressure) and can lead to collection of lipids + macrophades in the walls of arteries causing plaque.
What happens in Ischemia?
Ischemia restricts the blood supply to a part of the heart. The myocardial cells that die first are the ones part of the myocardium that is most distal to the arterial blood supply, The ENDOCARDIUM cells (the farthest away first). the area of myocardial cell death spreads with time extending from the endocardium to the myocardium and then the epicardium
How can you tell by looking at the tissue that the myocardial cells are dead or dying?
- loss of striations
- loss of branchng patterns
- loss of nuclei
- infiltration of neutrophils
- Na/K membrane gated channels are degraded --> edema
- Na : depolarized
- K: repolarized
What are the names of the heart coverings?
Pericardium: fluid filled sac providing protection against friction
Epicardium: outer layer of heart wall (visceral layer)
Myocardium (muscle itself): muscle tissue of heart
Endocardium: inner layer of heart wall
What are the chambers of the heart? what do they do?
- Left and Right Atria: 2 superior chambers of the heart, receive the blood
- Left and Right Ventricles: 2 lower chambers of the heart, pump blood up into the aorta or pulmonary arteries
What are the valves of the heart? where are they located? what is their function?
The valves are mechanical devices that permit the flow of blood in one direction only (prevent backflow)
- Atrioventricular: between the atria and the ventricle - (Right AV = tricuspid valve, Left AV= bicuspid or mitral valve)
- Semilunar valve: half-moon shaped flaps growing out from the lining of the pulmonary artery and the aorta. - ( Pulmoary semilunar valve = in the pulmonary trunk, Aortic semilunar valve = in the aorta)
What can be found only in the right ventricle and not in the left ventricle? what is its function?
the Trabeculae septomarginalis, it carries part of the right branch of atrioventricular bundle (bundle of His) from the septum to anterior papillary muscles.
How does the heart supply itself with blood?
The heart is supplied with blood by ways of the right and left coronary arteries which fill from the aorta when the ventricle relaxes. Both arteries originate from the aortic sinus:
1. Right coronary artery - (supplies blood to the RA & RV)
2. Left coronary artery- splits into:
a) circumflex artery (coronary groove)
b) anterior interventicular branch (paraconal in pig) (paracoronal interventicular groove)
The blood is then returned to the right atrium via the coronary sinus and the great cardiac vein.
what are the parts of the conduction system of the heart? where are they located?
sinoatrial node or Pacemaker: autorythmic cells located in right atrial wall near the superior vena cava
atriventicular node: located in right atrium along the lower part of the interatrial septum
atrioventricular bundle (bundle of his) & Purkinje fibers: originating in AV node extend down septum, become purkinje fibers at lateral walls of ventricles and papillary muscles
which are the only vessels in the body that fill when the heart is in diastole?
the coronary arteries
Where are the sympathetic and parasympatic control fibers of the heart located? what do they do?
Sympathetic: increases heart rate
- segments T2, T3, T4 of the spinal cord
-distributed through the middle cervical and cervico-thoracic (stellate) ganglia
-1st four ganglia of the thoracic sympathetic chain
Parasympathetic: decreases heart rate
- vagus (cranial nerve 10)
what is an ECG? what does it record?
ECG or electrocardiogram records the heart's electrical activity (conduction impulse)
What are the stages of the ECG graph? what do they represent?
- P wave: depolarization of the atrial walls
- PR interval: delay of AV node to allow filling of ventricles- atrial walls are completely depolarized
- QRS complex: atria repolarize and venticular walls depolarize
- ST segment: atrial walls are repolarized, venticular walls are depolarized
- T wave: venticular repolarization
When are the semilunar valves and atrioventricular valves open and closed?
semilunar valves are closed during P wave up to just after S and opens between S and end of T wave and then is closed again.
AV valves are open up until R (peak) and then close until after T wave at which point they open.
What are the sounds the heart makes? what do they represent?
LUB= closing of the AV valves and opening of the Semilunar valves
DUP= closing of the Semilunar valves and opening of the AV valves
Which parts of a ECG represent diastole and systole?
DIASTOLE: between one T wave and S = DUP--> LUB
SYSTOLE: between S and T = LUB--> DUP
what kind of muscles are found in the auricles ?
What is the structure shown in this picture (in right ventricle)? what is its function?
Function: allows electrical signals to pass from the septum to the lateral wall faster.
Describe Systemic Blood Circulation.
Starts at S/I vena cava >RA>RAV (tricuspid)>RV>PSV>PT>left and right pulmonary arteries> to the lungs > CO2--> O2 exchange> PV>LA>LAV (mitral/bicuspid)>ASV>aorta> to the body + into left and right coronary arteries
What two blood vessels experience reverse blood flow?
Pulmonary artery/Trunk : carries deoxygenated blood to the lungs
Pulmonary Vein: carries oxygenated blood from the lungs
Normally ateries carry oxygenated blood and veins carry deoxygenated blood.
How do trabeculae carnae relate to pectinate muscles? where are these structures located?
trabeculae carneae are larger and thicker than pectinate muscles
trabeculae carneae - in ventricles
pectinate muscles - in atria
what is the order of conduction starting from the SA node?
SA node--> AV node-->AV bundle (bundle of His)-->perkinje fibers--> ventricle wall