Heart

How can you use ECG to measure heart rate?

see how often the contraction cycle happens

Why does the heart need coronary circulation? Name main coronary vessels.

so nutrients can be absorbed by all heart layers main coronary vessels- right and left coronary artery and vein, coronary sinus

Define systole and diastole.

systole- contraction diastole- relaxation

Explain the terms: · Mediastinum · pericardial cavity · visceral and parietal pericardium · pericardial fluid

1) anatomical region that extends from the sternum to the vertebral column, from first rib to diaphragm, and between lungs. hold the heart 2) membrane around the heart 3) 2 layers of the pericardium around the heart 4) fluid in the pericardial cavity (space between serous pericardial layers) to reduce friction

Explain how ECG works and in a standard ECG (lead II) describe what each of the following means: • P-wave • QRS-complex • T-wave • P-Q interval • S-T segment • Q-T interval

1) atrial depolarization 2) rapid ventricular depolarization 3) ventricular repolarization 4) conduction time of beginning atrial excitation to ventricular excitation 5) depolarized contractile fibers in plateau phase in ventricle 6) beginning of ventricular depolarization to end of ventricular repolarization

Explain the locations and functions of the following heart structures: • bicuspid valve • tricuspid valve • mitral valve • pulmonary semilunar valve • aortic semilunar valve • chordae tendineae • papillary muscles • fossa ovalis • coronary arteries • aorta

1) between the left atrium and ventricle. control blood flow to the left atrium 2) between the right heart chambers. control blood flow to the right ventricle 3) bicuspid valve 4) at entrance to pulmonary trunk (right ventricle). control blood flow to the pulmonary trunk 5) at entrance to aorta (left ventricle). control blood flow to the aorta 6) fibrous cords connecting the atrioventricular(AV) valves to the papillary muscles 7) in ventricles attached to chordae tendineae. open AV valves 8) in right atrium. remnant to foramen ovalis (opening in interventricular septum in the fetal heart) 9) a branch of aorta the circles the heart like a crown. propel blood into capillaries of the heart 10) connect to left ventricle. send blood to the body

How does each of the following hormones affect the functions of heart and blood pressure: • ADH • ANP • Epinephrine • angiotensin II • aldosterone

1) increase blood volume, CO and arterial pressure 2) lower BP 3) enhance heart's pumping effectiveness 4) increase BP by vasoconstriction 5) increase BP and BV

Describe the following stages of heart cycle and indicate which heart valves are open and which are closed during each: • isovolumetric contraction • ejection • isovolumetric relaxation • ventricular filling

1) none open. cardiac muscles contract, but no blood leaves the heart yet. same volume, increased pressure 2) SL valves open. blood leaves due to high pressure opening SL valves 3) none open. cardiac muscles relax with no blood leaving or entering 4) AV valves open. Atrial contract to push blood into the ventricles

Define cardiac output (CO), stroke volume (SV) and heart rate (HR). What are the average numerical values of these parameters in a healthy adult?

CO- volume of blood ejected from the ventricle to the aorta each minute (5.25L/min) SV- volume of blood ejected by the ventricle in each contraction (70mL/beat) HR- heartbeats per minute (75bpm)

Give examples of the most common cardiovascular system diseases and the risk factors for getting them.

Coronary artery disease- plaque in coronary arteries. smoking diabetes, high BP and cholesterol obesity cause it Arteriosclerosis- thickening of artery walls and lost elasticity. high cholesterol causes this Congenital heart disease- defects in heart before birth. teratogens cause this Arrhythmias- abnormal heart rhythm

Describe action potential in cardiomyocyte: which ions are involved in each phase?

Depolarization- voltage gated Na+ channels open to allow Na+ out Plateau- slow voltage gated Ca2+ channels let Ca2+ in. then voltage gated K+ channels open to let K+ leave, causing a plateau Repolarization- more voltage gated K+ channels open, calcium channel closes.

Name 3 layers of the heart wall and describe which tissues each is made from.

Epicardium- made of 2 layers (visceral has mesothelium, second has fibroelastic and adipose tissue) Myocardium- thickest with cardiac muscle tissue wrapped in connective tissue Endocardium- thin layer of connective tissue

Describe the flow of blood through pulmonary and systemic circuits - name all the heart chambers and large blood vessels connected to the heart in proper order.

Pulmonary- Blood enters the heart from the inferior and superior vena cava to the right atrium. Blood goes through the tricuspid valve to the right ventricle. the blood is pushed through the pulmonary valve to the pulmonary trunk to the lungs. oxygenated blood comes to the heart through pulmonary veins to the left atrium. Systemic- Then blood is pushed through the bicuspid valve to the left ventricle. Blood is pushed through the aortic valve to the aorta. blood leaves the aorta to the arteries of the body. The enter the capillaries to become deoxygenated and travel into veins back to the heart. The blood enters the heart from the inferior and superior vena cava to the right atrium.

What causes the heart sound S1? What about S2? What are "heart murmurs" - are they dangerous?

S1- closing AV valves "lub" S2- closing SL valves "dub" heart murmurs- abnormal heart sounds due to valve problems. Not usually dangerous

Which part of the conductive system is considered to be the heart's "natural pacemaker"?

Sinoatrial (SA) node

Describe the effects of sympathetic and parasympathetic systems on heart activity.

Symp- increase HR and stroke volume Para- decrease heart rate

Define tachycardia, bradycardia and arrhythmia.

Tachy- rapid heart rate (> 100bpm) Brady- slow heart rate (< 50bpm) Arrhy- irregular heart rhythm

Which cranial nerves innervate the heart and which neurotransmitter do they release? Are they somatic, sympathetic or parasympathetic?

Vagus (X) nerve with acetylcholine. parasympathetic

What would happen to resting heart rate if vagus nerves are cut? What about sympathetic nerves?

Vagus- heart rate increases symp- heart wont stop

Describe the function of intercalated discs. Why are they important for heart muscle function?

allow action potentials to travel from cell to cell why- so cardiac muscles will be in sync when beating

What is the function of chordae tendineae and which heart valves have them attached? Give all possible names for these valves.

connect papillary muscles to atrioventricular valves (tricuspid, bicuspid (mitral))

Compare skeletal and cardiac muscle: which organelles/structures are more developed and less developed in each?

cardiac can activate themselves, have branches, and intercalated discs connecting them so action potentials can travel from one muscle to another. skeletal is just voluntary

What is the main difference in action potential between skeletal muscle cell and cardiomyocyte?

cardio myocyte has a plateau phase while skeletal doesn't

How would stimulation of the vagus nerves affect the heart function?

cause the heart to slow down

What is cardiac reserve?

difference between resting and maximal CO

Explain what can happen as a result of failure of various parts of the heart conductive system.

if SA node fails, AV node will take over (50bpm) if SA and AV node fail, bundle of his and purkinje fibers take over, but slower (20-30 bpm)

Where are the cardiovascular control centers located in the CNS?

medulla oblongota

What is the function of fibrous skeleton of the heart?

prevent overstretching of the valves

Explain the function of conductive system of the heart, make a diagram and name all its parts in order. Draw arrows to indicate the direction in which excitation spreads in a healthy conductive system.

provide the path for each cardiac cycle and keeps things in order

What is fibrillation and why can it be life-threatening?

the decreased heart output can cause tissues to be deprived of nutrients and the heart to stop

What is different in coronary arteries' function compared to other arteries in the body?

the send blood back to the heart to supply nutrients instead of away

What is the meaning of the term "functional syncytium"?

the wave of contraction that allows the heart to work as a unit