Functions Of The Heart Flashcards
The heart is located in the thoracic cavity between the lungs. What is this area called?
Mediastinum
What cavity is the heart located?
Thoracic
What membrane encloses the heart?
Pericardial
What are the 3 layers of the pericardial membrane?
Fibrous pericardium
Parietal pericardium
Visceral pericardium
Which pericardium membrane is the outermost?
Fibrous
Which pericardium layer lines the fibrous pericardium
Parietal
Which pericardial later is on the surface of the heart muscle?
Visceral
What is the other name for visceral pericardium
Epicardium
What lies beneath the parietal and visceral areas that prevents friction when the heart beats
Serous fluid
What is cardiac muscle called
Myocardium
What are the unit of contraction and contain the proteins myosin actin and troponin
Sarcomeres
What lines the chambers of the heart
Endocardium (simple squamous epithelium)
The lining of the vessels
Endothelium
What important physical characteristic does the endocardium have
Smoothness
What does the smoothness of the endocardium prevent
Blood clots
What are the 2 upper chambers of the heart
Atria
What are the 2 Lower chambers of the heart
Ventricles
Which walls of the heart are thinner
Atria
What wall separates the atria
Interatrial septum (made of myocardium)
What wall separates the ventricles
Interventricular septum
Which wall receive blood
Which walls pump blood
Atria
Ventricles
What veins return blood from the body to the right atrium
Cabal veins
What carries blood from the upper body
What carries blood from the lower body
Superior vena cave
Inferior
What valve will blood flow thru from the right atrium into the right ventricle
Right atrioventricular valve (tricuspid)
From where does the left atrium receive blood
By way of what veins
Lungs
Pulmonary
What valve does the blood flow through from the left atrium to the left ventricle
Left atrioventricular valve (bicuspid)
Hat hormone does the atrium produce for BP maintenance
Atrial natriuretic peptide ANP
What valve lies at the junction of the pulmonary artery and right ventricle
Pulmonary semilunar valve
What type of muscles lie in the lower portion of the right ventricle
Papillary
What fibrous connective tissue extends from the papillary muscles (in right ventricle) to the flaps of the tricuspid valve
Chordae tendineae
What does the chordate tendineae prevent
Inversion of the tricuspid valve
What is the largest artery of the body
Aorta
Which ventricle pumps blood to the body through the aorta
Left ventricle
What valve lies at the junction of the aorta and the left ventricle
Aortic semilunar valve
What are the first branches of the ascending aorta just beyond the aortic semi lunar valve
Right and left coronary artery’s
The two arteries branch into smaller arteries and arterioles then into what
Capillaries
What do the coronary capillaries do
They merged to form coronary veins which empty blood into a large coronary sinus that returns blood to the right atrium
What is the purpose of the coronary vessels
To supply blood to the myocardium because oxygen is essential for normal myocardial contraction
If a coronary artery becomes obstructed by a blood clot what happens to the myocardium
It becomes a ischemic (deprived of blood supply)
What will prolonged ischemia create
And infarct which is an area of necrotic tissue
What is the name for a heart attack
Myocardial infarction
What is the sequence of events in one heartbeat
The cardiac cycle
What is another term for contraction
Systole
What is the term for relaxation
Diastole
Does atrial or ventricular systolic start first
Atrial systole is followed by ventricular systole
Is atrial systole or ventricular systole longer
Ventricular
What causes the loudest and longest sound in the lub-dub which is the first sound
It is caused by ventricular systole closing the AV valves
The second sound in the lub-dub is caused by what
It is caused by the closure of the aortic and pulmonary semi lunar valves
If a valve does not close properly there is an extra sound and this is called what
A heart murmur
What is the serous membrane on the surface of the myocardium
Epicardium
What is the heart muscle which forms the walls of the four chambers
Myocardium
What is the endothelium that lines the chambers and covers the valves it is smooth to prevent clotting
Endocardium
What receives deoxygenated blood from the body by way of the superior and inferior or Caval veins
Right atrium
What is the right AV valve that prevents backflow of blood from the RV to the RA when the RV contracts
Tricuspid valve
What pumps blood to the lungs by way of the pulmonary artery
Right ventricle
What prevents backflow of blood from the pulmonary artery to the right ventricle when the right ventricle relaxes
Pulmonary semi lunar valve
What receives oxygenated blood from the lungs by way of the four pulmonary veins
Left atrium
What is the left baby valve which prevents backflow of blood from the left ventricle to the left atrium when the left ventricle contracts
Mitral valve
What pumps blood to the body by way of the aorta
Left ventricle
Prevents the back for blood from the awarded to the left ventricle when the left ventricle relaxes
Aortic semilunar valve
What is in both the right ventricle on my friend to go and prevents inversion of the AV valves when the ventricles contract
Papillary muscles and Chordae tendineae
What is the fibrous connective tissue that Anchors the four heart valves prevents enlargement of the valve openings and electrically insulates the ventricles from the atria
Fibrous skeleton of the heart
What is the most common cause of coronary artery disease
Atherosclerosis
What is atherosclerosis
When plaques of cholesterol and inflammatory cells form in the walls of a coronary artery
What enzymes do we have jeans for that are involved in cholesterol metabolism
Liver enzymes which regulate the transport of cholesterol in the blood in the form of lipoprotein’s and regulate delivers excretion of excess cholesterol and bile
What is believed to exert a protective effect by lowering blood lipid levels and women
Estrogen
What chemical markers in the blood signal the presence of inflammation
Homocysteine and C-reactive protein CRP
With coronary artery bypass surgery which vein is grafted around the obstructive coronary vessels to restore blood flow to the myocardium
Saphenous vein of the leg
What is the natural pacemaker of the heart
Sinoatrial SA node which are a group of cardiac muscle cells in the wall of the right atrium just below the opening of the superior vina cava
Why is the SA node considered specialized
Because it has the most rapid natural rate of contraction it depolarizes more rapidly than any other part of the myocardium
The cells of the SA node more permeable to what Ions then any other cardiac muscle cells
NA+ therefore they depolarize more rapidly than contract and initiate each heartbeat
From the SA node impulses for contractions travel to what node
The atrioventricular AV node
What does the transmission of impulses from the SA node to the AV node into the rest of the atrial myocardium bring about
Atrial systole
What connected tissue exes and electrical insulation between the two sets of Chambers including the atrium myocardium in the ventricular myocardium
The fibrous connective tissue
What is the only pathway for impulses from the atria to the ventricles
The atrioventricular bundle AV bundle also called the bundle of His
Where is the AV bundle located
Within the upper interventricular septum
Where does the AV bundle receive impulses from
The AV node and then transmits them to the right and left bundle branches
From the bundle branches the impulses travel along ______to the rest of the ventricular myocardium and bring about ventricular systole
Purkinje fibers
What test shows the electrical activity of the atria and ventricles
Electrocardiogram ECG
If the SA node does not function properly what will initiate the heart beat
The AV node will at a slower rate
What is also capable of generating the Beat of the ventricles at a much lower rate of 15 to 40 bpm
The AV bundle
What is an irregular heartbeat
Arrhythmia
What is a very rapid and on coordinated ventricular beats that is totally ineffective for pumping blood
Ventricle fibrillation
A normal resting heart rate or pulse of 60 to 80 beats per minutes is the rate of depolarization of what node
SA node
The SA node actually has a slightly faster rate which is closer to 100 bpm but it is slowed by what nerve impulses
Parasympathetic nerve impulses
What is a heart rate of less than 60 called
Bradycardia
What is a prolonged are consistent rate greater than 100 bpm called
Tachycardia
What is the amount of blood pumped by a ventricle in one minute
Cardiac output
Why is a certain level of cardiac output needed at all times
To transport oxygen to tissues and to remove waste products
What is the term for the amount of blood pumped by A ventricle per beat
And what is the average resting stroke volume Pwe beat
Stroke volume
60 to 80 mL
What formula enables us to determine cardiac output
Cardiac output = stroke volume X pulse (heart rate)
What is the normal average resting cardiac output
5 to 6 L per minute
The increase in stroke from him is the result of _____________, which states that the more the cardiac muscle fibers are stretched the more forcefully the contract
Starlings law of the heart
During exercise more blood returns to the heart this is called
Venous return
Increased venous return will stretch what
The myocardium of the ventricles
What is the percent of the blood in her ventricle that is pumped during systole. Which is another measure of the health of the heart
Ejection fraction
What percentage of blood does a ventricle empty when it contracts
60 to 70% a lower percentage would indicate that the ventricle is weakening
What part of the brain contains the two cardiac centers
The Medulla
What are the two cardiac centers of the medulla
Excelerator center and the inhibitory center
What does the Excelerator center and the inhibitory center do
Send impulses to the heart along autonomic nerves
What are the two divisions of the autonomic nervous system
Sympathetic and parasympathetic
The sympathetic impulses from the Excelerator center along sympathetic nerves do what
Increased heart rate and tons of contraction during exercise and stressful situations the (neurotransmitter is norepinephrine)
The parasympathetic impulses from the inhibitory center along the biggest nerves do what
Decreased heart rate (the neurotransmitter is acetylcholine)
What information is received by the middle like to initiate changes
Because the heart pumps blood is essential to maintain normal blood pressure. Blood contains oxygen which all tissues must receive continuously. Therefore changes in blood pressure and oxygen level of the blood or stimuli for changes in heart rate
What are Pressoreceptors
They are in the carotid senses and a word exciting ee which detect changes in blood pressure
What are chemo receptors
They are in the carotid bodies and they were dick body which she took changes in the oxygen content of the blood
What are the sensory nerves for the carotid receptors
Glossopharyngeal nerve’s (9th cranial)
What are the sensory nerves from the Aortic arch receptors
Vegas (10th cranial) nerves
Generated by the SA node through the conduction pathway; parasympathetic impulses (Vegas nerves) decrease the rate; sympathetic impulses increase the rate
Heart rate
The amount of blood pumped by ventricle in one beat
Stroke volume
The volume of blood pumped by ventricle in 1 minute; stroke volume X pulse
Cardiac output
The percentage of blood within the ventricles is pumped out per beat
Ejection fraction 60% to 70%
The difference between resting cardiac output and Maximum cardiac output during exercise
Cardiac reserve 15 liters or more
What detects a drop in blood pressure
The pressoreceptors in the carotid sinuses
What occurs when a drop in blood pressure takes place and is detected by the receptors in a carotid sinuses
The impulses travel along the glossopharyngeal nerve to the medulla and the decrease in the frequency of impulses stimulates the Accelerator center
When the Accelerator generates impulses they are carried by what nerves and to where
They are carried by the sympathetic nerves to the SA node AV node and ventricular myocardium
To correct hypoxemia the reflex arc would be what five things
- Aortic chemoreceptors 2.Vegus nerve sensory, 3 Accelerator Ctr. in the medulla 4. sympathetic nerves, and 5. the heart muscle, which will increase its rate and force of contraction to circulate more blood
What hormone is secreted by the adrenal and Medulla in stressful situations
Epinephrine
What is a factor of epinephrine
To increase heart rate and force of contraction. This will help supply more blood to tissues in need of more oxygen
Which chamber of the heart works harder with high blood pressure
The left ventricle
Elite ventricle is not an efficient pump and such weakness may progress to ______
Congestive heart failure
A heart valve that becomes thick and by fibrosis can lead to _____ and ______
Heart murmurs and less efficient pumping
Contraction of cardiac cells and balls action potentials at the cell membrane and the sliding of ____ and ____
Myosin and actin in sarcomeres
What is an arterioles
And arteriole is a small artery
What happens in a cardiac cycle
A sequence of events in one heartbeat in which a simultaneous contraction of the Atria is followed by a simultaneous contraction of the ventricles
What is the epicardium
The serous membrane on the surface of the myocardium
What is the pericardium
A sack which includes three membranes and encloses the heart
What is the pulmonary circuit
The vessel pattern in the lungs were oxygen and CO2 are exchanged
What is vasoconstriction
The decreased diameter of the vessel due to contraction of smooth muscle in the wall
What is the endothelium
The endothelium is the simple Squam us epithelium cells lining A vein or artery
What is the Tunica media
Middle layer of an artery or vein
Where are the centers. That regulate heart rate located
Medulla
What vessel does the left ventricle pumps blood into
Aorta
What prevents backflow of blood from the ventricles to the atria
Mitral and tricuspid valve
What do the kidney secrete when blood pressure decreases
Renin
What is the layer of the walls of arteries and veins that is smooth to prevent abnormal clotting
Lining, made of simple Squamous epithelium
What prevents backflow from the arteries to the ventricles
Aortic and pulmonary semilunar valves
What is the function of the serous fluid of the pericardial membranes
Prevent friction as the heart beats
Why does epinephrine increase blood pressure
It increases heart rate and force
What are the steps the blood flows through the heart
- oxygen poor blood flows from the body into the right atrium
- Blood flows through the right atrium into the right ventricle
- The right ventricle pumps the blood to the lungs where the blood releases waste gases and pics of oxygen
- The newly rich oxygen blood returns to the heart and enters the left atrium
- Blood flows through the left atrium into the left ventricle
- The left ventricle pumps oxygen-rich blood to all parts of the body
