(PAPHY LEC) Heart

What are the 3 Functions of the heart?

1. -

2. -

3. -

Generating blood pressure
Routing blood
Regulating blood supply

__________________

• Required for blood flow through the blood vessels

Generating blood pressure

__________________

• Two pumps, moving blood through the pulmonary and systemic circulations

Routing blood

___________________

• Adjusts blood flow by changing the rate and force of heart contractions as needed

Regulating blood supply

___________________

• The flow of blood from the heart through the lungs back to the heart

• Picks up oxygen and releases carbon dioxide in the lungs

Pulmonary circulation

___________________

• The flow of blood from the heart through the body back to the heart

• Delivers oxygen and picks up carbon dioxide in the body’s tissues

System circulation

The heart

Location:

• Anterior to the ____________

• Posterior to the ____________

• Left of the ____________

• Deep to the _________ to _________ intercostal spaces

• Superior surface of __________

vertebral column
sternum
midline
second
fifth
diaphragm

The heart is shaped like a _________, with an _____ and a ________. It is approximately the size of you __________

blunt cone
apex
base
fist

The heart consists of two __________ and two ___________

Atria
Ventricles

_________________

• a double-walled sac around the heart composed of

1. Superficial ________________

2. A deep two-layer ______________

Pericardium
fibrous pericardium
serous pericardium

The ________________ lines the internal surface of the fibrous pericardium

Parietal layer

The ________________ lines the surface of the heart

Visceral layer

They are separated by the fluid filled ______________

pericardial cavity

What are the 2 layers of pericardium?

1. -

2. -

Fibrous pericardium
Serous pericardium

__________________

• protects and anchors the heart

• prevent and overfilling of the heart with blood

Fibrous pericardium

_________________

• allows for the heart to work in a relatively friction-free environment

Serous pericardium

What are the 3 layers of the heart wall?

1. -

2. -

3. -

Epicardium
Myocardium
Endocardium

__________________

• Visceral layer of the serous pericardium (visceral pericardium)

• Provides protection against the friction of rubbing organs

Epicardium

_________________

• Cardiac muscle layer forming the bulk of the heart

• Responsible for contraction

Myocardium

__________________

• Endothelial layer over crisscrossing, interlacing layer of connective tissue

• Inner endocardium reduces the friction resulting from the passage of blood through the heart

Endocardium

Ventricles have ridges called _________________

Trabeculae carneae

The inner surface of the atria are mainly ______________

smooth

Auricles have raised areas called __________________

musculi pectinati

___________________

• Receiving chambers of the heart

• Each atrium has a protruding auricle

• Pectinate muscles mark atrial walls

• Veins entering the right atrium carry blood to the heart from the systemic circulation

1. -

2. -

3. -

• Veins entering the left atrium carry blood to the heart from the pulmonary circulation

- _________________

Atria
Inferior vena cava
Superior vena cava
Coronary sinus
Four pulmonary veins

_____________________

• Discharging chambers of the heart

• Papillary muscles and trabeculae carneae muscles mark ventricular walls

• Arteries carrying blood away from the heart

_______________ exits the right ventricle carrying blood to the pulmonary circulation

_______________ exits the left ventricle carrying blood to the systemic circulation

Ventricles
Pulmonary trunk
Aorta

Each atrium has a flap called an __________

Auricle

The ________________ separates the atria from the ventricles

coronary sulcus

The ____________________ separate the right and left ventricles

interventricular grooves

The _______________ separates the atria from each other

interatrial septum

The _____________ is the former location of the foramen ovalis through which blood bypassed the lungs in the fetus

fossa ovalis

The interventricular septum separates the ventricles

interventricular septum

Heart valves ensure ___________ blood flow through the heart

unidirectional

____________________ lie between the atria and the ventricles

Atrioventricular valves

Atrioventricular valves prevent __________ into the atria when ventricles contract

backflow

___________________ anchor the AV valves to papillary muscles

Chordae tendineae

_________________ separates the RIGHT ATRIUM and ventricle

_________________ separates the LEFT ATRIUM and ventricle

Tricuspid valve
Bicuspid valve

________________ prevent backflow of blood into the ventricles

Semilunar valves

___________________ lies between the LEFT VENTRICLE and aorta

Aortic semilunar valve

__________________ lies between the RIGHT VENTRICLE and pulmonary trunk

Pulmonary semilunar valve

Blood from the body flows through the ____________ into the ____________ and then to the LUNGS

Blood returns from the lungs to the ___________, enters the _____________, and is pumped back to the body

right atrium
right ventricle


left atrium
left ventricle

________________ branch off the aorta to supply the heart. Blood returns from the heart tissues to the right atrium through _____________ and ______________

Coronary arteries
Coronary sinus
Cardiac veins

Fibrous skeleton of the heart

• Consists of a plate of ______________________

• Forms ____________ around the AV and SL valves for support

• Provides a ______________ for heart muscle

• Electrically insulates the ____ from the ventricles

fibrous connective tissue

fibrous rings
point of attachment
atria

CARDIAC MUSCLE CELLS

• are ____________ and have a centrally located ___________

• _________ and ________ are organized to form ___________(striated)

• ___________ and ___________ are not as organized as in skeletal muscle

• Normal contraction depends on extracellular _____________

• Rely on ___________ for ATP production

• Joined by ___________

branched
nucleus
actin
myosin
sarcomeres
T tubules
sarcoplasmic reticulum
Calcium
aerobic respiration
intercalated disks

___________________ allow action potentials to move from one cell to the next, thus cardiac muscle cells function as a unit

intercalated disks

ACTION POTENTIALS

1. After depolarization and partial repolarization, a ____________ is reached, during which the membrane potential only slowly repolarizes

2. The opening and closing of voltage-gated ion channels produce the action potential

• The movement of Na+ through Na+ channels causes ______________

• During depolarization, ___ channels close and ____ channels begin to open

• Early repolarization results from closure of the ____ channels and the opening of some ___ channels

• The plateau exists because Ca2+ channels remain open

• The rapid phase of repolarization results from the closure of the ___ channels and the opening of many ___ channels

plateau phase
depolarization
K+
Ca2+
Na+
K+
Ca2+
K+

___________________

• Cardiac muscle cells are insensitive to further stimulation

____________________

• Stronger than normal stimulation can produce an action potential

Absolute refractory period
Relative refractory period

Cardiac muscle has a prolonged depolarization and thus a ______________________, which allows time for the cardiac muscle to relax before the next action potential causes a contraction

prolonged absolute refractory period

Some cardiac muscle cells are autorhythmic because of the spontaneous development of a _____________

prepotential

______________: slowly developing local action potential

Prepotential

The _____________ is the pacemaker of the heart

sinoatrial node

The duration of the prepotential determines the ____________

heart rate

The _________________ and the ________________ are in the right atrium

Sinoatrial node
atrioventricular node

The AV node is connected to the _____________ in the interventricular septum by the AV bundle

bundle brances

The bundle branches give rise to _______________ which supply the ventricles

Purkinje fibers

The ___________ initiates action potentials, which spread across the atria and cause them to contract

sinoatrial node

The sinoatrial node generates impulses about ________ times per minute

75

Atrioventricular node delays the impulse approximately _______ seconds

0.11

atrioventricular bundle splits into two pathways in the _____________

interventricular septum

Bundle branches carry the impulse toward the _______ of the heart

apex

________________ carry the impulse to the heart apex and ventricular walls

Purkinje fibers

___________________

• records only the electrical activities of the heart

Electrocardiogram

____________ corresponds to depolarization of the atria (sinoatrial node)

P wave

______________ corresponds to ventricular depolarization

QRS complex

_________ corresponds to ventricular repolarization

T wave

Atrial repolarization record is masked by the larger _____________

QRS complex

Based on the magnitude of the ECG waves and the time between waves, ECGs can be used to diagnose ___________________

heart abnormalities

________________ is the repetitive contraction and relaxation of the heart chambers

Cardiac cycle

______________ is the contraction of the atria

atrial systole

_____________ is the contraction of the ventricles

Systole

________________ is the relaxation of the atria

Atrial diastole

__________ is the relaxation of the ventricles

Diastole

During SYSTOLE,

• AV valves _________

• Pressure ________ in the ventricles

• Semilunar valves are forced to _______

• Blood flows into the ______ and ____________

close
increases
open
aorta
pulmonary trunk

AT THE BEGINNING OF DIASTOLE

• Pressure in the ventricles _____________

• Semilunar valves _____ to prevent backflow of the blood

decreases
close

When the pressure in the ventricles is lower than in the atria, the AV valves _____ and blood flows from the atria into the ventricles

open

During atrial systole, the atria _________ and complete the filling of the ventricles

contract

VENTRICULAR DEPOLARIZATION

• produces the ___________

• Initiates contraction of the ventricles, which increases ventricular pressure

• The AV valves ________

• The semilunar valves ________

• Blood is ejected from the heart

• The volume of blood in a ventricle just before it contracts is the ______________

• The volume of blood after contraction is the _______________

QRS complex
close
open
end-diastolic volume
end-systolic volume

VENTRICULAR REPOLARIZATION

• produces the __________

• Ventricles ________

• Blood flowing back causes the semilunar valves to _________

• The AV valves ____ and blood flows into the ventricles

T wave
relax
close
open

Approximately ____% of ventricular filling occurs when blood flows from the higher pressure in the veins and atria to the lower pressure in the relaxed ventricles

70

Atrial depolarization produces the _________

P wave

The atria ___________ and complete ventricular filling

contract

__________________ is the contraction of the ventricles forces blood into the aorta

Aortic Pressure Curve

_______________

• The maximum pressure in the aorta

Systolic pressure

Elastic recoil of the aorta maintains pressure in the aorta and produces the _____________

dicrotic notch

The minimum pressure in the aorta is the _________________

diastolic pressure

Heart sounds (lub-dup) are associated with _________________

closing of heart valves

First sound occurs as AV valves close and signifies beginning of ______

Second sound occurs when SL valves close at the beginning of _______________

systole
ventricular diastole

Systole: ______________________

Ventricular contraction causes the AV valves to close, which is the beginning of ventricular systole. The semilunar valves were closed in the previous diastole and remain closed during this period. The volume of blood in the ventricles does not change.

Period of Isovolumic Contraction.

Systole: __________________. Continued ventricular contraction pushes blood out of the ventricles causing semilunar valves to open.

Period of Ejection

Diastole:___________________ Blood flowing back toward relaxed ventricles causes the semilunar valves to close, which is the beginning of diastole. The AV valves are also closed

Period of Isovolumic Relaxation.

Diastole: ________________ The AV valves open and blood flows into the relaxed ventricles, accounting for most of the ventricular filling.

Passive Ventricular Filling.

Diastole: __________________. The atria contract and complete ventricular filling.

Active Ventricular Filling

_________________ is the average blood pressure in the aorta

Mean arterial pressure

Blood pressure = ___________ x _____________

Cardiac output
Peripheral resistance

______________ is the product of heart rate and stroke volume

Cardiac output

______________ is the number of heart beats per minute

Heart rate

________________ is the amount of blood pumped out by a ventricle with each beat

Stroke volume

Stroke volume = ________ - _________

End diastolic volume
End systolic volume

_______________

• amount of blood collected in a ventricle during diastole

End-diastolic volume

_____________________

• amount of blood remaining in a ventricle after contraction

End-systolic volume

___________________ is the difference between resting and maximal Cardiac output

Cardiac reserve