functions of the heart. generate blood pressure routing blood ensuring one way blood flow ...
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Functions of the Heart
Functions of the Heart
Generate blood Pressure Routing Blood Ensuring one way blood flow Regulating blood supply
The Heart
Located in the Thorax Part of the Mediastinum ( heart,
trachea and esophagus) Size of a Fist Blunt end is called apex, Flat portion
at the opposite end is the base
The Heart
Apex- most inferior anterior and to the left located at the fifth intercostal space
Base- superior and slightly posterior most superior part is in the
second intercostal space
The Pericardium
the heart is surrounded by a space called the pericardial cavity
the pericardium consists of a fibrous and a serous part
the serous pericardium consists of a parietal and a visceral pericardium
The Heart: Atria and Ventricles
Atria- located at the base
Ventricles- extends from apex to the base
Sulcus- Coronary Sulcus-extends around the heart and separates the atria from the ventricles
Vessels- veins and arteries and capillaries
Veins: Six large veins carry blood to the heart
- the superior vena cava- blood from body to right atrium - the inferior vena cava- blood from body to right atrium
- four pulmonary veins- blood from lungs to the left atrium
Arteries
The pulmonary trunks and the aorta exit the heart
The pulmonary trunk arises from the right ventricle splits into right and left pulmonary arteries which carry blood to the lungs
The Aorta carries blood to body
Blood Supply to the Heart Coronary Arteries- two coronary arteries originate from the
base of the aorta just above the aortic semi lunar valves
The left coronary artery originates on the left side of the aorta and it supplies most of the anterior wall of the heart and most of the wall of the right ventricle
The right coronary artery originates on the right side of the aorta and supplies most of the right wall of the right ventricle
The left coronary artery originates on the left side of the aorta and it supplies most of the anterior wall of the heart and most of the wall of the right ventricle
The right coronary originates on the right side of the heart and supplies most of the wall of the right ventricle
Heart Chambers
Consists of Four Chambers Two Atria
Two Ventricles
Internal Anatomy of the Heart
The Atria Atria- Right and Left atria receive blood
from veins
Right atria- reservoir for blood returning from
the body (superior vena cava, inferior vena cava and coronary sulcus)
Left atria – receive the blood from four
pulmonary veins
The Ventricles
The right and left ventricles of the heart are the major pumping chambers
The right ventricle pumps blood into the pulmonary arteries to the lung
The left ventricle pumps blood into the aorta which sends blood to the rest of the body
The Heart Valves
A- V ( Atrioventricular) Valves
Semilunar Valves ( Half Moon)
The A-V Heart Valves
A-V valves are located between the right atrium and right ventricle and between the left atrium and left ventricle
The A-V valves on the right are called the tricuspid valves (three cusps)
The A-V on the left side are called the bicuspid valves ( two cusps)
Heart Valves continued
Valves also exist between the right ventricle and the pulmonary arteries and the left ventricle and the aorta
These valves are called semilunar valves because they have a half moon shape.
Direction of Blood Flow through the Heart
Route of blood flow through the Right Heart
Blood returning from the body via the superior vena cava, the inferior vena cava and the coronary arteries empty into the right atrium
From the right atria blood flows through the tricuspid valve and enters the right ventricle
From the right ventricle blood flows through the pulmonary semilunar valves into the pulmonary trunk to pulmonary arteries ( to the lungs to pulmonary circulation)
Route of Blood flow through the Left Heart
Blood returning from the lungs enters the left atrium
From the left atrium blood passes through the Bicuspid valve into the left ventricle
From the left ventricle blood will then pas through the semilunar valves into the aorta and then to the systemic circulation
Animated Tutorial of the Circulation of Blood through the heart
ANSWER?
How is the movement of the blood through the heart accomplished ?
The Cardiac Cycle
To Main Pumps: The primer pump is the atria- because
they complete the filling of the ventricle
The power pump is the ventricle- because they produce the major force throught the systemic circulation
Contraction / Relaxation (Systole)/ ( Diastole)
Atrial Systole refers to contraction of the two atria
Ventricular systole refers to contraction of the two ventricle
Atrial diastole refers to relaxation of the two atria
Ventricular diastole refers to relaxation of the two ventricles
Major Events of the Cardiac Cycle Ventricular Systole- pushes blood back toward the atria, causing the A-V valves to
close - pressure in the ventricles exceeds the pressure in the pulmonary
trunk and aorta causing the semilunar valves to be forced open and blood is ejected into the pulmonary trunk and aorta
Ventricular diastole - The semilunar valves close, preventing blood from flowing back into the ventricles .
- The pressure continues to decline in the ventricle until finally the A-V valve open and the blood flows directly from the atria into the relaxed ventricle
.( During the previous ventricular systole, the atria were relaxed and the AV valves open, blood flows into the ventricles and fills them to approximately 70% of their volume
Atrial systole forces additional blood flow into the ventricles to complete their filling. The semilunar valves remain closed.)
Animated Tutorial of the Circulation of Blood through the heart
The Heart Sounds A stethoscope What you can hear S1 – The first heart sound (lubb) beginning of systole results from closure of the A-v
valves S2 – The second heart sound
(dupp) beginning of ventricular diastole results from closure of the semilunar valves ventricular systole – between S1 and S2 ventricular diastole- between S2 and S1
Abnormal Heart Sounds continued Murmur- result from faulty valves incompetent- the valves fail to
close tightly and blood leaks backward through the valve when it is closed
stenosed- the opening of the valve is narrowed
usually a swishing sound
Heart Sounds Demonstrations
Regulation of Heart Function Cardiac Output (CO)- the volume of
blood pumped by either ventricle per minute
Stroke volume (SV)- is the volume of blood pumped per ventricle each time the heart contracts
Heart Rate (HR)- number of heart contractions per minute
CO= SV x HR
The Vascular System
Arteries to Capillaries to Veins
Vessel Structure
Tunica Intima Tunica Media Tunica Adventitia
Blood Vessels
Arteries- are blood vessels that carry blood away from the heart
elastic muscular arterioles
Blood Vessels Continued
Capillaries- thin walled numerous site of gas and nutrient
exchange
Blood Vessels continued
Veins- carry blood to the heart veins are thinner, with less
elastic tissue venules small veins medium sized veins large veins
The Aorta
All Arteries branch from the aorta Three parts: ascending (coronaries) aortic arch ( head and upper
limbs) descending( thoracic, abdominal and common iliacs)
Blood Pressure
Blood pressure is a measure of the force blood exerts against the bllod vessel walls.
When the ventricles contract, blood is forced into the arteries , and the pressure reaches a maximum callled the systolic pressure
When the ventricles relax, blood pressure in the arteries falls to a minimum called the diatolic pressure