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92 terms

Chapter 19 - The Heart

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the heart as a double pump
The right side of the heart pumps blood though the pulmonary circuit The left side of the heart pumps blood to all the body tissues via systemic circuit
pulmonary circuit
the blood vessels that carry blood to and from the lungs
systemic circuit
vessels that transport blood to and from all body tissues
Name the two receiving chambers of the heart.
1. right atrium
2 left atrium
These atriums receive blood returning from the systemic and pulmonary circuits
Name the heart two main pumping chambers.
1. right ventricle
2. left ventricle (hollow belly)
these ventricles pump blood around the two circuits
The heart is a muscular double pump with two functions:
1.right side receives oxygen poor blood from the body tissues and then pumps this blood to the lungs to pick up oxygen and dispel carbon dioxide
2. left side receives the oxygenated blood returning from the lungs and pumps this blood thoughout the body to supply oxygen and nutrients to the body tissues
exterior landmarks of the heart
Start with the 2nd rib lateral to the sternal angle
1.superior right point
-lies where the costal cartilage of the 3rd rib joins the sternum
2.superior left point
- lies at the costal cartilage of the 2nd rib, a finger lateral to the sternum
3.inferior right point
-lies at the costal cartilage of the sixth rib, afinger lateral to the sternum
4. inferior left point (appex point)
-lies in the 5th intercostal space at the midclavicular line, the line extending inferiorly form the midpoint of the left clavicle
*the imaginary lines that connect these points are the size of a normal heart
major heart vessels
...
oracle flap
...
apex and base of heart
its apes points anteriorly and to the left
-its base is its posterior surface
great vessels valves
...
Name the components of the cardiovascular system.
-Blood vessels
-Pulmonary circuit-blood to lungs
-systemic- blood to organs of the body
Blood Flow
1. Blood returning to the heart fills artia
-blood puts pressure against the atrioventricular valves
-atrioventricular valves are forced open
2. As ventricles fill, atrioventricular valve flaps hang limply into ventricles
What vessels lead into each atria?
Right atrium
1.Superior vena cava
2. Inferior vena cava
Left atrium
1. Pulmonary veins
Trabeculae carneae
irregular ridges of muscle in the inside of ventricular wall
-"little beams of flesh",
-This is the name for the structures that are similar to the pectinate muscles of the atria. -
-muscular ridges on the walls of the two ventricles
-most easily seen in the right ventricle
-As is the case with the pectinate muscles, they resemble tree roots.
chordae tendineae
-are tendons linking the papillary muscles to the tricuspid valve in the right ventricle and the mitral valve in the left ventricle.
-As the papillary muscles contract and relax, the chordae tendineae transmit the resulting increase and decrease in tension to the respective valves,
-causing them to open and close.
-string-like in appearance
-referred to as "heart strings."
valves
1. pulmonary valve
2. aortic valve
3. Mitral valve
4. Tricuspid valve
remember note:TAMP
Fossa ovalis
a prominent feature of the interartrial septum is an oval depression called the fossa ovalis, the remnant of the foramen ovale, an opening in the interatrial septum of the fetal heart that normally closes soon after birth.
vena cava
One of two large vessels (superior and inferior) that return deoxygenated blood to the right atrium of the heart.
Two types of vena cava
!. superior vena cava(returns deoxygenated blood from
2. inferior vena cava (return deoxygenated blood from
Valves int the right ventricle
1. Tricuspid valve
2. Pulmonary semilunar vavle
Valves in the left ventricle
1. Aortic semilunar valve
2. Mitral (bicupsid) valve
Visceral pericardium
-membrane that surrounds the heart
Interventricular septum
an internal partition that separates the right and left ventricles of the heart
papillary muscle
- located in right and left ventricles
-project from the walls into the ventricular cavity
-cone shaped muscles that project into the walls of a ventricle
-they are attached to string-like structures called the chordae tendineae.
-The contraction of the papillary muscles closes these valves. When the papillary muscles relax, the valves open.
- the tricuspid valve in the right ventricle and the mitral valve in the left ventricle.
pectinate muscles
-muscular ridges that extend along the inner surface of the right atrium
pulmonary trunk
the artery that carries venous blood from the right ventricle of the heart and divides into the right and left pulmonary arteries
atria
-the two upper chambers of the heart- the receiving areas that pool incoming blood.
-Two upper chambers of the heart
Layers of the pericardium
-superficial layer
1.fibrous pericardium
2.parietal layer of the serous pericardium
Deep layer
1. visceral layer of the serous pericardium

-outer layer of this sac fibrous pericardium
-next layer double-layered serous pericardium
Tissue layers of the heart wall
from external to internal
1. epicardium
2. myocardium
3. endocardium
pericardium
-"around the heart"
-triple-layered sac that encloses the heart
Function of right ventricle
to receive blood from the right atrium
- pump it into the pulmonary circuit via the pulmonary trunk
How much does a typical heart weigh?
250-350 grams
Where does the heart lie?
in the thorax posterior to the sternum and costal cartilages
-rests on the superior surface of the diaphragm
-oblique position in the thorax
-with apex lying to the left of the midline and anterior to the rest of the heart
pericardial cavity
is between the superficial and deep layer of the the heart
-it contains lubricating serous fluid
-the epithelial cells of the serous pericardium that line the pericardial cavity secrete a lubricating film of serous fluid
-fluid reduces friction between the beating heart and the outer wall of the pericardinal sac
epicardium
one of the three layers of the heart wall
-"upon the heart"
-the visceral layer of the serous pericardium
-often infiltrated with fat, especially in older people
myocardium
one of the three layers of the heart wall
-"muscle heart"
-forms the bulk of the heart
-consists of cardiac muscle tissue
-the layer that actually contracts
endocardium
one of the three layers of the heart wall
-"inside the heart"
-located deep to the myocardium
-a sheet of simple squamous epitherlium resting on a thin layer of connective tissue
-lines the heart chambers and covers the heart valves
interatrial septum
internally divides heart chambers longitudinally at the wall between the atria
interventricular septum
internally divides heart chambers longitudinally at the wall between the ventricles
external boundaries of the four chambers
-marked by two grooves
1. first groove: coronary sulcus
-forms a crown by encircling the boundary betwn the atria and ventricles
2. second groove:interventricular sulcus
a.anterior interventricular sulcus
b.posterior interventricular sulcus
1)separates the 2 ventricles on the heart's inferior surface
The right atrium receives blood via what three veins?
1. superior vena cava
2. inferior vena cava
3. coronary sinus
fossa ovalis
a depression in the interatrial septum that marks the spot where an opening existed in the fetal heart called the foramen ovale
tricuspid valve
inferior and anteriorly the right atrium opens into the right ventricle through this valve
left atrium
makes up most of the heat's posterior surface or base.
right ventricle
forms most of the anterior surface of the heart
right atrium
forms the entire right border of the human heart
left ventricle
forms the apex of the heart and dominates the heart's inferior surface
crista terminalis
C shaped ridge
-a vertical ridge of smooth myocardium within the right atrium of the heart. It is on the lateral wall of the chamber. It extends between the right side of the orifice of the superior vena cava inferiorly to the right side of the valve of the inferior vena cava.
What is coronary artery disease caused by?
atherosclerotic blockage of cornonary sulcus and intervetricular sulci
Where is the coronary sulcus?
...
Intervetricular sulci
...
arrhythmia
a variation from the normal rhythm of the heartbeast
ventricular fibrillation
the ventricles are unable to pump blood into the arteries due to rapid, random firing of electrical impulses within ventricular muscle prevents coordinated contraction of the ventricle.
atrial fibrillation
multiple waves of impulses circle within the atrial myocardium, randomly stimulating the AV node which signals the ventricles to contract quickly and irregularly
pulmonary arterial hypertension
enlargement and sometimes ultimate failure of the right ventricle resulting from elevated blood pressure in the pulmonary circuit
heart failure
a progressive weakening of the heart as it fails to keep pace with the demands of pumping blood and cannot meet the demands for oxygenated blood.
congestive heart failure
the heart enlarges greatly while its pumping efficiency progressively declines.
destructive positive feedback loop
a weakened heart causes the sympathetic nervous system to stimulate the heart to pump harder. This demand further weakens the heart----which causes it to stimulate the hear to pump harder
atherosclerosis
an accumulation of fatty deposits in the inner lining of the body's arteries that can block blood flow through these arteries
coronary artery disease CAD
arteries supplying the heart wall are narrowed or blocked
-symptom angina pectoris
angina pectoris
"choked chest"
-thoracic pain caused by inadequate oxygen of heart muscle cells, which weaken but do not die
When do angina attacks mostly occur?
during exercise when the heart is vigorously contracting and there is a higher demand for oxygen
myocardial infarction
- heart attack
-when the blockage of a coronary artery is more complete or prolonged and oxygen starved cardiac muscle cell die
symptoms of myocardial infraction
-sharp pain strikes with lighting speed through the chest and sometimes the left arm and left side of the neck and does not subside.
silent ischemia
a condition in which blood flow to the heart is interrupted often like in angina but without pain to provide warning
coronary sinus
largest of the cardiac veins
-
What arteries delivery blood supply to the tissues of the heart?
right and left coronary arteries
-start at the base of the aorta and run in the coronary sulcus
branches of the left coronary artery
anterior interventricular
circumflex arteries
branches of the right coronary artery
marginal artery
posterior interventricular artery
What type blood vessel carries deoxygenated blood from the heart wall?
coronary sinus which occupies the posterior part of the coronary sulcus and returns almost all venous blood from the hear to the right atrium
Name the three veins that drain into the coronary sinus.
great cardiac vein
middle cardiac vein
small cardiac vein
vagus nerve
parasympathetic, decreased heart rate
conducting system
of the heart is a series of specialized cardiac muscle cells that carry impulses throughout the heart musculature signaling the heart chambers to contract in proper sequence
-sets basic heart rate
sinoatrial (SA) node
the impulse that signals each heartbeat begins here
-sets basic heart rate by generating 70-80 electrical impulses per minute
-heart's pacemaker
how does the signal of the SA node spread?
throughout the myocardium through the gap junctions in the intercalated discs
Intrinsic conduction system of the heart
1. The sinoatrial (SA) node (pacemaker) generates impulses
2. The impulses pause (0.1 sec) at the atrioventricular (AV) node
3. The atrioventicular (AV) bundle connects the atria to the ventricles
4. The bundle branches conduct the impulses through the interventricular septum
5. The Purkinje fibers stimulate the contractile cells of both ventricles
purkinje myocytes
long row of special, large-diameter, barrel-shapped cells
-these muscle cells contain few myofilaments because they are for conduction
-located in the deepest part of the venticular endocardium
where are purkinje myocytes found
between the endocardium and myocardium layers
sympathetic cardiac nerves
increase heart rate and force of contraction
-travel to the heart from the cervical and upper thoracic chain ganglia
What sets the heart's inherent rate of contraction?
SA node
visceral sensory fibers
nerves to the heart
name two types of visceral sensory fibers
parasympathetic fibers
sympathetic fibers
parasympathetic fibers
slow heart rate
-arise as branches of the vagnus nerve in the neck and thorax
What controls the autonomic input to the heart
cardiac centers (2 types) in the reticular formation of the medulla of the brain
Name the 2 types of cardiac centers and influence
cardioinhibitory center influences the parasympathetic neurons
-cardioacceleratory center influences the sympathetic neurons
heartbeat
a single sequence of atrial contraction followed by ventricular contraction
How many times does the average person heart beat per minute
70-80 times per minute
systole
the contraction of a heart chamber
-both atria and ventricles experience this
diastole
the time during which a hear chamber is relaxing and filling with blood
-both atria and ventricles experience this
Oxygen poor blood enters the heart through what valves of the heart?
Superior vena cava
Inferior vena cava
Coronary sinus
What is the the path of blood once it enters the right atrium?
tricupsid valve
right ventricle
pulmonary semilunar vavle
pulmonary trunk
to lungs
pulmonary arteries
to heart
pulmonary veins
left atrium
mitral vavlc\ve
left ventricle
aortic semilunar valve
aorta
to body through systemic circuit