Download The heart

UNIVERSITY OF SOMALIA
SEMESTER TWO
COURSE:ANATOMY AND PHYSIOLOGY 2
CHAPTER NINE:CARDIOVASCULAR SYSTEM
LECTURER: MAHAD ALI WARSAME
2014
Key terms
cardiovascular system: a collection of organs that
transport blood throughout the body (consists of
heart and blood vessels)
heart: organ made of cardiac muscle with four
chambers; responsible for pumping blood
atrium: chamber of the hear in the UPPER
section
ventricle: LOWER chambers of the heart
valves: flap-like structures in heart near arteries
the close to prevent blood from going backward
blood pressure: the force with which blood is
pumped through the arteries
Key terms
Capillaries :Smallest blood vessels; carries
blood to the extremities
Veins Medium sized blood vessels; carries
blood to the heart
Arteries Largest blood vessels; carries blood
away from the heart
White blood cells Cells that fight disease
Red blood cells Cells that carry oxygen
Cardiovascular system
 A closed system composed of the heart
and blood vessels
 The heart pumps blood
 Blood vessels allow blood to circulate to all
parts of the body
 The general function of the cardiovascular
system (cvs) is to deliver oxygen and
nutrients and to remove carbon dioxide and
other waste products
The heart is a hollow, muscular organ located
between the lungs in the center and a bit to the left
on the midline of the body its about 12 cm in length
& about 9 cm in width.
Blood: Blood is a viscous (thick) fluid that varies in
color from bright to dark red, depending on how
much oxygen it is carrying. its quantity differs with
the size of the person; the average adult male,
weighing 70 kg has about 5-6 liters of blood.
Con…
• This volume accounts for about 8% of the
total body weight. It is carried through a
closed system of vessels pumped by the heart.
The circulating blood is of fundamental
importance in maintaining the internal
environment in a constant state
(homeostasis).
o The heart is about the size of a clenched fist
and comprises the following:
o The heart composed of four layers:
Endocardium.
Myocardium.
Epicardium.
Pericardium.
• endocardium is the inner layer and is consists
of endothelial tissue that lines the inner
surface of the heart and the cardiac valves.
• The myocardium is the middle layer and is
composed of muscle fibers that enable the
heart to pump.
• Epicardium is the outer layer, is tightly
adherent to the heart and the base of the
great vessels.
• A thin, fibrous, double-layered sac known as
the pericardium surrounds the heart.
• The outer layer is known as the parietal
pericardium
• and the inner layer is called the visceral
pericardium
• Between these two layers is a small amount
of pericardial fluid (30 to 50 mL) that serves as
a lubricant between the two layers
• The heart consists of four chambers:
a) right and left atrium
b) right and left ventricles.
 Champers of heart
Four chambers of heart:
 Atria
 Receiving chambers
 Right atrium
 Left atrium
 Ventricles
 Discharging chambers
 Right ventricle
 Left ventricle
Heart valves
• A heart valve normally allows blood to flow in
only one direction through the heart. The four
heart valve opens or closes incumbent on
differential blood pressure on each side.
Con….
 The four main valves in the heart are:
The two atrioventricular (AV) valves, the
mitral valve (bicuspid valve), and the tricuspid
valve, which are between the upper atria and
the lower ventricles.
The two semilunar (SL) valves, the aortic valve
and the pulmonary valve, which are in the
arteries leaving the heart.
Cont..
Atrioventricular valves
These are the mitral and tricuspid valves,
which are situated between the atria and the
ventricles and prevent backflow from the
ventricles into the atria during systole.
Cont…
 Semilunar valves
Main articles: Aortic valve and Pulmonary
valveThe aortic and pulmonary valves are located
at the base of the aorta and the pulmonary trunk
respectively. These are also called the "semilunar
valves". These two arteries receive blood from
the ventricles and their semilunar valves permit
blood to be forced into the arteries, and prevent
backflow from the arteries into the ventricles.
Circulation of the blood
• The blood passes through the tricuspid valve
into the right ventricle, which then pumps the
blood through the pulmonic valve into the
pulmonary circulation.
• After gas exchange in the lungs, oxygenated
blood returns to the left atrium, passes
through the mitral valve, enters the left
ventricle, passes through the aortic valve, and
finally enters the aorta.
circulatory Routes or Circuits
All the vessels together may be subdivided into two groups or
circuits: pulmonary and systemic.
1. Pulmonary circulation: carry blood to and from the lungs.
They in include the pulmonary artery and its branches to the
capillaries in the lungs, as well as the veins that drain those
capillaries. The pulmonary arteries carry blood low in
oxygen from the right ventricle, while the pulmonary veins
carry blood high in oxygen from the lungs into the left
atrium. This circuit functions to eliminate carbon dioxide
from the blood and replenish its supply of oxygen.
2. Systemic circulation: it is the largest circulatory route. It
takes oxygenated blood from the left ventricle through the
aorta to all parts of the body.
Cardiac Output
• Cardiac output is the amount of blood
pumped out of the ventricle .
• The cardiac output in a resting adult is about 5
L per minute but varies greatly depending on
the metabolic needs of the body.
• Stroke volume (SV) :The amount of blood ejected
by the left ventricle with each heartbeat .
• the heart rate is 60 to 80 beats per minute
(bpm)
• The average resting stroke volume is about 70
mL, and Cardiac output can be affected by
changes in either stroke volume or heart rate.
Heart Rates
1. Bradycardia is a relatively slow heart rate of less than 60
beats/minute. During rest and sleep, the heart may beat
less than 60 beats/minute but usually does not fall below
50 beats/minute.
2. Tachycardia refers to a heart rate over 100
beats/minute.
3. Sinus arrhythmia is a regular variation in heart rate due
to changes in the rate and depth of breathing. It is normal
phenomenon.
4. Premature beats, also called extra systoles
are beats that come in before the the
expected normal beats. They may occur in
normal persons initiated by caffeine, nicotine,
or psycologic stresses. They are also common
in persons with heart disease
Pulse
Pulse – pressure
wave of blood
 Monitored at
“pressure
points” where
pulse is easily
palpated
Blood pressure
 Measurements by health professionals
are made on the pressure in large
arteries
 Systolic – pressure at the peak of
ventricular contraction
 Diastolic – pressure when ventricles relax
Variations in blood pressure
 Human normal range is variable
 Normal
 140–110 mm Hg systolic
 80–75 mm Hg diastolic
 Hypotension
 Low systolic (below 110 mm HG)
 Often associated with illness
 Hypertension
 High systolic (above 140 mm HG)
 Can be dangerous if it is chronic
Patient Assessment:
Cardiovascular System
• HEALTH HISTORY AND CLINICAL MANIFESTATIONS
For the patient experiencing an acute MI, the
nurse obtains the health history using a few
specific questions about the onset and severity
of chest discomfort, associated symptoms,
current medications, and allergies.
At the same time, the nurse observes the
patient’s general appearance and evaluates
hemodynamic status (heart rate and rhythm, BP).
Cardiac Signs and Symptoms
• Chest pain or discomfort (angina pectoris, MI,
valvular heart disease) Shortness of breath or
dyspnea (MI, left ventricular failure, HF)
• Edema and weight gain (right ventricular
failure, HF)
• Palpitations (dysrhythmias resulting from
myocardial ischemia, stress, electrolyte
imbalance)
• Fatigue (earliest symptom associated with
several cardiovascular disorders)
• Dizziness and or loss of consciousness (
hypotension, dysrhythmias, ,cerebrovascular
disorders)
Physical Exam
A) Inspection
C) Percussion
– General appearance
– Jugular venous distension (JVD) D) Auscultation
– Skin
– Extremities
B) Palpation
– Pulses
– Good stethoscope
– Positioning
– Normal tones
– Extra tones
HEART SOUNDS
• The normal heart sounds, S1 and S2, are
produced primarily by the closing of the heart
valves.
• The time between S1 and S2 corresponds to
systole This is normally shorter than the time
between S2 and S1 (diastole). As the heart rate
increases diastole shortens.
• S1—First Heart Sound. Closure of the mitral and
tricuspid valves creates the first heart sound (S1),
• S2—Second Heart Sound. Closing of the aortic and
pulmonic valves produces the second heart sound (S2).
Diagnostic Evaluation
•
•
•
•
•
Laboratory test(Cardiac Labs)
Chest X-ray
ECG
ECHOCARDIOGRAPHY(ECO)
Echocardiography is a noninvasive ultrasound
test that is used to examine the size, shape,
and motion of cardiac structures.
Blood vessels
Types of Blood Vessels
• Arteries - vessels that transport blood away
from the heart
• Veins - return blood back to the heart
• Capillaries - microscopic blood vessels that
allow exchanges between blood and tissues
Structure of a blood vessel
• Tunica externa (adventitia) - outermost layer
made of loose connective tissue. Serves to
anchor, protect and prevent overstretching
• Tunica media - middle layer composed of
smooth muscle; functions in dilation and
constriction of blood vessels
• Tunica interna( intima) - innermost layer made
of endothelium (s.squamous epithelium)
END