Transcript The Circulatory System

The Circulatory System
The Heart
Blood Vessels
Arteries
Veins
Blood
Function
To transport oxygen and nutrients to the body cells
To transport carbon dioxide and metabolic waste away from the body cells
hollow, muscular organ
The
HEART
the “pump” of the body
Located mid-sternally
Functions of an electrical
impulse
BLOOD VESSELS
Arteries
Veins
carry blood AWAY from the heart
carry blood TO the heart
STRUCTURE OF THE HEART
Tissue Layers
● Pericardium
○ outside layer
■ Pericardial fluid
● Myocardium
○ middle layer
● Endocardium
○ innermost layer
HEART STRUCTURE
Separated into left and right
spetum
Divided into Four Chambers, chambers are
separated by valves
Atria
upper chambers
Ventricle
lower chambers
HEART STRUCTURE
RIGHT SIDE
Atrium
receives deoxygenated
(blue) blood from the body cells
Tricuspid Valve
closes when the
right ventricle contracts
Ventricle
receives blood from the
right atrium and pumps it to the lungs
Pulmonary valve
closes when ventricle
relaxes
HEART STRUCTURE
LEFT SIDE
Atrium
Receives oxygen rich (red)
blood from the lungs
Mitral valve
closes when the left
ventricle contracts
Ventricle
Receives blood from left
atrium, pumps blood transported to
the rest of the body
Aortic valve
closes when the left
ventricle relaxes
HEART STRUCTURE
Heart Valves
are comprised of leaflets or cusps which act as “doors” to allow blood
flow
Atrioventricular valves (AV)
valves between the atria and ventricle, anchored to the walls
of the ventricle with chordae tendineae
Tricuspid and Mitral Valve
HEART STRUCTURE
Heart Valves
Semilunar Valves (SL)
valves found between the ventricle and the artery
Closure of these valves are the “dub” sound (second heart
sound, S2)
HEART
STRUCTURE
Valve Locations
● Aortic
○ right 2nd intercostal space/right
sternal border
● Pulmonary
■ left 2nd intercostal space/left
sternal border
● Tricuspid
■ left 4th/5th intercostal space/lower
left sternal border
● Mitral
■ left 5th intercostal space/left
midsternal
The Cardiac
Cycle
- The Heartbeat
-
the right and left
sides work
together in a
cyclic manner,
with periods of
rest and
contraction
Diastole
when the heart
chamber is at REST
(relaxing, very brief)
The chamber is filling
with blood
Systole
when the
ventricles are
contracting
The Cardiac Cycle
At the start of the cycle
Atria contract pushing blood into the ventricles
● Atrias then relax
○ blood from the BODY fills the RIGHT atrium
○ blood from the LUNGS fill the LEFT atrium
(as the atria are filling, systole begins, ventricles contract)
The Cardiac Cycle
As the Ventricles contract (systole)
● The RIGHT ventricle pushes blood to the
pulmonary artery
● sending to the lungs for oxygen
● The LEFT ventricle pushes blood to the
aorta
● sending blood to the be distributed to the
body
The Cardiac Cycle
Generated by an electrical impulse, from a group of nerve
cells
● Begins in the right atrium at the Sinoatrial Node (SA)
known as the “pacemaker” of the heart
● an electrical signal is sent out over the muscle of
the atria, telling the atria to contract pushing blood
into the ventricle
● After passing through the atria the impulse reaches the
Atrioventricular Node (AV) which is between the atrium
and the ventricle.
● The signal then gets passed to the Bundle of His
located in the septum.
○ Divided into right/left
■ know as right and left bundle branches
● Bundle Branches divide into
○ Purkinje Fibers- are the network
of nerves that are throughout the
ventricles, cause the ventricles
The Cardiac Cycle
This cycle occurs about every 0.8 seconds
EKG- electrocardiogram
records the electrical activity of the heart used to detect
abnormalities.
The Cardiac System
Artificial Pacemaker
is a small battery operated
device with electrodes, positioned in
the right atrium and apex of right
ventricle
Delivers an electrical impulse
when the heart’s natural rhythm is
defective
BLOOD VESSELS
Arteries
● carry blood away from the
heart
● largest artery - aorta
● smallest - arterioles
● muscular, elastic and thick
walls
High pressure
Flows at a fast speed
The vessels we feel for a pulse to
get a heart rate
heart rate is the amount of
times our heart beats in
1min.
BLOOD VESSELS
Smallest vein - venules
Veins
carry blood to the heart
Largest veinsSuperior Vena Cava
return blood from upper
part of body
Inferior Vena Cava
thinner and less muscular than
arteries
contain valves which keep blood
from flowing backwards
Low pressure
Flows at a slower speed
BLOOD VESSELS
Capillaries
connect arterioles and
venules
Thin walls w/ only one layer
of cells
oxygen/nutrients are
exchanged for carbon
dioxide/waste from the
tissue cells
Circulation
Three Types
● Coronary
○ blood circulation within the heart
● Pulmonary
○ blood flow between the heart and the lungs
● Systemic
○ blood flow between the heart and the cells of
the body
BLOOD
Approx. 4-7 liters in the body
Complex mixture of cells, water,
proteins and sugar
BLOOD
2 components
Plasma-55%
fluid
about 90% water
proteins, hormones,
electrolytes
Blood Cells-45%
solids
Erythrocytes
Leukocytes
Erythrocytes
● Red Blood Cells
● Produced in red bone marrow
○ 1 million/min
● Live about 120 days
● Contain Hemoglobin
○ complex protein & iron compound
■ carries oxygen and carbon
dioxide
Leukocytes
● White blood cells
● Produced in bone marrow and lymph tissue
○ 4,500-11,000 circulate
● Live 3-9 days
● Fight infection
○ pass through capillary walls into tissues at
the infection sight
Thrombocytes
Platelets
Formed in bone marrow
Live 5-9 days
Cell responsible for clotting process
stops bleeding
CIRCULATORY SYSTEM AND VITAL SIGNS
PULSE
Pulse sites
The amount of beats our heart
takes in 1 min.
-temporal (head)
60-100 beats per min
-carotid (neck)
-popliteal
-radial (wrist)
tibial
-posterior
-brachial
dorsalis pedis
-
Taken at arteriole sites
-femoral
(groin)
CIRCULATORY SYSTEM AND VITAL SIGNS
Blood Pressure
measurement of force exerted by the heart against the arterial
walls when the heart contracts and relaxes
measured in millimeters of mercury (mmHg)
Blood Pressure
Systolic=top number
highest level of pressure within the arteriole walls reach when the
heart contracts
Diastolic=bottom number
lowest level of pressure within the arteriole walls reached when
the heart’s at rest
Blood Pressure
Sphygmomanometer
instrument used by inflating a cuff around a limb and inflated until
circulation is cut off. A small valve slowly deflates the cuff, and with a
stethoscope placed over the artery, the health care professional listens for the
rush of blood pulsing through the artery.
The first sound heard is the systolic number, the last number heard as
the sound fades is the diastolic.