Cardiovascular System: Heart Flashcards
Hearts Location
. Located between the right and left lungs in the lower portion of the mediastinum
. Protected by the sternum anteriorly and by the bodies of the thoracic vertebrae posteriorly
. Apex (blunt point) is at the lower left edge, lying on the diaphragm
Apical beat (heart sound at the apex)
heard best between the 5th and 6th rib (5th intercostal space) left midclavicular line
The Atria (Latin “atrium” – central court or main room)
small, upper chambers
thin, less muscular walls
“receiving chambers” - receive blood from the veins
Atrium’s
Right Atrium – receives unoxygenated blood (blood devoid of oxygen) from the biggest veins– the inferior
and superior vena cavae
Left Atrium – receives oxygenated blood (blood with oxygen) coming from the lungs through the pulmonary veins
The Ventricles (Latin “ventriculus”- stomach)
large, lower chambers
thicker, more muscular walls
“discharging chambers”- pump blood into arteries
Ventricle’s
Right Ventricle – pumps unoxygenated blood to the lungs through the pulmonary artery
Left Ventricle – pumps oxygenated blood to the different parts of the body, through the aorta
Interatrial Septum (Latin “saeptum” – a fence)
- separates the 2 atria
Interventricular
Septum
- separates the 2 ventricles
The septa prevent what?
a mixture of oxygenated
and unoxygenated blood
LAYERS OF THE HEART
. Endocardium - lines the inside of the chambers of the heart, being constantly bathed in blood
. Myocardium - the thick layer of heart muscle itself that pumps blood out of the heart
. Pericardium – the lining and covering of the heart which is composed of 2 layers:
1. visceral pericardium/epicardium – adherent to the heart
2. parietal pericardium – outer layer that acts like a loose-fitting sack, allowing enough room for the heart to beat
Pericardium is composed of 2 layers:
- visceral pericardium/epicardium – adherent to the heart
- parietal pericardium – outer layer that acts like a loose-fitting sack, allowing enough room for the heart to beat
Pericardial Fluid
– lubricant fluid between the visceral and parietal pericardia
HEART VALVES- the “Doors” of the Heart
Atrioventricular valves – the valves between the atria and ventricles that prevent the back flow of blood into the atria when the ventricles contract
1. tricuspid valve
2. mitral valve/bicuspid valve
Semilunar valves – between the ventricles and the arteries that carry blood away from the heart; prevent back flow of
blood into the ventricles
1. pulmonic/pulmonary valve
2. aortic valve
Atrioventricular valves includes what 2 valves?
- tricuspid valve – between the right atrium and right ventricle (Latin “cuspis” – cusps)
- mitral valve/bicuspid valve – between the left atrium and left ventricle (Latin “mitre” – headdress of a bishop)
Semilunar valves includes what 2 valves?
- pulmonic/pulmonary valve – at the root of the pulmonary artery, prevents blood from flowing back to the right ventricle
- aortic valve –at the root of the aorta, prevents blood from flowing back to the left ventricle
First heart sound (“lub”)
– caused by the closure of the atrioventricular valves during contraction of the ventricles
Second heart sound (“dup”)
– caused by closure of the
semilunar valves as the ventricles undergo diastole
What is a Heart Murmur
A sound made by blood flowing with turbulence through the heart
May be normal or abnormal
What is considered a Normal or “innocent” murmur?
are not associated
with signs and symptoms referable to a heart problem
What is considered an Abnormal murmur?
are often caused by defective valves, shunting of blood through septal defects or obstruction to flow of blood
- often accompanied by signs and symptoms of heart disease
Systole
- contraction of the heart
Diastole
- relaxation of the heart
Atrial systole
always comes first before ventricular systole.
Cardiac cycle
- one complete heartbeat which includes one contraction (systole) and one relaxation (diastole
Stroke Volume
What is the Normal stroke volume among adults?
– the quantity of blood that leaves the heart at every beat
. Normal stroke volume among adults is 60-100 ml/beat
Cardiac Output
– the amount of blood pumped by the heart in one minute
. Normal Cardiac Output among adults 4.5-6 liters/min
BLOOD FLOW THROUGH THE HEART
Superior & Inferior Vena Cava deliver blood devoid of oxygen -> Right Atrium -> Tricuspid valve -> Right Ventricle -> Pulmonary valve -> Pulmonary Artery -> Lungs where CO2 is released and O2 is taken up -> Pulmonary Veins carrying oxygenated blood -> Left Atrium -> Mitral valve
-> Left Ventricle -> Aortic valve -> Aorta -> to the whole body -> back to the Superior & Inferior Vena Cava
Pulmonary circulation
- movement of blood from right ventricle to the lungs and back to the left atrium
Systemic circulation
- movement of blood from left ventricle to the whole body & back to the right atrium
Circulation of Blood
Systemic circulation begins in the left ventricle -> aorta
-> arteries -> arterioles
-> capillaries in tissues where exchange of gases and substances occur -> venules -> veins -> superior and inferior vena cavae -> right atrium
pulmonary circulation begins in the right ventricle -> pulmonary valve -> left & right artery -> lungs -> left & right pulmonary veins -> left atrium
BLOOD SUPPLY TO THE CARDIAC MUSCLES
The myocardium must have constant supply of nutrients and oxygen to function effectively.
Coronary circulation – the delivery of oxygen and nutrient rich blood to the heart muscle and the return of un-oxygenated blood from the myocardium to the veins
. Coronary arteries
. Cardiac veins
Coronary circulation consist of arteries & veins. List what do they do?
. Coronary arteries - from the aorta, deliver oxygenated blood to the cardiac muscles
. Cardiac veins - deliver oxygen-poor blood back from the myocardium to the right atrium through the coronary sinus
Coronary Heart Disease
Narrowing of the coronary vessels caused by the build-up of plaque resulting in slowing down (ischemia)
or cessation of blood flow to the heart
Symptoms:
.chest pain or chest
.discomfort (angina)
.fatigue
.shortness of breath
.general weakness
what does Angina mean?
chest pain or chest
what does ischemia mean?
slowing down or cessation of blood flow
What causes a Myocardial Infarction (MI, “Heart Attack”)
Caused by occlusion of one or more coronary arteries due to an atherosclerotic plaque or a blood clot causing damage or death of the heart muscle
Signs and Symptoms:
.severe chest pain
.anxiety
.diaphoresis
.shortness of breath
.collapse
Coronary Artery Bypass Surgery (CABG)
A surgical treatment for coronary heart disease wherein veins or arteries are “harvested” from other parts of the body and used to bypass the occluded vessel(s) to restore or improve coronary circulation
conduction system of the heart works like a game of relay. Precise coordination among team members is vital to success.
Coordinated contraction of the cardiac muscle fibers is necessary to deliver each cardiac cycle successfully.
. Intercalated discs – intercellular structures that electrically connect cardiac muscle fibers so that they can beat as one.
Intercalated discs
– intercellular structures that electrically connect cardiac muscle fibers so that
they can beat as one.
What are the structures in the conduction relay of the heart?
Impulse conduction begins at the pacemaker, the sinoatrial node -> atrial muscles contract -> AV node -> Bundle of His -> Bundle Branches Purkinje fibers -> ventricles beat
Electrocardiogram (ECG, EKG) – a graphic record of the heart’s electrical activity. What does Depolarization & Repolarization mean during an EKG?
Depolarization = contraction = systole
Repolarization = relaxation = diastole
ECG Tracing Waves:
What is the P, QRS and T wave?
. P wave- represents the depolarization of the atria
. QRS Complex- represents depolarization of the ventricles
. T wave - repolarization of the ventricles
Normal Sinus Rhythm
What is the rate of beats/min?
Rhythm that is normally generated by the sinus node and traveling in a normal fashion in the heart
. Rate of 60-80 beats/minute among adults
Sinus Tachycardia
– normal heart rhythm that occurs at a rate faster than normal
Sinus Bradycardia
– normal heart rhythm that occurs at a rate slower than normal
Heart Block
Impulse from the SA node is blocked from getting into the ventricles resulting in slower, oftentimes irregular beating of the ventricles
Possible causes:
.endocarditis
.coronary heart disease
.myocardial infarction
.congenital heart disease
.cardiomyopathy
Ectopic Beats
- small changes in an otherwise normal heartbeat that lead to extra or skipped heartbeats
- often occur without a clear cause and are most often harmless
Fibrillation
- rapid randomized contractions of small areas of the myocardium, causing a totally irregular, often rapid, heart rate
- may originate from the atria or ventricles
Myocarditis
Inflammation of the myocardium often caused by viral, bacterial or fungal infection
Manifestations:
.Abnormal heart beat or heart murmur
.Shortness of breath
.Chest pain
.Fever
.Edema
Prognosis is dependent on the cause of the inflammation and the overall health of the person
Congenital Heart Disease
. Abnormalities in cardiovascular structures that occur before birth
. Defects may involve the interventricular/interatrial septa, heart valves, chambers or the blood vessels
. May produce symptoms at birth, during childhood, or not until adulthood
- Other congenital defects may cause no symptoms
Signs and symptoms:
.Cyanosis
.Poor feeding
.Murmur
.Poor weight gain
.Difficulty of breathing
Types of Blood Vessels:
- Arteries - carry or distribute blood from the heart to the capillaries in all parts of the body
.aorta – biggest artery
.arterioles – small arteries - Veins - carry or collect blood from the capillaries back to the heart
.vena cavae – biggest veins
.venules – small veins - Capillaries – microscopic vessels connecting arterioles and
venules within tissues
Arterie, what structures do they have included?
Arteries and arterioles help maintain blood pressure by dilating or constricting.
aorta – biggest artery
arterioles – small arteries
Veins what are they made of?
act as blood reservoirs because they carry blood under lower pressure.
vena cavae – biggest veins
venules – small veins
Capillaries
– microscopic vessels connecting arterioles and venules within tissues.
. serve as exchange vessels for nutrients (glucose), oxygen, wastes and fluids.
. Glucose and oxygen move out of the blood in the capillaries into the interstitial fluid then into cells.
. Carbon dioxide, waste products and other substances move from the cells to the interstitial fluid then into the capillaries
Layers in Blood Vessel Walls:
- tunica externa/adventitia (L “tunicare” – tunic, coat) – the outer layer of connective tissue fiber
- tunica media – middle layer of smooth muscle tissue; thicker and with lamina layers in arteries
- tunica intima – a single layer of squamous epithelium called endothelium
How do veins & capillaries prevent blood backflow?
Veins have valves in tunica intima that prevent the backflow of blood.
Capillaries have tunica intima only.
how much plasma re-enters the circulatory system?
About ninety percent (90%) of plasma fluid re-enters the capillaries and venules to join again the circulatory system.
Main branches of the aortic
arch:
Aorta – biggest artery that branches to supply the different parts of the body with oxygenated blood. It descends down the thoracic and abdominal cavities then finally divides into 2 branches to supply the lower limbs.
- Brachiocephalic
1.1 Right Common Carotid
1.1.1 External Carotid*
1.1.2 Internal Carotid
1.2 Right Subclavian*
1.2.1 Vertebral
1.2.2 Internal Thoracic/Mammary - Left Common Carotid
2.1 External Carotid*
2.2 Internal Carotid - Left Subclavian
3.1 Vertebral
3.2 Internal Thoracic/ Mammary
The Circle of Willis
A system of arteries that sits at the base of the brain
. Formed when the internal carotid artery (ICA) enters the cranial cavity bilaterally and divides into the anterior cerebral artery (ACA) and middle cerebral artery (MCA). The anterior cerebral
arteries are then united by an anterior communicating (ACOM) artery.
. Posteriorly, the basilar artery, formed by the left and right vertebral arteries, branches into a left and right posterior cerebral artery (PCA), forming the posterior circulation. The PCAs complete the circle of Willis by joining the internal carotid system anteriorly via the posterior communicating (PCOM) arteries.
Subclavian artery -> hand
As the subclavian artery passes the first rib, it becomes the axillary artery which continues on to become the brachial artery.
The brachial artery divides
into the radial and ulnar
arteries that supply the
forearm /hand structures.
Thoracic Aorta
The thoracic aorta is in the posterior mediastinum, from the level of T4 to T12.
It gives off paired intercostal arteries on both sides.
Abdominal Aorta
A direct continuation of the thoracic aorta
Begins at the level of T12
Branches:
1. Celiac
1.1 Gastric
1.2 Splenic
1.3 Hepatic
2. Superior Mesenteric
3. Renal
4. Gonadal
5. Inferior Mesenteric
6. Lumbar
7. Common Iliac
7.1 Internal Iliac
7.2 External Iliac
External Iliac
When the external iliac artery passes posterior to the inguinal ligament, its name changes to femoral artery* which bifurcates into superficial* and deep branches
Femoral Artery
femoral – most accessible in
newborns
The superficial femoral artery becomes the popliteal artery* as it courses through the popliteal area. It then
bifurcates into the anterior
tibial artery and posterior
tibial artery.
Posterior Tibial Artery
The posterior tibial artery branches into the peroneal (fibular) artery which supplies blood to the
lateral part of the leg
Anterior Tibial Artery
As the anterior tibial artery
crosses the anterior aspect of the ankle joint, it becomes the dorsalis pedis artery.
Principal Veins of the Body
The Superior and Inferior Vena Cavae* are the largest veins in the body.
Cranial Venous Sinuses Also called dural venous
sinuses
are venous channels found between layers of dura mater
. Receive blood from internal and external veins of the brain, receive CSF and ultimately empty into the internal jugular vein
Internal Jugular Vein
The inferior petrosal sinus and the sigmoid sinus join to form the internal jugular vein.
. The two internal jugular veins collect the blood from the brain, the superficial parts of the face, and the neck
Azygos Vein
. Runs up the right side of the thoracic vertebral column then enters the superior vena cava
. System of veins that drain the thoracic and abdominal walls
Basilic Vein/Cephalic Vein
. Large superficial veins that drain the upper limb
. The two veins communicate through the median cubital vein
Saphenous Veins
Greater Saphenous Vein
Lesser Saphenous Vein
. Large superficial veins that drain the lower extremity
HEPATIC PORTAL CIRCULATION
. Liver receives venous blood from the abdominal organs (spleen, stomach, pancreas, gall bladder, intestines) through the hepatic portal vein
. From the liver, blood re-enters the circulation through the hepatic veins then into the inferior vena cava
. This “second capillary bed” in the liver serves to:
a. maintain glucose homeostasis
b. detoxify the blood of possible toxic substances from ingested food
“second capillary bed”
– blood has passed through the capillaries in the visceral organs and will pass through the capillaries of the liver again
Unique Features of Fetal Circulation
. Gas exchange occurs in the placenta.
. Umbilical vein carries oxygenated blood from the placenta to the fetus (passing through the ductus venosus).
. Umbilical arteries carry unoxygenated blood from the fetus to the placenta.
Foramen ovale and ductus arteriosus
are intracardiac shunts that close when the fetus is delivered.
Blood pressure (BP)
is the pressure or “push” of
blood as it flows through the blood vessel.
. Pressure is highest in the arteries especially the aorta and lowest in the veins especially the superior & inferior vena cavae
blood pressure gradient
- is the difference between the mean pressure in the aorta and the pressure at the termination of the vena cavae (100 mmHg – zero mmHg = 100 mm Hg).
- is responsible for keeping the blood circulating. Without the gradient, blood will not flow to and perfuse the tissues. This may be life-threatening
What is the normal BP in adults?
Normal BP = less than 120/80 (adults)
What is Hypertension?
= high blood pressure; increased risk for stroke
what is Hypotension and how is it related to shock?
= low blood pressure
Shock = severe hypotension that compromises the supply of nutrients and oxygen to tissues
Factors that affect blood pressure
- blood volume
- strength of heart contractions
- heart rate (when the stroke volume does not change, increase in HR will result in increase BP)
- blood viscosity
- resistance to blood flow
Peripheral resistance
– any force that acts against the flow of blood; affected by blood viscosity and by
vasomotor mechanism (vasodilatation or
vasoconstriction of peripheral vessels)
PULSE
. Expanding and recoiling of an artery that can be felt using the fingertips.
. Provides information on the rate, rhythm and strength of the heart:
- Nine major “pulse points”: superficial temporal, facial,
carotid, brachial, radial, femoral, popliteal, posterior
tibial, dorsalis pedalis arteries
. Carotid and Brachial – checked in CPR
. Radial – most accessible, most frequently used in
adults and older children
. Femoral - utilized in newborns and young infants
What is the largest layer in the vein vs the artery?
Artery - Tunica Media
Vein - Tunica Externa
