Lab 9 Flashcards
what parts of the heart to autorhythmic cells (1%) make up?
SA node, AV node, AV bundle (bundle of His), bundle fibers, purkinje fibers
Slow heart rhythm name (ECG)
Bradycardia
Fast heart rhythm name (ECG)
Tachycardia
Uncoordinated atrial and ventricular contractions name (ECG)
Heart block
rapid, irregular out-of-phase contractions;
useless for pumping blood…name (ECG)
fibrillation
pulmonary ventilation
movement of air into and out of the lungs (breathing) (pulmonary system)
External respiration
O2 and CO2 exchange between the lungs and blood (pulmonary system)
gas transport
O2 and CO2 in the blood (circulatory system)
internal respiration
O2 and CO2 exchange between blood vessels and tissues (circulatory system)
hilum
Indentation in the lung where the bronchi,
vessels and nerves enter/ leave
conducting zone
Conduits to gas exchange sites
…Includes all upper and most lower respiratory tract
structures
respiratory zone
Site of gas exchange
…Includes microscopic structures
such as respiratory bronchioles,
alveolar ducts and alveoli
primary muscles of inhalation
external intercostal muscles and diaphragm
Spirometer
used to measure respiratory
volumes and capacities
FEV1
Forced Expiratory Volume
in one second: an
important clinical indicator (should be 80% of FVC (forced vital capacity) in the first second)
FEV1= less than 80%:
obstructive pulmonary disease: bronchitis, asthma, emphysema (think wheezing: hard to breathe out all the way)
FEV1= more than 80%:
restrictive pulmonary disease (lung can’t expand fully and wants to collapse on itself)
The heart is located in
the _____ of the thoracic cavity
mediastinum
Two-thirds of the heart lies to the left of the…
midsternal line
○ Carries oxygen-depleted blood away
from the heart and to the lungs
○ Returns oxygen rich blood back to
the heart
The pulmonary circulation
○ Carries oxygenated blood away from
the heart to the rest of the body
○ Returns deoxygenated blood back to
the heart
The systemic circulation
The heart is covered by an outer covering called
the
pericardium
Pericardium
a double-walled sac
○ Parietal layer
—has both a serous and a
fibrous component.
○ Visceral layer hugs the heart tissue proper
and is known as the epicardium.
epicardium
visceral layer of the pericardium that hugs the heart tissue proper
What is the function of the
pericardium?
The pericardium secretes serous fluid.
The serous fluid reduces friction as the
heart beats within the pericardial cavity.
The coronary circulation
supplies the heart tissue with blood.
What vessels comprise the coronary
circulation?
Vessels that deliver oxygen rich blood to
the myocardium are the coronary
arteries.
Vessels that remove deoxygenated blood
from the heart muscle are the cardiac
veins.
Vessels that deliver oxygen rich blood to
the myocardium are the
coronary arteries.
Vessels that remove deoxygenated blood
from the heart muscle are the
cardiac veins.
From where do the coronary arteries
receive oxygenated blood?
The major arteries of the coronary
circulation arise directly from the aorta
Where does the deoxygenated blood go
after passing through the capillary beds of
the myocardium?
The deoxygenated blood enters the
coronary veins, pools in the coronary
sinus then empties into the right atrium.
What are the consequences of coronary
artery blockage?
Blockage leads to ischemia (substrate and
oxygen deprivation). Prolonged ischemia
can significantly damage heart tissue
resulting in myocardial infarction (heart
attack). The damage caused by the
infarction is not reversible due to the poor
regenerative capacity of cardiac muscle
tissue.
substrate and oxygen deprivation to the hard is called
ischemia
Prolonged ischemia
can significantly damage heart tissue
resulting in
myocardial infarction (heart attack)
What is a disease that promotes the
development of plaques within blood vessel
walls?
Atherosclerosis results in the build-up of
fatty materials within arterial walls that
leads to chronic inflammation, thickening
and blockage of blood vessels.
Has a large opening along the superior
aspect of the heart next to the right
auricle (posterior view)
Superior vena cava
Superior vena cava function
Brings deoxygenated blood from the
top half of the body to the right atrium
Inferior and slightly left to the superior
vena cava (posterior view)
inferior vena cava
Inferior vena cava function
● Drains into the right atrium
● Returns deoxygenated blood to the
heart from the lower tissues of the
body
Large and most anterior blood vessel
visible along the superior aspect of the
heart (anterior view)
Pulmonary trunk
pulmonary trunk pathway and function
● Originates at the R ventricle and
branches into the L & R pulmonary
arteries
● Carry deoxygenated blood away from the
heart to the lungs
Next to the left auricle
Pulmonary vein
pulmonary vein pathway and function
● Delivers oxygenated blood from the
lungs into the left atrium
● Four pulmonary veins
● Empty into the left atrium
Arising at the center of the superior
aspect of the heart (anterior view)
aorta
aorta pathway and function
Largest of the blood vessels
● Originates at the left ventricle and
carries oxygenated blood away from
the heart to the rest of the body
● Has three major branches
What are the major arteries that emerge
at the aortic arch?
The main branches of the aorta are the:
-brachiocephalic artery
-left common carotid artery
-and left subclavian artery
● Portion of ventricular myocardium
● Separate left and right ventricle
interventricular septum
Atrioventricular (AV) valves function, and name them
Separate the atria from the ventricles. Have cusps - flaps to prevent the backflow of blood from the ventricle to atrium.
Mitral/bicuspid valve (left) and tricuspid valve (right)
● Chordae tendineae
● Extend from the cusps of the AV valve
● Anchor them to the ventricle walls via
papillary muscles - projections of the
ventricular myocardium.
papillary muscles
projections of the ventricular myocardium that anchor the chordae tendineae to the ventricle walls
How does the left AV valve differ
structurally from the right AV valve?
The left AV valve has two cusps
(called the bicuspid or mitral valve)
● The right AV valve has three cusps
(called the tricuspid valve)
(LAB RAT)
pulmonary valve function
(semilunar) prevents
blood from flowing back into the
right ventricle from the pulmonary
trunk.
do semilunar valves have chordae tenineae? what are their names?
no! aortic valve and pulmonary valve
What are the two layers of the parietal pericardium?
Fibrous and serous pericardium
What is the most anterior great vessel? What is its function?
Pulmonary artery/pulmonary trunk; carry deoxygenated blood to the lungs
To what circuit does each ventricle correspond?
Right ventricle: pulmonary circulation; left ventricle: systemic circulation
What is the structural difference between AV and
semilunar valves?
Semilunar valves lack chordae tendineae (rather, have pocket-like cusps)
What are the three main branches of the aorta?
Brachiocephalic artery; L common carotid artery; L
subclavian artery
What are the 3 layers of the heart wall,
from superficial to deep?
Epicardium, myocardium, endocardium
functional syncytium
the autorhythmic cells working to contract the myocardium synchronously
How many impulses per minute does the sinoatrial (SA) node typically generate?
On average, the SA fires 75 times per minute.
How does the firing rate of the SA node compare to that elicited
by other components of the conduction system?
The SA fires at the fastest rate. AV node generates 50 impulses per minute
and the ventricular autorhythmic cells (AV bundle and Purkinje fibers) have
a lower inherent firing rate of 30 impulses per minute.
Given the above information, what is the primary function of the
SA node?
The SA node sets the pace of the heart- often called the heart’s pacemaker.
- Low R-R intervals
- Slow heart rate
Symptoms
* Fatigue
* Lightheadedness
Bradychardia (less than 60 bpm)
- short R-R intervals
- Fast heart rate
Symptoms
* Fatigue
* Lightheadedness
Tachycardia (greater than 100 bpm)
- long p-r interval
- Delay in atrial to
ventricular
depolarization
Symptoms
* Typically
asymptomatic
first degree heart block
- dropped qrs
- Not all atrial
depolarizations lead
to ventricular
depolarization
Symptoms
* Dizziness
second degree heart block
- no relation between p and qrs and t waves
Description - Disconnect between
atrial and ventricular
depolarization
Symptoms
* Dizziness – needs
immediate emergency
attention
complete heart block
- no discernable waves
- No coordinated
electrical rhythm
Symptoms
* Unconsciousness
ventricular fibrillation
the left lung is
_________ than the right lung
and has a __________________
along its medial aspect to
accommodate the heart.
smaller (2 lobes vs 3); cardiac notch
- On the medial aspect of each
lung is an indentation called
the _________ through which
pulmonary and systemic blood
vessels, bronchi, lymphatic
vessels and nerves enter and
leave the lungs. - Each _______________ plunges
into the hilum on its own side
and begins to branch almost
immediately.
hilum; main bronchus
- Once inside the lungs, each of the
main bronchi subdivide into
________________ bronchi. - The lobar bronchi then divide into
_______________________________bronchi
which divide repeatedly into smaller
and smaller bronchi (fourth-order, fifthorder, etc.) This branching pattern is
commonly referred to as the respiratory tree.
secondary (lobar); third-order (tertiary)
Is the number of lobar bronchi the same
in the left and right lung?
No, there are three on the right
two on the left (similar to the
number of lobes)
Smaller bronchi terminate at passages
smaller than 1 mm in diameter–what
are these passages called?
bronchioles
The respiratory tree terminates at
grape-like structures that are the site of
gas exchange –what are these structures
called?
alveoli
Bronchi epithelia type
Ciliated Pseudo-stratified columnar
Bronchioles epithelia type
simple cuboidal
Alveoli epithelia type
simple squamous
clinical tools
that can measure the rate and volume of air that passes through the respiratory system.
pulmonary function tests
Total lung volume can
be divided into a
series of volumes and
capacities that can be
measured with a ______
spirometer
What is vital capacity (VC)?
- It is the maximum amount of air that
can be moved forcefully in and out of
the lungs - VC is approximately 3-5L in healthy
adults
