November 15, 2023 Flashcards
Answer questions at beginning of lecture:
Use words to describe in detail the consequences of degranulation
Draw a graph of FEV1 performance after exercise at 40% and 75% of VO2max
Explain the causes of eccentric and concentric hypertrophy, and describe cellular and
heart morphology
What is the percentage of Exercise-Induced Bronchoconstriction (EIB) in asthmatics and non-asthmatic patients?
Exercise-Induced Bronchoconstriction (EIB)
- Occurs in 50-90% of all asthmatics, and in up to 10% of non-asthmatic patients
Exercise-Induced Bronchoconstriction (EIB) determined by
Intensity
Duration
Types of exercise
how does Intensity influence Exercise-Induced Bronchoconstriction (EIB)
Intensity:
EIB is proportional to intensity (and VE) up to about 70% VO2max
very low intensity walking has many no effect
how does duration influence Exercise-Induced Bronchoconstriction (EIB)
Duration:
less than 1 minute = no EIB (short, anaerobic activity = no effect)
1-10 minutes = progressive EIB seen post-exercise
Greater than 10 minutes = sometimes ‘run-through’ asthma (due to increased catecholamines that increase during exercise; prevent degranulation); but
sometimes not as symptoms can begin with increased duration
how does type of exercise influence Exercise-Induced Bronchoconstriction (EIB)
Worst: running, hockey, skiing (cold)
Best: swimming (warm, humid environment)
what is the Mechanisms Involved in EIB post-exercise
EIB post-exercise is proportional to:
VE / Air temp and air H2O (inversely proportional to air temp and humidity)
higher air temp = lower EIB
lower air temp = higher EIB
page 131
how does air temperature affect water loss during exercise
The drier and colder the air, the greater the heat and water loss during exercise, especially when ventilation rates are high
higher air temp = lower EIB
lower air temp = higher EIB
high humidity = lower EIB
low humidity = higher EIB
dry air = high EIB
Airway cooling can lead to _______
reflex bronchoconstriction (minor cause of EIB)
what produces a hyperosmolar environment in the airway
Loss of water produces a hyperosmolar environment in the airway (more important cause of EIB)
A hyperosmolar environment in the airways refers to an increased concentration of solutes (such as ions and other particles) in the fluid lining the respiratory passages
a hyperosmolar environment in the airway can cause …..
coughing and mucous production even in some non-asthmatic people;
the hyperosmolar environment stimulates the release of histamine and leukotrienes leading to airway narrowing, bronchoconstriction and dyspnea, reflected in FEV1 test
Suggestions for People with Asthma:
- Select exercise type and intensity carefully
- Nasal, rather than mouth breathing may be helpful
- Training can:
- Reduce VE at submaximal workloads
- May reduce medication requirements - Drug: use 10-15 mins prior to exercise; this decreases EIB post exercise
- People with asthma can exercise regularly
- A slow warm up prior to more intense exercise may prevent some symptoms
what is the Fick Equation
Fick Equation: formula used in physiology to calculate cardiac output
Q = HR x SV;
(a-v)O2 = vols%
which is smaller Ventricular cells or skeletal muscle cells
Ventricular cells are much smaller than skeletal muscle cells and have one nucleus
and connectivity to neighbouring cells
what do Connexin proteins at gap junctions within intercalated discs allow for
Connexin proteins at gap junctions within intercalated discs allow ion flow between cells; channel for sodium to pass through in order to depolarize adjacent cells
page 132
Cardiac cellular dimensions during altered Pressure and Volume Overload (OL) conditions lead to
Leads to hypertrophy
what does High afterload refer to
High afterload: pushing against high BP
Example of pressure overload:
hypertension (high BP) is a pathological change (also occurs in resistance training exercise; transient, which leads to physiological changes)
Example of volume overload:
chronically high cardiac output (ex: chronic endurance training) , or valve regurgitation (heart tries to pump out blood but it just comes back; leads to stretching of heart and hypertrophy in a different way; pathological)
what is Eccentric hypertrophy:
Eccentric hypertrophy:
occurs in volume overload and cells get longer
what is Concentric hypertrophy:
Concentric hypertrophy:
occurs in pressure overload and cells get thicker
Larger cells lead to a larger heart in both cases (Eccentric hypertrophy and Concentric hypertrophy) but the chambers will have different geometries
what is Atherosclerosis:
the narrowing and hardening of arteries due to the accumulation of plaques
Plaque in heart:
lipid rich core with abnormal buildup of connective tissue, smooth muscle, and macrophages; can become calcified and harden
Occlusion:
blockage
“Occlusion” refers to the blockage or closure of a passage, vessel, or opening
Ischemia and angina pectoris relationship:
blood flow less than normal and can lead to angina pectoris (chest pain)
Necrosis:
cell death due to lack of blood flow
Myocardial infarction (MI):
heart attack
which tissue in the body has the highest mitochondrial content
the heart
The heart has a very high blood flow (BF) and very high mitochondria per cell
what is diastole
Diastole is the relaxation phase of the heart, during which the heart muscle (myocardium) relaxes and chambers fill with blood.
what is systole
Systole is the contraction phase of the heart, during which the heart muscle (myocardium) contracts, forcing blood out of the chambers and into the arteries.
what percentage of BF to the myocardium occurs during diastole
80% of BF to the myocardium occurs during diastole
what percentage of BF to the myocardium occurs during systole
20% during systole
true or false:
The longer the diastolic period, the better the BF to the myocardium
true
Why is Blood Flow Particularly Important for the Heart?
Blood flow is important for the heart because O2 extraction is at a maximum
Aerobic energy for the heart =
Aerobic energy for the heart = Heart VO2 = Blood flow x (a-v)O2
Aerobic energy for muscle =
Aerobic energy for muscle = muscle VO2 = blood flow x (a-v)O2
*Heart has such a high mito content, that the output in a resting state is only 5 (extraction is 15 vols%) whereas in muscle it is 15 (extraction is 5 vols%)
page 134
*Extraction of O2 even before exercise in the heart is already almost maxed out
page 134
what is the only way to increase VO2 in heart during maximal exercise
During maximal exercise, the only way to increase VO2 in heart is to increase blood flow
what are the two ways in which skeletal muscle can increase VO2
in skeletal muscle, to increase VO2 , both extraction and blood flow can increase
Cardiac conduction is very high, except where in the heart?
Why is slow conduction velocity here beneficial?
Conduction velocity is high except at the AV node (action potential here is slow)
This is beneficial because it allows time for the atria to contract and fill the ventricles before the ventricles contract and eject blood (allows for flow of blood into ventricles)
Use of ECG as a Diagnostic Tool:
P wave =
QRS complex =
T wave =
P wave = depolarization of atria
QRS complex = depolarization of the ventricles + repolarization of atria
T wave = repolarization of the ventricles
what is Depression in S-T segment diagnostic of
Depression in S-T segment is diagnostic of conduction problems and is reflective of cardiac ischemia
May not notice this at rest, so it is important to do a stress test to reveal underlying pathology that you wouldn’t see otherwise
