week 9-1 Flashcards
Chronic Heart Failure
- Supply can no longer keep up with demand
- Heart has weakened and can no longer maintain the cardiac output required
(↓CO) - Cause: Any pathology that affects regular heart function
- Coronary artery disease, previous Myocardial infarction
- Chronic uncontrolled high blood pressure
- Others: leaky or narrowed heart valves, infection/inflammation of the heart,
arrhythmias
Stroke Volume (SV) is a function of
preload, afterload and myocardial contractility
Systolic Dysfunction
ventricles can’t pump hard
enough during systole
* Due to weakened ventricle
* Lower ejection fraction, lower CO
Diastolic Dysfunction
not enough blood fills into
the ventricles during diastole
* Due to stiffened ventricle
* Normal ejection fraction, lower CO
Initial Compensation
to attempt to restore CO
In terms of systemic circulation, multiple mechanisms in place to attempt to maintain sufficient cardiac output and mean arterial pressure in order to perfuse tissues
Eventual Decompensation leads to congestive
heart failure
- CO decreases
- Decreased tissue function, fatigue
- Ejection Fraction reduced (EF = SV / EDV)
- End-diastolic volume increases because ventricle output is less than inflow of
blood - Blood begins to back up into pulmonary or systemic circulation (depending on
the side of the heart that is failing)
CONGESTIVE HEART FAILURE
left side heart failure
- left ventricle weakens and cannot empty
- decreased cardiac out
- decreased renal blood flow stimulated renin-angiotensin and aldosterone secretion
- backup of blood into the pulmonary vein
- high pressure in pulmonary capillaries leads to pulmonary congestion or edema
right side
- right ventrilce weakens cannot empty
- decreased cardiac output
- decreased renal blood flow stimulated renin-angiotensin and aldosterone secretion
- back up of blood into systemic circulation
5.increased venous pressure results in edema in less and live and abdominal organs - very high venous pressure causes distended neck veins and cerebral edema
Ischemic stroke cause
- Causes:
- Atherosclerotic plaque build up in e.g. carotid artery
leads to blockage - Blood clot that travels to the brain from e.g.
atherosclerotic progression or other location
area deprived of blood
hemorrhagic stroke
- A burst blood vessel leads to bleeding in an area of the
brain, causing local swelling and damage - Most common cause: Severe hypertension
- Symptoms are severe – extreme headache, loss of
consciousness, coma, death - Anti clotting treatment would be life threatening in
this case.
Transient Ischemic Attack
“mini stroke
* Temporary blockage of a cerebral artery that resolved
* Symptoms the same as a stroke but can be milder and will fully resolve within 24 hours (even
within minutes in some cases) without treatment.
* Can be a warning sign of impending stroke (40% of people who have a TIA will eventually go
on to have a full stroke, usually within a few days after the TIA)
Stroke – Risk Factors
- Age
- High Cholesterol, Atherosclerosis
- Hypertension
- Atrial Fibrillation
- Oral contraceptive use + Cigarette smoking
- Previous TIA
stroke treatment
- Antithrombotic therapy (if appropriate)
- Anti-inflammatories (glucocorticoids)
- Surgery to remove obstruction
- OTs, PTs, Speech-language Pathologist
stroke prevention
- Reduce risk factors
- Prophylactic treatments
- Healthy Lifestyle modifications
Atrial fibrillation
- Disturbance in electrical conduction
through the atria. - Causes the heart to beat very fast
(>150 BPM) - Atria are not able to contract, rather
they “quiver”. This enables some blood
to pool in the atria and increase risk of
stroke
Bronchodilation
Decreased resistance to air flow
* Paracrine response
* Increased PCO2 relaxation of
bronchiole smooth muscle
* SNS response
* Epinephrine binds to β2-
adrenergic receptors
relaxation of bronchiole smooth
muscle
Bronchoconstriction
Increased resistance to air flow
* Paracrine response
* Histamine released by local
mast cells in an immune
response
* PNS response
* ACh binds to muscarinic
receptors constriction of
bronchiole smooth muscle
Bronchoconstriction
Increased resistance to air flow
* Paracrine response
* Histamine released by local
mast cells in an immune
response
* PNS response
* ACh binds to muscarinic
receptors constriction of
bronchiole smooth muscle
Compliance
How easily the
lung can expand
* Physical properties of the
lung that determine
compliance:
- Elasticity
- Alveolar Surface Tension
Elastance
Ability of the lung
to spring back after being
stretched. Inverse of
compliance
- Due to the presence of
elastin fibers throughout
the lung interstitial space
Obstructive Lung Diseases:
- Ventilation is obstructed (usually due to increased resistance to airflow)
- E.g. Asthma, Bronchitis, Emphysema, Chronic Obstructive Pulmonary Disease (COPD)
Restrictive Lung Diseases:
- Reduced lung compliance increased stiffness limited expansion
- E.g. Pulmonary Fibrosis
Vascular Disorders that impair gas exchange and/or perfusion:
- Pulmonary Edema
- Pulmonary Embolism
