Adrenergic antagonists: Beta blockers
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Adrenergic antagonists: Beta blockers
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Introduction to the cardiovascular system
Anatomy of the heart
Anatomy of the coronary circulation
Bones and joints of the thoracic wall
Vessels and nerves of the thoracic wall
Arteriole, venule and capillary histology
Artery and vein histology
Cardiovascular system anatomy and physiology
Pressures in the cardiovascular system
Blood pressure, blood flow, and resistance
Stroke volume, ejection fraction, and cardiac output
Coronary circulation
Resistance to blood flow
Compliance of blood vessels
Microcirculation and Starling forces
Measuring cardiac output (Fick principle)
Cardiac preload
Cardiac afterload
Law of Laplace
Hypertension
Hypertension: Pathology review
Hypertension: Clinical (To be retired)
Atherosclerosis and arteriosclerosis: Pathology review
Fats and lipids
Cholesterol metabolism
Dyslipidemias: Pathology review
Hypercholesterolemia: Clinical (To be retired)
Electrical conduction in the heart
Cardiac conduction velocity
Anatomy clinical correlates: Heart
Coronary artery disease: Clinical (To be retired)
Coronary artery disease: Pathology review
Myocardial infarction
ECG basics
ECG normal sinus rhythm
ECG cardiac infarction and ischemia
Angina pectoris
Normal heart sounds
Abnormal heart sounds
Cardiac cycle
Cardiac contractility
Aortic valve disease
Aortic dissection
Aneurysms
Aortic dissections and aneurysms: Pathology review
Aortic aneurysms and dissections: Clinical (To be retired)
Mitral valve disease
Heart failure
Heart failure: Pathology review
Heart failure: Clinical (To be retired)
Valvular heart disease: Clinical (To be retired)
Dilated cardiomyopathy
Restrictive cardiomyopathy
Hypertrophic cardiomyopathy
Ventricular septal defect
Ventricular arrhythmias: Pathology review
Ventricular tachycardia
Ventricular fibrillation
Supraventricular arrhythmias: Pathology review
ECG cardiac hypertrophy and enlargement
Atrioventricular block
Bundle branch block
Heart blocks: Pathology review
Premature atrial contraction
Premature ventricular contraction
Wolff-Parkinson-White syndrome
Atrial fibrillation
Atrioventricular nodal reentrant tachycardia (AVNRT)
ECG QRS transition
ECG intervals
Myocarditis
Coronary steal syndrome
Long QT syndrome and Torsade de pointes
Reading a chest X-ray
Development of the cardiovascular system
Fetal circulation
Atrial septal defect
Patent ductus arteriosus
Tetralogy of Fallot
Hypoplastic left heart syndrome
Memory Anchors and Partner Content
Transcript
Contributors
Elizabeth Nixon-Shapiro, MSMI, CMI
Antonia Syrnioti, MD
Samantha McBundy, MFA, CMI
Alpha blockers and beta blockers are two types of postsynaptic anti-adrenergic medications that prevent their respective receptors from being stimulated by catecholamines, like norepinephrine and epinephrine.
The nervous system is divided into the central nervous system, so the brain and spinal cord; and the peripheral nervous system, which includes all the nerves that connect the central nervous system to the muscles and organs.
The peripheral nervous system can be divided into the somatic nervous system, which controls voluntary movement of our skeletal muscles; and the autonomic nervous system, which controls the involuntary movement of the smooth muscles and glands of our organs; this system is then further divided into the sympathetic and parasympathetic nervous systems.
Now, the autonomic nervous system is made up of a relay that includes two neurons. We’ll focus on just the sympathetic nervous system.
Signals for the autonomic nervous system start in the hypothalamus, at the base of the brain. Hypothalamic neurons have really long axons that carry signals all the way down to the thoracic and lumbar spinal cord nuclei, where they synapse with preganglionic neuron cell bodies.
From there, the signal goes from the preganglionic neurons down its relatively short axon, exits the spinal cord, and reaches the nearby sympathetic ganglion, which is made up of lots of postganglionic neuron cell bodies.
The postganglionic neurons are also called adrenergic neurons, because they release the neurotransmitter norepinephrine, which is also called noradrenalin; and to a much lesser degree, epinephrine also known as adrenaline.
Summary
Adrenergic antagonists are a type of drug that blocks the action of adrenaline in the body. Adrenaline is a hormone that is released in response to stress or excitement, and it causes the heart rate to speed up and the blood vessels to narrow.
Beta-blockers are a type of adrenergic antagonist that blocks the sympathetic activation of Beta-adrenergic receptors. Beta-blockers work by blocking the action of adrenaline, which is responsible for the body's fight-or-flight response. This makes them ideal for treating conditions where the body's natural response to stress is harmful, such as high blood pressure and heart arrhythmia.
Sources
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- "Rang and Dale's Pharmacology" Elsevier (2019)
- "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
- "Chronotropic incompetence, beta-blockers, and functional capacity in advanced congestive heart failure: Time to pace?" European Journal of Heart Failure (2008)
- "Beta-blockers for hypertension" Cochrane Database of Systematic Reviews (2017)
- "Blood pressure lowering efficacy of beta-1 selective beta blockers for primary hypertension" Cochrane Database of Systematic Reviews (2016)
- "Treatment of Angina: Where Are We?" Cardiology (2018)
- "Bisoprolol compared with carvedilol and metoprolol succinate in the treatment of patients with chronic heart failure" Clinical Research in Cardiology (2017)
- "A Review of Nebivolol Pharmacology and Clinical Evidence" Drugs (2015)
- "Management of arrhythmia in sepsis and septic shock" Anaesthesiol Intensive Ther (2017)
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