Adrenergic antagonists: Beta blockers


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Adrenergic antagonists: Beta blockers

Block 3A


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: 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


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


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



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.


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.


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