Cardiac Physiology - Pacemaker Cells

Specialized heart muscle cells that initiate and regulate heartbeat rhythm.

Electrical signals that travel through the heart, triggering muscle contractions.

Inside of the cell becomes positive, causing heart muscle contraction.

Inside of the cell becomes negative again, the heart muscle relaxes.

Capable of spontaneously generating action potentials without external stimuli.

Contractile muscle cells in the heart.

The heart muscle, made up of myocytes.

Channels in pacemaker cells that allow sodium to leak into the cell, contributing to its spontaneous depolarization.

Supplies blood to the anterior wall of the left ventricle, the interventricular septum, and part of the left ventricle's lateral wall.

Causes anterior wall infarction, potentially leading to heart failure, cardiogenic shock, pulmonary edema, and ventricular septal defect.

Characterized by ST elevation in leads V1-V4 and ST depression in reciprocal leads (II, III, aVF).

Supplies the lateral and posterior walls of the left ventricle.

Causes lateral or posterior wall infarctions, potentially resulting in heart dysfunction if severe.

Characterized by ST elevation in leads V5, V6 (low lateral) or I, aVL (high lateral).

Originates from the aorta and is divided into the left and right coronary arteries.

Occurs during diastole (when the heart relaxes).

The baseline on an ECG, representing no electrical activity.

P-wave, QRS for every P-wave, regular R-R interval, HR 60-100 bpm, indicate a normal heartbeat pattern.

Ventricular contraction increases pressure without changing volume; all valves are closed.

Blood is pushed out of the ventricles into the arteries; volume decreases, pressure increases until valve closure.

Ventricles relax, pressure drops while volume stays the same; all valves are closed.

Blood flows into ventricles from the atria, increasing volume at low pressure until filled.

Sometimes seen, likely related to Purkinje fiber repolarization/late ventricular repolarization, not well-understood.

Graphical representation of ventricular pressure and volume throughout a cardiac cycle (one heart beat)

A type of heart failure where the heart's ventricles have difficulty relaxing and filling with blood, leading to reduced cardiac output.

Thickening of the left ventricle of the heart, usually due to increased workload.

Disease of the heart muscle, can be ischemic (due to blocked blood flow) or non-ischemic (from other causes).

A heart region generating action potentials faster than the sinus node (SA node).

Electrical signals circling through the heart, often due to scar tissue, causing extra heartbeats.

A slow heart rate originating from the SA node, typically less than 60 bpm.

A fast heart rate originating from the SA node (usually over 100 bpm).

A condition with an extra electrical pathway between the atria and ventricles

A stroke caused by a lack of oxygen to the brain due to low blood flow (systemic hypoperfusion).

The area of brain tissue that dies from lack of oxygen within minutes of a stroke.

The area surrounding the ischemic core that might survive if blood flow is restored quickly.

A mechanism of cell death in a stroke where sodium influx leads to water swelling the cell and impairing its function

Calcium buildup leads to the production of harmful molecules that damage brain cells during a stroke

Bleeding in the brain tissue that causes stroke, typically triggered by high blood pressure.

Bleeding between the meninges in the spaces surrounding the brain, often caused by ruptured aneurysms.

Contraction of blood vessels after a subarachnoid hemorrhage, reducing blood flow to the brain.

The hemisphere of the brain that controls language, speech, analytical thinking, and higher-order functions like math. For most right-handed individuals, this is the left hemisphere.

The hemisphere of the brain associated with visual-spatial reasoning, creativity, and artistic abilities. For most right-handed individuals, this is the right hemisphere.

A type of brain injury that occurs when blood flow is significantly reduced in areas where major arteries meet, making those areas vulnerable to damage.

A vulnerable region in the brain located between the anterior cerebral artery (ACA) and the middle cerebral artery (MCA). Reduction in blood flow in either artery can lead to damage in this zone.

A vulnerable region in the brain located between the middle cerebral artery (MCA) and the posterior cerebral artery (PCA). This area is at risk of damage if blood flow is reduced in either artery.

The percentage of blood pumped out of the heart with each beat. A low EF indicates more blood stays in the heart.

Focus on reducing afterload to make it easier for the weakened heart to pump blood.

Aim to increase preload, helping the stiff ventricle fill more effectively with blood.

The left ventricle is dysfunctional, impacting blood flow to the body causing systemic symptoms.

The right ventricle is dysfunctional, impacting blood flow to the lungs causing pulmonary symptoms.

Excess fluid in the heart chambers, often associated with right heart failure and can be assessed by echocardiography.

A visible bulging of the jugular veins in the neck, often indicating increased pressure in the heart or major veins.

Difficulty breathing when lying down, which improves when sitting or standing up.

Sudden shortness of breath that wakes you up at night.

A soft, low-pitched heart sound that is often heard during diastole (the relaxation phase of the heart). It can be a sign of heart failure.

A high-pitched heart sound that is heard just before the S1 (the first heart sound). It can be a sign of stiffening of the heart muscle.

Enlargement of the liver and spleen, which can be a sign of heart failure.

Swelling caused by fluid retention in the tissues. It is a common symptom of heart failure.

A type of cirrhosis (scarring of the liver) caused by long-standing heart failure.

A thick band of nerve fibers connecting the left and right hemispheres of the brain, enabling communication between them.

A sudden loss of brain function due to a disruption of blood supply, leading to damage in a specific area of the brain.

The specific neurological symptoms and signs that result from brain damage in a particular area due to stroke.

Stroke affecting the anterior cerebral artery, typically causing weakness and sensory loss in the legs and feet.

Stroke affecting the middle cerebral artery, commonly causing weakness and sensory loss in face, arm, and hand, as well as language problems in the dominant hemisphere.

Stroke affecting the posterior cerebral artery, leading to visual disturbances, including blindness in the affected eye.

Relating to the opposite side of the body, meaning if a stroke occurs on the left side of the brain, the right side of the body will be impacted.

National Institutes of Health Stroke Scale, a tool used to assess the severity of a stroke.

Paralysis of one side of the body, typically occurring after a stroke affecting the opposite hemisphere of the brain.

Loss of vision in the same half of the visual field in both eyes, often caused by a stroke affecting the visual cortex in one hemisphere.

Strokes in the anterior cerebral artery (ACA) typically cause weakness and sensory loss in the lower limbs and trunk, sometimes accompanied by urinary incontinence and akinetic mutism.

Strokes in the posterior cerebral artery (PCA) often present with visual deficits, particularly homonymous hemianopia, while motor and sensory impairments are less common but can occur if the thalamus is involved.

Strokes in the middle cerebral artery (MCA) are common and typically cause contralateral weakness, sensory loss, and possible aphasia depending on the affected area.

Impairment of language function, affecting speaking, understanding, reading, or writing, commonly caused by a stroke affecting language centers in the brain.

Strokes involving the basilar or vertebral arteries can affect the brainstem, cerebellum, and occipital lobes, resulting in symptoms like dizziness, vertigo, ataxia, double vision, dysarthria, dysphagia, or even locked-in syndrome.

Activated form of Factor VII, crucial for initiating the extrinsic coagulation pathway. It triggers the activation of Factor X.

The final stage of the coagulation cascade where the intrinsic and extrinsic pathways converge, leading to the formation of a stable fibrin clot.

A precursor protein (Factor II) that is converted into thrombin by Factor Xa. Thrombin is essential for fibrinogen activation.

A soluble protein (Factor I) in the blood that is converted by thrombin into fibrin, the building block of blood clots.

Important for the synthesis of several clotting factors (II, VII, IX, and X) by the liver. It carboxylates these factors, increasing their binding to calcium and collagen.

Produces most of the clotting factors (I, II, V, VII, IX, X, XI, and XII), anticoagulants (Protein C, Protein S, and Antithrombin), and processes Vitamin K.

Measures the time it takes for blood to clot, specifically testing the extrinsic and common pathways (Factors I, II, V, VII, and X).

Liver disease can interfere with the production of clotting factors, anticoagulants, and Vitamin K metabolism, leading to prolonged clotting times and bleeding issues.

Elevated unconjugated bilirubin levels in the blood, often associated with liver dysfunction or blockage of bile flow. This leads to jaundice, a yellowish discoloration of the skin and whites of the eyes.

Reduced levels of albumin, a protein produced by the liver, can be a sign of liver disease. Albumin helps maintain blood volume and pressure, and its decrease can lead to swelling (edema).

Enlarged veins in the esophagus or stomach, often caused by portal hypertension. This occurs when blood flow from the intestines to the liver is blocked, leading to a backup of blood in the veins.

A small muscle that controls the flow of bile from the common bile duct into the duodenum. It acts like a gatekeeper, regulating when bile is released into the small intestine.

A hormone produced in the duodenum that stimulates gallbladder contraction. This increases the flow of bile into the duodenum to aid in the digestion of fats.