Anatomy and Physiology I - Chapter 10

Cardiac Muscle Tissue

- Striated (striped), branching, and 1 nucleus per cell. - Have specialized junctions between cells called intercalated discs. - Have absolute refractory period, stays aerobic.

Cardiac Cycle

A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles. Right and left atria go through systole and diastole together at the same time and ventricles also work together with each other.

Pericardium

A fluid-filled, double-walled membrane surrounding the heart. Makes up the pericardial sac (parietal pericardium) and epicardium (visceral pericardium).

Atrial Systole

After the SA node fires, the atria depolarize and contract together, creating a decrease in volume and higher pressure in the atria than the ventricles. The increase in pressure pushes blood through AV valves into the ventricles. Pressure of the blood from atria's contracting forces the AV valves to open.

Pericardial sac (parietal pericardium)

Anchors the heart to great vessels (aorta and venae cavae), the posterior wall of the thorax, sternum and diaphragm. Has a tough outer fibrous layer that does not allow for expansion.

Brachial Artery

Artery typically used in measuring blood pressure.

Atrial Diastole

Atria repolarize and relax, elastic fibers in the walls of the atria return to shape, volume increases and pressure decreases. Blood pressure in the superior and inferior venae cavae and pulmonary veins is greater than in the atria, causing blood to rush into the right and left atria.

Four phases of the cardiac cycle

Atrial Systole, Atrial Diastole, Ventricular Systole, and Ventricular Diastole.

Tendinous Chords

Attaches cusps of AV valves to the papillary muscle, anchoring the valves to the muscle.

Aortic Valve

Blood is forced through this valve when leaving the left ventricle.

Left Ventricle

Blood leaves the left atrium and enters this chamber of the heart.

Pulmonary Valve

Blood leaves the right ventricle through this valve.

Left Atrium

Blood returns from the lungs to this structure within the heart.

Pulmonary Circulation

CO2 is unloaded, O2 is loaded.

Deoxygenated Blood

Carbon dioxide-rich/Oxygen-poor blood that enters the right atrium of the heart from the superior and inferior venae cavae.

Angina Pectoris

Cardiac disorder characterized by heaviness or pain in the chest caused by temporary or reversible myocardial ischemia.

Myocardial Infarction

Cardiac disorder characterized by the death of myocardial tissue due to ischemia.

Atherosclerosis

Cardiovascular disorder characterized by the buildup of fatty deposits with in arterial walls.

Venous Return

Causes blood to move through the veins back to the heart. Aided by pressure gradient, gravity, thoracic pump, cardiac suction, and skeletal muscle pump.

Tunica Interna

Composed of simple squamous epithelial tissue and fibrous tissue, very smooth and secretes a chemical to repel platelets so blood can flow easily through the vessel.

Systole

Contraction of the heart.

Negative Chronotropic Effect

Decreases heart rate. Example includes potassium.

Epicardium (visceral pericardium)

Delicate layer composed of simple squamous epithelial tissue over loose areolar connective tissue, in direct contact with the surface of the heart.

Intercalated Discs

Enable fast transmission of electrical impulses from one cell to another.

Heart Rate x Stroke Volume

Equation used to calculate cardiac output. (Ex: HR 115 beats/min x Stroke Volume of 95 = 10,925 ml/min)

Effects of aging and hypertension on the Cardiovascular System

Increased vascular resistance, decreased stroke volume, and thicker, less elastic vessels prone to atherosclerosis.

Positive Chronotropic Effects

Increases heart rate. Examples are Caffeine, norepinephrine, epinephrine, nicotine, and thyroid hormone.

Pulse Pressure

Indicates a surge of pressure that small arteries must withstand with each ventricular contraction. Determined by the equation systolic pressure minus diastolic pressure. Increases as stroke volume increases.

Endocardium

Inner lining of the four chambers of the heart, composed of simple squamous epithelial tissue over loose areolar connective tissue.

Conducting Arteries

Largest of the arteries, carry blood away from the heart, have a thicker tunica media. Include the pulmonary arteries, common carotid, and aorta

Systematic Circulation

O2 is unloaded, CO2 is loaded

Ventricular Systole

Once the conduction system has carried out electrical impulses from the AV node to purkinje fibers, ventricles depolarize and contract together. Papillary muscles also contract pulling on the tendinous cords to ensure AV valves stay closed and prevent backflow to the atria. Contraction of the ventricles decrease volume and increase pressure in the ventricles, causing blood to be pushed through the pulmonary and aortic valves.

Semilunar Valves

Pulmonary and Aortic Valves

Diastole

Relaxation of the heart.

Pulmonary Veins

Returns blood from the lungs to the heart.

Tunica Externa

Serves as an anchor for vessels to surrounding tissue, and provide passage for nerves and small vessels supplying blood to the external wall.

Capillaries

Smallest of all blood vessels. Allow the exchange of fluids and other materials between tissue and blood.

Resistance Arteries

Smallest of the arteries. Examples are arterioles

Sinoatrial (SA) Node

Structure located in the right atrium that starts a heartbeat, sends an electrical impulse to stimulate the atria to contract. Considered the "pacemaker" of the heart.

Atrioventricular (AV) Bundle

Structure that carries the electrical impulse from the AV node toward the apex of the heart.

Purkinje Fibers

Structure that fans out from the end of the AV bundle to the wall of the ventricles.

Coronary Sulcus

Structure that marks the separation of the atria from the ventricles.

Atrioventricular (AV) Node

Structure that sends the electrical impulse to stimulate the ventricles to contract.

Interatrial Septum

Structure that separates the right and left atria.

Interventricular Septum

Structure that separates the right and left ventricles.

Pulmonary Trunk

Structure that takes blood from the right ventricle to the lungs to pick up oxygen.

Aorta

Structure that takes oxygenated blood from the heart to the rest of the body.

Chronotropic Factor

Term used to describe anything that changes the heart rate.

Vagal Tone

Term used to describe the ability of the autonomic nervous system to control the pace of the SA node through the vagus nerve.

Cardiac Output

Term used to describe the amount of blood ejected by each ventricle each minute.

Stroke Volume

Term used to describe the amount of blood ejected from the ventricle per beat. Affected by preload, contractility, and afterload.

Preload

Term used to describe the amount of tension in the myocardium of the ventricular walls.

Cardiac Reserve

Term used to describe the difference between the cardiac output of the heart at rest and the maximum cardiac output the heart can achieve.

Frank Starling Law of the Heart

Term used to describe the fact that the heart must pump out the amount of blood it receives.

Afterload

Term used to describe the pressure in the pulmonary trunk and aorta during diastole.

Ectopic Focus

Term used when any other part of the conduction system other than the SA node is setting the pace of the heart.

Heart -> Arteries -> Capillaries -> Veins

The correct sequence of vessels that blood travels as it leaves the heart

120/72 mm/Hg

The normal blood pressure for a 20-30 year old.

Pulmonary Arteries

The pulmonary trunk splits into this structure, taking blood to the lungs, where it absorbs oxygen and drops off carbon dioxide.

Right and Left Ventricles

Two inferior chambers of the heart, pump blood out of the heart.

Right and Left Atria

Two superior chambers of the heart, receive blood.

Atrioventricular (AV) Valves

Type of valve that separates the atria from the ventricles.

Bicuspid (Mitral) Valve

Valve that lies between the left atrium and the left ventricle. Blood leaves the left atrium and passes through this valve to the left ventricle.

Tricuspid Valve

Valve that lies between the right atrium and the right ventricle. Blood leaves the right atrium and passes through this valve to the right ventricle.

Ventricular Diastole

Ventricles repolarize and relax, elastic fibers in ventricle walls return ventricles to shape, and increase volume and decrease pressure in the ventricles. Pressure is now higher in the atria, causing blood to move through AV valves from the atria to the ventricles.

Arteries

Vessels that carry blood away from the heart.

Veins

Vessels that carry blood towards the heart. Have valves to prevent backflow of blood.

P Wave

Wave on the ECG that shows depolarization of the atria.

T Wave

Wave on the ECG that shows repolarization of the ventricles.

P, Q, R, S, and T waves

Waves on an ECG.

Q, R, and S Waves

Waves on the ECG that shows depolarization of the ventricles.