APP Lecture 1: Cardiovascular Anatomy

Thoracic Cavity

Cavity between neck and abdomen

Contents of the thoracic cavity

Pulmonary anatomy

Cardiac anatomy

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Mediastinum

Space between the pleura in the thoracic cavity

2 main parts of the mediastinum

Superior and inferior

3 parts of the inferior mediastinum

Anterior

Middle

Posterior

Superior border of the mediastinum

Superior thoracic aperture

Inferior border of the mediastinum

Diaphragm

Vertebral levels of the superior mediastinum

T1-T4

Vertebral levels of the inferior mediastinum

T5-T9

Separated into anterior, middle, and posterior

Vessels in the superior mediastinum

Superior vena cava

Brachiocephalic veins

Arch of the aorta (Brachiocephalic trunk, left common carotid artery, left subclavian artery)

Thoracic duct

Nerves in the superior mediastinum

Phrenic

Vagus

Left recurrent laryngeal

Cardiac and Pulmonary Plexus

Viscera of the superior mediastinum

Esophagus

Trachea

Thymus

Inferior anterior mediastinum contents

Thymus remnant (sometimes)

Lymph nodes

Inferior middle mediastinum contents

Pericardium

Heart

Ascending aorta

Superior vena cava

Pulmonary trunk

Pericardiacophrenic vessels

Inferior posterior mediastinum contents

Esophagus

Thoracic duct

Thoracic aorta

Azygos and Hemiazygos veins

Vagus nerve

Esophageal plexus

Thoracic Splanchnic nerves

Sympathetic trunk

Fibrous Pericardium

Surrounds the heart and great vessels

Inelastic

Roots heart in thorax

Protects heart

Serous Pericardium: 2 sections

Parietal and Visceral

Creates lubricated surface between both layers, reducing friction of the heart

Parietal Serous Pericardium

Against the fibrous layer

Visceral Serous Pericardium

Against heart and great vessels

Pericardium primary arterial blood supply

Pericardiacophrenic artery

Pericardium primary venous blood return

Pericardiacophrenic vein

What provides blood supply for the visceral pericardium?

The coronary system

What provides general somatic afferent innervation to the pericardium?

Phrenic nerve

Where does phrenic nerve pain refer to?

Shoulder/neck/arm

C3-C5 dermatomes

What provides vasomotor innervation to the pericardium?

Sympathetic Trunk

Where is the heart located?

Inferior middle mediastinum

What shape is the heart?

Trapezoidal, roughly

What are the 4 chambers of the heart?

Right atrium

Left atrium

Right ventricle

Left ventricle

Which 2 heart chambers are receiving chambers

The right and left atrium

Which 2 heart chambers are discharge chambers?

The right and left ventricles

What is the anterior (sternocostal) heart surface formed by?

Mainly the right ventricle

What is the diaphragmatic (inferior) heart surface formed by?

Mainly the left ventricle, partly the right ventricle

What is the right pulmonary heart surface formed by?

Mainly the right atrium

What is the left pulmonary heart surface formed by?

Mainly the left ventricle

What makes up the superior border of the heart?

Right and Left atria and auricles

What makes up the inferior border of the heart?

Mostly the Right ventricle, some Left ventricle

What makes up the right border of the heart?

Mostly right atrium

What makes up the left border of the heart?

Mostly left ventricle

What makes up the apex of the heart?

Mostly left ventricle

How many layers of the heart wall?

3

What are the 3 layers of the heart wall?

Endocardium

Myocardium

Epicardium

Endocardium

Inner layer of the heart wall made of epithelium and supporting connective tissue

Lubricates inner heart surface

Myocardium

Muscled layer of the heart wall made of cardiac muscle

Provides the pumping force

Epicardium

Outer layer of the heart wall made of visceral pericardium

Heart “skeleton”

Fibrous support structure

Keeps valve openings patent

Valve leaflet attachment site

Anchors myocardium, allowing for its twisted loop form

Forms electrical insulator

Right atrium receives what type of blood from where?

The sinus venorum of the right atrium receives oxygen-poor blood from the superior and inferior vena cava and coronary sinus

Where does the right atrium pump blood to?

Right ventricle via atrioventricular orifice

What muscles form the anterior walls of the right atrium?

Pectinate muscles

What is the oval indentation in the right atrium?

Fossa ovalis

Where is Trabeculae carnae located?

In the right ventricle

What do the papillary muscles in the right ventricle do?

Contract to pull chrodae tendinae taught

What are the chordae tendinae in the right ventricle?

Connective tissue connecting papillary muscles to atrioventricular valves

Prevents valve buckle during systole

Where is conus arteriosus located?

Right ventricle

What kind of blood does the left atrium receive and from where?

Oxygen-rich blood from the 4 pulmonary veins

What does the left atrium do?

Pumps blood into the left ventricle

What kind of muscles are in the left atrium?

Pectinate muscles

What does the left ventricle do?

Pumps blood to the body through the aorta

What structures are in the left ventricle?

Papillary muscles

Chordae tendinae

Trabeculae carnae

Thick myocardium

Atrioventricular valves

Prevent backflow from ventricles into atria

Semilunar valves

Prevent backflow back into ventricles

Right Atrioventricular valve

Tricuspid

Prevent backflow into left atrium

Left Atrioventricular valve

Bicuspid

Prevent backflow into right atrium

Pulmonary Valve

Prevents backflow into right ventricle

Aortic valve

Prevents backflow into left ventricle

Opens into the right and left coronary arteries in respective sinuses

3 divisions of the cardiac plexus

Sympathetic

Parasympathetic

Afferent (visceral)

2 ways the heart is innervated

Via the cardiac plexus

Via the conduction system

Cardiac plexus

Convoluted nerves from Vagus nerve branches and sympathetic trunk (via splanchnic nerves)

Parasympathetic innervation

Derive from CN X branches

Synapse in local ganglia located on the cardiac structures

Stimulation results in reduced heart rate, output, contractile force

Visceral afferent associated with parasympathetics

Provide general visceral afferent innervation

Run from heart to medulla via vagal cardiac nerves

Sympathetic innervation

Presynaptic fibers in thoracic spinal nerves, run into sympathetic chain

Postsynaptic fibers exit trunk through cardiopulmonary splanchnic nerves, go to targets in heart

Stimulation results in increased heart rate, increased blood pressure and pulse

Visceral Afferent innervation

Provide general visceral afferent innervation

Run from heart to medulla via splanchnic nerves into the spinal cord at T1

Conduction system

Anterolateral wall of right atrium near SVC

Initiates impulse conducted to muscles, causing contraction in atria

Impulse spreads rapidly

Conduction system signaling pattern

Signals arrive at AV node

SA node impulse disturbed from AV node through AV bundles and their branches

Left and right bundles give off Purkinjie fibers that stimulate papillary muscles and the walls of the ventricles