The Heart

• The main organ responsible for the efficiency of the blood’s circulatory system

• Incredible strength and endurance

• Hollow, cone-shaped

• Weighs less than 1 pound, about the size of a closed fist

• Located in the mediastinum, the medial cavity of the thorax, the apex of the heart lies on the diaphragm and points left of the body

Blood Flow Through the Heart

• Deoxygenated blood enters through the Superior & Inferior Vena Cava

• Into the Right Atrium

• Through Tricuspid Valve

• Into Right Ventricle

• Through Pulmonary Semilunar Valve

• Out of the Right & Left Pulmonary Arteries

• Into the Right & Left Lungs

• Oxygenated blood returns through the Right & Left Pulmonary Veins

• Into the Left Atrium

• Through Mitral Valve

• Into the Left Ventricle

• Through the Aortic Semilunar Valve

• Through the Aorta

• Delivered to the rest of the body

Cardiovascular

• Consists of two main components; the heart (cardio) and the blood vessels (vascular).

• The heart produces contracting force in order to distribute the blood throughout the body and connects the pulmonary and systemic circulatory systems.

• Blood vessels make up the vessel network in the body, and function to carry blood from the heart to organs, delivering various substances and removing metabolic wastes from the body.

• The cardiovascular system is only part of the circulatory system.

Circulatory

• Circulatory system mainly includes the heart, blood vessels, blood, lymph and lymph vessels.

• It is a closed system that consists of the heart, and two circulatory branches, named the pulmonary circulation and the systemic circulation.

• The pulmonary system carries blood to the alveoli (air sacs) of the lungs so that gasses may be exchanged

• The systemic system provides blood supply to all body tissues; delivering oxygen, nutrients, and other needed substances while carrying away carbon dioxide and other metabolic waste

Major Blood Circuits

• Blood leaves the heart through arteries and returns by veins

• The two main circulations of the body:

  • General or systemic circulation carries blood throughout the body

  • Pulmonary circulation carries blood to the alveoli (air sacs) of the lungs so that gasses may be exchanged

• The heart is double pump that serves both.

Stethoscope

• Used during health assessments to listen to sounds of the heart, lungs, abdomen, and cardiovascular system.

• The bell is pressed lightly against the body part to listen to low-pitch sounds, such as abnormal cardiovascular sounds.

• The diaphragm is pressed firmly against the body part to listen to high-pitched sounds, such as normal heat sounds, breath sounds, and bowel sounds

• Ear tips should face towards the bridge of the nose.

• The apex is where the heartbeat is most easily felt and heard through the stethoscope

• Press your fingers between the fifth and sixth ribs (midclavicular line, just below center of breast), you can easily feel the apical impulse caused by the the apex of your heart contacting the chest wall

• Place the diaphragm of a stethoscope over the hearts apex

• This is the area between the fifth and sixth ribs, along an imaginary line extending from the middle of the left clavicle

• The heartbeat is heard and felt easily at the apex, now you know where the heart is located (not the left side of the body)

Electrocardiogram

Types of rhythms

Major categories

• Sinus

  • Originate

• Atrial

  • Originates

Regularity

• Is it regular?

  • Look at R-R interval

  • Regularly

  • Basically

  • Totally irregular

Rate

• What is the exact rate?

  • Over a 6 second period count the R’s and multiply by 10

  • Count small squares between R waves and divide by

  • You can also count big boxes and divide by 300

  • Scale:

    • 1 large P wave

Cardiac Conduction

Stroke Volume

Preload Contractility Afterload

fast filling time sympathetic stimulation increased vascular resistance

decreased filling time parasympathetic stimulation decreased vascular resistance