The Heart

The Heart

by Nikki Chenevert

​Heart Basics

​The heart pumps 7,000 liters of blood through the body each day, contracting some 2.5 billion times in an average lifetime. This muscular pump forces blood through arteries, which connect to smaller-diameter vessels called arterioles. Arterioles branch into the tiniest tubes, the capillaries, which are sites of nutrient, electrolyte, gas, and waste exchange. Capillaries converge into venules, which in turn converge into veins that return blood to the heart, completing the closed system of blood circulation. These structures—the pump and its vessels—form the cardiovascular system

Multiple Choice

What function does the heart do?

• Protects organs and produces red blood cells.
• Generates heat.
• Breaks down food into nutrients.
• The heart is a pump, which moves the blood. The arteries and veins are the pipes where the blood flows.

Multiple Choice

What is the main function of the artery?

• It controls your brain and your thought process.
• They carry oxygen- poor blood BACK to the heart.
• Arteries carry oxygen- rich blood AWAY from the heart.
• It receives information (senses) and sends messages to the body about how to react to things.

Multiple Choice

Which is the correct pathway that blood takes as it leaves the heart, circulates throughout the body, and returns to the heart?

• arterioles, arteries, venules, veins, capillaries
• veins, venules, capillaries, arteries, arterioles
• arterioles, arteries, capillaries, veins, venules
• arteries, arterioles, capillaries, venules, veins

Multiple Choice

Which of the following is the smallest blood vessel?

• Venules

• Arterioles

• Veins

• Capillaries

Multiple Choice

These carry blood away from the heart

• arteries
• veins
• venules
• capillaries

Multiple Choice

These carry blood to the heart:

• arteries
• veins
• capillaries
• arterioles

​The Pulmonary Circuit

​The pulmonary (pul′mo-ner′′e) circuit sends oxygen depleted (deoxygenated) blood to the lungs to pick up oxygen and unload carbon dioxide.

​

The systemic (sistem′ik) circuit sends oxygen-rich (oxygenated) blood and nutrients to all body cells and removes wastes.

​

Without circulation, tissues would lack a supply of oxygen and nutrients, and wastes would accumulate. Such deprived cells soon begin irreversible change, which quickly leads to their death.

​

Figure 13.1 shows the general pattern of blood transport in the cardiovascular system.

Multiple Choice

What is pulmonary circulation?

• Blood travelling to and from the lungs
• Blood travelling to and from the body
• A blood clot in the lungs
• The vessel that brings blood to the lungs

Multiple Choice

The systemic circulation carries blood

• from the heart to the body cells and back to the heart
• to the lungs and back to the heart

​Introduction

​The heart is a hollow, cone-shaped, muscular pump. It lies within the thoracic cavity and rests on the diaphragm (fig. 13.2).

​FIGURE 13.2

​The heart is

(a) within the mediastinum and

(b) enclosed by a layered pericardium

​The Size of the Heart

​Size and Location of the Heart Heart size varies with body size. An average adult’s heart is about 14 centimeters long and 9 centimeters wide (fig. 13.3).

​

​- The average size of a human heart is approximately the size of a closed fist.

 

- An increased size of the heart does not always represent trauma. 

​

Many athletes have an enlarged heart because just as their skeletal muscles are conditioned and developed so is their cardiac muscle.   Contrastingly, if a sedentary person has an enlarged heart this might be a symptom of trauma, blockage, etc. to the heart or blood vessels.

Multiple Select

if a sedentary person has an enlarged heart this might be a symptom of _______ to the heart or blood vessels. Select all that apply.

• trauma

• blockage

• conditioned cardiac muscles

• conditioned skeletal muscle

Multiple Choice

The heart is a muscular pump, about the size of your ______, that keeps the blood moving to every part of the body.

• foot
• fist
• face
• finger

​within the mediastinum lung border

​The heart is within the mediastinum, bordered laterally by the lungs, posteriorly by the vertebral column, and anteriorly by the sternum. The base of the heart, which attaches to several large blood vessels, lies beneath the second rib. The heart’s distal end extends downward and to the left, terminating as a bluntly pointed apex at the level of the fifth intercostal space.

​

​13.2 Size and Location of the Heart  

​- A Term given to refer to this area is Middle Mediastinum.

            Middle Mediastinum has 4 landmarks to define its area:

                        Anterior landmark - Sternum

                        Posterior landmark – Vertebral Column

                        Lateral landmarks – 2 lungs

 

                        Therefore, the mediastinum is area behind (posterior) the sternum but in front (anterior) of the vertebral column and between the 2 lungs.  It doesn’t include the lungs themselves.

 

- 2/3 of the heart’s mass lies to the left of the body's midline.

Multiple Choice

Which side of the heart pumps oxygen-rich blood to the rest of the body?

• Right
• Left

Multiple Choice

Which side of the heart pumps blood into the lungs?

• Right
• Left

Parietal Sac - AKA "Pericardium"

* The heart is enclosed in a membranous sac with 2 layers: parietal and visceral.

​

1. Parietal pericardium – the outer serous membrane

 

      * Fibrous pericardium – a layer of tough fibrous CT located on the outside of parietal pericardium.

 

       It is attached to the diaphragm, posterior portion of the sternum, the vertebra and the large vessels at the base of the heart.

​Tissue covering the heart

​The pericardium (per′′˘-kar ı ′de-um) encloses the heart and the proximal ends of the large blood vessels to which it attaches. The pericardium consists of an outer bag, the fibrous pericardium. The fibrous pericardium is dense connective tissue.

​

It is attached to the central portion of the diaphragm, the posterior of the sternum, the vertebral column, and the large blood vessels emerging from the heart.

​

​

Visceral pericardium- AKA "Epicardium"

the inner serous membrane made of simple epithelium.

 

      * This layer adheres to the myocardium itself.

 

     * Also, blood vessels that nourish the heart are located in the epicardium.

​Tissue covering the heart

​The fibrous pericardium surrounds a more delicate, double-layered sac.

​

The innermost layer of this sac, the visceral pericardium (epicardium), covers the heart. At the base of the heart, the visceral pericardium turns back on itself to become the parietal pericardium, which forms the inner lining of the fibrous pericardium (figs. 13.2 and 13.4; see reference plate 3, p. 25). Between the parietal and visceral layers of the pericardium is a space, the pericardial cavity, that contains a small volume of serous fluid (fig. 13.4). This fluid reduces friction between the pericardial membranes as the heart moves within them.

Clinical application: Pericarditis

​* Between the layers of the parietal sac is pericardial fluid which acts as a lubricant. 

Pericardial fluid is filtered plasma and it prevents friction between the membranes of the heart as it moves.

    * An over accumulation of fluid in the parietal sac caused by excessive over production of the pericardial fluid or failure to reabsorb the fluid can result in abnormal heart movements called Cardiac Tamponade.

 

Note: Cardiac Tamponade can also be associated with any trauma that results in bleeding into the pericardial sac.

Clinical application: Pericarditis

​In pericarditis, inflammation of the pericardium due to viral or bacterial infection produces adhesions that attach the layers of the pericardium to each other. This condition is very painful and interferes with heart movements.

Check Your Recall

​1. Where is the heart located?

​

2. Distinguish between the visceral pericardium and the parietal pericardium.

Multiple Choice

Name this part.

• Superior vena cava
• Right ventricle
• Inferior vena cava
• Pulmonary vein

Multiple Choice

Identify the structure the arrow is pointing to

• right atrium
• right ventricle
• left atrium
• left ventricle

Multiple Choice

The largest structures in your heart are the two chambers.

• False
• True

Multiple Choice

Identify the structure the arrow is pointing to

• right atrium
• right ventricle
• left atrium
• left ventricle

Multiple Choice

Name this part.

• Pulmonary veins
• Left atrium
• Aorta
• Pulmonary artery

Multiple Choice

Identify the structure the arrow is pointing to

• right atrium
• right ventricle
• left atrium
• left ventricle

Multiple Choice

Which is the correct sequence of blood flow through the heart and lungs?

• left ventricle, left atrium, lungs, right ventricle, right atrium
• right atrium, right ventricle, lungs, left atrium left ventricle
• lungs, right atrium, right ventricle, left atrium, left ventricle
• right atrium, right ventricle, left atrium, left ventricle, lungs

Multiple Choice

Identify the structure the arrow is pointing to

• right atrium
• right ventricle
• left atrium
• left ventricle

Multiple Choice

Name this part.

• Right atrium
• Left ventricle
• Right ventricle
• Left atrium

Multiple Choice

Identify the structure the arrow is pointing to

• Pulmonary Vein
• Pulmonary Artery
• Vena Cava
• Aorta

Multiple Choice

Name this part.

• Left ventricle
• Pulmonary artery
• Right atrium
• Pulmonary veins

Multiple Choice

Identify the structure the arrow is pointing to

• Pulmonary Vein
• Pulmonary Artery
• Vena Cava
• Aorta

Multiple Choice

Name this part.

• Superior vena cava
• Right ventricle
• Right atrium
• Inferior vena cava

Multiple Choice

Identify the structure the arrow is pointing to

• Pulmonary Vein
• Pulmonary Artery
• Vena Cava
• Aorta

Multiple Choice

Name this part.

• Right ventricle
• Pulmonary artery
• Left ventricle
• Right atrium

Multiple Choice

Identify the structure the arrow is pointing to

• Pulmonary Vein
• Pulmonary Artery
• Vena Cava
• Aorta

Multiple Choice

Identify the structure the arrow is pointing to

• Valves
• Septum
• Pulmonary
• Systemic

Multiple Choice

Identify the structure the arrow is pointing to

• Valves
• Septum
• Pulmonary
• Systemic

Multiple Choice

______ carry blood to the heart.

• Arteries
• Veins
• Capillaries
• Vena Cava

Multiple Choice

_____ carries blood away from the heart.

• Blood cells
• Veins
• Capillaries
• Arteries

Multiple Choice

Pulmonary circulation involves blood flow to and from the heart and the _______.

• body
• digestive organs
• brain
• lungs

Multiple Choice

The arteries that feed the heart muscle

• Capillaries
• Coronary
• Chordae teindineae
• Coronary sinus

Multiple Choice

Which valve(s) prevents backflow from of blood into the ventricles?

• Semilunar Valves
• Cardiac Valve
• Mitral Valve
• Tricuspid Valve

Multiple Choice

The _____ valve lies between the right atrium and right ventricle.

• bicuspid
• aortic semilunar
• pulmonary
• tricuspid

Multiple Choice

What is #3?

• Superior Vena Cava
• Right Pulmonary Vein
• Right Ventricle
• Right Atrium