Unit 3 - Cardiovascular

Describe the general functions of Blood

Transportation

• Blood transports oxygen, carbon dioxide, nutrients, waste, and hormones

Regulation

• Blood regulates the body temperature by carrying heat across body.

• Blood also helps regulate the pH of the body (acidic vs basic) w/ CO2 movement, and regulates fluid balance across the body

Protection

• WBC and antibodies in the blood protect against infection.

Compare and contrast Pulmonary vs Systemic circulation

Heart: pump @ center moving fluid for 2 circulating system

Pulmonary circulation: delivers blood to the lungs where it gets oxygenated

Systemic circulation: brings blood to all the tissues in the body, thus bringing oxygen to all the cells of the body and removing carbon dioxide

Describe the position of the heart in the thoracic cavity.

Heart is positioned:

• in thoracic cavity

• left of midline

• titled posterior to the sternum for protection of heart

Explain the structural and functional differences between the atria and the ventricles.

• The top 2 chambers seen anteriorly are called atria (sing. atrium)

• The bottom 2 chambers seen anteriorly are ventricles

• The posteriosuperior region is flat and called the base

• The inferior, pointed end is the apex

Pericardium

• Fibrous sac that contains the heart

• Functions:

  • Restricts heart’s movement within thorax, so it does NOT move from thorax

  • Prevents overflow (by restricting how expansive the heart can be)

• Location:

  • attached

    • superior to large vessels leaving heart

    • inferior to diaphragm

Wall of the heart

Areolar CT and endothelium are so close to each that nothing can get through

Label the Auricle, Coronary sulcus, Anterior interventricular sulculus

Define them

Auricle: anterior flap-like extension at each atrium that expands the volume

Sulcus: large grooves on external surface of the heart

Coronary vessels: nest in sulci

Coronary sulcus: divides the atria from ventricles

Interventri sulci: divide the ventricles from each other (posterior and anterior)

coronary sinus + posterior interventricular sulcus

coronary sinus inside the coronary sulcus

Internal Anatomy - Right atrium

• Blood is received from the venous systemic circulation by the right
  atrium

  • 3 vessels empty into the right atria: superior vena cava, inferior vena cava, and the coronary sinus

• Intratrial septum

  • is the thin wall between the atria

• Fossa ovalis

  • depression in intratrial septum

  • was a hole from the fetal period that closed.

• Blood leaves the R. atria through the atrioventricular (AV) opening
  when the AV valve (sometimes called tricuspid valve) opens.
  

Fetal vs Adult heart

Fetal heart

• gets O2 from person who’s pregnant

• fetus is NOT breathing so they have foramen ovale as shortcut but still have for practice

Internal Anatomy - Right Ventricle (Part 1)

• Receives blood from Right Atrium

• Chordae tendinae:

  • fibrous cords that anchor AV valve to the ventricle walls

    • this keep AV valve from flipping backwards when the ventricle contracts —→ one directional flow
      

AV valves function

• AV valves open when atrial pressure is greater than ventricular pressure

• AV valves close when atrial pressure is less than ventricular pressure

Internal Anatomy - Right Ventricle (Part 2)

• Right ventricle contracts,

  • forces the blood upwards via the pulmonary semilunar valve, into the pulmonary trunk

• The pulmonary trunk splits into pulmonary arteries that bring
  deoxygenated blood to the lungs for gas exchange.
  

Heart Valves Function

1. Pressure forces blood via semilunar valves

2. Pressure goes —> semilunar valves closes,

• this makes cup that holds blood up

• the more blood sits in cup —> the more the valve is closed shut —> making an impenetrable seal

Internal Anatomy - Left Atrium

• The pulmonary veins bring the now-oxygenated blood to the left
  atrium

• The left atrium also has an auricle

• The blood flows anterio-inferiorly to the ventricle via the
  atrioventricular opening when the AV valve opens

*** left AV valve = bicuspid valve = mitral valve ****

Internal Anatomy - Left Ventricle

left ventricle contracts,

• forcing blood through the aortic semilunar valve and into the aorta

Ventricular walls

Left ventricular wall is thicker than Right ventricular wall

• b/c it has to pump for systemic circuit, needing strong pump

Meanwhile right ventricular wall

• pumps blood to shorter distance (lungs)

• lower pressure, so body is exposed to more oxygen

Ventricular Contraction and the Myocardial Vortex

Twist motion

• occurs when contracting in order to cause bigger pressure

Coronary Circulation

• The left and right coronary arteries exit the aorta and feed the cardiac
  muscle itself.

• They branch into smaller blood vessels

• The venous return (deoxygenated blood) occurs through the cardiac
  veins (merge into coronary sinus)

• Blood flows in the coronary vessels during the periods between heart
  contractions.

  • Blood flow is impaired when the heart beats excessively
    (tachycardia)
    

3 Types of Blood vessels

Arteries:

• carry blood AWAY from heart

Capillaries

• site for O2 diffusion

Veins

• carry blood TO from heart