2) Heart and Fetal Circulation

Cardiovascular System - Major Components

– Heart

– Blood vessels

– Blood

Cardiovascular System - Major Function

– Transportation

• Nutrients and Oxygen

• Waste Products

• Hormones

Location of the heart in body

Middle mediastinum

Heart - 2 Circuits

Pulmonary & Systemic

Hint for identifying pulmonary circuit

pulm = lu

Pulmonary Circuit

_____ side of heart pumps blood to lungs, then it goes back to _____side of heart

Right, left

Hint for Identifying Systemic Circuit

System = Body

Systemic Circuit

_____ side of heart pumps blood to the body, then it goes back to _____side of heart

Left, right

Why does blood need to go to the lungs?

To become oxygenated

What parts of the body does this blood go to?

Everywhere

Pathway of Blood Through the Mature Heart

Right Side

Deoxygenated blood FROM body enters right side of heart & gets pumped TO lungs

Pathway of Blood Through the Mature Heart

Left Side

Oxygenated blood FROM lungs enters left side of heart & gets pumped TO body

Chambers of the Heart

Vein =

Take blood towards heart

Bump into atria

Chambers of the Heart

Artery =

Take blood away from heart

Leave via ventricles

Great Vessels of the Heart

Superior vena cava (SVC)

Inferior vena cava (IVC)

Pulmonary veins

Pulmonary trunk & arteries

Aorta

Great Vessels of the Heart: Veins

Superior vena cava (SVC)

Inferior vena cava (IVC)

Pulmonary veins

Great Vessels of the Heart: Arteries

Pulmonary trunk & arteries

Aorta

SVC

Returns blood from thoracic wall, upper limb, head and neck

IVC

Returns blood from the abdomen, pelvis, and lower limb

Entering & Exiting the Right Side

Right Atrium of heart - Anterior

Receives deoxygenated blood from:

1. Superior vena cava

2. Inferior vena cava

3. Coronary sinus*

Entering & Exiting the Right Side

Right ventricle - Anterior

Discharges deoxygenated blood into the pulmonary circuit via the:

1. Pulmonary trunk; splits into pulmonary arteries*

Entering & Exiting the Right Side

Right atrium - Posterior

Receives deoxygenated blood from:

1. Superior vena cava

2. Inferior vena cava

3. Coronary sinus

Entering & Exiting the Right Side

Right ventricle - Posterior

Discharges deoxygenated blood into the pulmonary circuit via the:

1. Pulmonary trunk; bifurcates into right and left pulmonary arteries

Entering & Exiting the Left Side

Left atrium - Anterior

Receives oxygenated blood from

1. Four pulmonary veins*

1. 2 Right pulmonary v.

2. 2 Left pulmonary v.

Entering & Exiting the Left Side
Left ventricle - Anterior

Discharges oxygenated blood into the systemic circuit via the:

1. Aorta; ascending aorta, arch of aorta, descending aorta

Entering & Exiting the Left Side

Left atrium - Posterior

Receives oxygenated blood from

1. Four pulmonary veins

1. 2 Right pulmonary v.

2. 2 Left pulmonary v.

Entering & Exiting the Left Side

Left ventricle - Posterior

Discharges oxygenated blood into the systemic circuit via the:

1. Aorta; ascending aorta, arch of aorta, descending aorta

Oxygenated blood travels in:

Arteries and Veins

• Arteries away from heart

• Veins towards heart

The RIGHT side of the heart receives ___________ blood from the body, and pumps it to the lungs.

deoxygenated

The RIGHT side of the heart receives deoxygenated blood from the _____, and pumps it to the lungs.

body

The RIGHT side of the heart receives deoxygenated blood from the body, and pumps it to the _____.

lungs

The LEFT side of the heart receives ___________ blood from the lungs, and pumps it to the body.

oxygenated

The LEFT side of the heart receives oxygenated blood from the _____ , and pumps it to the body.

lungs

The LEFT side of the heart receives oxygenated blood from the lungs, and pumps it to the _____.

body

How do we prevent backflow in chambers?

Valves

Valves of the heart: Atrioventricular Valves

Between atria & ventricles

Valves of the heart: Semilunar Valves

Between ventricles & outflow arteries

Atrioventricular valves prevent backflow into _____

atria

Semilunar valves prevent backflow into _____

ventricles

Atrioventricular Valves: Tricuspid Valve

*Tri=3

“Try (tri) before you buy (bi)”

Between right atrium and right ventricle

Atrioventricular Valves: Bicuspid or Mitral Valve

*Bi =2

“Try (tri) before you buy (bi)”

Between left atrium and left ventricle

Atrioventricular Valves: Tricuspid Valve

Left or Right?

Right

Atrioventricular Valves: Bicuspid or Mitral Valve

Left or Right?

Left

Semilunar Valves: Pulmonary Semilunar Valve

Left or Right? Where?

Right → lungs

Semilunar Valves: Aortic Semilunar Valve

Left or Right? Where

Left → aorta

Semilunar Valves: Pulmonary Semilunar Valve

Between right ventricle and pulmonary trunk

Semilunar Valves: Aortic Semilunar Valve

Between left ventricle and aorta

Heart Contraction & Sounds

Systole

Ventricles contract to pump blood out of the heart

– Tricuspid & bicuspid valves close (don’t want back-flow)

– Together, these are S1 (“lub”)

Heart Contraction & Sounds

Diastole

Ventricles relax so blood can fill them again

– Tricuspid & bicuspid valves open, and the pulmonary and aortic

semilunar valves close (don’t want back-flow from outflow vessels)

– This is S2 (“dub”)

Layers of the Heart

Arterial Coronary Circulation: Maximal blood flow to the _____ occurs when the heart is relaxed (diastole)

myocardium

Arterial Coronary Circulation: There is very little blood flow through the _____ when the heart is contracting (systole):

• Contraction of myocardium compresses coronary arteries

• Entrances into the coronary circulation are partially blocked by the cusps of the open aortic semilunar valve

coronary circulation

Arterial Coronary Circulation: There is very little blood flow through the coronary circulation when the heart is contracting (systole):

• Contraction of myocardium _____ coronary arteries

• Entrances into the coronary circulation are partially blocked by the cusps of the open aortic semilunar valve

compresses

Arterial Coronary Circulation: There is very little blood flow through the coronary circulation when the heart is contracting (systole):

• Contraction of myocardium compresses coronary arteries

• Entrances into the coronary circulation _____ the cusps of the open aortic semilunar valve

are partially blocked by

Anterior interventricular artery (Lower arrow on right side

• Coronary a. disease

• Plaque build up

*Coronary = “crown”

Memorize the Arterial Coronary Circulation

Memorize the Venous Coronary Circulation

Memorize all coronary Circulation

Memorize Intrinsic Conduction System

Intrinsic Conduction System

The rate of the intrinsic cardiac muscle contraction set by these pacemaker cells is altered by the sympathetic (_____________) and by the parasympathetic (_____________) divisions of the autonomic nervous system.

accelerates the heartbeat, decelerates the heartbeat

Parasympathetic - Intrinsic Conduction System

*Parasympathetic = Rest + Digest

Lowers heart rate

Sympathetic - Intrinsic Conduction System

*Sympathetic = Fight or Flight

Increases heart rate

Fetal vs. Post-natal Circulation

Fetus has _____ lungs

Fetus has non-functioning lungs

Fetal vs. Post-natal Circulation

Fetus _____ provide its own nutrients

can not

Fetal vs. Post-natal Circulation

Fetus can not remove its own _____

waste

• Fetus has non-functioning lungs

• Fetus can not provide its own nutrients

• Fetus can not remove its own waste

What must fetus use to compensate for these deficiencies?

Use the mother’s circulation

Fetal Circulation – Placenta

The placenta develops in the uterus alongside the fetus to allow _____ to communicate.

maternal and fetal blood

Fetal Circulation – Placenta

The placenta develops in the uterus alongside the fetus to allow maternal and fetal blood to communicate.

• This communication occurs via ______

umbilical vessels in the umbilical cord

Fetal Circulation – Placenta

The placenta develops in the uterus alongside the fetus to allow maternal and fetal blood to communicate.

• This communication occurs via umbilical vessels in the umbilical cord

• 1 umbilical vein (towards!)

• Bringing oxygen and nutrients TO the fetal heart. Why is this

oxygenated?

From mothers circulation

Fetal Circulation – Placenta

The placenta develops in the uterus alongside the fetus to allow maternal and fetal blood to communicate.

• This communication occurs via umbilical vessels in the umbilical cord

• 1 umbilical vein (towards!)

• Bringing oxygen and nutrients TO the fetal heart. Why is this

oxygenated?

• 2 umbilical arteries (away!)

• Take deoxygenated blood _____ the fetal hear

AWAY from

Fetal Circulation:

_____ passes through primitive liver and carries oxygenated blood to the IVC

Umbilical vein

Umbilical vein regresses to form the _____, which is found within the inferior edge of the falciform ligament

ligamentum teres (round ligament of the liver)

Fetal Circulation

The _____ is a hole that shunts blood from the right atrium to the left atrium to bypass the lungs

foramen ovale

Fetal Circulation - Foramen Ovale

Small amount of blood flows to _____ to nourish the tissue

the lungs

Closure after birth forms the _____

fossa ovalis

Fetal Circulation

The _____ shunts blood that made it to the left pulmonary artery to the aorta

ductus arteriosus

Fetal Circulation - ductus arteriosus

Closure after birth forms the _____

ligamentum arteriosum

Derivatives Summarized:

Umbilical vein —>

Ligamentum teres

Foramen ovale —>

Fossa ovalis

Foramen ovale —>

Ligamentum arteriosum

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