The Circulatory System Mrs. Legro’s 6 - PowerPoint Presentation

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The Circulatory System

Mrs. Legro’s 6

th

Grade Science

2017 - 2018

Objectives & Vocabulary

Compare and contrast arteries, veins and capillaries.

Explain how blood moves through the heart.

Identify the functions of the pulmonary and systemic circulation systems.

Vocabulary Words

Atrium

Ventricle

Coronary circulation

Pulmonary circulation

Systemic circulation

Artery

Vein

Capillary

Also referred to as the “Cardiovascular System”

Makes up the network that delivers blood to the body’s tissues.

With each heartbeat, blood is sent throughout our bodies, carrying oxygen and nutrients to all of our cells.

It is divided into three sections:Coronary circulation: heartPulmonary circulation: heart to lungsSystemic circulation: heart to body

The beating of your heart controls blood flow through each section.

What is The Circulatory System?

Coronary Circulation: Heart

The heart is the key organ of the circulatory system

Main function is to propel blood throughout the body

Usually beats 60 – 100 times per minute

More than 30 million times per year

About 2.5 billion times in a 70-year lifetime.

The heart consists of 4 compartments called chambers:

Two upper chambers: right and left

atriums (atria)

.Receive the blood entering the heart.Two lower chambers: right and left ventricles

.

Pumps blood out of the heart.These valves separate the ventricles and atria:

The

tricuspid valve

separates right atrium from right ventricle.The mitral valve separates left atrium from left ventricle.

Two other important valves:

Pulmonary valve: It is a one-way valve that allows blood to leave the heart via the arteries. It’s opened by the increased blood pressure (systole).Aortic valve: It is a one-way valve that lets blood from the LV be pumped up (ejected) into the aorta.All valves are one-way

Anatomy of the Heart

The heart has two main veins

:

Superior

Vena Cava: this large vein carries deoxygenated blood into the heart from the upper portion of the body and empties into the right atrium.Inferior Vena

Cava: this large vein carries

deoxygenated blood into the heart from the lower portion of the body and empties into the right atrium.

Pulmonary

Artery:

deoxygenated

blood that enters

here is carried to the lungs.Pulmonary Vein: Oxygenated blood returns to the heart via the pulmonary veins.Aorta: the body’s largest artery. It supplies oxygenated blood to the circulatory system.Anatomy of the Heart

It is the flow of blood through the heart to the lungs and back to the heart. It carries

deoxygenated

blood away from the heart, to the lungs, and returns

oxygenated blood back to the heart.

Pulmonary Circulation

Systemic Circulation

The movement of oxygen-rich blood to all of your organs and body tissues (except heart and lungs)

It is the largest of the three sections of your circulatory system.

How Systemic Circulation Works

Oxygen-rich blood flows from your heart in the arteries of this system.

Then

nutrients and oxygen are delivered by blood to your body cells and exchanged for carbon dioxide and wastes.Finally, the blood returns to your heart in the veins of the systemic circulation system.

Arteries, Veins, Capillaries

Arteries

are blood vessels that carry blood away from the heart.

Thick, elastic walls made of connective tissue and smooth muscle tissue.

Each

ventricle of the heart is connected to an artery.Every time your heart contracts, blood is moved from your heart into arteries.

Arterial walls have three layers:

Endothelium:

is on the inside and provides a smooth lining for blood to flow over as it moves through the artery.Media: is the middle part of the artery, made up of a layer of muscle and elastic tissue.Adventitia:

is the tough covering that protects the outside of the artery.

Veins have the same three layers as arteries, but veins are thinner and less flexible.

Arteries, Veins, Capillaries

Veins

are the blood vessels that carry blood back to the heart

.

They contain valves that prevent blood from flowing backward.

Arteries, Veins, Capillaries

Capillaries

are microscopic blood vessels that connect arteries and veins.

The walls

are very thin - only one cell thick.Nutrients and oxygen diffuse into body cells through the thin capillary walls.Waste materials and carbon dioxide diffuse from body cells into the capillaries.

Arteries, Veins, Capillaries

Putting it all together

…

How Does the Heart Work?

One complete heartbeat makes up your

cardiac cycle,

which consists of 2 phases.

First phase is the ventricles contracting. This is called

systole

.

This sends blood into pulmonary and systemic circulation.

The second phase is when your ventricles relax. This is called

diastole

.This causes the ventricles to fill with blood from the atria. The cycle then starts again.https://www.youtube.com/watch?v=CWFyxn0qDEU

Your Heart is an Electrical Machine!

An electrical system in the heart causes it to beat in its regular rhythm.

The

SA node (sinoatrial node) is a small area of tissue in the wall of the right atrium. The SA node sends out an electrical signal to start the contracting of the heart muscle.

These electrical impulses cause the atria to contract first.

The electrical impulses then travel down to the

AV node (atrioventricular node)

, which acts like a relay station.

From here, the electrical signal travels through the right and left ventricles, causing them to contract and force blood out into the major arteries.

Oxygen-poor blood

fills the

RA

and then flows to the RV, where it is pumped to the lungs through the PA’s.

How Does the Blood Flow?

The lungs refresh the blood with a new supply of oxygen, which comes from the air you breathe in.

The now

oxygen-rich blood

, returns from the lungs and enters the

LA

. The oxygen-rich blood then flows from the LA to the LV. The blood is then pumped through the main artery that supplies blood to the body, called the aorta, to supply tissues throughout your body with oxygen.

Your heart is nourished by blood, too.

Oxygen-rich blood

is delivered by

coronary arteries

that extend over the surface of your heart.

RA:

Right Atrium

RV:

Right Ventricle

PA:

Pulmonary Artery

LA:

Left Atrium

LV:

Left Ventricle

How Does the Blood Flow?

https://

www.mayoclinic.org/diseases-conditions/heart-disease/multimedia/circulatory-system/vid-20084745

Things That Can Go Wrong

Cardiovascular Disease:

any disease that affects the heart, blood vessels and blood.

Atherosclerosis: Fatty deposits build up on arterial walls. This can happen by eating foods high in cholesterol and saturated fats.If a coronary artery is blocked, a heart attack can occur.

Hypertension:

Also known as high blood pressure. When blood pressure is higher than normal most of the time, extra strain is placed on the heart-the heart has to work harder to keep blood flowing.

Atherosclerosis can cause hypertension.

Heart Failure:

This occurs when the hear cannot pump blood efficiently.May be caused when heart muscle tissue is weakened by disease or when heart valves do not work properly.

What Does Atherosclerosis Look Like?

https://www.ypo.education/heart/atherosclerosis-t33/video/