Download The Circulatory and Respiratory Systems

These slimy
looking
things are
keeping you
alive right
now!
The Circulatory
& Respiratory Systems
Getting stuff where it needs to go!
What do these systems do?
The circulatory and
respiratory systems work
together to bring oxygen
and nutrients to and
remove waste from
working cells.
Major Components of the Circulatory System:
Blood Vessels
Heart
Blood
Lymph Nodes
Lymphatic Vessels
The Heart


The heart is the central organ of the cardiovascular
system.
It beats more than 2.5 BILLION times in an average
life span!
Heart Anatomy

The septum vertically divides
the heart into two sides.


The right side pumps blood to
the lungs, and the left side pumps
blood to other parts of the body.
Each side has an two chambers:



The upper chambers are called
atria (singular – atrium).
The lower chambers are called
ventricles.
Blood flows from the atria to the
ventricles.
A simplified view of blood circulation
through the heart:
Blood Vessels

There are three types of blood vessels:
1.
2.
3.

Arteries
Capillaries
Veins
They allow blood to
travel in between the
heart, lungs, and body
tissues in one
direction only.
Arteries

Arteries are the large, muscular
vessels that carry blood away
from the heart.


(think: “Artery – Away”)
Arteries have three main layers:
1.
2.
3.
A layer of endothelial tissue on
the inside
A thick layer of smooth muscle
tissue in the middle
Connective tissue on the outside
Capillaries


Arteries branch off into
smaller and smaller
vessels, eventually
branching into a
network of tiny vessels
called capillaries.
The walls of capillaries
are only one cell thick
so that gases and
nutrients can diffuse
into and out of cells.
Capillaries

Capillaries are so thin that red blood cells
must travel single file!!
Veins



Capillaries then merge to
form larger and larger
vessels, eventually forming
veins.
Veins carry blood back to the
heart.
Veins also have three layers:
1.
2.
3.
Endothelial tissue on the
inside
A thin layer of smooth
muscle tissue in the middle
A layer of connective tissue
on the outside.
Veins

Veins also have valves, which prevent blood from flowing
backward.

Because they
only have a
thin layer of
muscle, veins
rely on the
squeezing of
skeletal
muscles to
help them
return blood
to the heart.
Some cross-section comparisons:
Here’s what happens to your arteries when
you eat too many cheeseburgers!
The Lymphatic System

The circulatory system
also includes the
lymphatic system, which
returns fluids from the
body tissues to the blood
stream.


The fluid is called lymph.
Lymph vessels are similar
to the heart in that they
rely on the squeezing of
skeletal muscle to help
move the fluid inside, and
have valves to prevent
backflow.
Lymphatic vessel
with valve (V)
Your body has a huge network of lymph
vessels!

On its way back to the bloodstream, lymph will pass through
lymph nodes, which trap foreign particles, and play a role in
fighting disease.
Blood


Blood is a liquid connective tissue that transports
nutrients and gases through the body.
Blood is composed of:




Plasma (55%)
Red Blood Cells (45%)
White Blood Cells (<1%)
Platelets (<1%)
Plasma


Plasma is a sticky, straw-colored fluid that’s 90% water.
Substances like vitamins, minerals, amino acids, glucose,
and hormones are dissolved in plasma.
Red Blood Cells



Also known as
erythrocytes, red blood
cells (RBCs) are formed in
bone marrow.
RBCs contain hemoglobin,
which is the molecule that
actually transports oxygen,
and carbon dioxide.
You have more than 30
trillion RBCs circulating in
your body.

2 million of these die and
are replaced every second!
White Blood Cells


Also known as
leukocytes, these cells
help to defend the
body against disease.
There are several
different types of
white blood cells that
perform different jobs
to help in body
defense.
Platelets


Platelets are fragments of
very large cells formed in
the bone marrow.
They congregate at the
site of the wound, sticking
together to form a plug
that will eventually harden
into a clot or scab.
Major Components of the Respiratory System:





Pharynx
Larynx
Trachea
Bronchi
Lungs



Bronchioles
Alveoli
Diaphragm
There are two kinds of respiration:

External respiration is
the exchange of gases
between the
atmosphere and the
blood.

Internal respiration is
the exchange of gases
between the blood and
cells of the body.
Anatomy of the Respiratory System

Air passes from the
atmosphere into:




the mouth and
nose, where it is
moistened &
filtered,
the pharynx, the
larynx,
then the trachea,
which branches
into:
two bronchi, each
of which leads into
a lung.
The Lungs

Each bronchus
branches into
smaller and smaller
tubes, eventually
branching into the
smallest, which are
called bronchioles.

The bronchioles
end in tiny air sacs
called alveoli.
The Lungs

Alveoli



A network of capillaries surrounds each alveolus.
External gas exchange occurs between the air in the alveolus and blood
in the capillaries.
The structure of alveoli increases the surface area of the lungs,
maximizing the amount of gas exchange that can occur.
Gas exchange in the lungs



Blood coming from the body
is low in oxygen and high in
carbon dioxide.
Air in the alveoli is high in
oxygen and low in carbon
dioxide.
These differing
concentrations allow oxygen
to travel from the air into
the blood, and carbon
dioxide to travel from the
blood into the air.
The Mechanism of Breathing


“Breathing in” is called inspiration or inhalation.
“Breathing out” is called expiration or exhalation.
Inspiration


When you take a deep
breath, your chest
expands and ribs
move up and out.
At the same time, the
diaphragm flattens and
pushes down on the
abdomen.

This increases volume
and lowers air
pressure, causing air to
rush into the lungs.
Expiration

During expiration, the exact opposite process takes place.

Diaphragm and ribs relax, reducing volume and increasing
pressure.

This forces air out of the lungs into the atmosphere.
Here’s what smoking does to your lungs!