Download Human Circulatory System

BILL
Why does the body need oxygen?
 How does the body get required oxygen
into the body?

Needs oxygen to produce ATP through
cell respiration
 Inhales gases through the lungs, which
enters the bloodstream and diffuse into
the body cells (Respiratory system)

Ventilation, Gas Exchange and
Respiration
Ventilation is defined as the inhalation
and exhalation of air.
 Gas Exchange is the diffusion of gases
results in gas exchange.

 2 main sites of gas exchange:
 Lungs – Oxygen moves from lungs to blood,
and CO2 moves opposite
 Capillary beds – Oxygen diffuses out of
blood stream into body cells and CO2 moves
from tissues to blood.
What is Respiration

Respiration – the release of carbon
dioxide and the uptake of oxygen within
the cells to produce energy

The human circulatory system brings
about the exchange of oxygen and
carbon dioxide between the blood, the
air, and the tissues
Reasons for need of ventilation
system
Our bodies simply are too large to allow
for simple diffusion of gases across a
membrane (similar to amoeba).
 Ventilation system must also work to
ensure that the concentration of gases
to be beneficial to body.

 Major concentration gradient allows for
diffusion of gases within our bodies.
Major Structures
Nose

Trachea
Pharynx

Bronchi


 Bronchioles

Larynx

Lungs
 Alveoli
 Capillary
Movement of Air

With each breath, air enters the body
through the air passages and fills the
lungs, where gas exchange takes place

Air enters the body through passages
that include the nose and the mouth
Movement of Air
Movement of Air
Pharynx


Serves as a passageway for
both air and food
Air travels down the pharynx
into the
Larynx


Located at the top of the
trachea
Contains the vocal cords
Trachea

rings of cartilage maintain
shape of “windpipe”
Movement of Air
Trachea branches into
Bronchi
 Air passes into two large
passageways in the chest
cavity
 Each bronchus leads into
one of the lungs and
subdivides into smaller
bronchi called bronchioles
Movement of Air

The bronchioles subdivide until they
reach millions of tiny air sacs called
alveoli
Alveoli
 Grouped in clusters
 Surrounded by capillaries for gas
exchange
Features of Alveoli
Adaptation
Advantage
Spherical shape
Provides a large surface area for
efficient gas exchange.
Flattened, single cell thickness
Allows for easy exchange (doesn’t
have to travel through thick cell
layers)
Moist inner lining of alveolus
Assists in diffusion
Associated capillary bed
Gases can enter blood stream
quickly and efficiently.
Movement of Air
Alveoli Sacs
Gas Exchange Within Alveoli

Oxygen dissolves in the alveoli and then
diffuses across the thin-walled
capillaries into the blood

Carbon dioxide in the bloodstream
diffuses in the opposite direction, across
the membrane of an alveolus and into
the air within it
Gas Exchange

Air that is inhaled contains:
 21% oxygen
 And .04% carbon dioxide

There are 150 million alveoli in each
lung, providing an enormous surface
area for gas exchange
BILL

Draw and label the parts of respiratory
system (pg. 170). Include the following:
nose, pharynx, larynx, trachea, bronchi,
bronchioles, lungs, alveoli.
Breathing

Movement of air into and out of lungs

Ordinary air pressure drives air into
lungs

How does the body use this force to
inflate the lungs?
Mechanism of Breathing

Key Points:
 Lungs do not contain muscle, therefore they are
unable to perform any purposeful movement.
 Lungs rely totally on the surrounding muscle to
force air in and out (diaphragm, abdomen and
intercostal muscles).
 The lungs are sealed in two sacs, called the
pleural membranes, inside the thoracic (chest)
cavity, creating a closed environment
Mechanism of Breathing

Based on inverse relationship of pressure
and volume
 As volume increases, pressure decreases and
vice versa
Mechanism of Breathing
1.
2.
3.
4.
5.
Inhalation causes the diaphragm to contract and the
abdominal and intercostal muscles help raise the rib
cage, increasing the volume of the thoracic cavity
As volume increases, the pressure of the cavity
decreases, leading to less pressure pushing on the
lungs
The volume of lung tissue increases, because of the
decreased pressure
The pressure inside the lungs now decreases, creating
a partial vacuum
Air comes in through the oral/nasal cavity because of
the vacuum and fills the alveoli of lungs with air
Breathing
Breathing

Exhaling is a passive event and the
steps of inhalation are reversed.

The diaphragm muscle relaxes, causing
the rib cage to lower and decreasing
volume of cavity, air rushes out of the
lungs due to increased pressure
Breathing
Breathing
Breathing Animation
How is Breathing Controlled?
Medulla oblongata controls breathing in
the brain
Medulla Oblongata  Monitors the amount of carbon dioxide
in the blood
 As carbon dioxide rises, impulses from
brain cause diaphragm to contract,
bringing air into lungs

Respiratory Disorders
Pneumonia is a common lung infection
caused by bacteria, a virus, or fungi.
 Inflammation of the alveoli, the results in
an excess lining inside of lungs
 Can result in a buildup of fluids inside
the lungs
 Treated with rest, fluids, and aspirin/antiinflammatory drugs to treat fever

Respiratory Disorders
Bronchitis is an inflammation of the
lining of the bronchial tubes.
 May develop from a cold or other
respiratory infections
 Treated with rest, fluids, and possibly
prescription for bronchodilator or oral
steroids

Heart Lung Machine

http://il.youtube.com/watch?v=DUGXO-6MOn0

http://il.youtube.com/watch?v=RlRi3R9LXng&featur
e=related