Transcript snc2p u1l15 organs and organ systems in animals circulatory and respiratory systems

Lesson 15
February 8th, 2011
THE CIRCULATORY SYSTEM
BODY SYSTEMS WORKING TOGETHER MAINTAINING A STEADY STATE
Our body systems function in a way to maintain
homeostasis, which means “steady state.”
 An acceptable range of physical and chemical
conditions in which body cells, tissues, and
organs can operate efficiently.


To keep the body within this acceptable range,
different organ systems must work together to
maintain homeostasis in the body.
CIRCULATORY SYSTEM
The Circulatory system is the transport system for
the body and has four principle functions:
Two parts to the Circulatory system
1. Pulmonary circuit
 Right side of the heart
 Pumps blood to the lungs where blood picks up
oxygen and returns to the left side of the heart.
CIRCULATORY SYSTEM
Two parts to the Circulatory system
2. Systemic circuit
 Left side of the heart
 Pumps blood through arteries to the whole
body, they deliver oxygen and other materials.
CIRCULATORY SYSTEM
THE CIRCULATORY SYSTEM HAS AND HAS FOUR
PRINCIPLE FUNCTIONS
1.
2.
3.
4.
Transportation of oxygen and
carbon dioxide
Distribution of nutrients and
transport of wastes
Maintenance of body temperature
Circulation of hormones
THE CIRCULATORY SYSTEM - STRUCTURE
Three main components
1.
2.
3.
A fluid which transports materials (blood)
A system of blood vessels through which the
fluid moves.
A pump that pushes the fluid through the body
(heart)
HEART STRUCTURE

The mammalian heart consists of a double
pump separated by a wall of muscle called the
Septum. The pump on the right powers the
pulmonary circuit and the pump on the left
powers the systemic circuit.
HEART STRUCTURE
Each side contains:
 Atrium – (plural atria) receive blood from veins
and pump it into the ventricles.
 Ventricle - Pump blood to distant tissues.

Valves prevent blood from flowing backwards
through the system.
ATRIOVENTRICULAR VALVES

Tricuspid valve


located on the right side of the heart
Bicuspid Valve
 located

on the left side of the heart.
The Atriums contract together as do the
ventricles. When the valves close they create a
sound. This is why you heart has a lubb dubb
sound.
BLOOD VESSELS

Arteries are blood vessels that carry blood away
from the heart.
 Thick
walls
 Layers
of muscle and connective tissue

The Aorta leads from the left ventricle and
branches into the many arteries.
BLOOD VESSELS

To distribute blood to as many tissues as
possible, the arteries branch into smaller
vessels called arterioles, which branch into
capillaries.
 Blood

cells are exchanged at the capillary level.
Capillaries flow into venules which then lead to
veins which go back to the heart.
BLOOD VESSELS

Blood flow is greatly reduced in the veins but
must return to the heart. To help blood flow
back to the heart veins contain valves that
prevent the blood from flowing backwards.

Skeletal muscles also contribute to pumping
the blood back to the heart by squeezing the
veins during muscle contraction.
THE RESPIRATORY SYSTEM
•
All animals exchange gases with their
surroundings. Animals take in oxygen gas and
release carbon dioxide is the process of
respiration. The oxygen is used to react with
nutrients in the mitochondria to release energy.
Since we cannot store gases very well in our
bodies we are continually exchanging gases
with the atmosphere.
THE HUMAN RESPIRATORY SYSTEM
Air usually enters the reparatory system through
your nostrils where the following occurs:
 The nasal and oral cavities join at the back of
the mouth to form the Pharynx.
 Air passes from the pharynx, through the
trachea.
THE HUMAN RESPIRATORY SYSTEM
The trachea contains the larynx (voice box)
 Air from the trachea moves into two Bronchi
(singular bronchus)
 From there it goes into smaller tubes called
bronchioles

bronchioles continue to branch until they reach
a dead end of tiny air sacs called alveoli
 This is where gas exchange actually happens.
 Each lung contains around 150 million which
creates a huge about of surface area

A network of capillaries surround each cluster of
alveoli
–
–
–
The blood entering the network is low in oxygen
concentration and a high carbon dioxide
concentration.
CO2 is diffused out of the blood and O2 diffuses into
the blood.
The blood leaves the capillaries rich in O2
SYSTEMS THAT AID IN CLEANING THE AIR WE
BREATHE.

Dust and foreign particles are trapped and
filtered by tiny hairs and mucus in the nose

Goblet cells which produce mucus are located
on the trachea, bronchi and bronchioles.
 The
mucus traps bacteria, dust, pollen, which is
then carried out of the lungs by cilia.
 This is known as the bronchial escalator
HOW WE BREATHE
Breathing involves two stages.
1. Inspiration –(inhaling) – air is moved into the
lungs
•
2.
Expiration – (exhaling) – air is forced out of
the lungs.
Air moves in and out of the lungs due to a change
in pressure.

Air will always move from an area of high
pressure to an area of low pressure.
INSPIRATION

In order to decrease the air pressure in our
lungs two things happen.
1. The diaphragm contracts and moves down
ward
 The
diaphragm is a sheet of muscle at the
bottom of the ribcage.
INSPIRATION
2. The external intercostals muscles contract and
the ribcage moves upwards and out.
 This results in an increase in volume and a
decrease in pressure.
 Air
rushes into the lungs

The autonomic nervous system controls
inspiration and expiration by nerve impulses
SMOKING AND LUNG CANCER

Lung cancer is one of the most dreaded but
most preventable diseases. The number one
cause of lung cancer is cigarette smoke.
SMOKING AND LUNG CANCER
It kills around 18 000 people per year in
Canada
 It is related to around 87% of all lung
cancers responsible for 30% of all cancer
deaths
 Between 10,000-20,000 people die each
day from smoking (worldwide stat)

SMOKING AND LUNG CANCER

The smoke irritates the cells in the bronchi and
bronchioles
 This

causes the cells to secrete more mucus
A single cigarette can cause cilia to stop
moving for hours.
DISORDERS OF THE RESPIRATORY SYSTEM
Bronchitis
 Inflammation or swelling of the bronchi and
bronchioles.
 Caused by viral or bacterial infection or by
chemicals from smoking.
 Narrowing air passages plus extra mucus make
breathing more difficult.
 Coughing
is a reflex to help clear the pathways.
BRONCHIAL ASTHMA
3 million Canadians suffer from it.
 Usually caused by allergic reaction to a foreign
substance

 Excess
mucus is produced
 Muscles surrounding the bronchi and bronchioles
spasm making it difficult to breath.

Inhalers (puffers) cause the bronchi and
bronchioles to increase in diameter.
QUESTIONS: HOMEWORK
How is the respiratory system related to the
circulatory system?
 Where does the diffusion of gases occur in the
respiratory system?
 How does Inspiration occur?
 How does the inflammation of the bronchi and
bronchioles affect breathing?
 What are the main functions of the circulatory
system?

If shown a blood vessel attached to the heart.
How could you tell if it was an artery or a vein?
 What is the only artery that carries
deoxygenated (used blood) blood away from the
heart?
 What special feature do veins have that help to
bring blood back to the heart and prevent
pooling in the legs?

A LOOK AT BREATHING – LAB – HAND IN

When you breathe, you move about 500 mL of
air in and out of your lungs. Usually we are not
aware of our breathing. What can you learn
about how you breathe if you concentrate on
your breathing?