Transcript 30.1 Respiratory and Circulatory Functions

30.1 Respiratory and Circulatory Functions
KEY CONCEPT
The respiratory and circulatory systems bring oxygen
and nutrients to the cells.
30.1 Respiratory and Circulatory Functions
The respiratory and circulatory systems work together to
maintain homeostasis.
• The circulatory system transports
blood and other materials.
– brings supplies to cells
– carries away wastes
– separates oxygen-poor and
oxygen-rich blood
Oxygen-rich blood
Oxygen-poor blood
30.1 Respiratory and Circulatory Functions
• The respiratory system is where gas exchange occurs.
– picks up oxygen from inhaled air
– expels carbon dioxide and water
sinus
nose
mouth
epiglottis
trachea
lungs
30.1 Respiratory and Circulatory Functions
The respiratory system moves gases into and out of the
blood.
• The lungs contain the bronchi, bronchioles, and alveoli.
• Millions of alveoli give the lungs a huge surface area.
• The alveoli absorb oxygen from the air you inhale.
alveoli
bronchiole
30.1 Respiratory and Circulatory Functions
• Breathing involves the diaphragm and muscles of the rib
cage.
• Air flows from areas of high pressure to low pressure.
Air inhaled.
Air exhaled.
Muscles and
rib cage relax.
Muscles contract and
rib cage expands.
Diaphragm flattens
and moves downward.
Diaphragm relaxes
and rises.
30.1 Respiratory and Circulatory Functions
The circulatory system moves blood to all parts of the
body.
• The system includes the heart,
arteries, veins, and capillaries.
– heart pumps blood throughout body
– arteries move blood away from
heart
– veins move blood back to heart
– capillaries get blood to and from
cells
arteries
veins
30.2 Respiration and Gas Exchange
Respiratory diseases interfere with gas exchange.
• Lung diseases reduce airflow and oxygen absorption.
– Emphysema destroys alveoli.
– Asthma constricts airways.
– Cystic fibrosis produces sticky mucus.
30.2 Respiration and Gas Exchange
• Smoking is the leading cause of lung diseases.
30.3 The Heart and Circulation
KEY CONCEPT
The heart is a muscular pump that moves the blood
through two pathways.
30.3 The Heart and Circulation
The tissues and structures of the heart make it an
efficient pump.
• Cardiac muscle tissue works continuously without tiring.
NORMAL HUMAN HEART
30.3 The Heart and Circulation
• The heart has four chambers: two atria, two ventricles.
• Valves in each chamber prevent backflow of blood.
pulmonary valve
aortic valve
left atrium
right atrium
mitral valve
left ventricle
tricuspid
right ventricle
septum
• Muscles squeeze the chambers in a powerful pumping
action.
30.3 The Heart and Circulation
• Blood flows through the heart in a specific pathway.
– oxygen-poor blood enters right atrium, then right
ventricle
– right ventricle pumps blood to lungs
– oxygen-rich blood from lungs enters left atrium, then left
ventricle
– left ventricle pumps blood to body
30.3 The Heart and Circulation
• Blood pressure is a measure of the force of blood pushing
against artery walls.
– systolic pressure:
left ventricle
contracts
– diastolic pressure:
left ventricle
relaxes
• High blood pressure can precede a heart attack or stroke.