KEY CONCEPT The respiratory and circulatory systems bring oxygen and nutrients to the cells.

Oxygen-poor blood

Oxygen-rich blood

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

• The respiratory system is where gas exchange occurs.– picks up oxygen from inhaled air – expels carbon dioxide and water

nose

sinus

mouth

epiglottistrachea

lungs

When you stand up after lying down, why do your heart rate and breathing rate increase?

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.

alveolibronchiole

• Breathing involves the diaphragm and muscles of the rib cage. • Air flows from areas of high pressure to low pressure.

Air inhaled.

Muscles contract andrib cage expands.

Diaphragm flattensand moves downward.

Air exhaled.

Muscles andrib cage relax.

Diaphragm relaxesand rises.

veins

arteries

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

• There are three major functions of the circulatory system.– transporting blood, gases, nutrients

– collecting waste materials– maintaining body temperature

30.2 KEY CONCEPT The respiratory system exchanges

oxygen and carbon dioxide. Your cells perform cellular respiration.

They need:

They give off:

Gas exchange occurs in the alveoli of the lungs.

• Oxygen and carbon dioxide are carried by the blood to and from the alveoli.– oxygen diffuses from alveoli into capillary – oxygen binds to hemoglobin in red blood cells – carbon dioxide diffuses from capillary into alveoli

ALVEOLI GAS EXCHANGES

capillaries

alveolus

capillary

co2

o2

Co2 diffusesinto alveolus.

O2 diffusesinto blood.

Gas exchange occurs in the alveoli of the lungs.

• Breathing is regulated by the brain stem.• This means you don’t have to think about it, Why is that

important?

midbrainpons

medulla oblongata

spinal chord

Respiratory diseases interfere with gas exchange.

• Lung diseases reduce airflow and oxygen absorption.– Emphysema destroys alveoli.

– Asthma constricts airways.– Cystic fibrosis produces sticky mucus.

• Smoking is the leading cause of lung diseases.

KEY CONCEPT The heart is a muscular pump that moves

the blood through two pathways.

The tissues and structures of the heart make it an efficient pump.

• Cardiac muscle tissue works continuously without tiring.

NORMAL HUMAN HEART

• The heart has four chambers: two atria, two ventricles.• Valves in each chamber prevent backflow of blood.• Muscles squeeze the chambers in a powerful pumping action.

aortic valve

left atrium

mitral valve

left ventricle

septum

pulmonary valve

right atrium

tricuspid

right ventricle

• The heartbeat consists of two contractions.– SA node, or pacemaker, stimulates atria to contract– AV node stimulates ventricles to contract

SA node

VA node

• 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

• Blood flows through the heart in a specific pathway.

1

2 4

3

The heart pumps blood through two main pathways.

• Pulmonary circulation occurs between the heart and the lungs.– oxygen-poor blood enters lungs– excess carbon dioxide and water

expelled– blood picks up oxygen – oxygen-rich blood returns to heart

• Systemic circulation occurs between the heart and the rest of the body.– oxygen-rich blood goes to

organs, extremities– oxygen-poor blood returns

to heart

• The two pathways help maintain a stable body temperature.

KEY CONCEPT Blood is a complex tissue that

transports materials.

Blood is composed mainly of cells, cell fragments, and plasma.

• Whole blood is made up of different materials.– plasma– red blood cells – white blood cells – platelets

red blood cells,white blood cells,and platelets

plasma

• Plasma is a key factor in maintaining homeostasis. – molecules diffuse into and out of plasma– contains proteins that stabilize blood volume– contains clotting factors – contains immune proteins

Platelets and different types of blood cells have different functions.

• The bone marrow manufactures most of the blood components.

red blood cell

platelet

white blood cell

• Red blood cells make up 40-45 % of all blood cells.– transport oxygen to cells and carry away carbon dioxide– have no nuclei and contain hemoglobin

• White blood cells fight pathogens and destroy foreign matter.

red blood cell

platelet

white blood cell

• Protein markers define blood types and Rh factors.– ABO blood group the most common– Rh factor can be negative or positive– blood types must be compatible for transfusions

• Platelets help form clots that control bleeding.

platelets

fibrin

red blood cell

white blood cell