RESPIRATORY AND CIRCULATORY

SYSTEMS

CIRCULATORY SYSTEM pgs 933-939

• Moves fluid throughout the body

STRUCTURES• Heart – muscular organ that pumps blood to all

parts of the body.

• Vessels: smooth muscle surrounded by connective tissue

a. arteries – carries blood from the heart

b. veins –carries blood to the heart

c. capillaries –narrow blood vessels that pass

blood (cells) in single file.

MOVEMENT OF BLOOD

• right side: (deoxygenated) blood from body to heart to lungs

• left side: (oxygenated) blood from lungs to the heart to body.

RESPIRATORYpgs 946-950

EXTERNAL FUNCTION

• exchange of gases between atmosphere and blood

MECHANISM

• Large skeletal muscle (diaphragm) contracts pulling lungs down causing them to fill with air

INTERNAL FUNCTION

• exchange of gases between blood and cells

• Gases diffuse across due to concentration gradients

lungs (alveoli) capillaries (carrying blood)

Figure 42.UN02

Exhaled air

Alveolarepithelialcells

Pulmonaryarteries

Systemicveins

Heart

CO2 O2

Body tissue

Systemiccapillaries

Systemicarteries

Pulmonaryveins

Alveolarcapillaries

Alveolarspaces

Inhaled air

CO2 O2

Homeostasis:Blood pH of about 7.4

CO2 level

decreases. Stimulus:Rising level ofCO2 in tissues

lowers blood pH.Response:Rib musclesand diaphragmincrease rateand depth ofventilation.

Carotidarteries

AortaSensor/control center:Cerebrospinal fluid

Medullaoblongata

Figure 42.29

HOMEOSTASIS

• Breathing control centers are in the brain• The rate and depth of breathing in response to pH

changes (O2 and CO2 concentrations)