CIRCULATORY and RESPIRATORY pp 940-942

BLOOD Transports nutrients, O2, CO2, & waste Defends the body against disease Plasma: liquid medium Red blood cells (erythrocytes): transport CO2 and O2 White blood cells (leukocytes): defend against disease Platelets: form blood clots

RED BLOOD CELLS Most common in the blood Also made in the red bone marrow Made of iron-containing hemoglobin to attract oxygen Lack of nucleus leaves space to transport materials

CIRCULATORY SYSTEM 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 to the organs 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.

RESPIRATORY

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

Exhaled air Inhaled air Alveolar spaces Alveolar epithelial cells CO2 Figure 42.UN02 Exhaled air Inhaled air Alveolar spaces Alveolar epithelial cells CO2 O2 Alveolar capillaries Pulmonary arteries Pulmonary veins Systemic veins Systemic arteries Heart Figure 42.UN02 Summary figure, Concept 42.2 Systemic capillaries CO2 O2 Body tissue

Sensor/control center: Aorta Cerebrospinal fluid Figure 42.29 Homeostasis: Blood pH of about 7.4 CO2 level decreases. Stimulus: Rising level of CO2 in tissues lowers blood pH. Response: Rib muscles and diaphragm increase rate and depth of ventilation. Carotid arteries Figure 42.29 Homeostatic control of breathing. Sensor/control center: Aorta Cerebrospinal fluid Medulla oblongata

HOMEOSTASIS Breathing control centers are in the brain The rate and depth of breathing in response to pH changes (O2 and CO2 concentrations)