Download Circulatory System

Chapter 6
Body Systems
• Anatomy – structure
• Physiology – function
• Homeostasis – stable internal environment
Circulatory System
• Pumps blood
throughout body,
delivering oxygen and
nutrients to cells;
carbon dioxide and
wastes away from body
• Made of: heart, blood,
arteries, & veins
Two pathways
• Systemic circulation
- heart pumps oxygenated blood away thru
arteries to cells
- cells absorb O2 ; release CO2 & other
wastes
- some waste – eliminated by kidneys, etc
- carries blood back to heart
• Pulmonary circulation
- heart pumps deoxygenated blood, CO2 &
wastes to lungs
- blood releases CO2, wastes; picks up O2
- oxygenated blood flows back to heart to
enter systemic circulation
Blood
• Fn: distribute heat, transport O2 and wastes
• Made of: red blood cells, white blood cells,
platelets, & plasma
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RBCs = erythrocytes
Large surface area – efficient gas exchange
Hemoglobin binds to oxygen & transports it
Form in bone marrow; live ~120 days
Formation depends upon oxygen levels
• WBCs = leukocytes
• Protect body against infection; fight viruses &
bacteria
• Healthy – 5,000 – 10,000 WBCs per mL blood
• Infection – 10,500+ (ex. appendicitis)
• Immune system suppressed – below 3,500 (ex.
HIV, flu)
• Platelets = thrombocytes
• = cell fragments surrounded by cell membrane
• Form blood clots (release clotting factors)
• Plasma – liquid portion of blood
• 92 % water, rest = salts, nutrients, enzymes,
proteins, dissolved gases, etc
• Transports nutrients, vitamins, and gases
• Regulates pH, maintains fluid balance,
controls body temp
Path of blood thru Heart
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Heart – 2 atria (top), 2 ventricles (bottom)
Capillaries – smallest vessels
Alveoli – tiny air sacs in lungs
Arteries - away from heart
Veins – to heart
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Deox blood to right atrium
To right ventricle thru tricuspid valve
Pumped into pulmonary artery to lungs
Gas exchange - CO2 from caps into alveoli; O2
from alveoli into caps
• Ox. blood to left atrium thru pulmonary vein
• To left ventricle thru bicuspid valve
• To aorta to body
• Path