Circulatory System Overview

Circulatory System

• Two types of circulatory systems: open and closed.
• Open systems lack a true heart and capillaries.
• Closed systems keep blood within vessels, separate from body tissues.
• Closed systems have a heart that pumps blood through a continuous loop.
• The heart is the "most hardworking" organ in a closed system.
• The heart has four chambers: two atria and two ventricles.
• The pericardium is a thin sac that surrounds the heart.
• The pericardium protects, lubricates, and keeps the heart in place within the chest.
• The parietal pericardium aids in producing serous fluid.
• The visceral pericardium, also known as the epicardium, is the innermost layer.
• The visceral pericardium directly covers the heart and roots of the great vessels.
• Atria receive blood returning to the heart.
• Ventricles pump blood out of the heart.
• Blood flows through the heart in a specific order:
  • Right atrium receives carbon dioxide-rich blood.
  • Blood is pumped to the right ventricle and then to the lungs.
  • Lungs replace carbon dioxide with oxygen.
  • Oxygen-rich blood enters the left atrium from the lungs.
  • Blood is pumped to the left ventricle and circulates throughout the body.
• Blood is a special fluid primarily contained within blood vessels.
• Red blood cells transport oxygen, nutrients, and water.
• White blood cells fight diseases and protect the body from infection.
• Platelets gather at injury sites to aid in clotting.
• Plasma is a straw-colored liquid containing other blood components. Plasma is mostly water.
• Blood types are determined by the presence or absence of antigens.
• Blood vessels are tubes or channels that carry blood throughout the body.
• The aorta is the largest blood vessel, delivering nutrients and hormones.
• The superior vena cava carries blood from the upper body to the heart.
• The inferior vena cava carries blood from the lower body to the heart.
• Pulmonary arteries carry blood from the heart to the lungs.
• Pulmonary veins collect oxygen-rich blood from the lungs and transport it to the heart.
• Sickle cell disease (SCD) is an inherited blood disorder.
• People with SCD have red blood cells that become hard and sticky, forming a C-shaped cell instead of a healthy disc shape.

Respiratory System

• Lungs are the same size.
• Lungs are the only organ that can float in water.
• The respiratory system is a group of organs that provide oxygen to the body's cells.
• Oxygen is essential for cells to produce energy.
• Carbon dioxide is a by-product of cellular respiration.
• Breathing is the physical process of air entering and leaving the lungs.
• Inspiration (inhalation) is the movement of air from the environment into the alveoli.
• Expiration (exhalation) is the movement of air out of the lungs.
• Cellular respiration is the process of releasing and capturing energy from food molecules in the form of ATP.
• The nose is the primary entry point for air.
• Nasal cavities filter, warm, and humidify incoming air.
• The mouth (oral cavity) is an alternate air entry point.
• The pharynx (throat) connects the nasal cavity and mouth to the trachea. It serves as a passageway for air and food.
• The epiglottis prevents food from entering the trachea.
• The nasopharynx is located at the back of the nasal cavity and contains the nasopharyngeal tonsil.
• The oropharynx is located behind the mouth.
• The isthmus connects the nasopharynx and oropharynx.
• The larynx (voice box) is a tough, flexible segment.