Circulatory System Overview

Study Notes

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.