Circulatory System

" Even in Kansas, the Republicans would not give the Tin Man a heart "

Circulatory System - Functions in transport (gases, nutrients and wastes); regulation (ions, pH, and hormones); and protection (immune).

          Arteries - Carry blood away from the heart.

          Veins - Carry blood back to the heart.

          Capillaries - Are very tiny and thin-walled, where the exchange of gases and nutrients between the blood vessels and body tissues occurs.

Pulmonary system - Connects the heart and lungs.

Systemic system - Connects the heart with all of the tissues of the body.

Plasma - 55% of blood, mostly water with proteins, salts, gases dissolved in it.

Erythrocytes - RBC - Most of 45% cellular part. Transport oxygen from the lungs and CO2 to the lungs. Humans have around 30 trillion RBC's in our blood supply.

          Hemoglobin - A respiratory pigment that gives the RBC's their red color. Carries the O2 & CO2 molecules.

Leukocytes - WBC - Help defend the body from disease. We have 1 for every 700 RBC.

          Macrophage - A type of WBC that is a kills foreign invaders.

Platelet - Cellular fragments that aid in blood clotting. We have about 1 for every 16 RBC.

Coronary arteries - Supply freshly oxygenated blood directly to the heart.

Heart rate - The number of beats/min (at rest is about 72 beats per minute).

Cardiac output - The volume of blood pumped by the heart in 1 minute. For a resting adult cardiac output is 5 - 6 L/min.

Cardiovascular disease - Disease of the heart or blood vessels. Causes 50% of all deaths in the US

Blood pressure   120/80 - Actual pressure of blood in an artery.

          Hypertension - high blood pressure, can lead to a stroke or heart attack. Hypertension in males and females is 140/90.

          Systolic pressure   120 - The top number. This is the time when the 2 ventricles contract and push fresh blood out of the heart.

          Diastolic pressure   80 - The bottom number. It is the relaxation time (lowest pressure) between successive contractions of the heart.

Lymphatic system - Returns interstitial fluid (leaked fluid) to the blood.

          Interstitial fluid - fluid (plasma) forced by pressure out of the capillaries and bathes the tissues of the body with gasses amd nutrients.


Large Veins from Body --> Right Atrium --> Right Ventricle --> Pulmonary Artery (Only Artery with Deoxygenated Blood) --> Lungs --> Pulmonary Veins (Only Veins with Oxygenated Blood) --> Left Atrium --> Left Ventricle --> Aorta to Body.

Return to Greg Sievert's GB 100 Syllabus
Last updated on 8 January 2018