The Circulatory System http://www.brightstorm.co m/science/biology/the-hum an-body/circulatory-syste m/
Dec 26, 2015
The Circulatory System
http://www.brightstorm.com/science/biology/the-human-body/circulatory-system/
The Circulatory System
• A System of interconnected, one-way roads– From superhighways to back alleys– Allows the transport of materials from one place
to another• Hormones• Oxygen• Cellular Wastes• Nutrients
– Heart, Blood vessels, and Blood
The Heart
• Consists mainly of cardiac muscle that pumps blood throughout the system
• 4 Chambers– 2 upper Atria– 2 lower ventricles
• Valves keep the blood flow going in only 1 direction http://www.youtube.com/watch
?v=hCp4hVC2fnM
Heartbeat
• Cardiac muscle contracts without stimulation by the nervous system– Specialized cardiac muscle cells send out electrical
impulses that stimulate the contractions– Normally this all happens in perfect
synchronization– http://www.nhlbi.nih.gov/health/health-topics/to
pics/hhw/electrical.html
Blood Vessels
• Arteries – carry blood away from the heart– Thick walls that can withstand the pressure of the
blood being pumped– Generally carry oxygen-rich blood– Largest is the aorta which receives blood directly
from the heart• Veins – carry blood toward the heart– Lower pressure so the veins have valves that prevent
backflow of deoxygenated blood– Larges is the inferior vena cava
Blood Vessels
• Capillaries– Smallest of all the blood vessels– Connect very small arteries and veins– Exchange gases and other substances between
cells and the blood– Very thin-walled
Blood Vessels and Homeostasis
• Can either constrict (narrow) or dilate (get bigger)– These processes are signaled by the autonomic
nervous system or the endocrine system– This process controls the amount of blood flowing
to different organs
Blood Vessels and Blood Pressure
• Highest in the arteries and lowest is the veins– When they take your blood pressure they are
measuring the pressure in the arteries• High blood pressure = Hypertension• Can be controlled with diet, exercise and medication• http://www.healthcentral.com/high-blood-pressure/int
roduction-47-115.html
Cardiovascular Disease
• Atherosclerosis– Build up of plaque on
the insides of arteries• Debris, cholesterol, and
other substances
– High fat diet and smoking
– Arteries narrow and blood flow is restricted
http://www.youtube.com/watch?v=fLonh7ZesKs
Coronary Heart Disease
• A heart attack occurs when the blood supply to a part of the heart muscle is blocked or shut off
• Leading cause of death in adults in the US• Risks – smoking, lack of exercise, high-fat diet• Healthy life style choices reduce risk• Video: Heart Attack
Blood
• A fluid connective tissue• Fluid part is called plasma– Contains many dissolved substances and blood
cells• Red blood cells• White blood cells• Platelets
– http://www.apan.net/meetings/busan03/materials/ws/education/demo-los/blood-rlo/whatisblood.swf
Blood
• Red blood cells carry oxygen and contain hemoglobin a protein rich in iron that binds with oxygen
• White blood cells are generally larger than red blood cells, but fewer in number– Part of the body’s defense system
• Platelets – cell fragments involved in blood clotting – release clotting chemicals at the site of a wound