Download Chapter 37-1

Chapter 37-1
Circulatory System
Circulatory System
 Transportation system of the body
 Closed system – blood is contained in
vessels within the body
 Consists of:
1. heart
2. arteries
3. veins
4. capillaries
Heart
 Composed of mostly cardiac
muscle
 Size of a closed fist
 Enclosed in the PERICARDIUM:
- protective tissue
 Surrounded by the MYOCARDIUM:
- thick layer of muscle
-contractions of this pumps
the blood throughout the body
Heart
 Heart muscle contracts about 72 times per minute
 Divided into 2 halves (right & left) by the septum:
- prevents mixing of oxygen-poor blood with oxygen-rich blood
 Upper portion – right & left ATRIUM
- receives blood
 Lower portion – right & left VENTRICLE
- pumps blood out
Circulation Through the Body
Heart function as 2 separate pumps
PULMONARY CIRCULATION




right side of heart
pumps blood from the heart to lungs
when blood gets to lungs, CO2 leaves
it and oxygen is picked up
SYSTEMIC CIRCULATION


left side of heart
blood flows from lungs to heart to rest of
body
Circulation Through the Heart
1.
2.
3.
4.
5.
6.
Oxygen-poor blood enters through the
INFERIOR & SUPERIOR VENA CAVA
to the RIGHT ARTRIUM.
Blood moves through the TRICUSPID
VALVE to the RIGHT VENTRICLE.
Blood then travels through the
PULMONARY ARTERIES to the
LUNGS where blood picks up oxygen
& gets rid of CO2.
Oxygen-rich blood travels to the LEFT
ATRIUM
It moves through the MITRAL VALVE
into the LEFT VENTRICLE
Lastly, blood is pumped through the
AORTA to delivery the oxygen-rich
blood to the rest of the body
Blood Vessels
 3 types:
1. arteries:
- pump oxygen-rich blood away from heart to tissues
2. capillaries:
- where oxygen is dropped off & carbon dioxide and
other wastes are picked up
3. veins:
- pump oxygen-poor blood back to heart
Blood Pressure
 Force of blood on the arteries walls
 Decrease when the heart relaxes
 Increases during exercise
 Average of healthy person – 120/80
Diseases of the Circulatory System
High Blood Pressure - Hypertension
- forces heart to work harder
- may weaken or damage heart muscle & blood vessels
- may lead to coronary heart disease
- increases risk of heart attack & stroke
Diseases of the Circulatory System
ATHEROSCLEROSIS
- fatty deposits called PLAQUE build up on the walls of arteries
- dangerous in coronary arteries
- if blocked, part of heart muscle will die due to lack of oxygen
- leads to heart attack
- can also form blood clots
- if clot breaks free – can go to brain and cause a stroke
Heart Attack
 Symptoms:
1. nausea
2. shortness of breath
3. severe, crushing chest pain
Stroke
 Brain tissue will eventually die due to lack of oxygen
 Brain function may be lost in that area
 Causes:
1. paralysis
2. loss of the ability to speak
3. death
Circulatory System Health
 Cardiovascular disease is easier to prevent than to cure
 To prevent:
1. regular exercise
2. eating healthy
3. avoid smoking