31.1: Circulation
The circulatory system:
1- transports materials
2- helps maintain a constant body temperature
3- protects the body from disease
Blood is made up of: plasma, red blood cells, white
blood cells, and platelets.
Plasma is the liquid part of blood.
Oxygen sticks to the hemoglobin in red blood cells
and is carried to the tissues.
Anemia is caused by not enough hemoglobin or red blood
cells.
White blood cells help defend the body against diseases.
Platelets are used to clot blood.
Arteries are thick, muscular, elastic vessels that
carry blood away from the heart.
Veins are thinner vessels that carry blood back to
the heart.
Capillaries are very thin vessels where nutrients &
oxygen leave the blood and wastes enter the blood.
Marker proteins on red blood cells are responsible
for the 4 blood types: A, B, AB, and O.
Marker proteins are also responsible for the Rh factor
(+ if theyre there, - if theyre not).
The lymphatic system consists of vessels that return
fluid and proteins to the blood. It also helps to destroy foreign
matter.
31.2: How Blood Flows
The heart has 4 chambers: 2 atria and 2 ventricles.
Path of blood: body cells > right atrium > right ventricle
> lungs > left atrium > left ventricle > body cells
A bundle of specialized cells (the pacemaker) control
the hearts beating.
The pulmonary circulatory system brings blood to and
from the lungs (to exchange gases). Carbon dioxide is given off and
oxygen is picked up.
The systemic circulatory system brings blood to and
from the body cells.
Blood pressure is the result of blood exerting force
on the walls of blood vessels.
Cardiovascular diseases include heart attacks and hypertension.
Hypertension is high blood pressure.
31.3: The Respiratory System
Lungs take in oxygen needed for respiration.
Path of air: nose > pharynx > larynx > trachea > bronchioles
> alveoli
During inhalation, the diaphragm contracts and the
rib cage moves up, forcing air into the lungs.
During exhalation, the diaphragm relaxes and the rib
cage moves down, forcing air out of the lungs.
Oxygen moves from the air sacs (alveoli) at the end
of the bronchioles into the bloodstream.
Carbon dioxide is transported as bicarbonate ions to
the lungs, where it enters the alveoli and is exhaled.
Receptors in the brain, which are sensitive to the
levels of carbon dioxide and oxygen in the blood, regulate your breathing
rate.
Respiratory disorders include asthma (bronchioles contrict),
emphysema (alveoli dont stretch), and lung cancer. |