Transcript Chapter 19

Chapter 19
Circulatory System
Ch 19.1 – Cardiovascular System
A. Cardiovascular system includes your heart,
blood and blood vessels
1. Movement of materials into and out of cells
occurs by diffusion
2. Movement also occurs by active transport
B. Heart – controls blood flow through body
1. Has 4 chambers
a) 2 Atriums –
upper chambers
b) 2 Ventricles –
lower chambers
2. Three types of Circulation:
a) Coronary Circulation – flow of blood through
chambers in heart
b) Pulmonary Circulation – flow of blood in
lungs (picks up O2 and drops of CO2)
c) Systemic Circulation – flow of blood through
blood vessels in rest of body
C. Blood Vessels – carry blood to every part of
your body
1. Arteries – blood vessels that carry blood away
from the heart (most contain oxygenated blood)
a) Each ventricle is connected to a major artery
- right ventricle to pulmonary artery
- left ventricle to aorta
b) Each time heart beats (contracts) blood is
moved into arteries
2. Veins – blood vessels that carry blood back
toward the hear (usually deoxygenated)
a) Two major veins
- Superior Vena Cava: returns blood from
head and neck
- Inferior Vena Cava: returns blood from
lower body
b) blood is moved with muscular contractions
and one-way valves keep blood moving toward
heart (against gravity)
3. Capillaries – microscopic blood vessels that
connect arteries to veins
Is Our Blood Really Blue?
D. Blood Pressure – the force of blood on the
walls of the blood vessels
1. BP is highest in arteries and lower in veins
a) it rises and falls with every heartbeat
b) Normal adult pulse is b/w 60-100 bpm
2. Measured with 2 numbers
a) Systolic BP – first; pressure when ventricles
contract pushing blood out of heart (higher #)
b) Diastolic BP – second; measures pressure
while ventricles are relaxed and filling with
blood (lower #)
3. Your brain tries to keep BP constant; sends
messages to heart to raise and lower BP by
speeding up or slowing down heartrate
E. Cardiovascular Disease – leading cause of death
in United States
1. Hypertension – high blood pressure
a) when BP is high heart must work harder
b) may be caused by stress or plaque build
up in blood vessels
2. Atherosclerosis – fatty (plaque) deposits built up
on arterial walls which clogs blood flow
a) Can occur in any blood vessel but is most
dangerous in coronary arteries
b) If blood flow is cut off to heart tissue this
causes a heart attack (aka myocardial infarction)
c) Heart attacks may cause cardiac arrest which
is when a heart stops beating/contracting
3. Prevention of Cardiovascular disease
a) Eat healthy avoiding too much salt, saturated
fat and cholesterol
b) Exercise to eliminate excess weight and clear
plaque from blood vessel walls
Ch 19.2 - Blood
A. Functions of Blood
1. RBC’s carry O2 from lungs to body cells and
CO2 from body cells to lungs to be exhaled
2. Carries waste products from cells to kidneys
to be removed in urine
3. Carries nutrients from small intestine to cells
4. WBC’s fight infections
5. Other molecules in blood clot to heal wounds
B. Parts of Blood
1. Plasma – liquid part of blood
a) made mostly of water
b) has nutrients and minerals dissolved in it
c) carries wastes from cells
2. Red Blood Cells (RBC’s) – supply body with O2
[Erythrocytes]
a) Hemoglobin – iron molecule in RBC’s that
carries O2 and CO2
b) Life span is 120 days
3. White Blood Cells (WBC’s) – fight infections
[Leukocytes]
a) Body reacts to invaders by increasing #
b) WBC’s enter infected tissues, destroy bacteria
and viruses, then absorb the dead cell
c) Life span of WBC’s is a few days to months
4. Platelets – irregularly shaped cell fragments
a) Release chemicals that form filaments of
fibrin which trap blood cells to form a clot
b) Life span 5-9 days
C. Blood Clotting
1. Platelets stick to wound and release chemicals
2. Chemicals produce threadlike fibers called
fibrin that form a sticky net
3. The net traps blood cells to form a clot
4. Skin cells regenerate and fill in the wound
D. Blood Types – A, B, AB and O
1. Based partly on antigens
a) chemical ID tags on blood cells
b) Type O blood has no antigens – can
donate to any type (AKA universal donor)
2. Also based on antibodies
a) Proteins in plasma that identify substances that
do not belong in the blood and destroy them
b) Type AB blood has no antibodies – can
receive from any type (AKA universal receiver)
3. Rh factor – another chemical ID tag on cells
a) Rh+ has it; Rh- does not
b) If people who lack the Rh factor (Rh-) receive
Rh+ blood they will produce antibodies against it
E. Blood Diseases
1. Anemia – affects RBC’s
a) hemoglobin molecules not healthy which
causes body tissues to not get enough O2
b) caused by large loss of blood or dietary
lack of iron
2. Sickle Cell Anemia – affects RBC’s
a) body tissues do not receive enough oxygen
due to misshapen RBC’s
3. Leukemia – affect’s WBC’s
a) Cancer in which WBC’s made in excess but
they are immature so do not fight infections
properly
Ch 19.3 – Lymphatic System
A. The lymphatic system (AKA immune system)
collects tissue fluid and returns it to the blood
1. Lymph – tissue fluid that has diffused into
lymphatic capillaries
a) contains water and dissolved substances
b) contains lymphocytes – type of WBC
2. Lymph is carried through lymph capillaries and
vessels to large veins near the heart
3. Lymph is moved by contraction of muscles
4. Lymphatic vessels have valves to keep lymph
from flowing backward
B. Lymphatic Organs
1. Lymph nodes
a) bean-shaped organs of various sizes found
throughout the body
b) filter microorganisms and foreign material
from lymphocytes
2. Tonsils
a) organs in throat that protect body from
harmful microorganisms that enter through the
mouth
3. Thymus
a) makes WBC’s
b) located behind sternum wrapped around
trachea (windpipe)
4. Spleen
b) located behind stomach
a) filters blood to remove damaged RBC’s and
harmful microorganisms
C. HIV Virus – attacks a type of lymphocyte
(WBC) called helper T-cells
1. Healthy people have 500-1500 helper T-cells
2. If a persons helper T count drops below 200
they are diagnosed with AIDS (Acquired
Immune Deficiency Syndrome)
3. HIV is spread through body fluids from blood,
breast milk and sexual contact (but not tears,
sweat, saliva or urine)
4. HIV, like all viruses, have no medicinal cures,
however drugs have been developed
to slow the progression of the virus
so people can live longer with this
infection than in years past