Transcript Unit 12: Transport and Immunity

Unit 7: Circulatory System
Absorption & Circulation
A. Absorption
1. Where in the body are nutrients and materials absorbed
by the body?
a. Lungs – O2
b. Small Intestine
- nutrients = amino acids, glucose, lipids
B. Circulation
Distribution of materials
1. Cells
- need to live in a watery environment
- circulate the material around the cell
- single celled organisms and even the cells in your body
have to stay moist
2. Human Circulatory System
a) Blood – liquid transport material
made of 4 parts:
1) Red Blood Cells (RBC) –
- use hemoglobin to carry
oxygen
- red in color because of iron
Fe
- made in bone marrow
- destroyed by the liver and
spleen (last for 3 months)
- most numerous cell in the
body
2) White Blood Cells (WBC) –
- large cells – not very numerous
- many different kinds of WBC
(we will learn about this later)
- fight infection – make more WBC
3) Platelets
- small cell fragments
- made in bone marrow
- clot blood = stop bleeding
4) Plasma
- liquid part of blood
- made mostly of H2O
- Yellow in color
- Carries – urea, CO2, glucose, amino acids
b) Blood Vessels
tubes that carry blood
1) Arteries
- Carry blood away from the
heart
- Usually carry oxygenated blood
Pulmonary artery carries
deoxygenated blood
- thick walled and muscular
- Pulse = muscular contractions
to push blood
- Aorta = largest artery in the
body
2) Vein
- Carry blood to the heart
- Usually carry deoxygenated
blood
- Pulmonary veins carry
oxygenated blood
- thinner wall than arteries
- have valves – stop back flow of
blood
Valve Animation
3) Capillary
- Smallest blood vessels
- one cell thick
- Found in every part of the
body
- Diffusion of materials
- Blood flows from arteries to
capillaries to veins
b) Veins
- thinner and less muscle than arteries
- carry blood back towards the heart
- generally carry deoxygenated blood
except for pulmonary veins - oxygenated
- contain one way valves to keep blood flowing in one
direction
- blood flow is helped by skeletal muscle
Valve Animation
c) Capillaries
- site where materials are exchanged between cells and
blood
- 1 cell thick – allows for diffusion
- blood passes through 1 cell at a time – single file
3. Heart
a) Structure
- hollow organ with thick muscular walls
- myocardium - muscle = cardiac muscle
* specialized muscle tissue
Make a fist demo
- the heart is divided into 4 chambers
* atrium = upper chamber (left and right)
* ventricle = lower chamber (left and right)
pumps blood out of the heart
- divided into the left and
right sides by the septum
prevent the mixing of
blood
right side –
deoxygenated blood
left side – oxygenated
blood
b) Blood Flow Through the Heart
- acts as two pumps in one
- 1 pump - right side – deoxygenated blood pumps to the
lungs
- other pump – left side –
oxygenated blood pumps
to the body
- Atria  Valve 
Ventricle  Artery
right side - tricuspid valve
left side - bicuspid valve
c) Blood Circulation
- Pulmonary Circulation
- circulation to the lungs
carbon dioxide leaves the
blood, oxygen enters
deoxygenated  oxygenated
- Systemic Circulation
- circulation to the body renal,
hepatic, neural, etc.
oxygen leaves the blood,
carbon dioxide enters
oxygenated  deoxygenated
Blood returns to the heart through the
vena cava  right atrium  tricuspid valve 
right ventricle  pulmonary artery 
capillaries in the lungs (drop off CO2 pick up O2) – the
blood has become oxygenated 
pulmonary vein  left atrium  bicuspid valve  left
ventricle  aorta  arteries 
capillaries in the body (drop off O2 pick up CO2) – the
blood becomes deoxygenated 
veins  vena cava – to do it all again!
Heart  Lungs  Heart  Body
it takes ~7 minutes for a red blood cell to complete the trip
d) Heart Rate / Heartbeat
- heart has its own “pace maker” – bundle of nerves to
control and time the rhythm of the beats
- sinoatrial node (SA) – causes atria to beat first
- artioventricular node (AV) – cause ventricle to beat
second two beats more efficient
- need for oxygen changes heart rate
e) Blood Pressure
- because it is a closed circulatory system – there is a force
exerted on the heart and arteries
- sphygmomanometer – measures blood pressure
normal: 120/80
120 – systolic pressure = pressure of ventricle contractions
80 – diastolic pressure = pressure when heart is relaxed
4. Disorders of the Circulatory System
a) Atherosclerosis – fatty deposits build
up on the artery walls
- obstruct blood flow, make arteries
less elastic
- causes majority of circulatory system
diseases
b) Hypertension = High Blood Pressure
- “silent killer” - a narrowing of the
arteries and/or more viscosity to the blood
- Damages the heart by making it work harder to pump
Blood, could also cause your arteries to rupture –
Increases the risk of heart attack and stroke
- Causes: excess sodium intake, poor diet, saturated fats,
smoking, alcohol, caffeine, obesity, stress, aging, not
enough exercise
- Treatment / cure: medication, diet, lifestyle
c) Heart Attack = Coronary Thrombosis
- blockage in the coronary arteries (arteries that bring blood
to the heart muscle)
- heart muscle begins to die
- symptoms: nausea, shortness of breath, chest pain, intense
pressure
- Treatment – clot dissolving drugs, bypass surgery
d) Stroke
- blood clots break free and get stuck in a blood vessel in
the brain
- causes brain cells not to get O2
- lose brain function – depends where it happens
e) Anemia
- blood lacks ability to
carry oxygen
- not enough iron