Unit 12: Transport and Immunity
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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