1. Agenda 1/25 and 1/26 Harvey and heart history reading
Blood system anatomy notes
Heart diagrams
Homework:
1. Heart beat control video and notes
2. WB # 170, 171, 172

2. Reading Questions
1. Before Harvey’s work, what did most physicians believe about blood flow?
2. Summarize what Harvey’s theorized about the heart working as a pump.
3. How was Harvey’s theory about circulation different that was scientists thought at the time?
4. What did scientists before Harvey think the heart did? Where did they think blood came from?
5. Explain the kind of evidence Harvey gathered to support his theory of the blood as a pump and circulation.
6. How did this reading demonstrate the ever changing nature of science?

3. Arteries, capillaries, and veins
Arteries: blood vessels taking blood away from the heart
Veins: Collect blood from capillaries and return it to the heart
Nothing to do with oxygenated or deoxygenated blood
Not different colors!
Ex: Newly oxygenated blood is brought back to heart by the pulmonary veins
Capillaries: smaller vessels that attach to arteries and veins and transport blood to all tissues
Can’t be seen without maginification

4. Artery Structure
Arteries have thick, smooth, muscle layer used by the autonomic nervous system (remember-involuntary)
The smooth muscles can change the diameter of the lumen (inside) of blood vessels
Arteries also have elastic fibers that keep blood pressure high
As blood is pumped into artery, the elastic fibers stretch out which allows more blood to fit into the space
After that contraction is over, the elastic fibers go back to their normal state

5. Veins Structure
Veins collect blood from capillary beds (lots of capillaries from one source)
Less blood pressure, so the blood flows slower through veins
Veins have thin walls and a large internal diameter
One-way flow- blood always moving to the heart

6. Three types of blood vessels

7. Comparing blood vessels

8. The Heart Designed as a pair of side by side pumps
Each side receives blood from veins and goes into the atria
Atria are thick-walled muscular pumps that build up enough pressure to pump blood out to your body (blood pressure)

9. Flow of blood in heart
Right side: sends blood through pulmonary circulation
Capillary beds in lungs picks up oxygen, released carbon dioxide
Left Side: sends blood through systemic circulation
Aorta sends blood out to all parts of your body
Valves prevent backflow of blood

10. Example Blood Flow Steps
1. Blood enters right atrium from superior vena cava
2. Blood is pumped to right ventricle
3. Blood goes from right ventricle to lungs via the pulmonary artery. Blood picks up oxygen, releases CO2 in capillaries in lungs
4. Blood returns to the heart via pulmonary veins and flows into the left atrium
5. Blood enters the left ventricle
6. Blood leaves left ventricle and is pumped out through the aorta

11. Diagram
Color, label, and write the steps for blood flow through the heart on your diagram

12. 6. 3. 1. 4. 5. 2.

13. Labeled Real Heart

14. Agenda 1/29 and 1/30

15. Control of Heart Rate
Cardiac muscle contracts and relaxes by nervous system control
Myogenic muscle contraction
Myogenic activity still needs to be controlled
Sinoatrial Node (SA node)
Has properties of nervous and cardiac tissue
Sends out electrical signal to initiate contraction in both right and left atrium
Ex: HR=72 bpm, SA node sends signal every 0.8 seconds
Atrioventricular Node (NA node)
Receives signal from SA nodes, delayed for 0.1 seconds and sends another electrical signal
2nd signal initiates contraction in right and left ventricle

16. Heart Beating Video

17. Heart Rate and Homeostasis
The heart rate may need to increase above its resting rate (like during exercise)
As you use more energy, you use more ATP, so more oxygen is needed to ‘fuel’ cellular respiration
You also have to get rid of CO2 faster, since you are produces more through cellular respiration
Medulla
Area in brainstem that can sense carbon dioxide levels rising
Sends a signal through the cardiac nerve to tell SA node to send the signal more frequently
Once exercise stops, the medulla sends a signal through the vagus nerve to tell the SA node to slow down
Epinephrine (adrenalin)
Epinephrine is released during times of stress and tells your SA node to fire more frequently

18. Changes in Blood Pressure
Diastole- Chamber is NOT contracting
Systole- Chamber IS contracting
1. Both chambers at rest
2. Atria in systole, ventricles in diastole
3. Atria in diastole, ventricles is systole

20. Heart Diseases Atherosclerosis- slow build up of plaques Heart Attack
Plaques are lipids, cholesterol, cell debris, and calcium
Takes many years to become a serious problem
As arteries build up plaque, they become less flexible
How much build up you have depends on genetics and diet
Heart Attack
Your heart has 3 arteries that branch from the aorta
If a portion of those arteries gets blocked, oxygen can’t get to the heart
This is how atherosclerosis can lead to a heart attack (myocardial infarction)