1. Heart and Blood Vessels
12.1A Circulatory System
Heart and Blood Vessels

2. Main Functions of the Circulatory System
Carries nutrients throughout the body
Transports O2 and CO2
Transports hormones
Transports urea (wastes) from cells to kidneys
Maintains body temperature
Carries antibodies

3. Major Components of the Circulatory System
Heart: Muscular organ
Serves as a pump to create a pressure gradient and distribute blood to body
High to low pressure
Blood Vessels: Arteries, Veins, Capillaries
Serves as passageways for blood distribution
Blood: Plasma, RBC, WBC, Platelets
Transport medium for materials such as O2, CO2, nutrients, wastes, electrolytes, and hormones
-Arteries and veins are like highways and the capillaries are the on and off ramps as well as the stop lights for roads (forced to stop and change direction, keep going and slow down

4. Two Types of Circulatory Systems
Open circulatory system:
Blood, called hemolymph, flows freely in body cavity
Found in invertebrates, insects
Closed circulatory system:
Blood contained in vessels
Found in vertebrates, earthworms, squid

5. The Heart Made of cardiac muscle
Pumps rhythmically and involuntary without fatigue
It uses the valves to pump in 1 direction to 2 different systems
It is a single organ, however, the right and left sides of the heart function as two separate pumps
Separates oxygen-rich and oxygen-poor blood!!
-your heart pumps subconsciously, we don’t need to think about telling our heart to pump because it automatically does it

6. Place your hand over your heart… See pg. 480 in text
-use PAL
-slide 3 and 4 under heart in anatomical view for front view and slide 7 for back view
-the heart has a broad base at the top and tapers to a point called the apex at the bottom. Our heart is actually on an angle so that the base predominately lies to the right and the apex to the left of the sternum…have them find their clavicle, palpitate all the way to the middle notch and the n palpitate down (this is your sternum). When our heart beats forcefully, the apex thumps against the inside of the chest wall on the left side -> that is why we think the entire heart is on the left.

7. Chambers of the Heart
Right side of the heart receives deoxygenated blood coming back from the body
Left side of the heart pumps oxygenated blood towards the rest of the body
Pulmonary arteries carries deoxygenated blood from the heart towards the lungs.
Pulmonary veins carries fresh, oxygenated blood from our lungs to the heart
Atria (singular is atrium) receive blood (upper chambers), ventricles squeeze blood out (lower chambers)
Valves separate the different chambers: atrioventricular valves and semilunar valves
-have PAL side by side
-slides for heart in anatomical view
-close your fingers into a fist, from your thumb to your middle finger are your atriums and the remaining two are ventricles …explain how the lub-dub begins …ask how many think the heart pumps from left to right...explain, using the hands, how it actually is the atriums then the ventricles
-ask why the left side of the heart has smaller chambers than the right

8. How the Heart Works
Perhaps create my own and trace 1 drop of blood through the system

9. Blood Vessels
Arteries: carry blood away from the ventricles to the tissues
Small arteries are called arterioles, they are the control valves
Veins: carry blood towards the atria from the tissues
Small veins are called venules
Capillaries: smallest blood vessels that connect arterioles and venules
-look at page 347 figure 8-11…arterioles are used to create many branches within organs ….remember we need constant pressure in order for blood to move ….its two functions are distribute the cardiac output among systemic organs and to help regulate pressure
-pg for capillaries
-PAL = arteriole on slide 13, capillary on slide 14, venuole on slide 16 with a valve

10. Arteries Thick, highly elastic, muscular walls
Generally carry oxygen rich blood away from the heart and throughout the body (means they are systemic arteries)
Blood is under high pressure
Generally buried deep in the body, except the carotid artery in the neck
Slide in anatomical structures for arteries 8 (in red), arteriole is on slide 13
-slide 20 shows atherosclerosis
-look at page 341 figure 8-6

11. Veins Thinner, less muscular, elastic walls
Contain valves, which ensure one way blood flow
Generally carry oxygen deficient blood towards the heart from the body (means they are systemic veins)
Blood is under low pressure
Located closer to the surface of the body
Varicose veins result from malfunctioning valves, and pooling of blood in veins
-slide 9 of veins in anatomical structures

12. Capillaries One cell thick
Allows for gas and nutrient molecules to pass through by diffusion
Allows for only 1 RBC to flow through in a single fashion

13. Homework Go on the website and review tomorrow’s lecture
Review any posted youtube videos for clarification
Review 12.1
Do pg. 481 #4-6
Do pg. 486 #7, 8, 10, 11