2. Lab 9-The Heart and General Circulation. Arteries carry blood away from the heartVeins carry blood to the heartArteries and veins are connected to each other by capillariesThe right side of the heart receives returning blood that is low in oxygen (deoxygenated)Blood moves from the right side of the heart to the lungs where it becomes oxygenated. Blood is returned to the left side of the heart which circulates it throughout the body.
1. 1 The Heart and General Circulation The heart and blood vessels are collectively known as the cardiovascular system
The heart is a hollow muscular organ whose contractions creates the force and pressure which moves blood throughout our body
The heart is a pump
It secretes hormones that help regulate blood pressure and the body’s fluid and electrolyte balance.
3. 3 Lab 9-The Heart and General Circulation Anatomy of an Artery, Vein and Capillary Both arteries and veins have an inner layer of simple, squamous epithelium cells, a middle layer of smooth muscle, and an outer connective layer.
Arteries have thicker muscular layers than veins because they must be able to withstand the high pressures generated by the heart.
Veins are thinner walled and have valves to help keep the blood moving, against gravity, to the heart.
4. 4 Lab 9-The Heart and General Circulation Vein valves prevent the backflow of blood.
The smallest arteries are called arterioles; the smallest veins are called venules. These connect via capillaries.
All blood vessels except capillaries have smooth muscles in their walls.
Capillaries are a thin layer of squamous cells which allows for exchange of nutrients, wastes and gases.
5. 5 Lab 9-The Heart and General Circulation Layers of an artery
innermost layer is the endothelium
is a layer of flattened, squamous epithelial cells which fit so closely together that they create a slick surface so that blood can flow smoothly.
middle layer which is primarily smooth muscle with elastic connective tissue
outermost layer is a supporting layer of connective tissue which anchors vessels to surrounding tissues
7. 7 Lab 9-The Heart and General Circulation Veins
like the walls of arteries, the walls of veins consist of 3 layers of tissue.
Outer 2 layers are much thinner than those of arteries
veins have larger diameters than arteries
the pressure in veins is much lower than that in arteries which is why their walls are not as strong as arteries
8. 8 Lab 9-The Heart and General Circulation veins can act as a blood volume reservoir
the larger diameter of veins allows them to stretch to accommodate large volumes of blood at low pressures
because veins can stretch, it is more difficult for them to return blood to the heart against the force of gravity
people who spend a lot of time on their feet may get varicose veins because of this
9. 9 Lab 9-The Heart and General Circulation Factors which help veins to return blood to heart
contraction of skeletal muscles
as we move and muscles contract and relax, they press against veins and help push blood to the heart
one way valves in the veins
11. 11 Lab 9-The Heart and General Circulation the work of the skeletal muscles helps the valves pump blood. This is called a skeletal muscle pump
movements associated with breathing also help pump blood. This is called a respiratory pump and helps to push blood from the abdomen to the chest and to the heart.
when we breathe, there are pressure changes in the thoracic and abdominal cavities
during inhalation, abdominal pressure increases and squeezes abdominal veins
12. 12 Lab 9-The Heart and General Circulation simultaneously, pressure within the thoracic cavity decreases which dilates the thoracic veins and thus propels the blood.
13. 13 Lab 9-The Heart and General Circulation The Heart
heart has blood vessels attached to it
the large vessels are the
aorta which transports blood away from the heart to the entire body.
the pulmonary trunk (pulmonary vein and artery) which transports blood to and from the lungs.
14. 14 Lab 9-The Heart and General Circulation The superior and inferior vena cava which return blood to the right atrium
the 4 chambers of the heart are the
2 atria: the right atrium and the left atrium
2 ventricles: the right and left ventricles
blood enters the heart through the right atrium, flows through an atrioventricular valve into the right ventricle
16. 16 Lab 9-The Heart and General Circulation From the right ventricle, to a pulmonary valve to the pulmonary artery to the lungs
oxygenated blood returns to the heart through the pulmonary vein
and enters the left atrium
flows through another atrioventricular valve to the left ventricle
then through another valve to the aorta to the entire body
17. 17 Lab 9-The Heart and General Circulation the heart muscle has its own supply of blood vessels: coronary arteries and coronary veins (see pictures on page 117 of lab manual)
All of the chambers of the heart fill at the same time
note that the pulmonary circulation has the oxygen level of the arteries and veins reversed
19. 19 Lab 9-The Heart and General Circulation the heart pumps 2 “circuits” at the same time--
the right ventricle to the pulmonary trunk
and the left ventricle to the entire body
the outer wall of the left ventricle is thicker than the right ventricle
this ventricle does more work than any other chamber--it must overcome the pressure of the aorta in order to pump blood into it
21. 21 REMINDER Look at the bulleted lists on lab manual pages 118 and 119
you will need to know where these items are located for the lab test
Use the models and charts to help you locate these; don’t try to find them in the fetal pig
22. 22 Lab 9-The Heart and General Circulation In general, blood vessels are named for the body cavity which they pass through
The aorta modifies its name as it enters different body areas
aortic arch as it leaves heart
thoracic aorta: where aorta straightens out
abdominal aorta: when aorta goes through the diaphragm
after this, the aorta splits to go into each leg; it now becomes the femoral artery
23. 23 Lab 9-The Heart and General Circulation Main arterial branches of the aorta (see page 124)
brachiocephalic (first branch off aorta) artery
subclavian (underneath clavicle) artery
renal artery (kidney)
external/internal iliac (ileum=hip bones) arteries
24. 24 Lab 9-The Heart and General Circulation Major veins(see page 125)
superior vena cava
inferior vena cava (is the major vein in thoracic, pelvic, and abdominal cavities)
25. 25 REMINDER Pathway of circulation; you need to know this
follow instructions on page 119
Do the sounds of the heart and the heart rate activities (page 119)
26. 26 Lab 9-The Heart and General Circulation Functional Anatomy
Contraction of the heart muscle is called systole
during systole, blood is pumped out of, or ejected from, the heart into the circulatory system
Relaxation of the heart muscle is called diastole
during diastole, the heart fills with blood
27. 27 Lab 9-The Heart and General Circulation Blood Pressure
When blood pressure is taken,
the higher number is the systolic pressure
the lower number is the diastolic pressure
You will be taking each other’s blood pressure with an automatic blood pressure cuff
wrap the cuff snugly around your partner’s arm(with the velcro side facing you, not your partner)
the cuff is placed around the upper part of the arm so the bottom edge rests immediately above the elbow
28. 28 Lab 9-The Heart and General CirculationREMINDER page 1 of 3: 1. Use the sheep heart and the models to view internal anatomy. Learn all the heart structures on the models. Remember to label figure 13.5 (page 118) to include the heart chambers--atria and ventricles.
2. Locate all blood vessels from the bulleted lists on pages 118-119 on the models. Use the figures on lab manual pages 124-125 to help you.
3. See the instructions on page 119 for the pathway of circulation and follow this activity.
29. 29 REMINDER page 2 of 3: 4. Do the sounds of the heart and the heart rate activities
5. Perform the blood pressure activities on pages 122-123.
We will also begin dissecting the fetal pig today. Remember that everyone needs to participate in the dissection.
Tie long hair back so it doesn’t mix with the inside of the pig when you bend down to look at it.
30. 30 REMINDER page 2 of 3: 7. Don't do the indicated cuts on page 101. If you did these cuts, you would cut the penis. Follow the diagram in the handout placed on your table.
You need to locate the following endocrine glands: thyroid, thymus, and pancreas (see diagram on page 102 of the lab manual).
DO NOT locate the adrenal glands; they are very hard to find.
Remember to use Table 11.1 to help you learn about these glands, their hormones and the function of these hormones.
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