Lab 11: Cardiovascular System

Cardiovascular system

Circulates blood throughout the body.

• Blood carries oxygen and nutrients to cells

• Also transports waste (CO2) away from cells

Consists of:

• Heart

• Blood vessels

Blood vessels

• Arteries and arterioles – carry (generally oxygenated) blood away from the heart.

• Veins and venules – carry (generally deoxygenated) blood towards the heart.

• Capillaries – where nutrient and gas exchange takes place; single layer of cells.

Heart The human heart has 4 chambers total.

Atrium – where blood enters the heart

Heart

Ventricle – where blood leaves the heart

Heart: Blood Flow

Fetal Pig: External Heart Anatomy

Major Veins: Venae Cavae

Attached to the right atrium are major veins:

• superior vena cava: anterior (near head)

• inferior vena cava: posterior (near tail end)

They return de-O2 blood from head/body to heart

Heart valves: controlling blood flow Heart valves control blood flow within the heart and prevent backflow.

Atrioventricular valves occur between the atria and ventricles:

• bicuspid valve on the left

• tricuspid valve on the right

Both valves are reinforced by chordae tendinae attached to muscular projections within the ventricles.

Heart valves: controlling blood flow

Additional valves within the heart:

• Pulmonary semilunar valve – between the right ventrical and pulmonary trunk

Heart valves: controlling blood flow

• Aortic semilunar valve – between the left ventrical and the aorta

Major Arteries

• Pulmonary arteries: Along with umbilical arteries, only arteries to carry de-O2 blood.

Major Arteries

• Aorta: largest artery in the body, carries blood to the body.

Blood pressure

• Blood pressure = force that carries blood to all parts of the body.

• A blood pressure reading is the pressure that blood puts on the walls of arteries.

Blood pressure

There are 2 parts to a blood pressure:

• Systolic = the peak blood pressure when the heart is beating or squeezing out blood

• Diastolic = the pressure when your heart is filling with blood or resting between beats.

How to measure blood pressure

• Grab a stethescope and sphygmomanometer.

• Clean earpieces with alcohol and kimwipe before you use it.

• Wrap cuff about an inch above the elbow, it should fit snug.

How to measure blood pressure

• Using your middle and index fingers, gently feel for the pulse in the elbow. This is the brachial artery, put the stethoscope here.

• Do not use your thumb to feel for the pulse because your thumb has a pulse of its own.

How to measure blood pressure

• Make sure valve on the pump is closed and then start pumping air into the cuff.

• Meanwhile listen for sounds. When you hear it, make a note. This will be your systolic.

How to measure blood pressure

• Keep pumping until around 160 or just about 10mm past when you last heard the thumping sound.

• Then VERY SLOWLY release the pressure in the cuff with the valve on the pump, letting the gauge fall about 5 points a second.

How to measure blood pressure

• Record the pressure at which you stop hearing the thumping sounds. This is your diastolic.

• Record your results: systolic/diastolic

Finishing Up

• Save your pig! We are going to use it again. Put it back in bag with wet paper towels and label.

• Clean your workstation with disinfectant spray. Rinse utensils.

Reminders

Quiz 4 is next week!

On Tues. Nov 22nd (our last class )

Questions on mammalian anatomy and cardiovascular system.

No class on Thurs. Nov 24th & Dec. 1st

2nd Practical Exam on Thurs. Dec 8th