Circulatory System

Honors BiologyPowerpoint #4

Unit 8 – Chapter 37

Circulatory System

Circulatory System• Structures: oHeart, Blood vessels, blood

• Functions: oBrings O2, nutrients and hormones

to cells, takes away CO2 and wasteoFights infectionoRegulates body temperature.

Heart

• Made of cardiac muscle

• Beats on average 65-85 beats per minute

• Pumps to circulate blood throughout the body

Take your heart Rate

Blood Vessels:

• Carry blood to cells• Lined with smooth muscle

tissue • Three kinds:

1. Arteries2. Capillaries3. Veins

Arteries (carries blood

away)

• Carry oxygenated blood from the heart to the rest of the body.

Direction of blood flow

Capillaries• Branch off of the Arteries• The smallest of the blood vessels

o some have diameters as small as 1 red blood cell

• Takes blood to all cells where diffusion occurs

Direction of blood flow

Capillaries

Veins• Takes deoxygenated blood from

the capillaries back to the heart

Direction of blood flow

Comparing arteries and veins

• Why do arteries have thicker and stronger walls?

Veins• Have valves to prevent backflow because

not receiving pressure from heart• Muscles help pump blood back to heart

through the veins

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Varicose veins

Treatment for varicose/spider veins

• Sclerotherapy. doctor injects the veins with a solution that scars and closes those veins, causing the blood to reroute through healthier veins.

• Vein ligation/vein striping

• Laser surgery. Laser surgery works by sending strong bursts of light into the vein that make the vein slowly fade and disappear. No incisions or needles are used. The treatment is often less effective than sclerotherapy.

Blood

• The human body has 4-6 liters of blood

• Blood:o45% of blood is

Cellso55% of blood is

plasma

Blood Cells: 3 kinds• Red Blood Cells: transports

oxygen, contain hemoglobin (gives them color)

• White Blood Cells (leukocytes): attack foreign substances or organisms.

• Platelets: stick to broken blood vessels to stop bleeding when you are cut

Plasma • 90% water• 10% other materials:

oDissolved gases o SaltsoNutrientso EnzymesoHormonesoWaste products

Blood Flow in the Heart

Upper body

The Heart• The human heart has four chambersoLeft and right ventricleoLeft and right atrium

• The left side of the heart pumps oxygenated blood to the body

• The right side of the heart pumps

deoxygenated blood to the lungs

Right Atrium

Right Ventricle

Left Atrium

Left Ventricle

https://www.youtube.com/watch?v=BEWjOCVEN7M

1) The right atrium receives deoxygenated blood from the body through the superior and inferior vena

cava.

2) The right atrium pumps blood through the tricuspid (AV) valve and into the right ventricle

3) Right Ventricle Contracts and pushes blood through pulmonary valve towards

lungs

4) Blood is pushed through the pulmonary arteries to the lungs to

receive oxygen

5) Oxygenated blood returns to the left atrium from the lungs through

the pulmonary veins

6) Blood passes through the bicuspid (mitral) valve into the

left ventricle.

7) Contraction of Left ventricle pumps blood through aortic

valve to the aorta

8)Blood travels through aorta and then to all regions of the body where it feeds cells with

oxygen picked up from the lungs and nutrients from the digestive tract.