Warm-Up 4/291. What is the function of the sinoatrial node?2. What does the QRS complex of an EKG represent?3. What two vessels are the semi-lunar valves located

in?

External Parts

• Enclosed by membrane called pericardium

• Double layered sac • Contains pericardial

fluid to reduce the friction of the beating heart

Pericardium Layers

• Visceral pericardium – Inner membrane– Surrounds heart– Attached to myocardium

• Parietal pericardium– Outer membrane – Anchors heart to sternum and

diaphragm

Parietal pericardium

Layers of heart walls

Pericardium – outer layer of fibrous tissue

Myocardium – middle layer of thick muscle

Endocardium – inner layer of epithelial cells

Three-layered wall

Chordae tendineae

• “heart strings”

• Attach to AV valves

• Anchor flaps on valves in closed position when needed

Fibrous skeleton

Mitral valve

Posterior

Opening ofleft coronaryartery

Aorticvalve

Tricuspidvalve

Pulmonary valve

6

The Blood Vessels

• The cardiovascular system has three types of blood vessels:

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

• Capillaries – where nutrient and gas exchange occur

• Veins (and venules) – carry blood toward the heart.

The Arteries• Thick strong wall (three layers or tunics)

– Endothelial lining– Middle layer of smooth muscle and elastic tissue– Outer layer of connective tissue

• The largest artery is the aorta. • The smooth muscle of the middle layer can constrict to regulate

blood flow and blood pressure. • Arterioles are smaller than arteries have have a thinner middle and

outer layers• Arterioles can constrict or dilate, changing blood pressure and flow

into capillaries.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Arteriole

Capillary

Endothelium

Smoothmuscle cell

Precapillarysphincter

9

The Capillaries• Capillaries have walls only one cell thick to

allow exchange of gases and nutrients with tissue fluid.

Anatomy of a capillary bed

13

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Arteriole

Capillary

Venule

© Don. W. Fawcett/Visuals Unlimited

The Veins• Venules drain blood from capillaries, then

join to form veins that take blood to the heart.

• Veins often have valves that prevent the backward flow of blood when closed.

Blood vessels

Towardheart

Varicose veins

What causes varicose veins?High blood pressure inside your superficial leg veins causes varicose veins.Factors that can increase your risk for varicose veins include having a family history of varicose veins, being overweight, not exercising enough, smoking, standing or sitting for long periods of time

Treatment often involves destroying the vein

VIDEOS!

TODAY!1. If you have not finished labeling the events on each image

of your flip book you need to complete that. 2. Once you have completed that show that to Mr. Baker and

he will give you the first portion of the case study. 3. Once you are done with that check with Mr. Baker and

show him the work and he will give you the second portion.4. Complete the second portion and show it to Mr. Baker and

he will give you the third portion of the case study.

THE THIRD PORTION OF THE CASE STUDY IS DUE TO Mr. BAKER BY END OF CLASS THURSDAY!

No Warm-Up!Get into groups of 4-5

Using your group members and any available props, you will act out the journey of a drop of blood through the

circulatory system.

On this journey you will need to describe the events of the cardiac cycle as they happen.

This may be a skit, a dance, mime, anything as long as it is some physically active and accurate representation.Include all events we’ve discussed, including arteries,

arterioles, capillaries, venules and veins in your presentation as well.

You will have 45min to create. Then you will present to the class.

In your groups you will be acting out the path of a drop of blood through the body.

You must create and perform a skit, dance, mime, some physically active representation of the path of a drop of blood through the body

and the events of the cardiac cycle.Include all events on your 1-22 slips of paper,

but include arteries, arterioles, capillaries, venules and veins in your presentation as well.

You will have 1 hour to create. Then you will present to the class.