QuickTime™ and a decompressor

are needed to see this picture.

Blood VesselsBlood Vessels

Ms. Hawthorne7th Grade

Chapter 4 Section 2

Ms. Hawthorne7th Grade

Chapter 4 Section 2

Quick FactQuick Fact

» Why does your blood look blue through your skin?

» Blood is a bright red in its oxygenated form (i.e., leaving the lungs). It's a dark red in its deoxygenated form (i.e., returning to the lungs). Veins appear blue because light, penetrating the skin, is absorbed and reflected back to the eye. Since only the higher energy wavelengths can do this (lower energy wavelengths just don't have the *oomph*), only higher energy wavelengths are seen. And higher energy wavelengths are what we call "blue."

» Why does your blood look blue through your skin?

» Blood is a bright red in its oxygenated form (i.e., leaving the lungs). It's a dark red in its deoxygenated form (i.e., returning to the lungs). Veins appear blue because light, penetrating the skin, is absorbed and reflected back to the eye. Since only the higher energy wavelengths can do this (lower energy wavelengths just don't have the *oomph*), only higher energy wavelengths are seen. And higher energy wavelengths are what we call "blue."

Blood VesselsBlood Vessels

» Arteries» Capillaries» Veins

» Arteries» Capillaries» Veins

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

ArteriesArteries

» When blood LEAVES the heart, it travels through arteries.

» Right ventricles pumps to lungs

» Left ventricle pumps blood through aorta

» Organs get blood from arteries that branch off aorta

» When blood LEAVES the heart, it travels through arteries.

» Right ventricles pumps to lungs

» Left ventricle pumps blood through aorta

» Organs get blood from arteries that branch off aorta

Coronary ArteryCoronary Artery

» First vessels that branch off the aorta

» Carry blood to the heart

» First vessels that branch off the aorta

» Carry blood to the heart

QuickTime™ and a decompressor

are needed to see this picture.

Artery StructureArtery Structure

» Very thick» Three layers

» Innermost: Epithelial Tissue

» Middle: Muscle Tissue

» Outer Wall: Flexible Connective Tissue

» Very thick» Three layers

» Innermost: Epithelial Tissue

» Middle: Muscle Tissue

» Outer Wall: Flexible Connective Tissue

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

CapillariesCapillaries

» Tiny blood vessels that receive blood from the arteries

» It is here that substances are exchanges between the blood and body cells» Diffusion: high concentration to low»Ex: glucose into cells

» Tiny blood vessels that receive blood from the arteries

» It is here that substances are exchanges between the blood and body cells» Diffusion: high concentration to low»Ex: glucose into cells

VeinsVeins

» From capillaries, these vessels carry blood BACK to the heart

» Three layers» Thinner than arteries

» From capillaries, these vessels carry blood BACK to the heart

» Three layers» Thinner than arteries

QuickTime™ and a decompressor

are needed to see this picture.

Blood Flow in VeinsBlood Flow in Veins

» Less force than when in arteries

» Help move blood» 1. Muscles inside veins contract and move blood along

» 2. Skeletal muscles nearby contract and move blood along

» 3. Larger veins have valves to prevent backwards flow

» Less force than when in arteries

» Help move blood» 1. Muscles inside veins contract and move blood along

» 2. Skeletal muscles nearby contract and move blood along

» 3. Larger veins have valves to prevent backwards flow

Blood PressureBlood Pressure

» Pressure = force exerted over an area

» BP = blood exerting pressure against walls of blood vessels

» Caused by = force with which ventricles contract

» As blood moves away from the heart, the pressure lowers. Why?

» Highest in arteries, lowest in veins.

» Pressure = force exerted over an area

» BP = blood exerting pressure against walls of blood vessels

» Caused by = force with which ventricles contract

» As blood moves away from the heart, the pressure lowers. Why?

» Highest in arteries, lowest in veins.

QuickTime™ and a decompressor

are needed to see this picture.

Measuring BPMeasuring BP» Sphygmomanometer = instrument used

» Expressed with 2 numbers in mm of Mercury

» 1st number: measure of BP while ventricles contract

» 2nd number: lower, MP while ventricles relax

» Typical young BP: 120/80

» Sphygmomanometer = instrument used

» Expressed with 2 numbers in mm of Mercury

» 1st number: measure of BP while ventricles contract

» 2nd number: lower, MP while ventricles relax

» Typical young BP: 120/80

PulsePulse

» Expansion and relaxation of the artery wall

» When ventricle contracts, it squirts blood through arteries in the body & walls expand.

» After blood passes, the walls narrow again.

» Pulse = heart beat

» Expansion and relaxation of the artery wall

» When ventricle contracts, it squirts blood through arteries in the body & walls expand.

» After blood passes, the walls narrow again.

» Pulse = heart beat