Circulatory System

Functional Connections
food, water intake

1. Function
2. Components

oxygen intake

DIGESTIVESYSTEM• Heart• Blood• Vessels (vein & arteries)• Lungs• Lymphatic system

nutrients,
water,
salts

eliminationof carbon
dioxideRESPIRATORYSYSTEM

oxygencarbondioxideCIRCULATORYSYSTEM

URINARYSYSTEMwater,
soluteseliminationof food
residues

rapid transport
to and from allliving cells

elimination ofexcess water,
salts, wastes

Circulatory System

Parts of the Circulatory System

1. Accepts oxygen, nutrients, and other substancesfrom the respiratory and digestive systems anddelivers them to cells• Fluid – blood, hemolymph, coelomic fluid

2. Accepts carbon dioxide and wastes from cells anddelivers them to respiratory and urinary systems
for disposal• Tubes – arteries go away from heart;veins return to heart• Pump – heart or pulsating vessel

3. Also functions in temperature and pH control.

Circulatory Systems in Various Phyla
No Circulatory System
Porifera
Cnidaria
Playthelminthes
Nematoda

Open Circulatory System
Arthropoda
Mollusca (except squid and octopuses)
Echinodermata
Chordata (tunicates)

Circulatory Systems
Open system

Annelida
Closedsystem

Arthropoda

Annelida

Closed Circulatory System
Annelida
Mollusca (squid and octopuses)
Chordata (cephalochordates and vertebrates)

Figure 33.10
from page 559
of your text

Closed Circulatory System• Heart pumps blood in large arteries away fromyour heart. Diffusion occurs in tiny capillaries.
Blood returns to heart in large veins.
• Large vessels for bulk transport fast flow (2-4 cm/sec)
 large diameter (10-12 mm diameter) thick walls (muscular)

Capillaries

Circulation
involves a pump(heart), arteries,veins, capillaries• Capillaries for diffusion
 Slow flow (<1 mm/sec)
 Small diameter (0.008 mm)
 Very thin walls (single cell layer) Fit one RBC through at a time. RBCs scrape walls.

Arteries
Veins
Oxygen-rich bloodCapillaries

Oxygen-poor blood

Blood Volume and Composition
Blood is alive! Blood is 90% water.
1. Plasma portion• 50-60 percent of volume• Water, plasma proteins, dissolved ionsand molecules
2. Cellular portion• 40-50 percent of volume• Red cells, white cells, and platelets

Erythrocytes
1. Red blood cells transport oxygen fromlungs to aerobically respiring cells andcarry carbon dioxide wastes from them.
2. Red blood cells have no nucleus (no DNA).
They are created in bone marrow withenough proteins to last about 120 days.
3. Phagocytes engulf old cells.

Leukocytes(White Blood Cells)
1. Cleaners and defender – engulf damaged
and dead cells and anything tagged asforeign.
2. Some signal the immune system to mount adefense.
3. Elevated levels of white blood cells
indicate to physicians that there is aninfection.

Red Blood Cells in a Clot

Megakaryocytes(Platelets)
1. There are hundred of thousands of platelets
circulating in blood.
2. They live for about 8 days.
3. They respond to injury by releasingchemicals that initiate blood clotting

Macrophages, Lymphocytes, andRed Blood Cells

Blood Vessels
1. Arteries: maintransporters ofoxygenated blood
2. Arterioles: diameter isadjusted to regulate
blood flow

Figure 33.14 frompage 562 of yourtext

Sickle Cell Anemia

The Venous System
1. Blood flows from capillaries into venules,
then on to veins
2. Veins are large-diameter vessels with somesmooth muscle in wall
3. Valves in some veins prevent blood fromflowing backward

3. Capillaries: diffusion
occurs across thin walls
Figure 33.14 frompage 562 of yourtext

Venous PressureFigure 33.19
from page 565 ofyour text

1. VeinsDiameter
Cross-sectional Velocity
Vessel(mm) Number
Area (cm2) (cm/sec)
Aorta
1010.840
Large Arteries 340
3Capillaries
0.008 10-300 Billion 600<0.1
Large Veins
64020
Vena Cava
12.51
1.25-20• Large diameter• Low resistance• Valves• One-way flow
• Blood Reservoir•

Vessel Sizes and Flow Rates

50-60% ortotal blood
volumeFlow Analogy

river inriver outlake

12

3

1

1

2

2

3

3

Vertebrate Hearts and Circulation
Vertebrate Systems
1. Fish• Two-chamber heart pumps blood through one
circuit

2. Amphibians• Heart pumps blood through two partiallyseparate circuits

3. Birds and mammals
2-chambered heart 3-chambered heart 4-chambered heart
FishesAmphibians,Birds, Crocodiles,
ReptilesMammals• Four-chamber heart pumps blood through two
entirely separate circuits

The HeartThe HeartLEFTRIGHT

The Heart

Vena Cava
Delivers
oxygen-poor
blood to heart

The HeartAorta

Aorta
Delivers
oxygen-richblood to body

Pulmonary Artery
Delivers
oxygen-poor
blood to lungs

The Heart

The Heart
Left atrium

Right atrium

Left atrium
Right atrium

Left ventricle
Right ventricle

Left ventricle
Right ventricle

The HeartThe Heart
Left atrium

Right atrium

Left atrium
Right atrium

Left ventricle
Right ventricle

Left ventricle
Right ventricle

Human Heart

Left Atrium

Human Heartin Chest

Left Atrium

Right Atrium

Right Atrium
Right Atrium
RightVentricle

Right Ventricle
Right Ventricle
Left Ventricle

Left Ventricle

Conduction and Contraction

Heart Contraction Animation

SA node1. SA node in right atrium
is pacemaker
2. Electrical signals cause
contraction of atria
3. Signal flows to AV
node and down septum
to ventricles
Figure 33.13(b)from page 561 ofyour text

Superior
vena cava
Oxygen-poor bloodfrom head andupper limbs

AV nodeInferior
vena cava
Oxygen-poor bloodfrom lower trunkand legs

Pulmonary veins
Oxygen-rich
Blood to heart

Pulmonary artery
Oxygen-poor
Blood to lungs

Heart Contraction Animation
Aorta (artery)
Oxygen-rich
Blood to body

Pulmonary Circuit
right pulmonary artery

Short loopthatoxygenates
bloodcapillarybed ofrightlung

pulmonary
trunk(fromsystemiccircuit)

Figure 33.9(b)from page 559 ofyour text

RightAtrium

left pulmonary artery

capillary(to systemic bed ofcircuit)
left lungpulmonary
veins
heart

lungs

Circulation Animation

Systemic
CircuitLonger loop thatcarries blood toand from bodytissues

capillary beds of headand upper extremities(to pulmonary aortacircuit)(frompulmonarycircuit)

Circulation Animation

heart
capillary beds of otherorgans in thoracic cavity

capillary bed of liver
capillary bedsof intestines
Figure 33.9(a)from page 559 ofyour text

capillary beds lower extremities

2nd Pump

1st Pump

Direction of Blood FlowLUBDUBLUBDUB

1. Superior and inferior vena cava
2. Right atrium
3. Right ventricle
4. Pulmonary artery
5. Pulmonary veins
6. Left atrium
7. Left ventricle
8. Aorta

Arteriole Blood Pressure
1. Resting blood pressure measures maximum
systolic pressure and diastolic bloodpressure (most relaxed ventrical state).
2. An average measure of 120/80 mm Hg issystolic pressure over diastolic pressure inmillimeters of mercury (how far thepressure pushes Hg in a glass column.

Cardiac Cycle
Blood Pressure
Figure 33.12 frompage 561 of yourtext

1. Contraction phaseis systole – whenventricles arefully contracted.
2. Relaxation phaseis diastole – whenventricles arerelaxed.

Mid-to-latediastole.

Early
diastole

VentricularsystoleMeasure Blood Pressure
Blood pressure is measured using an inflatable cuff wrapped around thebiceps. The cuff is attached to a pressure gauge. A stethoscope isplaced over the brachial artery.

Blood Doping

Arteriosclerosis and Atherosclerosis

Athletes withdraw and save blood just before
an event. Withdrawal triggers manufacture of
new RBCs. Athlete then adds original bloodback into body. Extra RBCs increase O2
carrying capacity.

Arteriosclerosis – hardening of the arteries – arteries
thicken and lose elasticity
Atherosclerosis – deposition of fatty substances
inside artery walls and narrow the vessels.
Both cause high blood pressure, chest pain, heart attack,stroke, or death.

Circulatory System

Cholesterol
1. Cholesterol is used to make cell membranes, myelin
sheaths, bile salts, and steroid hormones.
2. The liver makes enough cholesterol for all of these,
but we ingest extra cholesterol and the body has todeal with it.
3. Most cholesterol in the blood is bound to proteins as
low-density lipoproteins (LDLs). A small amount isbound to high-density lipoproteins (HDLs).
4. HDL is taken up and metabolized by the liver.
5. Over time LDL deposits cholesterol on artery walls
and can lead to atherosclerosis.

10 Leading Causes of Death, United States,
1999 - 2001, All Races, Both Sexes

Atherosclerosis in Arteries
normalplaque buildup

Human heartwith coronary
arteries in redocclusion

No. of Deathsatherosclerotic
plaque2,500,000

Heart Disease - 37%

2,000,000

Cancer - 29%

1,500,000

Stroke - 9%

1,000,000

blood clot
narrowedlumenA

Other - 25%

500,000
0

normalpartialocclusionnearlyoccluded

Cause of Death

New Heart Bypass Surgery
Method Video Clip

Risk Factors for
Cardiovascular Disease• Smoking• Lack of exercise• Genetic factors• Diabetes mellitus• High cholesterol• Gender (maleness)• Obesity• Old age

Lymph Vascular System

Lymphatic System

1. Fluid enters lymph
1. The circulatory system is leaky

capillaries

2. Some fluid is forced out of the smallest

2. Capillaries merge intovessels and into the interstitial fluid

lymph vessels

3. Vessels of the lymphatic system pick up

3. Lymph vessels converge

this fluid, filter it, and return it to theinto ducts that funnel fluid

circulatory system

into veins in the lower neck

Figure 33.24(b)from page 568 ofyour text

Lymphoid Organs

Lymph Nodes
1. Located at intervals along

1. Central to the body’s defense

lymph vessels

2. Tonsils

2. Act as a filter for lymph

3. Spleen

3. Contain lymphocytes that

4. Thymus glandcan recognize a foreign
invader

Figure 33.24(c)from page 568 ofyour text

Figure 33.24 frompage 568 of yourtext