Chapter 38Circulation

Circulatory SystemCarries blood & related cells

through bodyMove nutrientsMove gasesMove wastesFight diseaseMaintain temperatureMaintain homeostatis

No Circulatory SystemOsmosis & diffusionExchanges across cell

membrane Protozoans

Exchanges across epidermal & gut walls Cnidarians, flatworms,

roundwormsExchanges with coelomic fluids

Echinoderms

Open Circulatory SystemMost mollusks, all arthropodsHeart, open vessels

Hemolymph Colorless No respiratory pigments Doesn’t transport gasses

HemocoelHemocyanin

Pigment in most mollusks, some arthropods

25% as efficient as hemoglobin

Efficient due to lack of gas transport

Closed Circulatory SystemAnnelids, cephalopods, all

vertebraesBlood confined to heart &

blood vesselsCapillaries—site of

exchangeHemoglobin

Gas & nutrient carrierSpecialized organs for gas

exchange

Closed Circulatory System2 Chambered Heart

Sharks, fishOne atrium, one ventricle

3 Chambered HeartAmphibians, reptilesTwo atria, one ventricleOxygenated & deoxygenated blood mix

4 Chambered HeartAlligators/crocodiles, birds, mammalsTwo atria, two ventriclesOxygenated & deoxygenated blood separate

Closed Circulatory System

HeartAtria

Thin-walledReceive blood from

veinsVentricles

Thick-walledReceive blood from

atriaPump blood to

lungs/gills & body

Atrioventricular valvesTricuspid—Right

atrium & ventricleMitral (bicuspid)—Left

atrium & ventricleSemilunar valves

Pulmonary—Right atrium & pulmonary artery

Aortic—Left atrium & aorta

VeinsRight Atrium

Right Ventricle

Pulmonary Artery

Lungs (Oxygenat

ed)Pulmonary Vein

Left Atrium

Left ventricle

Aorta

Body

Capillaries (Deoxygen

ated)

Circulation

Blood VesselsArteries

Carry blood away from heart

Usually carry oxygenated blood

Thick, muscular wallsArterioles

Smaller arteriesRegulate blood pressure

through constriction & dilation

Blood VesselsCapillaries

Simple squamous epitheliumMost numerous vesselsSite of nutrient & gas exchange

Blood VesselsVeins

Carry blood towards heartUsually carry unoxygenated bloodThin wallsLow blood pressureOne-way valvesBlood moves by muscle contraction

BloodPlasma

90% waterIons, gasses, nutrients,

proteins, wastesTransport mediumApproximately 55% of total

blood volumeCells

White, red, plateletsMade in red marrow

BloodErythrocytes (red blood cells, RBCs)

Contain hemoglobinNon-nucleated in mammalsLive 120 days

Thrombocytes (platelets)Blood clottingLive 7 days

Leukocytes (white blood cells, WBCs)Neutrophils

40-75% Phagocytize bacteria, fungi

Lymphocytes 20-45% Cells w/ viruses & bacteria Tumor cells

Monocytes 2-6% Bacteria, fungi,

cellular debrisEosinophils

1-6% Parasites, allergies

Basophils <1% Allergies

Blood TypesAntigens on surface of RBCsBody “reads” these, develops antibodies to any not

“self”At next exposure, antibodies attach, causing

clumpingBlood groups vary by animals

Humans—4 A, B, AB, O

Cats—3 A (vast majority), B, AB

Dogs—8 DEA 1-8 (DEA 4 & 6 on 98%)

Horses—8 A, C, D, K, P, Q, T, U

Blood TypesABO—Humans

Type O 45% of population Neither A nor B antigen Anti-A, Anti-B Receive only from O “Universal donor”

Type A 41% of population A antigen Anti-B Receive from A or O

Type B 10% of population B antigen Anti-A Receive from B or O

Type AB 4% of popuation A and B antigen No antibodies “Universal recipient”

Blood TypesRhesus factor

Rh positive—have antigen (85%)

Rh negative—do not have antigen, produce anti-Rh antibodies (15%)

If mother is Rh- and baby is Rh+, her antibodies can attack baby’s RBCs

First child usually normal

Lymphatic SystemCollects excessive fluid filtered out in

capillariesReturns excessive water & solutes to blood

streamMovement due to valves, muscle contraction

Lymphatic SystemFunctions as part of immune system

Lymph nodes Destroy pathogens & cellular debris Cells rapidly divide with infecion

Spleen Filters pathogens Filters dead or dying RBCs