transport in animals gastrovascular cavities –flatworms and cnidarians nutrients and gases can...

Transport in Animals

• Gastrovascular cavities– flatworms and cnidarians

• Nutrients and gases can move by processes such as diffusion and active transport.

Figure 42.1 Internal transport in the cnidarian Aurelia

Earthworm

Closed Circulation

Water

Water

Water

Water Water

MouthWater

Incurrentpore

Sponge Hydra Nematode

Gastrovas-cular cavity

Gastrovas-cular cavity

Gastrovascular cavity

Osculum(excurrentopening)

a.

b. c.

No Circulatory System

Grasshopper

Open Circulation

Anus

Hemolymph

Heart HeartLateralhearts

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Open Circulatory systems

• Insects, other arthropods and most mollusks

• No distinction between blood and the interstitial fluid

Open Circulatory systems

• Hemolymph– name of general body fluid– directly bathes the internal organs

• System of sinuses

• Heart and body movements cause circulation

Open Circulatory systems

• Slower circulation

• sluggish animals BUT...– Insects are very active

Figure 42.2 Open and closed circulatory systems

Closed Circulatory Systems

– Earthworms, squids, octopuses, and vertebrates

• Blood is confined to vessels and is distinct from interstitial fluid

• Consists of the heart, blood vessels and blood

Blood• Plasma – about 55% of blood volume

– 90% water– inorganic salts (electrolytes), metabolites

(vitamins, aa, glucose), wastes & hormones– proteins

• osmotic balance, viscosity

• buffers, transport lipids, antibodies, clotting factors (fibrinogen)

Plasma(92% water, 55%of whole blood)

Formedelements

Platelets andleukocytes (<1%)

Red blood cells(erythrocytes)(45% of wholeblood)

Other solutes (1.5%) Electrolytes Nutrients Gases Regulatory substances Waste products

Water (91.5%)

Plasma proteins (7%) Albumin (54%) Globulins (38%) Fibrinogen (7%) All others (1%)

Blood Plasma Red Blood Cells

PlasmaRed blood

cells

White blood cellsPlatelets

Platelets

4 million–6 million/mm3 blood

Neutrophils Eosinophils

Basophils LymphocytesMonocytes

3–8%

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0.5–1% 20–25%

60–70% 2–4%

150,000–300,000mm3 blood

Figure 42.14x Blood smear

BloodCellular Elements:

• Red Blood Cells (Erythrocytes)– Most numerous (5-6 million in one cubic ml)– Transport oxygen & carbon dioxide

BloodCellular Elements:

• White Blood Cells (Leukocytes)– Function in body’s defense– A cubic ml of blood has about 5,000 – 10,000– in interstitial fluid or in the lymphatic system –

where your body fights pathogens

4. Threads of fibrin trap erythrocytes and form a clot.

1. Vessel is damaged, exposing surrounding tissue to blood.

5. Once tissue damage is healed, the clot is dissolved.

3. Cascade of enzymatic reactions is triggered by platelets, plasma factors, and damaged tissue.

2. Platelets adhere and become sticky, forming a plug.

Prothrombin

Thrombin

Thrombin

Fibrinogen

Fibrin

Cellular Elements:

Platelets are cell fragments that pinch off from larger cells in the bone marrow

-Function in the formation of blood clots

Blood

Figure 42.16x Blood clot

Heart

• one atrium or two atria

• one or two ventricles

Heart

• one atrium or two atria– chambers that receive blood returning to the

heart

• one or two ventricles– chambers that pump blood out of the heart.

Blood vessels

• Arteries– branch into arterioles

• Capillaries

• Veins– venules merge into veins

Blood vessels

• Arteries– branch into arterioles– carry blood away from heart

• Capillaries– materials are exchanged

• Veins– venules merge into veins– carry blood back toward heart

Blood Vessel Structure

• Walls of arteries or veins have three layers:– epithelium– smooth muscle with elastic fibers– connective tissue – Arteries have thicker walls than veins

• Capillaries only have the inner epithelium layer

Capillary Exchange• Law of Continuity

– blood flows slowly in capillaries because larger total cross-section

– allows materials to be exchanged

Figure 42.10 The interrelationship of blood flow velocity, cross-sectional area of blood vessels, and blood pressure

Capillary Exchange• About 85% of the fluid that exits capillaries

re-enters at the venule end.

Return of Blood to Heart

• Pressure too low in veins

• contraction of skeletal muscles move blood

• one-way valves in veins prevent backflow

Variation in Vertebrate Circulation

FISH

• Two chambered heart and a single circuit of blood flow

Systemiccapillaries

Respiratorycapillaries

Gills

Sinusvenosus Ventricle

Conusarteriosus

Atrium

Body

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Vertebrate Circulatory Systems

Variation in Vertebrate Circulation

AMPHIBIAN

• Three chambered heart (two atria and one ventricle) and double circulation (two circuits of flow)

Lungs

Body

Pulmonarycapillaries

Systemiccapillaries

Ventricle

Conusarteriosus

Right atrium Pulmonary vein

Pulmocutaneousartery

Posterior vena cava

Truncus arteriosus

AortaCarotid arterySystemic artery

Left atriumSinus venosus

Ventricle

Conusarteriosus

Right atrium

Left atrium

a. b.

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Variation in Vertebrate Circulation

AMPHIBIAN

• Pulmonary circuit– blood is pumped to the lungs, where it is

oxygenated and carried back to the left atrium

• Systemic circuit– blood is pumped to the rest of the body, where

it gives up oxygen and is carried back to the right atrium

Variation in Vertebrate Circulation

AMPHIBIAN

• Double circulation assures a vigorous flow of blood to the vital organs

• single ventricle --some mixing of oxygen-rich and oxygen-poor blood.

Variation in Vertebrate Circulation

MAMMALS & BIRDS

• Have a four chambered heart and double circulation

• The left side of the heart handles oxygen-rich blood and the right side handles only oxygen-poor blood.

Head

Body

Lungs

Systemiccapillaries

Pulmonary artery

Pulmonarysemilunar valve

Inferiorvena cava

Superiorvena cava

Aorta

Tricuspid valve

Right ventricle

Leftventricle

Right atrium

PulmonaryveinsLeft atrium

Bicuspidmitralvalve

Systemiccapillaries

Pulmonaryartery

Superiorvena cava

Inferiorvena cava

Artery

PulmonaryveinAorta

Respiratorycapillaries

a. b.

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Mammalian or Bird Heart

• Valves prevent backflow of blood when the ventricles contract– Between each ventricle and atrium is an

atrioventricular (AV) valve• tricuspid and bicuspid (mitral)

– At the exits of the heart are the semilunar valves

Head

Body

Lungs

Systemiccapillaries

Pulmonary artery

Pulmonarysemilunar valve

Inferiorvena cava

Superiorvena cava

Aorta

Tricuspid valve

Right ventricle

Leftventricle

Right atrium

PulmonaryveinsLeft atrium

Bicuspidmitralvalve

Systemiccapillaries

Pulmonaryartery

Superiorvena cava

Inferiorvena cava

Artery

PulmonaryveinAorta

Respiratorycapillaries

a. b.

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QS

Mill

ivo

lts

Seconds

R

P wave

1 sec

+1

-1

0

1. The impulse begins at the SA node and travels to the AV node.

2. The impulse is delayed at the AV node. It then travels to the AV bundle.

SA node(pacemaker)AV node

AV bundle

Left and rightbundle branches

Left and rightbundle branches

Purkinje fibers

Purkinje fibers

Left atriumRight atrium

Purkinje fibers

Interventri-cular septum

AV bundle

Interventricularseptum

AV

AV bundle

Internodalpathway

3. From the AV bundle, the impulse travels down the interventricular septum.

4. The impulse spreads to branches from the interven- tricular septum.

5. Finally reaching the Purkinje fibers, the impulse is distributed throughout the ventricles.

T waveThe control of heart rhythm

Cardiac Cycle

• a complete sequence of the heart contracting to pump blood, relaxing to fill with blood.

• total length is about 0.8 s– The contraction phase is called systole– The relaxation phase is called diastole

Figure 42.6 The cardiac cycle

Cuff

Blood pressuregauge

Stethoscope

050

150100200

250

1. Cuff pressure: 150 mm Hg No sound: Artery closed

2. Cuff pressure: 120 mm Hg Pulse sound: Systolic pressure

3. Cuff pressure: 75 mm Hg Sound stops: Diastolic pressure

050

150100200

250 050

150100200

250

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