42_Lecture_Student_Presentation.ppt

(1)

PowerPoint®_{Lecture Presentations for}

Biology

Chapter 42

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Overview: Trading Places

• Every organism must exchange materials with its environment

• _{Exchanges ultimately occur at the cellular level}

(3)

• For most cells making up multicellular organisms, direct exchange with the environment is not possible

• _{Gills are an example of a specialized exchange}

system in animals

(4)

Concept 42.1: Circulatory systems link exchange surfaces with cells throughout the body

• _{In small and/or thin animals, cells can}

exchange materials directly with the surrounding medium

• In most animals, transport systems connect the organs of exchange with the body cells

• _{Most complex animals have internal transport}

(5)

Gastrovascular Cavities

• Simple animals, such as cnidarians, have a body wall that is only two cells thick and that encloses a gastrovascular cavity

• _{This cavity functions in both digestion and}

distribution of substances throughout the body

(6)

Fig. 42-2

Circular canal

Radial canal Mouth

(a) The moon jelly Aurelia, a cnidarian The planarian Dugesia, a flatworm

(b)

Mouth Pharynx

2 mm

(7)

Open and Closed Circulatory Systems

• More complex animals have either open or closed circulatory systems

• _{Both systems have three basic components:}

– A circulatory fluid (blood or hemolymph)

– A set of tubes (blood vessels)

(8)

• In insects, other arthropods, and most

molluscs, blood bathes the organs directly in an open circulatory system

• _{In an open circulatory system, there is no}

(9)

• In a closed circulatory system, blood is confined to vessels and is distinct from the interstitial fluid

• _{Closed systems are more efficient at}

(10)

Fig. 42-3

Heart

Hemolymph in sinuses surrounding organs

Heart

Interstitial fluid

Small branch vessels In each organ

Blood

Dorsal vessel (main heart)

Auxiliary hearts Ventral vessels (b) A closed circulatory system

(a) An open circulatory system

(11)

Organization of Vertebrate Circulatory Systems

• Humans and other vertebrates have a closed circulatory system, often called the

cardiovascular system

• _{The three main types of blood vessels are}

(12)

• Arteries branch into arterioles and carry blood to capillaries

• _{Networks of capillaries called}_{capillary beds}

are the sites of chemical exchange between the blood and interstitial fluid

(13)

• Vertebrate hearts contain two or more chambers

• _{Blood enters through an}_atrium_{and is pumped}

(14)

Single Circulation

• Bony fishes, rays, and sharks have single circulation with a two-chambered heart

• _{In single circulation, blood leaving the heart}

(15)

Fig. 42-4

Artery

Ventricle

Atrium Heart

Vein circulationSystemic

Gill

(16)

Double Circulation

• Amphibian, reptiles, and mammals have

double circulation

• _{Oxygen-poor and oxygen-rich blood are}

(17)

Fig. 42-5

Amphibians

Lung and skin capillaries

Pulmocutaneous circuit Atrium (A) Ventricle (V) Atrium (A) Systemic circuit Right Left

Reptiles (Except Birds)

Lung capillaries Pulmonary circuit Right systemic aorta

(18)

• In reptiles and mammals, oxygen-poor blood

flows through the pulmonary circuit to pick up oxygen through the lungs

• In amphibians, oxygen-poor blood flows

through a pulmocutaneous circuit to pick up oxygen through the lungs and skin

• Oxygen-rich blood delivers oxygen through the

systemic circuit

(19)

Adaptations of Double Circulatory Systems

(20)

Amphibians

• _{Frogs and other amphibians have a}

three-chambered heart: two atria and one ventricle

• The ventricle pumps blood into a forked artery that splits the ventricle’s output into the

pulmocutaneous circuit and the systemic circuit

(21)

Reptiles (Except Birds)

• _{Turtles, snakes, and lizards have a}

three-chambered heart: two atria and one ventricle

• In alligators, caimans, and other crocodilians a septum divides the ventricle

• _{Reptiles have double circulation, with a}

(22)

Mammals and Birds

• _{Mammals and birds have a four-chambered}

heart with two atria and two ventricles

• The left side of the heart pumps and receives only oxygen-rich blood, while the right side

receives and pumps only oxygen-poor blood

(23)

Concept 42.2: Coordinated cycles of heart

contraction drive double circulation in mammals

(24)

Mammalian Circulation

• Blood begins its flow with the right ventricle pumping blood to the lungs

• In the lungs, the blood loads O₂ and unloads CO₂

• Oxygen-rich blood from the lungs enters the heart at the left atrium and is pumped through the aorta to the body tissues by the left

ventricle

(25)

• Blood returns to the heart through the superior vena cava (blood from head, neck, and

forelimbs) and inferior vena cava (blood from trunk and hind limbs)

(26)

Fig. 42-6 Superior vena cava Pulmonary artery Capillaries of right lung

3 7 3 8 9 2 4 11 5 1 10 Aorta Pulmonary vein Right atrium Right ventricle Inferior vena cava Capillaries of abdominal organs and hind limbs

Pulmonary vein Left atrium Left ventricle Aorta Capillaries of left lung Pulmonary

(27)

The Mammalian Heart: A Closer Look

(28)

(29)

• _{The heart contracts and relaxes in a rhythmic}

cycle called the cardiac cycle

• The contraction, or pumping, phase is called

systole

• _{The relaxation, or filling, phase is called}

(30)

(31)

• The heart rate, also called the pulse, is the number of beats per minute

• _The_{stroke volume}_{is the amount of blood}

pumped in a single contraction

• The cardiac output is the volume of blood pumped into the systemic circulation per

(32)

• Four valves prevent backflow of blood in the heart

• _The_{atrioventricular (AV) valves}_separate

each atrium and ventricle

(33)

• The “lub-dup” sound of a heart beat is caused by the recoil of blood against the AV valves (lub) then against the semilunar (dup) valves

(34)

Maintaining the Heart’s Rhythmic Beat

(35)

• _The_{sinoatrial (SA) node}_{, or}_pacemaker_{, sets}

the rate and timing at which cardiac muscle cells contract

• Impulses from the SA node travel to the

atrioventricular (AV) node

• _{At the AV node, the impulses are delayed and}

(36)

• Impulses that travel during the cardiac cycle can be recorded as an electrocardiogram

(37)

Fig. 42-9-5 Signals spread throughout ventricles. 4 Purkinje fibers Pacemaker

generates wave of signals to contract. 1 SA node (pacemaker) Signals are delayed at AV node. 2 AV node Signals pass to heart apex. 3

Bundle

(38)

• _{The pacemaker is influenced by nerves,}

(39)

Concept 42.3: Patterns of blood pressure and flow reflect the structure and arrangement of blood

vessels

• _{The physical principles that govern movement}

(40)

Blood Vessel Structure and Function

(41)

(42)

• Capillaries have thin walls, the endothelium plus its basement membrane, to facilitate the exchange of materials

• Arteries and veins have an endothelium, smooth muscle, and connective tissue

• Arteries have thicker walls than veins to accommodate the high pressure of blood pumped from the heart

(43)

Blood Flow Velocity

• Physical laws governing movement of fluids through pipes affect blood flow and blood pressure

• Velocity of blood flow is slowest in the capillary beds, as a result of the high resistance and

large total cross-sectional area

(44)

(45)

Blood Pressure

• Blood pressure is the hydrostatic pressure that blood exerts against the wall of a vessel

• _{In rigid vessels blood pressure is maintained;}

(46)

Changes in Blood Pressure During the Cardiac Cycle

• Systolic pressure is the pressure in the arteries during ventricular systole; it is the highest pressure in the arteries

• _{Diastolic pressure}_{is the pressure in the}

arteries during diastole; it is lower than systolic pressure

(47)

Regulation of Blood Pressure

• Blood pressure is determined by cardiac output and peripheral resistance due to constriction of arterioles

• Vasoconstriction is the contraction of smooth muscle in arteriole walls; it increases blood

pressure

(48)

• Vasoconstriction and vasodilation help

maintain adequate blood flow as the body’s demands change

• _{The peptide}_endothelin_{is an important inducer}

(49)

Fig. 42-12

Ser

RESULTS

Ser

Ser Cys

Cys _—NH

3+

Leu Met

Asp Lys

Glu Cys Val Tyr Phe Cys His Leu Asp Ile Ile Trp _—COO–

Endothelin

Parent polypeptide Trp

Cys

(50)

Blood Pressure and Gravity

• Blood pressure is generally measured for an artery in the arm at the same height as the heart

• _{Blood pressure for a healthy 20 year old at rest}

(51)

Fig. 42-13-3

Pressure in cuff greater than 120 mm Hg

Rubber cuff inflated with air Artery 120 120

Pressure in cuff drops below 120 mm Hg

Sounds

Pressure in cuff below 70 mm Hg

70 Blood pressure reading: 120/70

(52)

• Fainting is caused by inadequate blood flow to the head

• Animals with longer necks require a higher systolic pressure to pump blood a greater distance against gravity

• Blood is moved through veins by smooth muscle contraction, skeletal muscle

contraction, and expansion of the vena cava with inhalation

(53)

Fig. 42-14

Direction of blood flow

in vein (toward heart) _{Valve (open)}

Skeletal muscle

(54)

Capillary Function

• Capillaries in major organs are usually filled to capacity

(55)

• Two mechanisms regulate distribution of blood in capillary beds:

– _{Contraction of the smooth muscle layer in the}

wall of an arteriole constricts the vessel

(56)

Fig. 42-15

Precapillary sphincters Thoroughfare channel

Arteriole

Capillaries

Venule

(a) Sphincters relaxed

(b) Sphincters contracted

(57)

• The critical exchange of substances between the blood and interstitial fluid takes place

across the thin endothelial walls of the capillaries

• The difference between blood pressure and

(58)

Fig. 42-16 Body tissue Capillary INTERSTITIAL FLUID Net fluid movement out Direction of blood flow Net fluid movement in Blood pressure Inward flow Outward flow Osmotic pressure

Arterial end of capillary Venous end

(59)

Fluid Return by the Lymphatic System

• The lymphatic system returns fluid that leaks out in the capillary beds

• _{This system aids in body defense}

• Fluid, called lymph, reenters the circulation directly at the venous end of the capillary bed and indirectly through the lymphatic system

(60)

• Lymph nodes are organs that filter lymph and play an important role in the body’s defense

• _{Edema is swelling caused by disruptions in the}

(61)

Concept 42.4: Blood components function in exchange, transport, and defense

• In invertebrates with open circulation, blood (hemolymph) is not different from interstitial fluid

(62)

Blood Composition and Function

• Blood consists of several kinds of cells

suspended in a liquid matrix called plasma

• _{The cellular elements occupy about 45% of the}

(63)

Fig. 42-17

Plasma 55%

Constituent Major functions Water Solvent for

carrying other substances

Ions (blood electrolytes)

Osmotic balance, pH buffering, and regulation of membrane permeability Sodium Potassium Calcium Magnesium Chloride Bicarbonate Osmotic balance pH buffering Clotting Defense Plasma proteins Albumin Fibrinogen Immunoglobulins (antibodies) Separated blood elements

Cellular elements 45%

Cell type Number Functions per µL (mm3_{) of blood}

Erythrocytes

(red blood cells) 5–6 million

Transport oxygen and help transport carbon dioxide

Leukocytes

(white blood cells) 5,000–10,000

(64)

Plasma

• Blood plasma is about 90% water

• _{Among its solutes are inorganic salts in the}

form of dissolved ions, sometimes called electrolytes

• Another important class of solutes is the

plasma proteins, which influence blood pH, osmotic pressure, and viscosity

(65)

Cellular Elements

• _{Suspended in blood plasma are two types of}

cells:

– Red blood cells (erythrocytes) transport oxygen

– White blood cells (leukocytes) function in defense

• _Platelets_{, a third cellular element, are}

(66)

• _{Red blood cells, or}_erythrocytes_{, are by far the}

most numerous blood cells

• _{They transport oxygen throughout the body}

• _{They contain}_hemoglobin_{, the iron-containing}

protein that transports oxygen

(67)

Leukocytes

• _{There are five major types of white blood cells,}

or leukocytes: monocytes, neutrophils, basophils, eosinophils, and lymphocytes

• They function in defense by phagocytizing

bacteria and debris or by producing antibodies

(68)

Platelets

(69)

Blood Clotting

• When the endothelium of a blood vessel is damaged, the clotting mechanism begins

• _{A cascade of complex reactions converts}

fibrinogen to fibrin, forming a clot

(70)

Fig. 42-18-2

Collagen fibers

Platelet plug Platelet releases chemicals

that make nearby platelets sticky

Clotting factors from:

Platelets Damaged cells

(71)

Collagen fibers

Platelet plug Platelet releases chemicals

that make nearby platelets sticky

Clotting factors from:

Platelets Damaged cells

Plasma (factors include calcium, vitamin K)

Prothrombin Thrombin

Fibrin clot

Red blood cell

(72)

Stem Cells and the Replacement of Cellular Elements

• The cellular elements of blood wear out and are replaced constantly throughout a person’s life

• Erythrocytes, leukocytes, and platelets all

develop from a common source of stem cells

in the red marrow of bones

(73)

Fig. 42-19

Stem cells

(in bone marrow)

Myeloid stem cells Lymphoid

stem cells

Lymphocytes

B cells T cells

Erythrocytes

Platelets

(74)

Cardiovascular Disease

• Cardiovascular diseases are disorders of the heart and the blood vessels

• _{They account for more than half the deaths in}

(75)

Atherosclerosis

• One type of cardiovascular disease,

(76)

Fig. 42-20

Connective tissue

Smooth

muscle Endothelium Plaque

(77)

Heart Attacks and Stroke

• A heart attack is the death of cardiac muscle tissue resulting from blockage of one or more coronary arteries

• A stroke is the death of nervous tissue in the brain, usually resulting from rupture or

(78)

Treatment and Diagnosis of Cardiovascular Disease

• Cholesterol is a major contributor to atherosclerosis

• Low-density lipoproteins (LDLs) are

associated with plaque formation; these are “bad cholesterol”

• High-density lipoproteins (HDLs) reduce the deposition of cholesterol; these are “good

cholesterol”

• The proportion of LDL relative to HDL can be decreased by exercise, not smoking, and

(79)

• _Hypertension_{, or high blood pressure,}

promotes atherosclerosis and increases the risk of heart attack and stroke

(80)

Concept 42.5: Gas exchange occurs across specialized respiratory surfaces

(81)

Partial Pressure Gradients in Gas Exchange

• Gases diffuse down pressure gradients in the lungs and other organs as a result of

differences in partial pressure

• _{Partial pressure}_{is the pressure exerted by a}

(82)

• A gas diffuses from a region of higher partial pressure to a region of lower partial pressure

• In the lungs and tissues, O₂ and CO₂ diffuse

(83)

Respiratory Media

• Animals can use air or water as a source of O₂, or respiratory medium

• In a given volume, there is less O₂ available in water than in air

(84)

Respiratory Surfaces

• Animals require large, moist respiratory

surfaces for exchange of gases between their cells and the respiratory medium, either air or water

• Gas exchange across respiratory surfaces takes place by diffusion

(85)

Gills in Aquatic Animals

(86)

Fig. 42-21

Parapodium (functions as gill) (a) Marine worm

Gills

(b) Crayfish (c) Sea star

Tube foot

Coelom

(87)

• Ventilation moves the respiratory medium over the respiratory surface

• _{Aquatic animals move through water or move}

water over their gills for ventilation

• Fish gills use a countercurrent exchange

system, where blood flows in the opposite

(88)

Fig. 42-22

Anatomy of gills

Gill arch

Water

flow Operculum

Gill

arch Gill filament_organization Blood vessels Oxygen-poor blood Oxygen-rich blood Fluid flow through gill filament Lamella

Blood flow through capillaries in lamella Water flow

between lamellae

Countercurrent exchange P_O2 (mm Hg) in water

P_O2 (mm Hg) in blood Net

diffu-sion of O2

from water to blood

150 120 90 60 30

110 80 20

Gill filaments

(89)

Tracheal Systems in Insects

• The tracheal system of insects consists of tiny branching tubes that penetrate the body

• The tracheal tubes supply O₂ directly to body cells

• The respiratory and circulatory systems are separate

(90)

Fig. 42-23

Air sacs

Tracheae

External opening

Body cell

Air sac Tracheole

Tracheoles Mitochondria Muscle fiber

2.5 µm Body wall

Trachea

(91)

Lungs

• _Lungs_{are an infolding of the body surface}

• The circulatory system (open or closed)

transports gases between the lungs and the rest of the body

• _{The size and complexity of lungs correlate with}

(92)

Mammalian Respiratory Systems: A Closer Look

• A system of branching ducts conveys air to the lungs

• Air inhaled through the nostrils passes through the pharynx via the larynx, trachea, bronchi,

bronchioles, and alveoli, where gas exchange occurs

• Exhaled air passes over the vocal cords to create sounds

(93)

(94)

Concept 42.6: Breathing ventilates the lungs

• The process that ventilates the lungs is

(95)

How an Amphibian Breathes

• An amphibian such as a frog ventilates its

(96)

How a Mammal Breathes

• _{Mammals ventilate their lungs by}_negative

pressure breathing, which pulls air into the lungs

• Lung volume increases as the rib muscles and

diaphragm contract

(97)

• The maximum tidal volume is the vital capacity

• _{After exhalation, a}_{residual volume}_{of air}

(98)

Fig. 42-25 Lung Diaphragm Air inhaled Rib cage expands as rib muscles contract

(99)

How a Bird Breathes

• Birds have eight or nine air sacs that function as bellows that keep air flowing through the lungs

• Air passes through the lungs in one direction only

(100)

Fig. 42-26

Anterior air sacs

Posterior

air sacs Lungs

Air

Lungs

Air

1 mm Trachea

Air tubes

(parabronchi) in lung

EXHALATION

Air sacs empty; lungs fill

(101)

Control of Breathing in Humans

• _{In humans, the main}_{breathing control}

centers are in two regions of the brain, the medulla oblongata and the pons

• The medulla regulates the rate and depth of breathing in response to pH changes in the cerebrospinal fluid

(102)

• Sensors in the aorta and carotid arteries

monitor O₂ and CO₂ concentrations in the blood

(103)

Fig. 42-27

Breathing control centers

Cerebrospinal fluid

Pons

Medulla oblongata

Carotid arteries

(104)

Concept 42.7: Adaptations for gas exchange include pigments that bind and transport gases

• The metabolic demands of many organisms

(105)

Coordination of Circulation and Gas Exchange

• _{Blood arriving in the lungs has a low partial}

pressure of O₂ and a high partial pressure of CO₂ relative to air in the alveoli

• In the alveoli, O₂ diffuses into the blood and CO₂ diffuses into the air

• _{In tissue capillaries, partial pressure gradients}

(106)

Fig. 42-28

Alveolus

P_O2 = 100 mm Hg

P_O2 = 40 P_O2 = 100

P_O2 = 100 P_O2 = 40

Circulatory system

Body tissue

P_O2 ≤ 40 mm Hg P_CO2 ≥ 46 mm Hg

Body tissue P_CO2 = 46 P_CO2 = 40

P_CO2 = 40 P_CO2 = 46

Circulatory system

P_CO2 = 40 mm Hg Alveolus

(107)

Respiratory Pigments

• Respiratory pigments, proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry

• _{Arthropods and many molluscs have}

hemocyanin with copper as the oxygen-binding component

(108)

Hemoglobin

• _{A single hemoglobin molecule can carry four}

molecules of O₂

• _{The hemoglobin dissociation curve} _{shows that}

a small change in the partial pressure of

oxygen can result in a large change in delivery of O₂

• CO₂ produced during cellular respiration lowers blood pH and decreases the affinity of

(109)

Fig. 42-UN1

 Chains

(110)

Fig. 42-29

O2 unloaded

to tissues at rest

O₂ unloaded to tissues during exercise 100 40 0 20 60 80

0 40 80 100

O2 s at u ra ti o n o f h em o g lo b in ( % ) 20 60 Tissues during exercise Tissues at rest Lungs

P_O2 (mm Hg)

(a) P_O2 and hemoglobin dissociation at pH 7.4

O2 s at u ra ti o n o f h em o g lo b in ( % ) 40 0 20 60 80

0 20 40 60 80 100 100

P_O2 (mm Hg)

(b) pH and hemoglobin dissociation pH 7.4

pH 7.2

Hemoglobin retains less O2 at lower pH

(higher CO2

(111)

Carbon Dioxide Transport

• Hemoglobin also helps transport CO₂ and assists in buffering

• CO₂ from respiring cells diffuses into the blood and is transported either in blood plasma,

bound to hemoglobin, or as bicarbonate ions (HCO₃–)

Animation: O

Animation: O₂₂ from Blood to Tissues from Blood to Tissues

Animation: CO

(112)

Fig. 42-30

Body tissue CO2 produced

CO2 transport

from tissues Capillary wall Interstitial fluid Plasma within capillary CO2 CO2 CO2 Red blood cell

H2O

H2CO3 _Hb

Carbonic acid

Hemoglobin picks up CO2 and H+

CO2 transport

to lungs HCO3–

Bicarbonate H

+

Hemoglobin releases CO2 and H+

To lungs HCO3–

HCO3–

Hb H+

+ HCO3–

H2CO3

H2O

CO2

(113)

Elite Animal Athletes

• Migratory and diving mammals have

(114)

The Ultimate Endurance Runner

(115)

(116)

Diving Mammals

• Deep-diving air breathers stockpile O₂ and deplete it slowly

(117)

You should now be able to:

1. Compare and contrast open and closed circulatory systems

2. Compare and contrast the circulatory systems of fish, amphibians, non-bird reptiles, and

mammals or birds

3. Distinguish between pulmonary and systemic circuits and explain the function of each

(118)

5. Define cardiac cycle and explain the role of the sinoatrial node

6. Relate the structures of capillaries, arteries, and veins to their function

7. Define blood pressure and cardiac output and describe two factors that influence each

(119)

9. Describe the role played by the lymphatic system in relation to the circulatory system

10. Describe the function of erythrocytes, leukocytes, platelets, fibrin

11. Distinguish between a heart attack and stroke

(120)

13. For humans, describe the exchange of gases in the lungs and in tissues