Figure 42.1. How does blood help regulate homeostasis?

Figure 42.1

How does blood help regulate homeostasis?

How does blood help regulate homeostasis?

• pH• Oxygen

• Nitrogen • Osmolality• Sugar• Minerals (e.g. calcium)

LECTURE PRESENTATIONSFor CAMPBELL BIOLOGY, NINTH EDITION

Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson

© 2011 Pearson Education, Inc.

Lectures byErin Barley

Kathleen Fitzpatrick

Circulation and Gas Exchange

Chapter 42

Figure 42.2

Circularcanal

Mouth

Radial canals 5 cm

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

Gastrovascularcavity

Mouth

Pharynx2 mm

Figure 42.3

(a) An open circulatory system

Heart

Hemolymph in sinusessurrounding organs

Pores

Tubular heart

Dorsalvessel

(main heart)

Auxiliaryhearts

Small branchvessels ineach organ

Ventral vessels

Blood

Interstitial fluid

Heart

(b) A closed circulatory system

Figure 42.4

(a) Single circulation (b) Double circulation

Artery

Heart:

Atrium (A)

Ventricle (V)

Vein

Gillcapillaries

Bodycapillaries

Key

Oxygen-rich blood

Oxygen-poor blood

Systemic circuit

Systemiccapillaries

Right Left

A A

VV

Lungcapillaries

Pulmonary circuit

Figure 42.5

Amphibians Reptiles (Except Birds)

Pulmocutaneous circuit Pulmonary circuit

Lungand skincapillaries

Atrium(A)

Atrium(A)

LeftRight

Ventricle (V)

Systemiccapillaries

Systemic circuit Systemic circuit Systemic circuit

Systemiccapillaries

IncompleteseptumIncompleteseptum

Leftsystemicaorta

LeftRight

Rightsystemicaorta

A A

V V

Lungcapillaries

Lungcapillaries

Pulmonary circuit

A AV V

LeftRight

Systemiccapillaries

Key

Oxygen-rich bloodOxygen-poor blood

Mammals and Birds

• 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– WHAT IS THE DIFFERENCE? – WHY DO AMPHIBIANS BOTHER?– Do they need lungs when underwater?


PATHWAY OF BLOOD, POST-HEART

Aorta

Arterie

sArte

riole

s

Capill

arie

sVen

ules

Veins

Venae

cava

e

Systolicpressure

Diastolicpressure

020406080

100120

01020304050

Pre

ss

ure

(mm

Hg

)V

elo

cit

y(c

m/s

ec

)A

rea

(c

m2)

01,0002,0003,0004,0005,000

• Heart animation


Animation: Path of Blood Flow in Mammals

http://www.argosymedical.com/Circulatory/samples/animations/Heart/index.html


Animation: Path of Blood Flow in MammalsRight-click slide / select “Play”

Superior vena cava

Pulmonaryartery

Capillariesof right lung

Pulmonaryvein

Aorta

Inferiorvena cava

Right ventricle

Capillaries ofabdominal organsand hind limbs

Right atrium

Aorta

Left ventricle

Left atrium

Pulmonary vein

Pulmonaryartery

Capillariesof left lung

Capillaries ofhead and forelimbs

Figure 42.6

Figure 42.7

Pulmonary artery

Rightatrium

Semilunarvalve

Atrioventricularvalve

Rightventricle

Leftventricle

Atrioventricularvalve

Semilunarvalve

Leftatrium

Pulmonaryartery

Aorta

• 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 diastole


Figure 42.8-1

Atrial andventricular diastole

0.4sec

1

Figure 42.8-2


Atrial systole and ventricular diastole

0.1sec

0.4sec

2

1

Figure 42.8-3


Atrial systole and ventricular diastole

Ventricular systole and atrialdiastole

0.1sec

0.4sec

0.3 sec

2

1

3

• 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 minute and depends on both the heart rate and stroke volume


• 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

• Backflow of blood through a defective valve causes a heart murmur


Maintaining the Heart’s Rhythmic Beat

• Some cardiac muscle cells are self-excitable, meaning they contract without any signal from the nervous system

• The sinoatrial (SA) node, or pacemaker, sets the rate and timing at which cardiac muscle cells contract

• Impulses that travel during the cardiac cycle can be recorded as an electrocardiogram (ECG or EKG)


Figure 42.9-1

SA node(pacemaker)

ECG

1

Figure 42.9-2

SA node(pacemaker)

AVnode

ECG

1 2

Figure 42.9-3

SA node(pacemaker)

AVnode Bundle

branches Heartapex

ECG

1 2 3

Figure 42.9-4

SA node(pacemaker)

AVnode Bundle

branches Heartapex

Purkinjefibers

ECG

1 2 3 4

• The pacemaker is regulated by two portions of the nervous system: the sympathetic and parasympathetic divisions– The sympathetic division speeds up the pacemaker– The parasympathetic division slows down the

pacemaker• The pacemaker is also regulated by hormones and temperature


Blood fun facts• It takes a drop of blood 20 to 60 seconds for one round-

trip from and to the heart.• We have approximately 100,000 miles of blood vessels • Two million red blood cells die every second.• The kidneys filter over 400 gallons of blood each day.• The average life span of a single red blood cell is 120

days.• There are 150 billion red blood cells in one ounce of

blood• Our hearts pump 48 million gallons of blood/year (in 10

oz. intervals)• White blood cells only last 4-6 hours

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


Blood Vessel Structure and Function

• A vessel’s cavity is called the central lumen• The epithelial layer that lines blood vessels is

called the endothelium• The endothelium is smooth and minimizes

resistance– Why might high blood pressure lead to problems?


The structure of blood vessels

Artery

Red blood cells

Endothelium

Artery

Smoothmuscle

Connectivetissue

Capillary

Valve

Vein

Vein

Basal lamina

Endothelium

Smoothmuscle

Connectivetissue

100 m

LM

Venule

15

mL

M

Arteriole

Red blood cell

Capillary

• Nitric oxide is a major inducer of vasodilation• The peptide endothelin is an important inducer of

vasoconstriction

Under what circumstances does the body use them?


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 is 120 mm Hg at systole and 70 mm Hg at diastole

• Fainting is caused by inadequate blood flow to the head– Which animals are at greatest risk?


Blood pressure reading: 120/70

120

70

Soundsstop

Soundsaudible instethoscope

120

Arteryclosed

1 2 3

Figure 42.12

Direction of blood flowin vein (toward heart) Valve (open)

Skeletal muscle

Valve (closed)

Blood is moved through veins by smooth muscle contraction, skeletal muscle contraction, and expansion of the vena cava with inhalationOne-way valves in veins prevent backflow of blood

Capillary Function

• Blood flows through only 510% of the body’s capillaries at a time

Two mechanisms regulate distribution of blood in capillary beds1. Contraction of the smooth muscle layer in the wall of an

arteriole constricts the vessel

2. Precapillary sphincters control flow of blood between arterioles and venules

• Blood flow is regulated by nerve impulses, hormones, and other chemicals


Figure 42.14Precapillarysphincters

Thoroughfarechannel

Arteriole

CapillariesVenule

(a) Sphincters relaxed

Arteriole Venule

(b) Sphincters contracted

Fluid exchange between capillaries and the interstitial fluid.

INTERSTITIALFLUID Net fluid movement out

Bloodpressure

Osmoticpressure

Arterial endof capillary Direction of blood flow

Venous endof capillary

Body cell

Fluid Return by the Lymphatic System

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

• Fluid, called lymph, reenters the circulation directly at the venous end of the capillary bed and indirectly through the lymphatic system– The lymphatic system drains into veins in the neck– Valves in lymph vessels prevent the backflow of fluid

• 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 flow of lymph


LYMPH NODES AND VESSELS. Where are these?

Concept 42.4: Blood components contribute to exchange, transport, and defense

• With open circulation, the fluid that is pumped comes into direct contact with all cells

• The closed circulatory systems of vertebrates contain blood, a specialized connective tissue


The composition of mammalian blood

Plasma 55%

Constituent Major functions

Water

Ions (bloodelectrolytes)SodiumPotassiumCalciumMagnesiumChlorideBicarbonate

Solvent forcarrying othersubstances

Osmotic balance,pH buffering,and regulationof membranepermeability

Plasma proteinsOsmotic balance,pH buffering

Albumin

Fibrinogen

Immunoglobulins(antibodies)

Clotting

Defense

Substances transported by blood

NutrientsWaste productsRespiratory gasesHormones

Separatedbloodelements

Basophils

Neutrophils Monocytes

Lymphocytes

Eosinophils

Platelets

Erythrocytes (red blood cells) 5–6 million

250,000–400,000 Bloodclotting

Transportof O2 and

some CO2

Defense andimmunity

FunctionsNumber per L(mm3) of blood

Cell type

Cellular elements 45%

Leukocytes (white blood cells) 5,000–10,000

Cellular Elements

• Suspended in blood plasma are three large components

1. Red blood cells (erythrocytes) transport oxygen O2

2. White blood cells (leukocytes) function in defense

3. Platelets, a third cellular element, are fragments of cells that are involved in clotting

© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.

• Red blood cells, or erythrocytes, are by far the most numerous blood cells– They contain hemoglobin, the iron-containing protein

that transports O2

– Each molecule of hemoglobin binds up to four molecules of O2

– In mammals, mature erythrocytes lack nuclei and mitochondria

Erythrocytes


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– They are found both in and outside of the circulatory

system


Blood clotting and formation of a thrombus

Collagen fibers

1 2 3

PlateletPlateletplug

Fibrinclot

Fibrin clot formation

Red blood cell 5 m

Clotting factors from:PlateletsDamaged cellsPlasma (factors include calcium, vitamin K)

Enzymatic cascade

Prothrombin Thrombin

Fibrinogen Fibrin

Stem cells(in bone marrow)

Myeloidstem cells

Lymphoidstem cells

B cells T cells

Lymphocytes

ErythrocytesNeutrophils

Basophils

EosinophilsPlateletsMonocytes

Figure 42.19Stem Cells and the Replacement of Cellular Elements

Cardiovascular Disease

• Cardiovascular diseases account for more than half the deaths in the United States

• Cholesterol, a steroid, helps maintain membrane fluidity

• Low-density lipoprotein (LDL) delivers cholesterol to cells for membrane production

• High-density lipoprotein (HDL) scavenges cholesterol for return to the liver– Risk for heart disease increases with a high LDL to HDL

ratio


Lumen of artery

Smoothmuscle

EndotheliumPlaque

Smoothmusclecell

T lymphocyte

Extra-cellularmatrix

Foam cellMacrophage

Plaque rupture

LDL

CholesterolFibrous cap

1 2

43

One type of cardiovascular disease,

athero-sclerosis, is caused by the buildup of plaque deposits within arteries

causes strokes and heart attacks

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

• Coronary arteries supply oxygen-rich blood to the heart muscle

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

• Angina pectoris is caused by partial blockage of the coronary arteries and results in chest pains


Heart health issues

Figure 42.21

Individuals with two functional copies ofPCSK9 gene (control group)

Plasma LDL cholesterol (mg/dL)

Individuals with an inactivating mutation inone copy of PCSK9 gene

Plasma LDL cholesterol (mg/dL)

Average 63 mg/dLAverage 105 mg/dL30

20

10

00 50 100 150 200 250 300 0

0

10

20

30

50 100 150 200 250 300

Per

cen

t o

f in

div

idu

als

RESULTS

Per

cen

t o

f in

div

idu

als

Concept 42.5: Gas exchange occurs across specialized respiratory surfaces

• Gas exchange supplies O2 for cellular respiration and disposes of CO2


Partial Pressure Gradients in Gas Exchange

• A gas diffuses from a region of higher partial pressure to a region of lower partial pressure– Partial pressure is the pressure exerted by a particular

gas in a mixture of gases


Figure 42.22

Parapodium(functions as gill)

(a) Marine worm (b) Crayfish

GillsGills

Tube foot

(c) Sea star

Coelom

Figure 42.23

Gillarch

O2-poor blood

O2-rich blood

Bloodvessels

Gill arch

OperculumWaterflow

Water flowBlood flow

Countercurrent exchange

PO (mm Hg) in water2

150

PO (mm Hg)

in blood2

120 90 60 30

140 110 80 50 20Net diffu-sion of O2

Lamella

Gill filaments

Tracheoles Mitochondria Muscle fiber

2.5

m

Tracheae

Air sacs

External opening

Trachea

Airsac Tracheole

Bodycell

Air

Figure 42.24

Human respiration bioflix

Pharynx

Larynx(Esophagus)

Trachea

Right lung

Bronchus

Bronchiole

Diaphragm(Heart)

Capillaries

Leftlung

Dense capillary bedenveloping alveoli (SEM)

50 m

Alveoli

Branch ofpulmonary artery(oxygen-poorblood)

Branch ofpulmonary vein(oxygen-richblood)

Terminalbronchiole

Nasalcavity

http://media.pearsoncmg.com/bc/bc_0media_bio/bioflix/bioflix.htm?9apexchange

RDS deaths Deaths from other causesRESULTS

40

30

20

10

00 800 1,600 2,400 3,200 4,000

Body mass of infant (g)

Su

rfac

e te

nsi

on

(d

ynes

/cm

)

What causes respiratory distress syndrome?

How an Amphibian Breathes

• An amphibian such as a frog ventilates its lungs by positive pressure breathing, which forces air down the trachea


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


Anteriorair sacs

Posteriorair sacs

Lungs

1 mm

Airflow

Air tubes(parabronchi)in lung

Anteriorair sacs

Lungs

Second inhalationFirst inhalation

Posteriorair sacs 3

2 4

1

4

31

2 Second exhalationFirst exhalation

Figure 42.27

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

• The tidal volume is the volume of air inhaled with each breath


Figure 42.28

Rib cageexpands.

Airinhaled.

Airexhaled.

Rib cage getssmaller.

1 2

Lung

Diaphragm

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

– The medulla adjusts breathing rate and depth to match metabolic demands

– The pons regulates the tempo


• Sensors in the aorta and carotid arteries monitor O2 and CO2 concentrations in the blood– These sensors exert secondary control over breathing


Homeostasis:Blood pH of about 7.4

CO2 level

decreases. Stimulus:Rising level ofCO2 in tissues

lowers blood pH.Response:Rib musclesand diaphragmincrease rateand depth ofventilation.

Carotidarteries

AortaSensor/control center:Cerebrospinal fluid

Medullaoblongata

Figure 42.29

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

• The metabolic demands of many organisms require that the blood transport large quantities of O2 and CO2


Exhaled air Inhaled air

Pulmonaryarteries

Systemicveins

Systemicarteries

Pulmonaryveins

Alveolarcapillaries

AlveolarspacesAlveolar

epithelialcells

Inhaledair

160

120

80

40

0Heart

8 1

2

3

46

7

CO2 O2

SystemiccapillariesCO2 O2

Body tissue5

(a) The path of respiratory gases in the circulatory system

(b) Partial pressure of O2 and CO2 at different points in the

circulatory system numbered in (a)

4321 5 6 7

Exhaledair

Pa

rtia

l p

res

su

re (

mm

Hg

)

PO2

PCO 2

8

Figure 42.30

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 favor diffusion of O2 into the interstitial fluids and CO2 into the blood


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– Most vertebrates and some invertebrates use

hemoglobin – In vertebrates, hemoglobin is contained within

erythrocytes


Hemoglobin

• A single hemoglobin molecule can carry four molecules of O2, one molecule for each iron- containing heme group– CO2 produced during cellular respiration lowers blood

pH and decreases the affinity of hemoglobin for O2; this is called the Bohr shift

© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.

Figure 42.UN01

Iron

Heme

Hemoglobin

Figure 42.31

2(a) PO and hemoglobin dissociation at pH 7.4

Tissues duringexercise

Tissuesat rest

Lungs

PO (mm Hg)2

(b) pH and hemoglobin dissociation

PO (mm Hg)2

0 20 40 60 80 1000

20

40

60

80

100

0 20 40 60 80 1000

20

40

60

80

100

Hemoglobinretains lessO2 at lower pH

(higher CO2

concentration)

pH 7.2pH 7.4

O2 unloaded

to tissuesduring exercise

O2 s

atu

rati

on

of

he

mo

glo

bin

(%

)

O2 unloaded

to tissuesat rest

O2 s

atu

rati

on

of

he

mo

glo

bin

(%

)

Carbon Dioxide Transport

• Hemoglobin also helps transport CO2 and assists in buffering the blood

• CO2 from respiring cells diffuses into the blood and is transported in blood plasma, bound to hemoglobin, or as bicarbonate ions (HCO3

–)


Animation: O2 from Lungs to Blood

Animation: CO2 from Blood to Lungs

Animation: CO2 from Tissues to Blood

Animation: O2 from Blood to Tissues


Animation: O2 from Blood to Tissues Right-click slide / select “Play”


Animation: CO2 from Tissues to Blood Right-click slide / select “Play”


Animation: CO2 from Blood to Lungs Right-click slide / select “Play”


Animation: O2 from Lungs to Blood Right-click slide / select “Play”

Figure 42.32 Body tissue

Capillarywall

Interstitialfluid

Plasmawithin capillary

CO2 transport

from tissuesCO2 produced

CO2

CO2

CO2

H2O

H2CO3 HbRedbloodcell Carbonic

acid

Hemoglobin (Hb)picks up

CO2 and H+.

H+HCO3

Bicarbonate

HCO3

HCO3

To lungs

CO2 transport

to lungs

HCO3

H2CO3

H2O

CO2

H+

HbHemoglobin

releases

CO2 and H+.

CO2

CO2

CO2

Alveolar space in lung

Respiratory Adaptations of Diving Mammals

• Diving mammals have evolutionary adaptations that allow them to perform extraordinary feats

– For example, Weddell seals in Antarctica can remain underwater for 20 minutes to an hour

– For example, elephant seals can dive to 1,500 m and remain underwater for 2 hours

• These animals have a high blood to body volume ratio


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

• Diving mammals can store oxygen in their muscles in myoglobin proteins

• Diving mammals also conserve oxygen by– Changing their buoyancy to glide passively

– Decreasing blood supply to muscles

– Deriving ATP in muscles from fermentation once oxygen is depleted


Figure 42.UN02

Exhaled air

Alveolarepithelialcells

Pulmonaryarteries

Systemicveins

Heart

CO2 O2

Body tissue

Systemiccapillaries

Systemicarteries

Pulmonaryveins

Alveolarcapillaries

Alveolarspaces

Inhaled air

CO2 O2

Figure 42.UN03

Fetus

Mother

PO (mm Hg)2

0 20 40 60 80 100

100

80

60

40

20

0

O2

satu

rati

on

of

hem

og

lob

in (

%)

Figure 42.UN04

Documents

Figure 42.1. How does blood help regulate homeostasis?