Circulation and Respiration Unifying concepts of animal circulation The human cardiovascular system Unifying concepts of animal respiration The

Circulation and Respiration Unifying concepts of animal circulation

The human cardiovascular system

Unifying concepts of animal respiration

The human respiratory system

UNIFYING CONCEPTS OF ANIMAL CIRCULATION

• Every organism must exchange materials with its environment, relying upon

– diffusion, the spontaneous movement of molecules from an area of higher concentration to an area of lower concentration, and

– a circulatory system, which facilitates the exchange of materials for all but the simplest animals.

© 2013 Pearson Education, Inc.

Open and Closed Circulatory Systems

• Circulatory systems typically consist of a

– central pump,

– vascular system, and

– circulating fluid.


• In an open circulatory system,

– the heart pumps blood into large open-ended vessels and

– fluid circulates freely among cells.

• Open circulatory systems are found in many invertebrates, including

– arthropods and

– most molluscs.



• In a closed circulatory system, blood

– stays within a set of tubes and

– is distinct from the interstitial fluid, the fluid that fills the spaces around cells.

• Closed circulatory systems are found in

– many invertebrates, including earthworms and octopuses, and

– vertebrates.



Figure 23.1

(a) Open circulatory system (b) Closed circulatory system

Tubularheart

Circulating fluid

Interstitial fluidHeart

Heart

Vessels

VesselsCapillaries

Artery(O2-richblood)

Artery(O2-poor blood)

Vessels

CapillariesArteriole

Venule

Vein

HeartVentricleAtrium

• The cardiovascular system of vertebrates consists of the

– heart and

– blood vessels.

• In the heart,

– the atrium receives blood and

– the ventricle pumps blood away from the heart.



• Blood is confined to three main types of blood vessels:

1. Arteries carry blood away from the heart into smaller arterioles as they approach the

organs.

2. Capillaries are the site of exchange between blood and interstitial fluid.

3. Venules collect blood from the capillaries and converge to form veins, which return blood

back to the heart.



THE HUMAN CARDIOVASCULAR SYSTEM

• In the human cardiovascular system, there are three main components:

– 1. the central pump is the heart,

– 2. the vascular system is the blood vessels, and

– 3. the circulating fluid is the blood.


The Path of Blood

• Humans and other terrestrial vertebrates have a double circulation system consisting of

– a pulmonary circuit between the heart and lungs and

– a systemic circuit between the heart and the rest of the body.


Figure 23.2

(a) Pulmonary circuit (b) Systemic circuit

O2-rich blood

O2-poor blood

LungLung

Heart

CO2

O2

CO2

CO2 CO2

O2

O2 O2

• One complete trip through the human cardiovascular system

– takes about one minute and

– requires two passes through the heart.

The Path of Blood


Figure 23.3-7

O2-rich bloodO2-poor blood

Capillaries ofhead, chest,and arms

Capillaries ofabdominal regionand legs

Capillariesof left lung

Capillariesof right lung

Pulmonaryartery

Pulmonaryartery

Superiorvena cava

Pulmonary vein

Inferiorvena cava

Pulmonary vein

Left ventricle

Left atriumRight atrium

Right ventricle

Aorta

27

5

461

54

33

Know this!

How the Heart Works

• The human heart

– is a muscular organ about the size of a fist,

– is located under the breastbone, and

– has four chambers.

• The path of blood flow through the human heart functions as two pumps moving blood between

– the heart and lungs and

– the heart and the rest of the body.


Figure 23.4

O2-rich blood

O2-poor blood

Right atriumLeft atrium

Leftventricle

Rightventricle

From body

Rightlung

Leftlung

Frombody

To body

Valves Valves

Know this!

The Cardiac Cycle

• The heart relaxes and contracts throughout our lives.

– Diastole is the relaxation phase of the heart cycle.

– Systole is the contraction phase.

• A heart murmur is a sound that may indicate a defect in one or more of the heart valves.


Figure 23.5-3

Heart is relaxed.Blood flows in.

DIASTOLE0.4sec

Atria contract. Blood isforced into ventricles.

0.1sec

SYSTOLE

Ventricles contract.Blood is pumped out.

0.3sec0.8

sec

1

2

3

The Pacemaker and the Control of Heart Rate

• The pacemaker, or SA (sinoatrial) node,

– sets the tempo of the heartbeat and

– is composed of specialized muscle tissue in the wall of the right atrium.

• Impulses from the pacemaker spread quickly through the walls of both atria, prompting the atria to contract at the same time.

• The AV (atrioventricular) node

– is a relay point that delays the signal and

– sends impulses to the ventricles.© 2013 Pearson Education, Inc.

Figure 23.6Pacemaker(SA node)

Right atrium

AV node

Right ventricle

Wire leadingto SA node

Artificialpacemaker

Heart

Pacemaker generateselectrical impulses.

Impulses spreadthrough atria.

Impulses reachventricles.

(b) Artificial pacemaker

(a) The heart’s natural pacemaker

1 2 3

• The impulses sent by the pacemaker can be

– detected by electrodes placed on the skin and

– recorded as an electrocardiogram (ECG or EKG).

• In certain kinds of heart disease, the heart fails to maintain a normal rhythm.

• The remedy for this failure of the electrical control of the heart is an artificial pacemaker, a small electronic device surgically implanted near the SA node.

The Pacemaker and the Control of Heart Rate


Blood Vessels

• If the heart is the body’s “pump,” then the “plumbing” is the system of arteries, veins, and capillaries.

– Arteries carry blood away from the heart.

– Veins carry blood toward the heart.

– Capillaries allow for exchange between the bloodstream and tissue cells.


• All blood vessels are lined by a thin layer of tightly packed epithelial cells.

• Structural differences in the walls of the different kinds of blood vessels correlate with their different functions.

Blood Vessels


Figure 23.7

From heart

Epithelium

Smoothmuscle

Connectivetissue

Artery

Arteriole

Capillary

Venule

Vein

ValveTo heart

Epithelium

Epithelium

Smoothmuscle

Connectivetissue

Blood Flow through Arteries

• The force that blood exerts against the walls of blood vessels is blood pressure.

– Blood pressure pushes blood from the heart to the capillary beds.

– A pulse is the rhythmic stretching of the arteries caused by the pressure of blood forced into the arteries during systole.


• Optimal blood pressure for adults is

– below 120 systolic and

– below 80 diastolic.

• High blood pressure, or hypertension, is persistent

– systolic blood pressure higher than 140 and/or

– diastolic blood pressure higher than 90.

Blood Flow through Arteries


Blood Flow through Capillary Beds

• At any given time, only about 5–10% of the capillaries have a steady flow of blood, with the exception of the brain

• Blood flow through capillaries may be diverted from one part of the body to another, depending on need.

• This is called shunting

• There are three main locations which demand blood: the brain, muscles, digestion

• In general, the body does one of these at a time© 2013 Pearson Education, Inc.

• The walls of capillaries are thin and leaky.

– At the arterial end of the capillary, blood pressure pushes fluid rich in oxygen, nutrients, and other substances into the interstitial fluid.

– At the venous end of the capillary, CO2 and other wastes diffuse from tissue cells into the interstitial fluid, and then into the capillary bloodstream.

Blood Flow through Capillary Beds


Figure 23.8

(a) Capillaries (b) Chemical exchange

Capillary

Red blood cell

Tissue cell

Interstitial fluid

Diffusionof O2 and

nutrients outof capillary

and intotissue cells

Diffusionof CO2 andwastes outof tissuecells and

into capillary

Fromartery

LM

To vein

To vein

Figure 23.8a

(a) Capillaries

Capillary

Red blood cell

LM

Figure 23.8b

(b) Chemical exchange

Tissue cell

Interstitial fluid

Diffusionof O2 and

nutrients outof capillary

and intotissue cells

Diffusionof CO2 andwastes outof tissuecells and

into capillary

Fromartery

To veinTo vein

Blood Return through Veins

• Blood returns to the heart

– after chemicals are exchanged between the blood and body cells and

– at a pressure that has nearly dropped to zero.


• Blood moves back toward the heart because of

– surrounding skeletal muscles that compress the veins and

– one-way valves that permit blood flow only toward the heart.

Blood Return through Veins


Figure 23.9To heart

Valve (open)

Skeletal muscle

Valve (closed)

Blood: know all of this

• An adult human has about 5 L (11 pints) of blood.

• By volume, blood is

– a little less than half cells and

– a little more than half plasma, consisting of about

– 90% water and

– 10% dissolved salts, proteins, and other molecules.


Figure 23.10

Blood

Platelets

White blood cells(leukocytes)

Red blood cells(erythrocytes)

Cellular elements (45%)

Plasma(55%)

Water (90%of plasma)

Proteins

Dissolved salts(such as sodium,potassium, calcium)

Substances beingtransported (suchas O2, CO2, nutrients,wastes, hormones)

Figure 23.10a

Platelets

White blood cells(leukocytes)

Red blood cells(erythrocytes)

Cellular elements (45%)

Plasma(55%)

Water (90%of plasma)

Proteins

Dissolved salts(such as sodium,potassium, calcium)

Substances beingtransported (suchas O2, CO2, nutrients,wastes, hormones)

Blood

• Suspended in plasma are three types of cellular elements:

1. red blood cells,

2. white blood cells, and

3. platelets.


Red Blood Cells and Oxygen Transport

• Red blood cells (erythrocytes)

– are the most numerous type of blood cell and

– are shaped like discs with indentations in the middle.


Figure 23.12

Red Blood Cells(cells that carry oxygen)

White Blood Cells (cells that fight infection)

Platelets(bits of membrane-enclosedcytoplasm that aid clotting)

CELLULAR COMPONENTS OF BLOOD

Fibrin

Red blood cell

Co

lori

zed

SE

M

Co

lori

zed

SE

M

Co

lori

zed

SE

M

Co

lori

zed

SE

M

Co

lori

zed

SE

M

• Carbohydrate-containing molecules on the surface of red blood cells determine the blood type. These are called surface antigens

Blood Typing


BloodGroup(Phenotype) OGenotypes

AntibodiesPresent inBloodRed Blood Cells

Reactions When Blood from Groups Below Is Mixed with Antibodies from Groups at Left

A B AB

O

A

B

AB

ii

IAIB

IBIB

or

IBi

IAIA

or IAi

CarbohydrateA

CarbohydrateB

Anti-A

Anti-B

Anti-AAnti-B

—

Figure 9.20

Blood Typing

https://www.youtube.com/watch?v=KXTF7WehgM8

Figure 9.20c

• Each red blood cell contains approximately 250 million molecules of hemoglobin, which

– contains iron and

– transports oxygen throughout the body.




• Anemia may result from

– an abnormally low amount of hemoglobin or

– a low number of red blood cells.

• The hormone erythropoietin (EPO) boosts production of red blood cells.


White Blood Cells and Defense

• White blood cells (leukocytes)

– fight infections,

– are larger than red blood cells,

– lack hemoglobin, and

– are much less abundant than red blood cells (about 700 times fewer).


Figure 23.12b

White Blood Cells (cells that fight infection)

Co

lori

zed

SE

M

Platelets and Blood Clotting

• Blood contains two components that aid in clotting:

1. platelets, bits of cytoplasm pinched off from larger cells in the bone marrow, and

2. clotting factors released from platelets that convert fibrinogen, a protein found in plasma, into a threadlike protein called fibrin.


Figure 23.12c

Platelets(bits of membrane-enclosedcytoplasm that aid clotting)

Fibrin

Red blood cell

Co

lori

zed

SE

M

Co

lori

zed

SE

M

• In the inherited disease hemophilia, excessive and sometimes fatal bleeding can occur from even minor cuts and bruises.

• Hemophilia is caused by a genetic mutation in one of several genes that code for clotting factors.

Platelets and Blood Clotting


• Leukemia

– is cancer of white blood cells and

– may require treatment using

– radiation,

– chemotherapy, and/or

– bone marrow transplantation.

Stem Cells and the Treatment of Leukemia


• The cardiovascular system contributes to homeostasis by

– exchanging nutrients and wastes with the interstitial fluid,

– controlling the composition of blood by moving it through the lungs, liver, and kidneys,

– helping to regulate temperature by moving blood to or away from the skin,

– distributing hormones, and

– defending against foreign invaders.

Cardiovascular Disease


• Cardiovascular disease

– includes all diseases affecting the heart and blood vessels,

– accounts for 40% of all deaths in the United States, and

– kills more than 1 million people each year.



• Coronary arteries

– supply the heart muscle and

– can narrow or close, contributing to a heart attack.



Figure 23.13

Coronary artery(supplies oxygento the heart muscle)

Dead muscletissue

Blockage

Aorta

• Atherosclerosis

– is a chronic cardiovascular disease and

– results from fatty deposits called plaque that develop in the inner walls of arteries, clogging the passages through which blood can flow.



Figure 23.14

Connectivetissue

Smoothtissue

PlaqueEpithelium

Normal artery Artery partially blocked by plaque

Partially blockedpassageway

Passagewayfor blood

• Cardiovascular disease

– involves inherited factors but

– can be reduced by

– not smoking,

– exercising regularly, and

– eating a heart-healthy diet.



UNIFYING CONCEPTS OF ANIMAL RESPIRATION

• Cells using cellular respiration

– need a steady supply of oxygen and

– must continuously dispose of CO2.

• The respiratory system promotes this gas exchange.

Figure 23.UN01

Environment

Cell

Glucose Oxygen Water EnergyCellular

respiration Carbondioxide

C6H12O66 O2 6 CO2 6 H2O ATP

CO2O2

The Structure and Function of Respiratory Surfaces

• Animals can get oxygen from

– the atmosphere, which contains about 21% oxygen, and

– bodies of water, which contain about 3–5% oxygen.



• Gas exchange occurs at the respiratory surface, which must be

– large enough to take up oxygen for every cell in the body and

– adapted to the lifestyle of the organism.


• Moist skin is used as a respiratory surface in earthworms.

• In aquatic environments, the main respiratory surfaces are

– skin and

– extensions of the body surface called gills.



Figure 23.15

Cross section ofrespiratory surface (the skin covering the body)

Respiratorysurface (gill)

Body surface

CapillariesCapillariesCO2

CO2

O2O2

(a) Skin (b) Gills

• In most land-dwelling animals, the respiratory surfaces are

– folded into the body and

– open to the air only through narrow tubes.



• Insects breathe using a tracheal system, an extensive network of internal tubes called tracheae that

– branch throughout the body and

– extend to nearly every cell.



Figure 23.16

Respiratorysurface(tracheae)

Body cells(no capillaries)

Respiratorysurface(within lung)

Bodysurface

Bodysurface

Capillary

(a) Tracheae (b) Lungs

CO2

CO2

CO2

O2

O2

O2

• Lungs

– are located in only one part of the body and

– are the most common respiratory surface of snails, some spiders, and terrestrial vertebrates.

• The circulatory system transports gases between the respiratory surface and the rest of the body.



Figure 23.17

Skin(entire body

surface)

Gills(extensions of the

body surface)

Tracheae(branching

internal tubes)

Lungs(localized

internal organs)

RESPIRATORY ORGANS

Moist skin of a leech Gills of a sea slugTracheae of a silkmoth caterpillar

Model of a pair ofhuman lungs

Tracheae(internaltubes)

Gills

THE HUMAN RESPIRATORY SYSTEM

• The human respiratory system has three phases of gas exchange:

1. breathing, the ventilation of the lungs by alternate

inhalation and exhalation,

2. transport of oxygen from the lungs to the rest of the body via the circulatory system, and

3. diffusion of oxygen from the blood and release of CO2 into the blood by cells of the body.


Figure 23.18-3

Circulatory system

Breathing

Lung

CO2

O2

Transport of gases bythe circulatory system

Exchange of gaseswith body cells

Mitochondria

Capillary

Cell

CO2

O2

2

1

3

The Structure and Function of the Human Respiratory System

• Air moves sequentially from the mouth and nose to

– the pharynx, where digestive and respiratory systems meet,

– the larynx (voice box) and trachea (windpipe),

– the bronchi (one bronchus to each lung),

– the bronchioles, the smallest branches of the tubes within the lungs, and

– the alveoli, the air sacs where gas exchange primarily occurs.


Figure 23.19

Larynx (voice box)

Trachea (windpipe)

(a) Overview of the human respiratory system (b) The structure of alveoli

Pharynx

Right lung

Bronchus

Bronchiole

Diaphragm

EsophagusNasal cavity

Left lung

Bronchiole

Bloodcapillaries

Fromheart

Toheart

AlveoliHeart

O2-richblood

O2-poorblood

O2

CO2

• Muscles in the voice box can stretch vocal cords within the larynx.

• During exhalation, outgoing air can produce vocal sounds as air passes by the stretched vocal cords.

The Structure and Function of the Human Respiratory System


Taking a Breath

• Breathing is the alternating process of

– inhalation and

– exhalation.

• During inhalation, the chest is expanded by the

– upward movement of the ribs and

– downward movement of the diaphragm.

• Air moves into the lungs by negative pressure breathing, as the air pressure in the lungs is lowered by the expansion of the chest.


Figure 23.20

Inhalation(Air pressure is higher in

atmosphere than in lungs.)

Exhalation(Air pressure is lower in

atmosphere than in lungs.)

Diaphragmrelaxes(moves up)

Diaphragmcontracts(movesdown)

Rib cageexpands asrib musclescontract

Rib cage getssmaller asrib musclesrelax

Airinhaled

Airexhaled

Lung

• Breathing can be controlled

– consciously, as you deliberately take a breath, or

– unconsciously.

• Breathing control centers in the brain stem

– automatically control breathing most of the time and

– regulate breathing rate in response to CO2 levels in the blood.

Taking a Breath


Figure 23.21-3

CO2 levels in theblood rise as aresult of exercise.

Brain

Breathing controlcenters in the brainmonitor the rising CO2 levels in the blood.

Breathing controlcenters

Nerve signals trigger contraction of muscles to increase breathingrate and depth.

Rib musclesDiaphragm

1

2

3

The Role of Hemoglobin in Gas Transport

• The human respiratory system

– takes in O2,

– expels CO2, but

– relies on the circulatory system to shuttle these gases between the lungs and the body’s cells.


Figure 23.22

AlveolusAir spaces

Capillariesof lung

Tissuecapillaries

CO2-rich,

O2-poor

blood

O2-rich,

CO2-poor

blood

O2 in

inhaled airCO2 in

exhaled air

CO2 O2

Tissue cells throughout body

CO2 O2

Heart

O2

CO

2

O 2CO2

Interstitialfluid

• However, there is one problem with this simple gas delivery system.

– Problem: Oxygen does not readily dissolve in blood plasma.

– Solution: Oxygen is carried in hemoglobin molecules within red blood cells.

• A shortage of iron

– causes a decrease in the rate of hemoglobin synthesis and

– can lead to anemia.

The Role of Hemoglobin in Gas Transport


Figure 23.23

Hemegroup

Ironatom

Polypeptide chain

O2 loadedin lungs

O2 unloadedin tissues

O2

O2

How Smoking Affects the Lungs

• Breathing exposes your respiratory tissues to potentially damaging chemicals, including one of the worst pollutants, tobacco smoke.


• Smoking

– kills half of all people who smoke, about 440,000 Americans every year,

– causes 90% of all lung cancer (one of the deadliest forms of cancer), and

• Tobacco smoke

– damages the cells that line the bronchi and trachea and

– interferes with the normal cleansing mechanism of the respiratory system, allowing more toxin-laden smoke particles to reach and damage the lungs’ delicate alveoli.

How Smoking Affects the Lungs


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Circulation and Respiration Unifying concepts of animal circulation The human cardiovascular system Unifying concepts of animal respiration The