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The Cardio-Respiratory System Ch 42 AP Biology

The Cardio-Respiratory System

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The Cardio-Respiratory System. Ch 42 AP Biology. What’s the Current Exchange Rate?. Multicellular, complex organisms require specialized structures to exchange with their environment internal transport systems circulate fluid connect the organs of exchange with the body cells - PowerPoint PPT Presentation

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The Cardio-Respiratory SystemCh 42AP Biology

What’s the Current Exchange Rate?

•Multicellular, complex organisms require specialized structures to exchange with their environment▫internal transport systems circulate fluid▫connect the organs of exchange with the

body cells More efficient with bulk transport

Open or Closed?• Both open and closed

circulatory systems have:▫ A circulatory fluid (blood

or hemolymph)▫ A set of tubes (blood

vessels)▫ A muscular pump (the

heart)

Come on in. We’re Open!• Arthropods and moluscs

have open systems• Less costly from energy

and pressure stance• hemolymph general body

fluid of blood and interstitial fluid▫ Heart contracts;

hemolymph out into sinuses

▫ Heart relaxes; hem. back in through ostia

www1.istockphoto.com/file_thumbview_approve/7..

Sorry. We’re Closed.• Vertebrates, squid,

earthworms• more efficient at

transporting circulatory fluids to tissues and cells to meet metabolic demands

• Specialized blood vessels, chambered heart

http://dcharmedone.files.wordpress.com/2007/12/closed.jpg

LE 42-4

FISHES

Gill capillaries

AMPHIBIANS

Lung and skin capillaries

REPTILES (EXCEPT BIRDS)

Lung capillaries

MAMMALS AND BIRDS

Lung capillaries

Gillcirculation

Heart:Ventricle (V)

Atrium (A)

Artery

VeinSystemic

circulation

Systemic capillaries Systemic capillaries

Systemiccircuit

Pulmocutaneouscircuit

Right Left

AA

V

A

V

A

V

Systemic capillaries

Right Left

Pulmonarycircuit

Rightsystemic aorta

V

A

V

Systemic capillaries

Right Left

Pulmonarycircuit

A

Systemiccircuit

Leftsystemic aorta

Systemic circuits include all body tissues except lungs. Note that circulatory systems are depicted as if the animal is facing you: with the right side of the heart shown at the left and vice-versa.

Hearts

•Insects: system of tracheal tubes, gas exchange throughout the length of the tubes

•Amphibians: 3 chambered heart•Reptiles: double circulation

▫Pulmonary circuit + systemic circulation▫NO mixing of oxygenated and deox blood

The Human Heart: go with the flow

• Pulmonary Circuit

• Systemic Circuit

www.williamsclass.com/.../CellsOrganization.htm

The Cardiac Cycle: a perfect marriage

Cardiac Circulation System

library.med.utah.edu/kw/ecg/mml/ecg_ccs.html

LE 42-8

Pacemakergenerates wave ofsignals to contract.

Signals are delayedat AV node.

Signals passto heart apex.

Signals spreadthroughoutventricles.

SA node(pacemaker)

ECG

AV node

Bundlebranches Heart

apex

Purkinjefibers

Cardiac Output

•the volume of blood pumped into the systemic circulation per minute

•Cardiac output can increase about fivefold during heavy exercise.

Structural Differences in vesselsarteries veins

• Thicker walls

• elasticity (elastic recoil) helps maintain blood pressure even when the heart relaxes

• Pressure high during systole

• thinner-walled

• blood flows back to the heart mainly as a result of skeletal muscle action

• one-way valves allow blood to flow only toward the heart

LE 42-9

Endothelium

Endothelium

Smoothmuscle

Connectivetissue

Capillary

100 µm

Basementmembrane

Endothelium

Smoothmuscle

Connectivetissue

Valve

Artery

Arteriole Venule

Vein

Artery Vein

Effects on Blood Pressure•1. cardiac output and•2. peripheral resistance due to

constriction of arterioles•Contraction of smooth muscles increase

peripheral resistance•nervous and hormonal responses constrict

blood vessels in response to stress

LE 42-12_4

Artery Arteryclosed

Pressurein cuffabove 120120Rubber cuff

inflatedwith air

Pressurein cuffbelow 120120

Soundsaudible instethoscope

Pressurein cuffbelow 70

70

Blood pressurereading: 120/70

Soundsstop

Taking a Blood Pressure

Circulatory System meets Lymphatic System•What is Lymph?

•How is the Circulatory System dependent on the Lymphatic System?

Blood. More than meets the eye.• Blood is a suspension:

lots of different stuff suspended in an aqueous solution.

Formed Elements vs Plasma

What’s the source?• Erythrocytes, leukocytes, and platelets develop

from a common source, pluripotent stem cells in the red marrow of bones

• The average life span of a RBC is 120 days▫ It cannot divide and self-renew

• RBCs are replaced by erythropoeisis▫ Circulatory meets Endocrine meets Renal meets

skeletal

Erythro-what?

a) Kidneys respond to a lower than normal oxygen concentration in the blood by releasing the hormone erythropoietin.

b) Erythropoietin travels to the red bone marrow and stimulates an increase in the production of red blood cells (RBCs).

c) The red bone marrow manufactures RBCs from stem cells that live inside the marrow.

d) RBCs squeeze through blood vessel membranes to enter the circulation.

e) The heart and lungs work to supply continuous movement and oxygenation of RBCs.

f) Damaged or old RBCs are destroyed primarily by the spleen

Respiratory

Surface area

Rate of diffusion proportional to surface area

Protists: occurs over entire surface (cnid. Flats)

Earthworms and amphibs: across moist skin

Gills: warmer, saltier, less O2

Insects: tracheal tubes: branch out to do exchange with all body parts. Open circ. System NOT involved in transport: O2 CO2

Do fish drink water???• Animals require large, moist respiratory surfaces

for adequate diffusion of gases between their cells and the respiratory medium, either air or water

• Gills are outfoldings of the body surface specialized for gas exchange

• Effectiveness of gas exchange in some gills, including those of fishes, is increased by ventilation and the countercurrent flow of blood and water

LE 42-21

Gillarch

Waterflow Operculum

Gillarch

Bloodvessel

Oxygen-richblood

Water flowover lamellaeshowing % O2

Gillfilaments

O2

Oxygen-poorblood

Lamella

15%40%

70%

100%

90%

60%

30% 5%

Blood flowthrough capillariesin lamellaeshowing % O2

Countercurrent exchange

Positive vs. Negative Pressure• Positive Pressure

Breathing-

• Negative Pressure Breathing-

etc.usf.edu/.../16400/16428/sling-shot_16428.htm

Breathing

•Diaphragm: negative pressure•Tidal volume: air in and out with reg breath•Residual volume: air that remains in alveoli

and tubes after you breath out.

•Us: air travels down 1 way street.•Birds: better: air travels through… no dead

ends

Lungs

•Lungs: only site of gas exchange: need circulatory system

•Breath: negative pressure breathing•Partial pressure: gas diffuses from its own

high partial press. To low (press. Just this 1 gas contributes to the press. Of air (a mix))

Control of Breathing• Nervous System

▫ Pons▫ Medulla

• Cardio Vascular System▫ Sensors in Aorta

• Respiratory System▫ Concentration of

CO2

LE 42-27

Inhaled air

Bloodenteringalveolar

capillaries

Alveolarepithelialcells

Alveolar spaces

Alveolarcapillaries

of lung

Exhaled air

Bloodleavingalveolar

capillaries

Pulmonaryveins

Pulmonaryarteries

Tissuecapillaries

HeartSystemicveins

Systemicarteries

Bloodleavingtissue

capillaries

Bloodenteringtissue

capillaries

Tissuecells

CO2O2

CO2O2

O2 CO2

CO2O2

< 40 > 45

40 45

CO2O2

100 40

CO2

O 2

CO2O2

40 45

CO2O2

104 40

O2

CO 2

CO2O2

CO2O2

CO2 O2

104 40

120 27160 0.2

LE 42-28

Polypeptide chain

O2 unloadedin tissues

O2 loadedin lungs

Iron atomHeme group

Hemoglobin binding of Oxygen• hemoglobin must reversibly bind O2, loading O2

in the lungs and unloading it in other parts of the body

• Loading and unloading of O2 depend on cooperation between the subunits▫binding of O2 to one subunit induces the

other subunits to bind O2 with more affinity• A drop in pH lowers affinity of hemoglobin for O2

•Bohr shift

Hemoglobin binding of CO2

• Carbon from respiring cells diffuses into the blood plasma and then into erythrocytes and is ultimately released in the lungs

•CO2 reacts with water to form carbonic acid▫ Lowers pH and induces release of O2 from Hgb

• Carbonic acid dissociates• Hgb binds H+ to prevent acidifying blood• Bicarbonate diffuses into plasma and is carried to

lungs• Carbonic acid is formed again in lungs

▫ Then converted back to CO2 and water and expelled

LE 42-29b

Bohr shift:additional O2 released fromhemoglobin atlower pH(higher CO2

concentration)

pH and hemoglobin dissociation

P (mm Hg)O2

1008060402000

20

40

60

80

100

O2

satu

rati

on

of

hem

og

lob

in (

%)

pH 7.2

pH 7.4

Carbon Monoxide Poisoning• Red blood cells pick up

CO quicker than they pick up oxygen.

• If there is a lot of CO in the air, the body may replace oxygen in blood with CO.

• This blocks oxygen from getting into the body, which can damage tissues and result in death.

http://www.mammalian.ca/

template.php?content=about

Diving Reflex• first line of defense

against hypoxia• self-preservation

technique triggered in extreme situations▫ suddenly submerged▫ water or caught in a

freezing environment• all of the major

systems slow almost to a halt▫ minimizing the need

for oxygen www.ohusc.k12.in.us/.../Page347.htm