Post on 02-Jan-2016
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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
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
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
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