Download - Chapter 42
Chapter 42
Circulation & Gas Exchange
Functions of the Circulatory System
• Transport oxygen to cells• Transport nutrients from the
digestive system to body cells• Transport hormones to body cells• Transport waste from body cells to
excretory organs• Distribute body heat
Gastrovascular Cavity of Aurelia
Open Circulatory System
Closed Circulatory System
Circulatory Systems in Fish, Amphibian, & Mammal
Ectotherms Endotherm
• P = atrial depolarization ~ 0.1 sec atria contracts• QRS = ventricular depolarization ventricles contract
(lub), contraction stimulated by Ca++ uptake• T = ventricular repolarization ventricles relax (dub)
Electrocardiogram (ECG)
Artery Vein
Valve
Tunica intima
Tunica media
Tunica externa
Artery
vein
Arteries
• Carry blood away from the heart.• Thick-walled to withstand
hydrostatic pressure of the blood during ventricular systole.
• Blood pressure pushes blood through arteries.
Veins
• Carry blood to the heart.• Thinner-walled than arteries.• Possess one-way valves that prevent
backwards flow of blood.• Blood flow due to body movements, not
from blood pressure.
One-Way Valves in Veins
Capillaries
capillary vesselcapillary vessel
venulevenule capillariescapillaries
arteriolearteriole
arteriole
venule
lymphatic capillaries
blood capillaries
lymphatic vessel
Lymph Lymph TransportTransport
• lacks pump for circulation• relies on activity of skeletal muscles and
pulsation of nearby arteries for movement of fluid
• 3L of lymph enters blood stream every 24 hrs• proteins easily enter lymphatic system• uptake of large particles such as cell debris,
pathogens, and cancer cells• lymph nodes where it is cleansed of debris
and examined by cells of the immune system (WBC)
Formation of Lymph
interstitial fluid
blood capillary
lymphatic capillary
tissue cell
Sphygnomamometer
Measuring Blood Pressure
brachial
carotid
Superficial Pulse Points- arteries, not veins
radial femoral
•Temporal artery•Facial artery•Common carotid artery•Brachial artery•Radial artery•Femoral artery•Popliteal artery•Posterior tibial artery•Dorsal pedis artery
60 beats/minute
popliteal
facial
temporal
Posterior tibial Dorsal pedis
White blood cells
Platelets
Red blood cells
Artery
• Deliver O2• Remove metabolic wastes• Maintain temperature, pH, and fluid volume• Protection from blood loss- platelets• Prevent infection- antibodies and WBC• Transport hormones
Plasma-55%
Formed elements-45%
Buffy coat-<1%
90% Water8% Solutes:• Proteins
Albumin (60 %)Alpha and Beta GlobulinsGamma Globulinsfibrinogens
• Gas• Electrolytes
• Organic NutrientsCarbohydratesAmino AcidsLipidsVitamins
• Hormones• Metabolic waste
CO2Urea
• Leukocytes• Platelets
• Erythrocytes (red blood cells)• Leukocytes (white blood cells)• Platelets
Erythrocytes
Erythrocyte7.5m in dia Anucleate- so can't reproduce; however, repro
in red bone marrow Hematopoiesis- production of RBC Function- transport respiratory gases Hemoglobin- quaternary structure, 2 chains
and 2 chains Lack mitochondria. Why? 1 RBC contains 250 million hemoglobin
molecules Men- 5 million cells/mm3
Women- 4.5 million cells/mm3
Life span 100-120 days and then destroyed in spleen (RBC graveyard)
Types of Leukocytes
GranulocytesNeutrophils- 40-70%Eosinophils- 1-4%Basophils- <1%
AgranulocytesMonocytes- 4-8%
Lymphocytes- 20-45%
Never let monkeys eat bananas
4,000-11,000 cells/mm 3
Leukocyte Squeezing Through Capillary WallDiapodisis
Fig. 42-21a
Parapodium (functions as gill)(a) Marine worm
Fig. 42-21b
Gills
(b) Crayfish
Fig. 42-21c
(c) Sea star
Tube foot
Coelom
Gills
Fig. 42-22
Anatomy of gills
Gillarch
Waterflow Operculum
Gillarch Gill filament
organization
Bloodvessels
Oxygen-poor blood
Oxygen-rich blood
Fluid flowthrough
gill filament
Lamella
Blood flow throughcapillaries in lamella
Water flowbetweenlamellae
Countercurrent exchange
PO2 (mm Hg) in water
PO2 (mm Hg) in blood
Net diffu-sion of O2
from waterto blood
150 120 90 60 30
110 80 20Gill filaments
50140
Countercurrent exchange system
Fig. 42-23
Air sacs
Tracheae
Externalopening
Bodycell
AirsacTracheole
Tracheoles Mitochondria Muscle fiber
2.5 µmBody wall
Trachea
Air
Tracheal Systems
Fig. 42-24
Pharynx
Larynx
(Esophagus)
Trachea
Right lung
Bronchus
Bronchiole
DiaphragmHeart SEM
Leftlung
Nasalcavity
Terminalbronchiole
Branch ofpulmonaryvein(oxygen-richblood)
Branch ofpulmonaryartery(oxygen-poorblood)
Alveoli
ColorizedSEM50 µm 50 µm
Fig. 42-25
Lung
Diaphragm
Airinhaled
Rib cageexpands asrib musclescontract
Rib cage getssmaller asrib musclesrelax
Airexhaled
EXHALATIONDiaphragm relaxes
(moves up)
INHALATIONDiaphragm contracts
(moves down)
Fig. 42-26
Anteriorair sacs
Posteriorair sacs Lungs
Air
Lungs
Air
1 mm
Trachea
Air tubes(parabronchi)in lung
EXHALATIONAir sacs empty; lungs fill
INHALATIONAir sacs fill
Fig. 42-27
Breathingcontrolcenters
Cerebrospinalfluid
Pons
Medullaoblongata
Carotidarteries
Aorta
DiaphragmRib muscles
Uptake of Oxygen by Hemoglobin in the Lungs
O2 binds to hemoglobin to form oxyhemoglobin
High Concentration of O2 in Blood Plasma
High pH of the Blood Plasma
Unloading of Oxygen from Hemoglobin in the Tissues
Low Concentration of O2 in Blood Plasma Lower pH of the Blood Plasma
When O2 is releaseddeoxyhemoglobin
Carbon Dioxide Chemistry in the Blood
COCO22 + H + H22O O H H22COCO3 3 HCOHCO33-- + H + H++
carbonic carbonic acidacid
bicarbonatebicarbonateionion
enzyme = carbonic anhydraseenzyme = carbonic anhydrase
Transport of Carbon Dioxide from the Tissues to the Lungs
• 60-70% as bicarbonate dissolved in the plasma (slow reaction)• 7-10% dissolved in the plasma as CO2
• 20-30% bound to hemoglobin as HbCO2 CO2 + hemoglobin HbCO2
Haldane Effect- the amt of CO2 transported in the blood is markedly affected by the degree of oxygenation of the blood
The lower the P02 and hemoglobin saturation w/O2, the more CO2 that can be carried by the blood
7. Deep-diving air-breathers stockpile oxygen and deplete it slowly
Deep Diving Breath-holding • Adaptations to pressure
- Collapse of lung cavity (ribs)- Collapse of lungs
7. Deep-diving air-breathers stockpile oxygen and deplete it slowly
Adaptations to oxygen conservation
• Oxygen stores 2-3 x more than humans– Humans: 36% of our total O2 in lungs and 51% in our
blood.– Weddell seal holds 5% of its O2 in its small lungs and
stockpiles 70% in the blood.
• Skeletal muscles and blood as primary storage site (myoglobin)
• Weddell seal to store about 25% of its O2 in muscle, 13% in humans
Deep-diving air-breathers stockpile oxygen and deplete it slowly
Adaptations to oxygen conservation • Reduce heart rate when diving (120 beats/min to 6
b/min)• seals and sea lions store oxygenated blood in their
extra-large spleen (which can be 45% of their body weight)
• Maintain blood flow to brain, heart
Average Dive Times
• Sperm whale: 90 minutes to 2 hrs• Northern elephant seal: 20 to 35 minutes• Harbor seal: 3 to 7 minutes• Walrus: 10 minutes• Bottlenose dolphin: 8 minutes• Killer whale: 10 minutes• Amazon river dolphin: 2 minutes • Loggerhead turtle: 20 minutes