1. The Cardio-Respiratory System
Ch 42
AP Biology

2. 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

3. 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)

4. 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..

5. 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

6. REPTILES (EXCEPT BIRDS) Lung and skin capillaries
FISHES
AMPHIBIANS
REPTILES (EXCEPT BIRDS)
MAMMALS AND BIRDS
Gill capillaries
Lung and skin capillaries
Lung capillaries
Lung capillaries
Gill
circulation
Pulmocutaneous
circuit
Right
systemic
aorta
Pulmonary
circuit
Pulmonary
circuit
Artery
Heart:
Ventricle (V)
Left
systemic
aorta A A A A A A
Atrium (A) V V V V V
Right
Left
Right
Left
Right
Left
Systemic
circulation
Systemic
circuit
Systemic
circuit
Vein
Systemic capillaries
Systemic capillaries
Systemic capillaries
Systemic capillaries
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.

7. 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

8. The Human Heart: go with the flow
Pulmonary Circuit
Systemic Circuit

9. The Cardiac Cycle: a perfect marriage
Cardiac Circulation System
library.med.utah.edu/kw/ecg/mml/ecg_ccs.html

10. LE 42-8 Pacemaker generates wave of signals to contract.
Signals are delayed
at AV node.
Signals pass
to heart apex.
Signals spread
throughout
ventricles.
SA node
(pacemaker) AV
node
Bundle
branches
Purkinje
fibers
Heart
apex
ECG

11. Cardiac Output
the volume of blood pumped into the systemic circulation per minute
Cardiac output can increase about fivefold during heavy exercise.

12. Structural Differences in vessels
arteries
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

13. LE 42-9 Artery Vein 100 µm Endothelium Valve Basement membrane
Smooth
muscle
Smooth
muscle
Capillary
Connective
tissue
Connective
tissue
Artery
Vein
Arteriole
Venule

14. 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

15. Taking a Blood Pressure
LE 42-12_4
Taking a Blood Pressure
Blood pressure
reading: 120/70
Pressure
in cuff
above 120
Pressure
in cuff
below 120
Pressure
in cuff
below 70
Rubber cuff
inflated
with air
120
120 70
Sounds
audible in
stethoscope
Sounds
stop
Artery
Artery
closed

16. Circulatory System meets Lymphatic System
What is Lymph?
How is the Circulatory System dependent on the Lymphatic System?

17. Blood. More than meets the eye.
Blood is a suspension: lots of different stuff suspended in an aqueous solution.
Formed Elements vs Plasma

19. 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

20. Erythro-what?

21. 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

22. Respiratory

23. 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

24. 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

25. Countercurrent exchange
LE 42-21
Oxygen-poor
blood
Lamella
Oxygen-rich
blood
Gill
arch
Gill
arch
Blood
vessel
15%
40%
Water
flow
70% 5%
30%
Operculum
100%
60%
90%
Water flow
over lamellae
showing % O2 O2
Blood flow
through capillaries
in lamellae
showing % O2
Gill
filaments
Countercurrent exchange

26. Positive vs. Negative Pressure
Positive Pressure Breathing-
Negative Pressure Breathing-
etc.usf.edu/.../16400/16428/sling-shot_16428.htm

27. 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

28. 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))

30. Control of Breathing Nervous System Cardio Vascular System
Pons
Medulla
Cardio Vascular System
Sensors in Aorta
Respiratory System
Concentration of CO2

31. LE 42-27 Inhaled air Exhaled air Alveolar spaces O2 CO2 O2 CO2
160
0.2
120 27
Alveolar spaces O2
CO2 O2
CO2
104 40
Alveolar
epithelial
cells O2
CO2
CO2 O2
Blood
entering
alveolar
capillaries
Blood
leaving
alveolar
capillaries
CO2 O2
Alveolar
capillaries
of lung 40 45
104 40 O2
CO2 O2
CO2
Pulmonary
arteries
Pulmonary
veins
Systemic
veins
Systemic
arteries
Heart
Tissue
capillaries
CO2 O2
Blood
leaving
tissue
capillaries
Blood
entering
tissue
capillaries 40 45
CO2 O2
100 40 O2
CO2 O2
CO2
Tissue
cells
< 40
> 45 O2
CO2

32. Heme group Iron atom O2 loaded in lungs O2 unloaded in tissues
LE 42-28
Heme group
Iron atom
O2 loaded
in lungs
O2 unloaded
in tissues
Polypeptide chain

33. 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

34. 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

35. O2 saturation of hemoglobin (%)
LE 42-29b
100
pH 7.4 80
Bohr shift:
additional O2
released from
hemoglobin at
lower pH
(higher CO2
concentration)
O2 saturation of hemoglobin (%) 60
pH 7.2 40 20 20 40 60 80
100
P (mm Hg) O2
pH and hemoglobin dissociation

36. 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.

37. Diving Reflex first line of defense against hypoxia
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