The Cardio-Respiratory System

1
The Cardio-Respiratory System

• Ch 42
• AP Biology

2
Whats 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. Were 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. Were Closed.

• Vertebrates, squid, earthworms
• more efficient at transporting circulatory fluids
  to tissues and cells to meet metabolic demands
• Specialized blood vessels, chambered heart

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6
LE 42-4
FISHES
AMPHIBIANS
REPTILES (EXCEPT BIRDS)
MAMMALS AND BIRDS
Gill capillaries
Lung and skin capillaries
Lung capillaries
Lung capillaries
Pulmocutaneous circuit
Pulmonary circuit
Gill circulation
Pulmonary circuit
Right systemic aorta
Artery
Heart Ventricle (V)
Left systemic aorta
A
A
A
A
A
A
Atrium (A)
V
V
V
V
V
Right
Left
Left
Right
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.
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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

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9
The Cardiac Cycle a perfect marriage
Cardiac Circulation System
library.med.utah.edu/kw/ecg/mml/ecg_ccs.html
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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
Endothelium
Endothelium
Smooth muscle
Smooth muscle
Capillary
Connective tissue
Connective tissue
Vein
Artery
Venule
Arteriole
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
Blood pressure reading 120/70
Pressure in cuff below 120
Pressure in cuff above 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

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19
Whats 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
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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

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

• Positive Pressure Breathing-
• Negative Pressure Breathing-

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

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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))

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Control of Breathing

• Nervous System
• Pons
• Medulla
• Cardio Vascular System
• Sensors in Aorta
• Respiratory System
• Concentration of CO2

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LE 42-27
Inhaled air
Exhaled air
120
27
160
0.2
Alveolar spaces
CO2
CO2
O2
O2
104
40
Alveolar epithelial cells
CO2
O2
CO2
O2
Blood leaving alveolar capillaries
Blood entering alveolar capillaries
CO2
O2
Alveolar capillaries of lung
40
45
104
40
CO2
O2
CO2
O2
Pulmonary veins
Pulmonary arteries
Systemic veins
Systemic arteries
Heart
Tissue capillaries
O2
CO2
Blood entering tissue capillaries
Blood leaving tissue capillaries
O2
CO2
40
45
100
40
O2
CO2
CO2
O2
Tissue cells
lt 40
gt 45
CO2
O2
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LE 42-28
Iron atom
Heme group
O2 loaded in lungs
O2 unloaded in tissues
Polypeptide chain
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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

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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
0
100
80
60
40
20
0
P (mm Hg)
O2
pH and hemoglobin dissociation
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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
• 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

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