1. The Mammalian Transport System
AICE Biology Chapter 8
The Mammalian Transport System

2. Gas Exchange Basics
Organisms need to exchange O2 and CO2 with the environment.
Gas exchange occurs by DIFFUSION.

3. Basics (continued) Marine flatworm
Single cells, and small organisms living in an aquatic environment can exchange gasses through body surfaces, because of large SURFACE TO VOLUME RATIO.
Marine flatworm

4. 5 1
Total surface area
(height  width 
number of sides 
number of boxes)
Total volume
(height  width  length
 number of boxes)
Surface-to-volume
ratio
(surface area  volume) 6
150
125
1.2

5. Circulatory Systems consist of
Heart – pumps blood
Arteries – carry blood away from the heart
Veins – carry blood back to the heart
Capillaries – connect arteries to veins, allow for gas exchange with tissues

6. Open and closed circulatory systems
Heart
Hemolymph in sinuses surrounding organs
Interstitial fluid
Small branch vessels in each organ
Anterior vessel
Lateral vessels
Ostia
Tubular heart
Dorsal vessel (main heart)
Ventral vessels
Auxiliary hearts
(a) An open circulatory system
(b) A closed circulatory system

7. Hearts Fish – 2 chambered heart (atrium and ventricle), one circuit
Amphibians – 3 chambered heart (2 atria, one ventricle, 2 circuits (pulmonary and systemic)
Reptiles – 3 chambered with some division of ventricle, 2 circuits
Mammals & Birds – 4 chambered heart, 2 circuits

8. The Fish Heart 2 chambered heart Single circuit
FISHES
Systemic capillaries
Gill capillaries
Systemic circulation
Vein
Atrium (A)
Heart: ventricle (V)
Artery
Gill circulation
2 chambered heart
Single circuit
Advantage: high pressure delivery to gills, high oxygenation to tissues
Disadvantage: low pressure delivery to tissues

9. Pulmocutaneous circuit
The Amphibian Heart
AMPHIBIANS
Systemic capillaries
Lung and skin capillaries
Right
Left
Systemic circuit
Pulmocutaneous circuit A V
3 chambered heart
Double circuit
Pulmonary
Systemic
Advantage: high pressure delivery to both lungs and tissues
Disadvantage: mixing of oxygenated and deoxygenated blood
REPTILES

10. The Reptile Heart 3 chambered heart, partial ventricular separation
REPTILES
Systemic capillaries
Lung capillaries
Right
Left
Pulmonary circuit V A
Systemic aorta
Right systemic aorta
3 chambered heart, partial ventricular separation
Double circuit
Pulmonary
Systemic
Advantage: high pressure delivery to lungs and tissues
Disadvantage: mixing of oxygenated and deoxygenated blood
MAMMALS AND BIRDS

11. The Mammal Heart 4 chambered heart, complete ventricular separation
MAMMALS AND BIRDS
Systemic capillaries
Lung capillaries
Right
Left
Systemic circuit
Pulmonary circuit V A
4 chambered heart, complete ventricular separation
Double circuit
Pulmonary
Systemic
Advantage: high pressure, high oxygenation delivery to lungs and tissues

12. Blood Vessels

13. Blood Vessels Arteries & Veins have 3 layers:
Endothelium
Tunica media
Smooth muscle & connective tissue
Tunica externa
Connective tissue
Capillaries, only 1 layer, the endothelium

14. Arteries vs. Veins High pressure Smaller diameter (narrow lumen)
Thick, muscular tunica media
Elastic tunica externa
Low pressure
Large diameter (large lumen
Thin tunica media
Thin, inelastic tunica externa
“One way” valves

15. Artery Vein Basement membrane Valve Endothelium Smooth muscle
Arteriole
Venule
Connective tissue
Smooth muscle
Endothelium
Valve
Basement membrane
Capillary

16. Arterioles & Venules Arterioles – small arteries Venules – small veins
Smooth muscle sphincters control flow to capillaries
Venules – small veins

17. Capillaries

18. Blood Plasma & Lymph

19. Composition of Blood Plasma
Water
Solutes
Plasma Proteins
Albumen, globulins
Ions
Sodium, Chloride, Potassium, Calcium
Glucose
Amino Acids
Urea

20. Tissue Fliud (extracellular fluid)
Extracellular space, fluid forms by filtration from capillaries

21. Composition of Tissue Fluid (Extracellular Fluid)
Same as plasma, minus most of the proteins:
Water
Solutes
Ions
Sodium, Chloride, Potassium, Calcium
Glucose
Amino Acids
Urea

22. Lymph
Tissue fluid is collected by a system of vessels called Lymphatic vessels.
Once in the lymphatic system, the fluid is called lymph.

24. Lymph Circulation
Unlike blood, lymph does not travel in a complete circuit
Instead, lymphatic vessels have valves that only allow fluid to flow toward the heart.
Lymph is “pumped” by contraction of skeletal muscles.
Along the way, it is filtered through nodes.
Lymph is added back to the blood at the vena cava.

25. A Lymph Node

26. Red Blood Cells
Biconcave disc
No nucleus in mammals
Hemoglobin

27. B cells
T cells
Lymphoid stem cells
Pluripotent stem cells (in bone marrow)
Myeloid stem cells
Erythrocytes
Platelets
Monocytes
Neutrophils
Eosinophils
Basophils
Lymphocytes

28. Hemoglobin 4 polypeptide chains Each contains an iron atom
Heme group
Iron atom
O2 loaded
in lungs
O2 unloaded
In tissues
Polypeptide chain O2
4 polypeptide chains
Each contains an iron atom
Each can bind 1 oxygen molecule

29. Hemoglobin Dissociation Curve
In this part of the graph, a
small change in PO2 leads to
a large change in how much
O2 unloads from
hemoglobin
% O2 changes
slowly
% O2
changes

30. The Bohr Shift High CO2 levels create carbonic acid H2CO3
Carbonic acid releases H+ ions
Hemoglobin binds H+ ions, releasing its bound O2 in the process.

31. The Bohr Shift
pH 7.4
pH 7.2
% O2 unloaded
% O2 unloaded
Bohr shift

32. Fetal Hemoglobin
Fetal hemoglobin has a higher affinity for O2 than adult hemoglobin.
This facilitates O2 loading for the fetus.

33. Fetal
hemoglobin
Adult (maternal)
hemoglobin

34. Myoglobin Found in muscles and other tissues
Like hemoglobin, except only one heme and iron per molecule.
Has a higher affinity for O2 than hemoglobin, facilitating the loading of O2 from the blood into the tissues

35. Problems With Oxygen Transport

36. Carbon Monoxide
Carbon monoxide, CO, forms a relatively stable bond with hemoglobin, forming carboxyhemoglobin.
This blocks the ability to bind oxygen.
Atmospheric concentrations of .1% or higher can be fatal.

37. High Altitude
Mt. Everest
The partial pressure of oxygen falls with increasing elevation.
(PO2 = 95 mm Hg)
Lake Titicaca
(PO2= 160 mm Hg)
Sea level
Percent of air
that is O2
0.21  760 mm Hg
(PO2 = 53 mm Hg)