1. Chapter 42
Circulatory System

2. Learning Objectives
TBD

3. Invertebrates with No Circulatory Systems
Simple invertebrates: sponges, cnidarians, and flatworms

4. Animal Circulatory Systems
Muscular heart pumps specialized fluid (such as blood) through tubular vessels
Blood
Carries O2 and nutrients to body tissues
Carries away CO2 and wastes

5. Open and Closed Circulatory Systems
Open circulatory system
In most invertebrates
Heart pumps hemolymph into vessels that empty into body spaces (sinuses) before returning to the heart
Closed circulatory system
In some invertebrates and all vertebrates
Blood is confined in blood vessels throughout the body (does not mix with interstitial fluid)

6. Open and Closed Circulatory Systems

7. Invertebrate Circulatory Systems
Open circulatory systems occur in arthropods and most mollusks
Closed circulatory systems occur in annelids and in mollusks such as squids and octopuses

8. Vertebrate Circulatory Systems
Evolved from a heart with a single series of chambers (single circuit) to a double heart that pumps blood through separate pulmonary and systemic circuits

9. d. Circulatory system of crocodilians, birds, and mammals
Lung capillaries
PULMONARY CIRCUIT
Right atrium
Left atrium
Right ventricle
Left ventricle
SYSTEMIC CIRCUIT
Figure 42.5
Evolutionary developments in the heart and circulatory system of major vertebrate groups.
Capillary networks in other body tissues
In the four-chambered heart of crocodilians, birds, and mammals, a complete septum forms two ventricles and keeps the flow of oxygenated blood from the lungs and deoxygenated blood entirely separate from the rest of the body.
Fig. 42.5d, p. 952

10. 42.2 Blood and Its Components
Plasma is an aqueous solution of proteins, ions, nutrient molecules, and gases
Erythrocytes are the oxygen carriers of the blood
Leukocytes provide the body’s front line of defense against disease
Platelets induce blood clots that seal breaks in the circulatory system

11. Mammalian Blood A fluid connective tissue
Blood cells (erythrocytes, leukocytes, platelets)
Suspended in a fluid matrix (plasma)

12. Plasma and Plasma Proteins
Contains water, ions, dissolved gases (O2 and CO2), glucose, amino acids, lipids, vitamins, hormones, and plasma proteins
Plasma proteins
Albumins (transport, osmotic balance, pH)
Globulins (transport, immunoglobins)
Fibrinogen (blood clotting)

13. Blood Cells Erythrocytes Leukocytes Platelets
Contain hemoglobin (transports O2 from lungs to body)
Leukocytes
Defend body against infecting pathogens
Platelets
Functional cell fragments that trigger clotting

14. Erythrocyte (red blood cell)
Leukocyte
(white blood cell)
Figure 42.6: Typical components of human blood.
The colorized scanning electron micrograph shows the three major cellular components. The sketch of the test tube shows what happens when you centrifuge a blood sample. The blood separates into three layers: a thick layer of straw-colored plasma on top, a thin layer containing leukocytes and platelets, and a thick layer of erythrocytes. The table shows the relative amounts and functions of the various components of blood.
Platelets
Fig. 42.6a, p. 954

15. Leukocytes and platelets
Plasma
Leukocytes and platelets
Figure 42.6: Typical components of human blood.
The colorized scanning electron micrograph shows the three major cellular components. The sketch of the test tube shows what happens when you centrifuge a blood sample. The blood separates into three layers: a thick layer of straw-colored plasma on top, a thin layer containing leukocytes and platelets, and a thick layer of erythrocytes. The table shows the relative amounts and functions of the various components of blood.
Packed cell volume, or hematocrit
Erythrocytes
Fig. 42.6b, p. 954

16. Fig. 42.6c, p. 954 Figure 42.6: Typical components of human blood.
The colorized scanning electron micrograph shows the three major cellular components. The sketch of the test tube shows what happens when you centrifuge a blood sample. The blood separates into three layers: a thick layer of straw-colored plasma on top, a thin layer containing leukocytes and platelets, and a thick layer of erythrocytes. The table shows the relative amounts and functions of the various components of blood.
Fig. 42.6c, p. 954

17. Natural killer (NK) cell
Leukocytes
Monocyte/macrophage
Eosinophil
B lymphocyte
Basophil
T lymphocyte
Platelets
Neutrophil
megakaryocyte
Erythrocyte
Natural killer (NK) cell
Figure 42.7
Major cellular components of mammalian blood and their origins from stem cells.
Lymphoid stem cell
Myeloid stem cell
(marrow)
(lymph)
Pluripotent stem cell
Fig. 42.7, p. 955

18. Types of Defense
Non-specific
Specific (antibody-mediated)

19. Neutrophils sticking to wall Endothelial cell of capillary1
Bacteria
at injury site
Macrophages
Mast cells 5
Cytokines
Capillary
Neutrophils
Chemokines 2
Histamine 4 3
Figure 43.1: The steps producing inflammation.
The colorized micrograph on the left shows a macrophage engulfing a yeast cell.
Neutrophils sticking to wall
Endothelial cell of capillary
1. A break in the skin introduces bacteria.
2. Activated mast cells release histamine.
3. Histamine and cytokines dilate local blood vessels.
4. Chemokines attract neutrophils, which pass between cells of the blood vessel wall.
5 Neutrophils engulf the pathogens and destroy them.
Fig. 43.1, p. 974

20. Adaptive (Acquired) Immunity
Triggered by antigens
Exogenous or endogenous macromolecules (proteins or polysaccharides)
Recognized by B cells and T cells via antibodies
Targets particular pathogens or toxin molecules

21. Light and Heavy Polypeptide Chains in an Antibody Molecule

22. b. Agglutination Antibody Antigen Bacterium Fig. 43.11b, p. 985
Figure 43.11
Examples of clearing antigens from the body.
Fig b, p. 985

23. Immunological Memory
First encounter with an antigen elicits a primary immune response
Later exposure to the same antigen elicits a rapid secondary immune response with a greater production of antibodies

24. The Mammalian Heart A four-chambered pump
Two atria at top of heart
Two ventricles at bottom of heart
Atrioventricular (AV) valves between atria and ventricles
Semilunar (SL) valves between ventricles and aorta / pulmonary arteries
Blood is pumped into two separate circuits
Pulmonary circuit (right heart)- to the lungs
Systemic circuit (left heart)- to the body

25. Blood Vessels Blood leaves the heart in large arteries
Branch into smaller arterioles
Arterioles deliver blood to capillary networks
Capillaries exchange substances between blood and interstitial fluid
Small venules collect blood from capillaries
Join into larger veins that return blood to heart

26. Pulmonary arteries (to lungs) VC-from body
To systemic circuit
To body
Aorta
Pulmonary arteries (to lungs)
VC-from body
Superior vena cava (returns blood from head, upper limbs)
Left pulmonary veins (return blood from lungs) From pulmonary circuit
Right pulmonary veins (return blood from lungs) PV
Right atrium
Left atrium AV
AV (MV) valve (shown open)
AV (TV) Valve (shown open)
Left ventricle
Right ventricle
Figure 42.9
Cutaway view of the human heart showing its internal organization.
Septum
Inferior vena cava (returns blood flow from trunk, legs)
KEY
Semilunar (SL) valves
Atrioventricular (AV) valves
To systemic circuit
Fig. 42-9, p. 957

27. systemic circuit systemic circuit
Capillary networks
of head and forelimbs
Superior vena cava
Pulmonary artery
Pulmonary artery
pulmonary circuit
pulmonary circuit
Aorta LA RA RV LV
Capillary network of right lung
Pulmonary vein
Pulmonary vein
Capillary network
of left lung
Figure 42.10: The pulmonary and systemic circuits of mammals.
The right half of the heart pumps blood into the pulmonary circuit, and the left half of the heart pumps blood into the systemic circuit.
Inferior
vena cava
To lower
body parts
Capillary networks of abdominal organs and lower limbs
systemic circuit
Fig , p. 958