1. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Body Tissues  Adult body cells are not all the same. There are many kinds of cells, all specialized for particular functions

2. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Body Tissues  As a zygote (fertilized egg) divides, the daughter stem cells gradually differentiate.  Cell differentiation = changing size, shape, structure, and activity to become more specialized.

3. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Body Tissues  Tissues = Groups of cells with similar structure and function  Objectives for this unit:  Know the different tissue types in the human body. For each one, know:  Where it’s found in the body  Its function  Its main features and its form (recognize by sight)

4. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Body Tissues  Four primary tissue types  Nervous (“Control”)  Muscle (“Movement”)  Connective (“Support”)  Epithelium (“Covering”)

5. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue  Cells: Neurons and nerve support cells  There are a variety of different kinds of neurons and support cells. Different body locations feature different varieties.  Location: Nervous system - brain, spinal cord, peripheral nerves Figure 3.21

6. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue  Function: send electrochemical impulses to other areas of the body  Irritability (reaction) and conductivity (control) Figure 3.21

7. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue  Features:  Neurons have a highly recognizable shape  Nervous tissue appears to be a network of neurons Figure 3.21

8. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue  Usual ID Difficulty:  Neurons typically infiltrate other tissue types  Neuron support cells harder to ID Figure 3.21 Spinal cord, transverse section

9. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscle Tissue  Three types of muscle tissue  In all three, muscle cells are arrayed in bunched chains called muscle fibers

10. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle  Cells:  Skeletal muscle cells  Location:  Any body muscles under conscious control, attached to skeleton and/or skin  Function:  Skeletal muscle cells move an area of the body by sliding over one another

11. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle  Features:  Long, cylindrical cells  Cells are striated (striped)  Multinucleate (more than one nucleus per cell)  Difficult to tell where one cell ends and the next begins Figure 3.20a

12. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle  Cells:  Cardiac muscle cells  Location:  The heart  Function:  Cause heart to contract/expand to pump blood (involuntary) Figure 3.20b

13. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle  Features:  Long, cylindrical, branching cells  Cells are striated  Uninucleate (one nucleus per cell)  Cells attach to each other at intercalated disks, appear as dark bands  (Intercalated discs are junctions that allow ions to pass freely from cell to cell, helping excitatory impulses to sweep across the whole heart) Figure 3.20b

14. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Smooth Muscle  Cells:  Smooth muscle cells  Location:  Surrounding hollow organs - like stomach, bladder, uterus, blood vessels  Function:  Contract or expand organs, involuntarily (example: peristalsis) Figure 3.20c

15. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Smooth Muscle  Features:  Long, cylindrical cells  No striations  Uninucleate Figure 3.20c

16. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Crime Scene Quiz  1. A victim is found with two bullet wounds, one in the cranial cavity, and one that shattered the sternum. There’s one viscera splatter on the wall, and another where the wall meets the floor, indicating that the victim was first shot while standing, and then shot again while slumped to the ground.  A histologist examines the wall splatter, and finds it is primarily composed of blood, bone, and these cells. Which bullet wound was made first?

17. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Crime Scene Quiz  2. An elderly woman is admitted to the emergency room with a jagged stab wound to the mid-femoral area. With her description of her assailant, the police locate a suspect with a prior history of assault and battery. They collect as evidence from his apartment a knife that tests positive under luminol for blood, and place him under arrest.  Under questioning, he insists he has never encountered the victim. Tissue is collected from the serrated blade of the knife, and analyzed under a microscope. This is what the crime scene investigators found.  What should the police do now?

18. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Crime Scene Quiz