1. Chapter 3
Cell Diversity

2. Learning Objectives
Cell Diversity
Cell Physiology

3. Cell Diversity: Connective
Fibroblasts: Elongated cell that secretes cable-like protein fibers.
Large rough ER and Golgi apparatus
Erythrocyte (RBC): carries O2 throughout the body.
No organelles, lots of hemogolbin

4. Cell Diversity

5. Cell Diversity: Covers and Lines
Epithelial Cell: intermediate filaments resist tearing
Hexagonal shape, pack together in sheets

6. Cell Diversity

7. Cell Diversity: Movement
Skeletal and Smooth Muscle cells
Elongated
Lots of contractile filaments

8. Cell Diversity

9. Cell Diversity: Store nutrients
Fat cells (adipose):
Spherical shape holds large lipid droplet

10. Cell Diversity

11. Cell Diversity: Fights disease
Macrophages, T-cells, B-cells (WBC’s):
Some have pseudopods (fake feet)
Lots of lysosomes

12. Cell Diversity

13. Cell Diversity: Gathers information and controls body functions
Nerve cell (neuron):
Axon: sends info
Dendrites: receives info
Lots of ER to synthesize membrane components.

14. Cell Diversity

15. Cell Diversity: Reproduction
Oocyte:
Female
Largest cell in the body
Lots of organelles
Sperm:
Male
Long and streamline
flagellum

16. Cell Diversity

17. Cell Physiology: Membrane Transport
Membrane transport—movement of substances into and out of the cell
Two basic methods of transport
Passive transport
No energy is required
Active transport
Cell must provide metabolic energy (ATP)

18. Solutions and Transport
Solution—homogeneous mixture of two or more components
Solvent—dissolving medium; typically water in the body
Solutes—components in smaller quantities within a solution
Intracellular fluid—nucleoplasm and cytosol
Interstitial fluid—fluid on the exterior of the cell

19. Selective Permeability
The plasma membrane allows some materials to pass while excluding others
This permeability influences movement both into and out of the cell

20. Passive Transport Processes
Diffusion: Movement of a substance from a high concentration to a low concentration
Usually lipid-soluble or small enough to pass through membrane pores
Osmosis
Water diffusion
Assisted by aquaporins
Facilitated diffusion: substances require a protein carrier
Usually lipid insoluble or large

21. Active Transport Processes
ATP is used for transport because the substance may
be too big
Not able to pass the lipid interior of the membrane
Have to move against a concentration gradient

22. Active Transport Processes
Two common forms of active transport
Active transport (solute pumping)
Vesicular transport
Exocytosis – substances leave the cell through a vesicle
Endocytosis – substances enter the cell through a vesicle
Phagocytosis – “Cell eating”
Pinocytosis – “cell drinking”

23. Exocytosis

24. Endocytosis Extracellular fluid Cytoplasm Pit
Recycling of membrane and receptors (if present) to plasma membrane
Cytoplasm
Extracellular fluid
Plasma membrane
Detachment of vesicle
Vesicle containing ingested material
Vesicle
Vesicle fusing with lysosome for digestion
Release of contents to cytoplasm
Lysosome
Transport to plasma membrane and exocytosis of vesicle contents
Ingested substance
Pit
(a)