1. The Cell
Chapter 2

2. Human Anatomy, 3rd edition
Introduction
Cell – structural and functional unit of an organism
Sizes vary
Two subdivisions
Cell membrane
Cytoplasm
Human Anatomy, 3rd edition
Prentice Hall, © 2001

3. Human Anatomy, 3rd edition
Cell Membrane
Structure
Lipid bilayer
Proteins float among the phospholipids
Molecules are constantly moving
Fluid mosaic model
Functions
Encloses components
Boundary through which substances enter or exit
Selectively permeable
Human Anatomy, 3rd edition
Prentice Hall, © 2001

4. Membrane Transport Passive processes Active processes
Molecules spread from an area of greater concentration to an area of lower concentration
Do not use cellular energy
Active processes
Molecules move from an area of lower concentration to an area of greater concentration
Use cellular energy
From high energy bonds of ATP

5. Passive Transport Processes
Diffusion
Osmosis
Facilitated diffusion
Filtration

6. Diffusion
Molecules move from an area of high concentration to an area of low concentration until they are uniformly distributed

7. Osmosis
Water molecules move from an area of lower solute concentration to higher solute concentration through a semipermeable membrane

8. Facilitated Diffusion
Molecules move across a membrane with the aid of a carrier protein
Human Anatomy, 3rd edition
Prentice Hall, © 2001

9. Filtration
Molecules are forced through membranes by mechanical pressure

10. Active Transport Processes
Ion pumps
Endocytosis
Exocytosis

11. Ion Pumps Molecule attaches to a carrier protein in the membrane
The molecule moves through the protein from low concentration to high concentration

12. Endocytosis & Exocytosis
Materials move into the cell by their inclusion into vesicles
Phagocytosis
Pinocytosis
Exocytosis
Materials move out of the cell
Cellular secretion
Human Anatomy, 3rd edition
Prentice Hall, © 2001

13. Inside the Cell Membrane
Cytoplasm
Cytosol
Thick fluid
Contains suspended particles
Organelles
Specific functions
Human Anatomy, 3rd edition
Prentice Hall, © 2001

14. Cytoplasm Contents Function Mostly water
Substance in which chemical reactions occur
Packages chemicals
Excretion of waste materials

15. Organelles
Perform specific functions necessary for cell structure, maintenance, and metabolism
Membranous or nonmembranous

16. Membranous Organelles

17. Human Anatomy, 3rd edition
Nucleus
“Control Center”
DNA
Nuclear Envelope
Nuclear pores
Nucleolus
Composed of RNA
Manufactures ribosomes
Human Anatomy, 3rd edition
Prentice Hall, © 2001

18. Human Anatomy, 3rd edition
Chromatin
Human Anatomy, 3rd edition
Prentice Hall, © 2001

19. Endoplasmic Reticulum (ER)
Network of channels running through the cytoplasm
Functions
Surface for chemical reactions
Transport
Storage
Secretion
Rough ER
Smooth ER
Human Anatomy, 3rd edition
Prentice Hall, © 2001

20. Human Anatomy, 3rd edition
Golgi Apparatus
Located near the nucleus
Associated with ER
Human Anatomy, 3rd edition
Prentice Hall, © 2001

21. Function of the Golgi Apparatus
Packaging and secretion of
Proteins,
Carbohydrates
Lipids
FG02_18.JPG
Title: The Function of the Golgi Apparatus
Notes: (a) This diagram shows the functional link between the ER and the Golgi apparatus. Transport vesicles shuttle secretory product from the ER to the Golgi, and transfer vesicles move material between Golgi saccules. (b)Exocytosis at the cell surface.
Keywords: Golgi, ER, endoplasmic reticulum, transport vesicles, secretory vesicles, transfer vesicles, saccules, maturing face, lysosomes, exocytosis, membrane protein
Human Anatomy, 3rd edition
Prentice Hall, © 2001

22. Lysosomes “Suicide packets” Produced by Golgi Apparatus
Contain digestive enzymes
Defense against disease
Break down cellular debris
Recycling of useful molecules in the cell

23. Human Anatomy, 3rd edition
Mitochondria
“Powerhouse” of the cell
Production of ATP
Double walled
Cristae
Matrix
mtDNA
Inherited from the mother
Human Anatomy, 3rd edition
Prentice Hall, © 2001

24. Nonmembranous Organelles

25. Human Anatomy, 3rd edition
Cytoskeleton
Protein framework
Microfilaments
Microtubules
Intermediate filaments
Human Anatomy, 3rd edition
Prentice Hall, © 2001

26. Human Anatomy, 3rd edition
Cilia
Projections of cell membrane
Short, many
Formed from microtubules
Cause currents at cell surface
Move substances along surface of cell or move entire cell
Human Anatomy, 3rd edition
Prentice Hall, © 2001

27. Human Anatomy, 3rd edition
Flagella
Projections of cell membrane
Few, long
Cause currents at cell surface
Move entire cell
Human Anatomy, 3rd edition
Prentice Hall, © 2001

28. Human Anatomy, 3rd edition
Ribosomes
Attached to rough ER
Scattered throughout cytoplasm
Sites of protein synthesis
Receive messages from RNA
Assembly of amino acids into proteins
Human Anatomy, 3rd edition
Prentice Hall, © 2001

29. Human Anatomy, 3rd edition
Centrioles
Near nucleus
9 bundles of microtubules
Function in cell reproduction
Human Anatomy, 3rd edition
Prentice Hall, © 2001

30. Intercellular Attachments
FG02_20A.JPG
Title: Cell Attachments
Notes: (a)Diagrammatic view of an epithelial cell, showing the major types of intercellular connections.
Keywords: epithelial cell, intercellular connections, tight junction, belt desmosome, terminal web, button desmosome, gap junctions
Human Anatomy, 3rd edition
Prentice Hall, © 2001

31. Human Anatomy, 3rd edition
Gap Junctions
Binding of membrane proteins hold cells together
Allow small molecules to pass through
Human Anatomy, 3rd edition
Prentice Hall, © 2001

32. Human Anatomy, 3rd edition
Tight Junctions
Partial fusion of the lipid parts of adjacent cell membranes hold cells together
Block water and solutes
Human Anatomy, 3rd edition
Prentice Hall, © 2001

33. Human Anatomy, 3rd edition
Desmosomes
Layer of proteoglycan and intermediate filaments hold cells together
Dense area binds to the cytoskeleton
Very strong, resist stretching and twisting
Human Anatomy, 3rd edition
Prentice Hall, © 2001

34. Extracellular Materials
Body fluids
Interstitial fluids
Plasma
Secreted inclusions
Substances forming matrix

35. Cells and Aging Physical signs Physiological signs
Extracellular characteristics
Immunology

36. Cell Growth and Replacement
Cell division
Mitosis
Occurs in somatic cells
Results in diploid cells
Meiosis
Occurs in reproductive cells
Results in haploid cells