1. Chapter 3 & 4
Cells & Tissues

2. Cells Cells vary in size and shape; all are microscopic
All cells share general structures
Cells are organized into three main regions
Nucleus
Cytoplasm
Plasma membrane
Organelles are specialized
structures with the cytoplasm

3. Plasma Membrane Forms outer boundary
Composed of thin, two-layered membrane of phospholipids and embedded with proteins
Is selectively
permeable

4. Cytoplasm Material outside the nucleus and inside the plasma membrane
Cytoskeleton internal framework of cell
Made up of microfilaments and microtubules
Provides support and movement of cell and organelles

5. Organelles

6. Ribosomes Made of protein and RNA
Manufactures enzymes and other proteins
Often called “protein factories”
Found at two locations
Free in the cytoplasm
Attached to rough
endoplasmic reticulum

7. Endoplasmic Reticulum (ER)
Network of connecting sacs and canals
Carry substances through cytoplasm
Two Types
Rough ER
Collects folds, and transports proteins made by ribosomes
Smooth ER
Manufactures fats, carbohydrates, proteins that make up cellular membrane

8. Golgi Apparatus Group of flattened sacs near nucleus
Chemical processing and packaging center
Collects chemicals into vesicles (little sacs) that move from the smooth ER outward to the plasma membrane

9. Mitochondria Composed of inner and outer membranous sac
“Powerhouses” of the cell
Involved with energy-releasing chemical reactions (cellular respiration)
Uses this released energy
to “recharge” ATP required
for cellular work
Each contains one DNA molecule

10. Lysosomes Membrane enclosed packets containing digestive enzymes
Have protective functions (eat microbes)

11. Centrosome
Microtubule-organizing region near the nucleus
Plays important role in organizing and moving structures within the cell
Centrioles – lie at right angles to each other with the centrosome
Function in moving
chromosomes during
cell reproduction

12. Cell Extensions
Microvilli – small, fingerlike projections that increase surface are and ability to absorb
substances (small intestines)
Flagellum – single projection that propels the male sperm cell
Cilia - hairlike extensions
Move materials across the cell surface
(respiratory tract or reproductive tubes)
Some serve sensory functions

13. Nucleus
Contains most of genetic code (genome) instructions for making proteins, which determine cell structure and function
Nuclear envelope – 2 separate membranes that allow molecules to move in and out of the nucleus
Nucleoplasm – a type of protoplasm that fills the nucleus
Nucleolus – dense region of the nucleus where the cell makes the subunits that form ribosomes
Chromatin and chromosomes – chromatin granules in the nucleus made up of DNA
46 nuclear chromosomes contain DNA, which contains genetic code

14. Cell Structure and Function
Every human cell has a designated function, some help maintain the cell, others regulate life processes
Specialized functions differ depending on the number and type of organelles

15. Quick Check Describe the structure of the plasma membrane of the cell?
What is cytoplasm?
What does it contain?
List five major structures of the cell and briefly describe their function.

16. Solutions and Transport
Solution – homogeneous mixture of two or more components
Solvent – dissolving medium
Solutes – components in smaller quantities within a solution
Intracellular fluid – fluid within the cell
Interstitial fluid – fluid outside of the cell

17. Movement of Substances Through Cell Membrane
Cell membrane must permit movement of substances into and out of the cell
Selective Permeability – ability to allow some materials to pass while excluding others
Achieved by two basic methods
Passive transport
No energy is required
Active transport
Requires energy – breakdown of ATP and the use of released energy is required

18. Passive Transport Processes
Diffusion
Substances scatter themselves evenly throughout an available space
Particles from and area of high concentration to an area of lower concentration, or down a concentration gradient

19. Passive Transport Processes
Osmosis
Diffusion of water through a selectively permeable membrane (when some solutes cannot cross the membrane)

20. Passive Transport Processes
Filtration
Movement of water and small solute particles, but not larger particles, through a filtration membrane
Movement caused by hydrostatic pressure on one side (higher pressure to area of lower pressure)

21. Active Transport Processes
Uphill movement of substances through a living membrane
Movement of substances is “up the concentration gradient”
Requires energy from ATP

22. Ion Pumps
Protein structures in the cell membrane called a carrier that use energy from ATP
Specific to one type of ion
Some work with others to
transport glucose, amino
acids, other substances
Example:
Calcium pumps in muscle cells
Sodium-potassium pumps

23. Phagocytosis
“Cell eating” – large particles are engulfed in a vesicle as a protective mechanism
Often used to destroy bacteria or debris from tissue damage

24. Pinocytosis
“Cell drinking” – engulfs fluids or dissolved substances into cells
Requires ATP to move the cytoskeleton in a way that engulfs material and pulls it into the cell

25. Quick Check
What is the difference between a passive transport and an active transport process?
What is osmosis?
What is filtration?
How does an ion pump work? Is it active or passive?
Describe the process of phagocytosis.
Describe the process of pinocytosis.

26. Cell Reproduction and Heredity
Mitosis – process
of cell reproduction
Cell divides to form two cells
Closely tied to the production of proteins
Two nucleic acids play a crucial role
Ribonucleic acid (RNA)
Deoxyribonucleic acid (DNA)

27. DNA Structure Large spiral-shaped molecule
Sugar (deoxyribose) and phosphate units make up the sides
Base pairs (adenine-thymine or guanine-cytosine) compose the ‘steps’
Base pairs always the same but the sequence differs in different DNA molecules
This is important because the
sequence determines heredity

28. DNA and Genetic Information
Gene – specific sequence of base pairs within a DNA molecule
Dictate formation of enzymes and other proteins by ribosomes
Indirectly determine a cell’s structure and function
Determines inherited traits

29. Genetic Code
Genetic information is stored in base-pair sequences on genes and directs the synthesis of a specific protein
RNA molecules and protein synthesis
DNA – contained in cell nucleus
Protein synthesis occurs in cytoplasm. Genetic information must pass from the nucleus to the cytoplasm.
Requires transcription and translation.

30. Transcription
Double-stranded DNA separates to form messenger RNA (mRNA)
Each strand of mRNA duplicates a particular gene from a segment of DNA
mRNA molecules pass from the nucleus to the cytoplasm where they direct protein synthesis in ribosomes and ER

31. Translation Involves synthesis of proteins in cytoplasm by ribosomes
Requires the use of information contained in mRNA
Codon – a series of three nucleotide bases that acts as a code for a specific amino acid

32. Protein Synthesis

33. Cell Life Cycle Cells have two major periods Interphase Cell grows
Cell carries on metabolic processes
Cell division
Division of the nucleus (mitosis) and cytoplasm resulting in two identical daughter cells

34. Mitosis

35. Prophase – first stage Chromatin granules become organized
Chromosomes (pairs of linked chromatids) appear
Centrioles move away from nucleus
Nuclear envelope disappears, freeing genetic material
Spindle fibers appear

36. Metaphase – second stage
Chromosomes align across center of cell
Spindle fibers attach themselves to each chromatic

37. Anaphase – third stage Centromeres break apart
Separated chromatids now called chromosomes
Chromosomes are pulled to opposite ends of the cell
Cleavage furrow develops at end of anaphase

38. Telephase – fourth stage
Cell division is completed
Nuclei appear in daughter cells
Nuclear envelope and nucleoli appear
Cytoplasm is divided (cytokenesis)
Daughter cells become fully functional

39. Results of Cell Division
Two identical cells result from cell division, growing tissues or replacing old or damaged cells
Differentiation – process by which daughter cells can specialize and form different kinds of tissue
Abnormalities of mitotic division can produce benign or malignant neoplasms (tumors)

40. Body Tissues Cells are specialized for particular functions Tissues:
Groups of cells with similar structure and function
Four primary types
Epithelium
Connective tissue
Nervous tissue
Muscle

41. Epithelial Tissue Found in different areas Functions Body coverings
Body linings
Glandular tissue
Functions
Protection
Absorption
Filtration
Secretion

42. Classification of Epithelial Cells
Shape of cells
Squamous – flattened
Cuboidal – cube-shaped
Columnar – column-like
Transitional – (varying shapes that can stretch)

43. Classification of Epithelial Tissue
Number of cell layers
Simple – one layer
Stratified – more than one layer

44. Simple Squamous Epithelium
Single layer of flat cells
Lines body cavities
Lines lungs & capillaries
Substances can readily pass through, making transportation its special function
Ex. Absorption of oxygen into the blood

45. Stratified Squamous Epithelium
Cells at the free edge are flattened
Found as a protective covering where friction is common
Locations
Skin
Mouth
Esophagus

46. Simple Columnar Epithelium
Single layer of tall cells
Often includes goblet cells, which produce mucus
Lines digestive tract

47. Stratified Transitional Epithelium
Shape of cells depends upon the amount of stretching
Lines and protects organs of the urinary system

48. Pseudostratified Epithelium
Single layer, but some cells are shorter than others
Often looks like a double cell layer
Sometimes ciliated, such as in the respiratory tract
May function in absorption or secretion

49. Simple Cuboidal Epithelium
Single layer of cube-like cells
Common in glands and their ducts
Forms walls of kidney tubules
Covers the ovaries

50. Connective Tissue Found everywhere in the body
Includes the most abundant and widely distributed tissues
Functions
Binds body tissues together
Supports the body
Provides protection

51. Connective Tissues Variations in blood supply Extracellular matrix
Some tissue types are well vascularized
Some have poor blood supply or are avascular
Extracellular matrix
Non-living material that surrounds living cells

52. Aerolar Tissue Also known as loose connective tissue
Most widely distributed connective tissue
Makes up fascia – the fibrous material that helps to bind skin, muscles, bones and other organs
Some made of collagen – a strong by flexible fibrous protein
Some made of elastin – a stretchy fiber

53. Adipose Tissue
Matrix is an areolar tissue in which fat globules predominate
Many cells contain large lipid deposits
Functions
Insulates the body
Protects some organs
Serves as a site of fuel storage

54. Reticular Tissue Delicate network of interwoven fibers
Forms internal supporting network of lymphoid organs
Lymph nodes
Spleen
Bone marrow

55. Dense Fibrous Tissues Thick bundles of strong collagenous fibers
Arranged in parallel rows
Strong and flexible, but do not stretch
Examples:
Tendon – attach muscle
to bone
Ligaments – attach bone

56. Bone Tissue Also known as osseous tissue Hard and calcified
Forms structural building blocks called osteons or Haversian systems
Protect and support the body
Storage of calcium

57. Cartilage Tissue
Matrix has consistency of a firm plastic or gristle like gel
Cartilage cells, called chrondocytes, are located in the many tiny spaces throughout the matrix

58. Blood and Hematopoietic Tissue
Blood cells (red and white) surrounded by fluid matrix
Functions include transportation and protection
Hematopoietic Tissue
Bloodlike connective tissue
found in the red marrow
cavity of bones and in the
spleen, tonsils, and lymph
nodes

59. Quick Check What are the 4 main types of tissues?
How are epithelial cells classified by shape?
What is the difference between simple and stratified tissue?

60. Muscle Tissue Function is to produce movement
Greater ability to contract than other tissue
Three types
Skeletal muscle
Cardiac muscle
Smooth muscle

61. Skeletal Muscle Can be controlled voluntarily
Cells attach to connective tissue
Cells are striated
More than one nucleus

62. Cardiac Muscle Found only in the heart
Cells attached to other cardiac muscle cells at intercalated disks
Function is to pump blood
Involuntary
Cells are striated
One nucleus per cell

63. Smooth Muscle Also known as visceral muscle Involuntary muscle
Attached to other smooth muscle cells
Surrounds hollow organs and blood vessels
No visible striations
One nucleus per cell

64. Nervous Tissue Function is rapid communication between body structures
Nerve cells, or neurons, and nerve support cells called glia, or neuroglia
All have:
Cell body
1 axon - transmits impulse
away from the cell body
1 or more dendrites – carry
impulses toward cell body

65. Quick Check List and describe 4 types of connective tissues.
List and describe the 3 types of muscle tissue.
What are the 2 types of processes found on nervous tissue? What is their function?