Background Basics:

Units of measure

Hydrophobic molecules

Proteins

Compound molecules

pH

DNA and RNA

Key Concepts

Functional

compartments of the body

Biological membranes

Intracellular

compartments

Tissue types

Tissue remodeling

Organs

Study of cell structure

= ?

Study of tissue

structure = ?

Study of how cells work

= ?

Functional Body

Compartments

• Various membrane lined body cavities

• Lumens of hollow organs are NOT part of internal environment

• Body has 3 fluid compartments

Fig 3-1

Fig 3-2

Membrane –2 Meanings!

• Epithelial membranes

vs.

• Cell membranes and

Membranes around organelles

Functions of Cell Membranes

1. Physical isolation

2. Regulation of exchange with environment

3. Communication between cell and environment

4. Structural support

Cell Membrane Structure: Fluid Mosaic Model

Thickness ~ 8nm

PLs, Sphingolipids and

Cholesterol

Proteins: peripheral (associated) or integral (transmembrane)

Fig 3-4

Phospholipid Behavior in H2O:

• Phospholipid bilayer

• Micelle– Role in digestion and

absorption of fats in GI tract

• Liposome– Larger, bilayer,

hollow center with aqueous core

Clinical relevance?

Cell Anatomy &

Intracellular

Compartments

ECF

Cellmembrane

Membranousorganelles

Non-membranous

organelles

The Cell

Fig 3-11

Cell differentiation

Mechanism: differential gene activation

From 1 zygote to 200 different types of cells

Cytoplasm

Cytosol:

= semigelatinous

intracellular fluid

Medium for suspension of

1. Organelles,

2. Ions, nutrients, wastes,

enzymes etc.…….

3. Inclusions

Organelles perform

specialized tasks.

Membranous

organelles

Non-membranous

Organelles

(Inclusions)

Cytoskeleton

Functions in

• Cell shape

• Internal organization

• Transport

• Cell to cell links (

tissues)

• Movement

Made of protein fibers1. Microfilaments (actin)

2. Intermediate filaments

(myosin, keratin)

3. Microtubules

Fig 3-14

Microtubules form Centrosomes and

Centrioles

1 centrosome contains 2 centriolesCentrosomes organize microtubules

Centrioles: bundles of microtubules

Pull chromosomes, form core in cilia

Special Structural Features of Cell

Membranes and Cytoskeletons

• Microvilli

• Cilia

• Stereocilia

• Flagella

Function?

1. Myosins (see Ch12)

2. Kinesins (movement along microtubules)

3. Dyneins (cilia and flagella movement)

Motor Proteins Create Movement

Compare to Fig 3-15

• Function: ?

• Fixed to ER or free in cytoplasm

Ribosomes

Membranous Organelles

Special compartments for special functions

– Separate harmful substances from other cell areas

– Separate function from other cell areas

__________on/-a

cell’s powerhouse.

Has own DNA

RER & SER

____________ synthesis,

storage, modification &

transport vesicle formation

Synthesis and conversion of FA,

steroids, lipids

In muscle: ______________

Golgi Complex

• Modification (labeling) of proteins

• Packaging into secretory (to ECF) or storage

vesicles

TEM

“Post office” of cell

Protein

Secretion

Cytoplasmic Vesicles: Lysosomes

Digestion (~ 50 enzymes) of bacteria and old organelles

Enzymes only active at pH of 100 – 1,000 x < cytoplasm

pH = ?Also dissolves Ca-carbonate of bone

Rheumatoid arthritis and

Tay-Sachs disease

Tay Sachs

Disease

(TSD)

Increased resistance to TB?

Peroxi-

somes

Major function: Degradation of long chain FAs

Generate hydrogen peroxide contain catalase

ALD

Smaller than Lysosomes -Different set of enzymes

Nucleus

• Control Center

• Nuclear envelope with

nuclear pore complexes

for diffusion and active

transport

• Chromatin (DNA and

proteins)

• One or more nucleoli

• Genes

Tissues: Cell to Cell Junctions

• Electrical synapses

• Cylindrical proteins

(connexins) form

channels

• Can open and close

• Rapid transfer of

signals in cardiac &

smooth muscle

Gap Junctions

Tight Junctions• Complete barrier

(brick wall)

• Fusion of adjacent cell membranes via claudin and occludin

• Found in

–

–

Tight vs. leaky

epithelium

Anchoring Junctions

• Cell to cell or cell to matrix

• Anchoring junctions (CAMs: cadherins)– Desmosomes

– Adherens junctions

• Cell matrix attachments (CAMs: integrins)– Hemidesmosomes

– Spot desmosomes or focal adhesions

In cancer: Loss of

desmosomes

consequence?

Histology• Structure and function of all basic tissue

types: remember from Anatomy or review on

your own (starting p.72 with epithelia)

• Review concept of stem cells (totipotent –

pluripotent – multipotent – unipotent or

progenitor cell)

• Definition of organ?

Example: skin, see textbook p.83

Tissue

Remodeling

Tissue remodeling throughout a persons life

• Apoptosis = Programmed cell death (suicide)

Cell breaks up into membrane bound blebs which will be phagocytosed by other cells.

• Necrosis = traumatic cell death

Lack of O2, trauma, toxins

Cells rupture tissue damage & inflammation

Running Problem: The Pap Smear

Page 51 on

Cervical cells. Uniform in size and shape

normal