241 Chapter 3: Compartmentation: cells and tissues

Compartments

Separate biological contents so conditions differ between areas

Advantages of Compartments

Specialization- organelles (mitochondria, nucleus) can perform specific functions

molecules grouped together in same area (enzymes of TCA are all inside mitochondria) 

Disadvantages of Compartment

Creates barriers; harder to transport molecules

Cells need transport system (e.g. channels and carriers) 

Body cavities 

Cranial cavity, thoracic cavity, abdominopelvic cavity 

Cranial Cavity

spinal cord and brain

Thoracic Cavity

lungs (pleural), heart (pericardial cavity)

Abdominal pelvic cavity

digestive and reproductive

Functional body cavities 

Extracellular and intracellular fluid 

Extracellular fluid 

1/3 of total fluid; interstitial fluid and plasma

interstitial fluid

around cells

Plasma location

inside blood vessels

Intracellular fluid

2/3 total of fluid; inside cells (nucleus and mitochondria)

What separates Compartments 

membrane 

What do all cells contain

phospholipid bilayer (cell membrane)

Bilayer 

hydrophilic heads face water,

Hydrophobic tails face inward forming a selective barrier 

What do all tissues have

membrane layer

2 meanings of membrane

1. Tissue lining a cavity (peritoneum, mucous membrane)

2. Cell membrane (phospholipid bilayer) 

4 functions of cell membrane

1. Physical isolation (separate inside vs outside) 

2. Regulation of exchange with environment (cntrl entry/exit of ion)

3. Communication between cell and its environment (protein as receptor)

4. Structural support (anchors cytoskeleton, cell junctions) 

What are membranes most of the time

Lipid and protein

Lipid membrane types

• Phospholipid; form bilayers, micelles, liposomes

• Cholesterol; stabilizes membrane

• Sphingolipid

Protein cell membrane types

Integral, peripheral, transmembrane, lipid anchored 

Integral Proteins

span across cell membrane and covalently bond to membrane’ receptors and channels.

removal can’t be done without damaging cell

Peripheral Proteins

Attach to another protein, easier to remove without disrupting integrity of cell

Transmembrane Proteins

type of integral protein; loops across multiple times

Lipid anchored Proteins

covalent bond to surface side of lipid

func; cell to cell communication i

Membrane Carbohydrates

• attached to lipid or protein on cell surface

• barriers (mucous membrane in stomach from stomach acid); have immune roles (blood types) 

Cells have different…

shapes and size corresponding to function

How many different cell types does human body have?

Around 200 different types with over 1 trillion in number

Cytoskeleton

Dynamic protein scaffold that extend throughout cytoplasm

5 functions of Cytoskeleton

1. cell shape; scaffolding 

2. Internal organelle organization; stabilize position of organelles 

3. Intracellular transport; provide railroad track  

4. Cell assembly into tissue; protein fiver connect with other cells outside 

5. Movement; cilia and flagella 

Motor proteins

convert energy to motion

3 groups of motor proteins

Myosin, Kinesin and Dynein

Myosin

Type of motor protein that Bind actin (muscle contraction)

Kinesin and Dynein

type of motor protein that moves vesicle along microtubules

Tissues provide

another form of specialization 

Histology

study of tissues structure and function

4 main themes in histology

1. shape and size of cells

2. arrangement of the cells

3. the way cells are connected to one another

4. the amount of extracellular matrix present

4 primary types of tissue

1. Epithelial

2. connective

3. muscle 

4. neural (nerve) 

Extracellular Matrix

• produced and secreted by cells

  • Vital in physiological processes (cancer spread by degrading ECM)

Components of ECM

proteoglycans and protein fibers (collagen)

Cell Junctions

Hold cells together to form tissues

2 types of cell junction

cell to cell

cell to matrix

Also can be; transient or strong

Strong cell junctions 

Communicating junctions; occluding junctions; anchoring junctions 

Communicating junctions

cell to cell; gap junctions that allow ions or charge between cells

Occluding junction

cell to cell; tight junction- prevent movement between cells

Anchoring Junctions cell to cell

• adherens junctions – anchor one cell to another cell

• desmosomes – strongest, attach to intermediate filaments
  within the cell
  

Anchoring Junctions cell to matrix

• hemidesmosomes – similar to desmosome but attachment is
  between cell and matrix

• focal adhesions – attach actin to matrix proteins

Tissues

groups of cells that perform a similar function/role

Epithelial Tissue

Barrier between inside and outside; regulates exchange of substance leaving the internal environment

Five functional types of epithelial tissue

1. Exchange epithelia

2. transporting epithelia

3. ciliate epithelia

4. protective epithelia

5. Secretory epithelia

Connective tissue

either cells or matrix; CT cells are constantly modifying ECM or matrix

Cells of connective tissue 

Fixed (adipose, fibroblasts) 

Mobile (red blood cells, white blood cells, macros) 

Matrix of Connective tissue

• Ground substances (bone, cartilage, blood plasma)

• protein fibers (produced by cell; collagen, elastin, fibronectin) 

What is ECM a combo of

ground substance and protein fibers

Muscle Tissue

Type of excitable tissue; minimal ECM

3 types of Muscle

skeletal, smooth and cardiac

Skeletal Muscle

Voluntary muscle, controlled consciously with 600+ in human body

Smooth Muscle

Involuntary muscle, controlled unconsciously and surrounds blood vessels and internal organs 

Cardiac muscle

control itself with help from nervous and endocrine system

Neural Tissue

very little ECM; carries info from one part of body to another long and short distances

What support neural tissue

glial cells