midterm

the study of cells and tissues, microanatomy

affects and determines function

fluid inside the cells, mostly comprised of cytoplasm, made up of 70% water

fluid surrounding the organelles

fluid outside the cells

a phospholipid bilayer that acts as a selective barrier for the cell

fluid-mosaic model

a “mosaic” of membrane proteins are free to move in a sea of lipid

molecules composed predominantly (but not exclusively) of hydrogen and carbon atoms

complex structure of different proteins

primarily collagen, some polysaccharides (situated like a tree: collagen is trunk, polysaccharides are branches - called a glycoprotein)

area immediately surrounding the plasma membrane of a cell

nonpolar

covalent

nonpolarity

insoluble

fatty acids

triglycerides

phospholipids

steroids

fatty acid chain → triglyceride → phospholipid

1 glycerol + 3 fatty acid chains

1 glycerol + 2 fatty acid chains + a phosphate group

the side with the fatty acid chains

C-H bonds are stable & don’t have any charges, lipids are insoluble in water

the side with the phosphate group

the phosphate group has unequal distributions of electrons, making it charged (polarized)

having both hydrophilic & hydrophobic parts

phospholipids are amphipathic

polar

H molecules have a slight positive charge, whereas O molecules are slightly negative

phosphate groups are attracted to the polar water molecules, and fatty acid chains are attracted to each other in an effort to get away from the polarity of water

does not

carried through by proteins in plasma membrane

extend to both sides of plasma membrane (has polar ends & a nonpolar middle)

half in, half out of membrane (has a nonpolar end & a polar end)

only on one side of the membrane, either intracellular or extracellular (polar)

stabilization, structure, fluidity

form layers

…permeability

a specialized junction that is composed of cadherins (doesn’t seal up opening, just a protein maze, loose connective tissue)

proteins that extend from the cell into the extracellular space, where they link up and bind with cadherins from an adjacent cell)

a specialized junction that involves physical binding of 2 cells (no opening, nutrients have to pass through cells to enter/exit structures on either side)

a specialized junction that creates an bridge-like opening between 2 cells (molecule flow based on concentration gradient, primarily in cardiac muscle)

study of the structure & function of a cell

a network of filaments & tubules that maintains cell shape, helps locate organelles within cytoplasm, & guides or directs cytoplasmic transport

ATP production

powerhouse of the cell

uses O2 & produces CO2

has its own DNA & ability to replicate itself

present in all cell types EXCEPT RBCs (more numerous in cells that utilize large amounts of energy ex: striated muscle cells)

a series of tubules that have no ribosomes on their walls (so they appear smooth)

involved in lipid synthesis & metabolism

involved in synthesis & secretion of steroid hormones

involved in MEMBRANE FORMATION & RECYCLING

hepatic (liver) form: detoxifies, processes some drugs

specialized SER found in skeletal & cardiac muscle cells (regulate Ca+2)

series of interconnected chambers with walls covered in ribosomes (so they appear rough)

essential for PROTEIN SYNTHESIS

HIGHLY DEVELOPED IN PROTEIN SYNTHETIC CELLS LIKE FIBROBLASTS

protein factories of a cell

take in amino acids & synthesize proteins

looks like a stack of pancakes

well developed in secretory cells

intermediary between ER & the cell (processes newly formed proteins; concentrates, packages & marks proteins for intra- or extra-cellular use)

PROTEIN PACKAGING PLANT

some become lysosomes

some strengthen the cell membrane

some get secreted

biopsy

cutting away a small piece of tissue or blood for analysis

mostly involves a needle, sometimes a scalpel (if patient is already in surgery)

organ may require “going in blind” (there are some visualization tools that can be used as guides)

freezing & chemical (fixative)

when thawed, proteins (enzymes) can continue activity

use of liquid nitrogen (-170 C)

sometimes another bottle of liquid is placed into the liquid nitrogen to contain the sample (“snap freezing”)

10

90

use of formalin, formaldehyde, glutaraldehyde

permanently cross-links amino acids & other biological molecules (creates covalent bonds that aren’t there naturally, locks in protein conformation)

sample placed in something like an alcohol solution afterwards to prevent bacteria

at least a few hours (can be longer)

dehydrated - ethanol

embedded in wax

remain stable

-80

microtome

cryostat

slices 5-20um sections to be placed on slide (thinner than a piece of hair)

paraffin (wax) has to be dissolved

Hematoxylin & Eosin (H&E) - red/pink color

specific stains - stain for specific structures within the tissue

antibody (Ab) binds to an antigen

something (ex: a 2nd Ab) recognizes that Ab - creates signal amplification, makes structures more visible

fluorescence can be used to visualize structures at this point

light (bright field) microscopy

fluorescent microscopy

electron microscopy

only structures selected by stains are visible

detailed, minute, can see structures that make up whatever is stained

careful quantification & statistical analysis, since data is collected blindly

very

avascular

layers

all

lines body cavities

lines blood vessels

endocrine & exocrine

protection, absorption, secretion, selective barrier

underlying tissue → basal lamina (blood side) → epithelial layer → apical surface (lumen side)

# of cell layers

shape of cells in the OUTERMOST layer

cell “accessories” in the outermost layer

simple epithelium

stratified epithelium

columnar cells permeate bottom layer, jumbled appearance

flat, plate-like

cube-shaped

tall

cilia

goblet cells (secrete mucus, particularly in digestive organs)

microvilli (extensions of cytoplasm that increase surface area, particularly in absorbent cells)

glycocalyx (extracellular carbs or lipids in ECM bind to membrane proteins)

form sheets

determine function

promote communication

impermeable

cells

transmembrane

completely different

membrane proteins

anchoring

cells

selectively permeable

transmembrane

communicating

permeable (between certain cells)

molecules able to cross membrane without assistance

limited based on chemistry of substance & cell membrane

intracellular vesicles fuse w/ cell membrane & release contents into extracellular fluid

extracellular molecules are consumed by cell & enter the cytosol in vesicles

facilitated diffusion (glucose)

primary active transport (3 Na out, 2 K in) - ATP

secondary active transport (Na in, another molecule in against concentration gradient)

skin

hair

nails

sweat glands

waterproof

self-repairing

largest

epidermis (outermost)

dermis (middle)

hypodermis (deep layer)

prevent dehydration & associated electrolyte imbalance

thermal regulation

barrier to mechanical & chemical trauma

barrier to micro-organisms

barrier to UV & other types of radiation

sensory

D3

Ca

urea, salts, H2O

epithelial

cornified (hard)

connective

hypodermis

subcutaneous connective tissue (loose)

superficial fascia lata (adipose)

true

multiple

5 layers

<5 mm

soles of feet

4 layers

<1 mm

dorsum of head, eyelids