Cell Anatomy

Cell

• Basic unit of living organisms

• ~60% water• Bathed in interstitial

fluid (external)• Vary in shape and

function• 3 main regions– Nucleus, plasma

membrane, cytoplasm

Nucleus• Control center,

contains genes• 3 regions– Nuclear envelope• Double membrane

– Nucleoli• Site of ribosome

assembly

– Chromatin• Genetic material• Condenses to form

chromosomes during cell division

Plasma Membrane• Barrier between cell contents and environment• Lipid bi-layer, cholesterol, proteins

– Assembled tail to tail• Head – hydrophilic• Tail- hydrophobic

• Selective permeability

Plasma Membrane Specialized Parts• Microvilli– Folds, increase surface

area• Membrane junctions– Tight junctions• Connect cells in sheets

– Desmosomes• Anchor, prevents pulling

apart

– Gap junctions• Communication

Cytoplasm

• Internal cellular material• Contains three elements– Cytosol• Fluid that suspends the other elements

– Inclusions• Stored products/nutrients

– Organelles• Metabolic machinery

Cell Organelles

• Mitochondria – site of ATP generation• Ribosomes – site of protein synthesis• Endoplasmic reticulum – fluid filed tubules– Rough ER – studded with ribosomes– Smooth ER – lipid metabolism, detoxification

• Golgi apparatus- flattened stack of sacs, modifies and packages

• Lysosomes – cell demolition site• Peroxisomes – detoxifies poisons and reactive

chemicals

Cell Organelles

• Cytoskeleton - Internal framework–Composed of• Intermediate filaments – resist forces• Microfilaments – cell motility, shape changes• Microtubules – determine shape, organelle

distribution

• Cell projections–Cillia – hair like appendages– Flagella – long projections, motility

Cell diversity

• Over 200 types in the human body• All vary in shape and function• Specialized– Connect– Cover– Move– Storage– Fight disease– Control/information gathering– Reproductive

Cell diversity