Histology Prelab - Cell Staining and Organelles Exam With
complete solution–Expert Verified | Latest Questions 2025
Dark stained areas of the nucleus - Heterochromatin
Appears dark blue/purple when stained with hematoxylin (inactive cell - not
transcriptionally active) - Heterochormatic Nucleus
Light stained areas of the nucleus - Euchromatin
Appears pale and exhibits a light blue/purple stain (active cell - transcriptionally active) -
Euchromatic Nucleus
Labile, Stable, and Static - Classifications of stem cells
-Rapid renewal
-Short life-span (days-weeks)
-Regular mitotic activity
-Most susceptible to cytotoxic drugs
-epithelium, WBC & RBC - Labile stem cells
-Occasional renewal
-Viable for years
-Rare to see mitotic cells visible in most of the tissue
-Progenitor cells can be induced by external stimuli or damage
-bone, CT, liver, pancreas, smooth muscle, epithelium of kidney, and alveolar cells in
lung - Stable Stem cells
-Rarely renew
-Long life span of tissue
limited source of stem cells
-tissue typically not replaced by stem cell when damaged
-neurons, cardiac, skeletal muscles - Static stem cells
Accidental cell death
-Irregular chromatin condensing, mitochondria swells, and breakdown of membrane and
ribosomes
-Induces Inflammatory Reaction - Necrosis
Programmed Cell Death
-Nucleus and Cytoplasm break into fragments called apoptotic bodies
-No inflammation - Apoptosis
Site of transcription
, Chromosomes (DNA) contain genetic information to encode all proteins in the body -
Nucleus Function
Membrane-bound structure containing chromatin that can appear dispersed or tightly
coiled (DNA and nuclear proteins) - Nucleus Description
-Heterochromatin (tightly coiled condensed chromatin) exhibits intense basophilia
-Euchromatin (extended and dispersed chromatin) - Nucleus Histological Appearance
Site of Ribosomal RNA Synthesis and ribosome assembly - Nucleolus Function
Dense non-membrane bound structure in the nucleus appearing as small circle in
nucleus - Nucleolus Description
Appears basophilic by light microscopy due to high concentration of heterochromatin -
Nucleolus Histological Appearance
(Nuclear envelope)
Mediates bi-directional and selective transport of molecules between nucleus and
cytoplasm - Nuclear Membrane Function
Surrounds the nucleus, contains nuclear pore complexes (openings) - Nuclear
Membrane Description
Visible in light microscopy, easiest to see in euchromatic nucleus (breaks down during
mitosis) - Nuclear membrane histological appearance
-Divides cell from external environment
-Mediates Cellular Interactions/signaling with ext. environment
-Site of membrane transport via channels and receptor activation
-Semi permeable and selective barrier - Cell plasma membrane Function
lipid bilayer containing intrinsic proteins and external coat of complex carbohydrates
known as the glycocalyx - Cell plasma membrane description
-Visible to light microscopy when stained (glycocalyx stained due to abundance of
complex carbohydrates)
-Stains best with PAS - Plasma membrane histological appearance
Surface: site of protein synthesis
Lumen: site of post-translational modifications and folding of proteins synthesized by
attached ribosomes - Rough Endoplasmic Reticulum Function
Extensive membrane system with ribosomes on surface - rER Description
-Appears as basophilic clumps in cytoplasm
complete solution–Expert Verified | Latest Questions 2025
Dark stained areas of the nucleus - Heterochromatin
Appears dark blue/purple when stained with hematoxylin (inactive cell - not
transcriptionally active) - Heterochormatic Nucleus
Light stained areas of the nucleus - Euchromatin
Appears pale and exhibits a light blue/purple stain (active cell - transcriptionally active) -
Euchromatic Nucleus
Labile, Stable, and Static - Classifications of stem cells
-Rapid renewal
-Short life-span (days-weeks)
-Regular mitotic activity
-Most susceptible to cytotoxic drugs
-epithelium, WBC & RBC - Labile stem cells
-Occasional renewal
-Viable for years
-Rare to see mitotic cells visible in most of the tissue
-Progenitor cells can be induced by external stimuli or damage
-bone, CT, liver, pancreas, smooth muscle, epithelium of kidney, and alveolar cells in
lung - Stable Stem cells
-Rarely renew
-Long life span of tissue
limited source of stem cells
-tissue typically not replaced by stem cell when damaged
-neurons, cardiac, skeletal muscles - Static stem cells
Accidental cell death
-Irregular chromatin condensing, mitochondria swells, and breakdown of membrane and
ribosomes
-Induces Inflammatory Reaction - Necrosis
Programmed Cell Death
-Nucleus and Cytoplasm break into fragments called apoptotic bodies
-No inflammation - Apoptosis
Site of transcription
, Chromosomes (DNA) contain genetic information to encode all proteins in the body -
Nucleus Function
Membrane-bound structure containing chromatin that can appear dispersed or tightly
coiled (DNA and nuclear proteins) - Nucleus Description
-Heterochromatin (tightly coiled condensed chromatin) exhibits intense basophilia
-Euchromatin (extended and dispersed chromatin) - Nucleus Histological Appearance
Site of Ribosomal RNA Synthesis and ribosome assembly - Nucleolus Function
Dense non-membrane bound structure in the nucleus appearing as small circle in
nucleus - Nucleolus Description
Appears basophilic by light microscopy due to high concentration of heterochromatin -
Nucleolus Histological Appearance
(Nuclear envelope)
Mediates bi-directional and selective transport of molecules between nucleus and
cytoplasm - Nuclear Membrane Function
Surrounds the nucleus, contains nuclear pore complexes (openings) - Nuclear
Membrane Description
Visible in light microscopy, easiest to see in euchromatic nucleus (breaks down during
mitosis) - Nuclear membrane histological appearance
-Divides cell from external environment
-Mediates Cellular Interactions/signaling with ext. environment
-Site of membrane transport via channels and receptor activation
-Semi permeable and selective barrier - Cell plasma membrane Function
lipid bilayer containing intrinsic proteins and external coat of complex carbohydrates
known as the glycocalyx - Cell plasma membrane description
-Visible to light microscopy when stained (glycocalyx stained due to abundance of
complex carbohydrates)
-Stains best with PAS - Plasma membrane histological appearance
Surface: site of protein synthesis
Lumen: site of post-translational modifications and folding of proteins synthesized by
attached ribosomes - Rough Endoplasmic Reticulum Function
Extensive membrane system with ribosomes on surface - rER Description
-Appears as basophilic clumps in cytoplasm
