Cell Specialisation/Cell Differenitation

Cell specialization

Process where unspecialized cells become specialized for specific functions

Cell differentiation

Another term for cell specialization

Importance of cell specialization

Allows cells to perform specific roles in the body

Cell specialization in embryos

Essential for development of different tissues and organs

Adult stem cells

Replace worn-out or damaged cells

Cause of cell specialization

Differences in gene expression

Cytoplasmic differences

Unequal distribution of organelles in early cells

Environmental conditions

Temperature and nutrients affecting gene activity

Neighboring cells

Chemicals from nearby cells influence differentiation

Gene regulation

Turning genes on or off without changing DNA

Stem cells

Cells that can differentiate into many cell types

DNA in specialized cells

Same DNA but different genes expressed

Function of stem cells

Growth, repair, and regeneration

Tissue

Group of similar cells performing a specific function

Types of animal tissue

Epithelial, muscular, connective, nervous

Epithelial tissue

Tissue that covers surfaces and lines cavities

Function of epithelium

Protection and selective permeability

Permeability

Ability to control movement of substances

Apical surface

Top surface of epithelial cells

Basal surface

Bottom surface attached to basal lamina

Cilia

Hair-like structures that move substances

Simple squamous epithelium

Thin flat cells for rapid diffusion

Location of simple squamous

Alveoli, capillaries, kidney tubules

Simple cuboidal epithelium

Cube-shaped cells for secretion and absorption

Location of simple cuboidal

Kidney tubules and gland ducts

Simple columnar epithelium

Tall cells for absorption and secretion

Location of simple columnar

Digestive tract and reproductive tract

Ciliated columnar epithelium

Columnar cells with cilia for movement

Location of ciliated epithelium

Respiratory tract and fallopian tubes

Pseudostratified epithelium

Single layer that appears layered

Location of pseudostratified

Respiratory tract

Stratified squamous epithelium

Multiple layers for protection

Keratinized epithelium

Found in skin

Nonkeratinized epithelium

Found in mouth lining

Glandular epithelium

Epithelium specialized for secretion

Endocrine glands

Ductless glands releasing hormones into blood

Exocrine glands

Glands that secrete through ducts

Muscle tissue

Tissue specialized for contraction and movement

Contractile proteins

Actin and myosin

Muscle contraction

Sliding of actin and myosin filaments

Skeletal muscle

Long striated multinucleated voluntary muscle

Myoblasts

Embryonic muscle precursor cells

Sarcolemma

Plasma membrane of muscle fiber

Sarcoplasm

Cytoplasm of muscle fiber

Sarcoplasmic reticulum

Stores calcium ions

Sarcomere

Functional unit of muscle contraction

Cardiac muscle

Muscle found only in the heart

Intercalated discs

Junctions connecting cardiac muscle cells

Pacemaker cells

Control heart rate

Myoglobin

Oxygen-binding protein in cardiac muscle

Smooth muscle

Non-striated involuntary muscle

Location of smooth muscle

Walls of hollow organs and blood vessels

Shape of smooth muscle

Spindle-shaped cells

Dense bodies

Anchor actin filaments in smooth muscle

Caveolae

Membrane indentations for calcium entry

Connective tissue

Tissue that supports, binds, and protects

Extracellular matrix

Ground substance plus fibers

Fibroblast

Most common connective tissue cell

Fibrocyte

Less active form of fibroblast

Adipocyte

Fat-storing cell

White adipocyte

Stores one large lipid droplet

Brown adipocyte

Stores many lipid droplets and high metabolism

Mesenchymal cell

Adult stem cell for connective tissue

Chondrocyte

Cartilage cell

Basophilic cytoplasm

Cytoplasm rich in rough ER

Osteocyte

Mature bone cell

Canaliculi

Channels connecting osteocytes

Function of osteocytes

Bone maintenance and remodeling

Red blood cell

Cell that transports oxygen

Hemoglobin

Iron-containing oxygen-binding protein

RBC nucleus

Absent in mature red blood cells

Advantage of no nucleus in RBC

More space for hemoglobin

Leukocytes

White blood cells

Granulocytes

WBCs with granules

Neutrophil

Phagocytic first responder to infection

Eosinophil

Targets parasites and allergic reactions

Basophil

Releases histamine and heparin

Histamine

Increases blood vessel permeability

Heparin

Prevents blood clotting

Agranulocytes

WBCs without granules

Lymphocytes

T cells, B cells, and natural killer cells

T cells

Cell-mediated immunity

B cells

Antibody production

Natural killer cells

Nonspecific immune defense

Monocytes

Largest WBCs that become macrophages

Nervous tissue

Tissue specialized for communication

Neuron

Nerve cell that transmits signals

Dendrites

Receive nerve impulses

Axon

Sends nerve impulses