Tissue Types Vocabulary (Pages 2-6)

Vocabulary flashcards covering epithelial, connective, muscle, and nervous tissue terms and their key definitions from Pages 2–6.

Epithelium

A continuous cellular layer forming barriers between inside and outside, covers surfaces, lines organs/cavities/tubes, is avascular, rests on basal lamina, has little ECM, is polarized, and regenerates rapidly.

Basal lamina

A thin sheet secreted by epithelial cells that forms the basal part of the basement membrane.

Reticular lamina

ECM produced by connective tissue that, with the basal lamina, contributes to the basement membrane.

Basement membrane

The ECM boundary between epithelium and underlying connective tissue, composed of basal and reticular lamina.

Epithelial polarity

Organization where apical and basolateral surfaces differ in structure and function.

Simple squamous epithelium

Single layer of flat cells; lines body cavities, heart chambers, blood vessels; sites of diffusion and filtration.

Simple cuboidal epithelium

Single layer of cube-shaped cells; lines kidney tubules and many glands/ducts; active in secretion and absorption.

Simple columnar epithelium

Single layer of tall cells; lines digestive tract; specialized for absorption and secretion (often with microvilli/goblet cells).

Pseudostratified columnar epithelium

Epithelium with nuclei at different levels but all cells contact basal lamina; typically in the respiratory tract; protection, secretion (mucus), and ciliary movement.

Stratified squamous epithelium

Multiple cell layers with outermost layer of squamous cells; protects against abrasion; keratinized forms skin; non-keratinized lines moist surfaces.

Keratin

Structural protein in epidermis that provides toughness and protection against dehydration and abrasion.

Stratified cuboidal epithelium

Two to three cell layers of equal height and width; relatively rare; lines some gland ducts.

Transitional (urinary) epithelium

Multilayered epithelium with dome-shaped apical cells that stretch as the bladder fills; found in the urinary tract.

Gland

Epithelium-derived tissue that secretes substances; can form ducts (exocrine) or release secretions into blood (endocrine).

Exocrine gland

Gland connected to an epithelial surface via a duct; secretions exit onto a surface.

Endocrine gland

Gland that releases secretions (hormones) into the bloodstream; ductless.

Merocrine secretion

Secretions released by exocytosis in vesicles; no loss of cytoplasm.

Apocrine secretion

Secretory product released with the loss of apical cell membrane fragment.

Holocrine secretion

Secretory product released as entire cells disintegrate; whole cells become part of secretion.

Connective tissue

Tissue that links, supports, and protects; abundant ECM; cells dispersed in ECM; stores energy; part of the immune system.

Extracellular matrix (ECM)

Non-cellular component of connective tissue consisting of fibers, ground substance, and fluid that provides structure.

Ground substance

Hydrated gel in the ECM that resists compression and fills space between cells and fibers.

Fibers

Protein components of the ECM: collagen (tensile strength), elastic (elasticity), and reticular (supportive network).

Collagen

Protein providing tensile strength in connective tissue.

Elastic fibers

Fibers that provide stretch and resilience to tissues.

Reticular fibers

Fine fibers forming a supportive network in organs.

Fibroblasts

Cells that synthesize ECM and fibers; main cell type in connective tissue proper.

Adipocytes

Fat cells that store lipids for energy, padding, and insulation.

Macrophages

Immune cells that phagocytose debris and pathogens; orchestrate immune responses.

Mesenchyme

Embryonic connective tissue; source of connective tissues; contains multipotent stem cells.

Connective tissue proper

Connective tissue type including loose and dense forms that bind, support, and fill spaces.

Areolar connective tissue

Loose connective tissue with open framework; binds epithelia to underlying tissues; abundant ground substance and fibers.

Adipose connective tissue

Loose connective tissue specialized for fat storage; provides padding, insulation, and energy storage.

Reticular connective tissue

Loose connective tissue forming a supportive stroma in organs associated with blood/lymph.

Dense connective tissue

Connective tissue with densely packed fibers and little ground substance; includes dense regular and dense irregular types.

Dense regular connective tissue

Fibers arranged in parallel; found in tendons and ligaments; resistant to stress in one direction.

Dense irregular connective tissue

Fibers arranged irregularly; resists stress in multiple directions; found in dermis and organ capsules.

Blood

Fluid connective tissue; cells suspended in a plasma matrix; transports nutrients, gases, and wastes.

Lymph

Fluid connective tissue with dissolved proteins and lymphocytes; drains tissue fluid into the lymphatic system.

Cartilage

Supportive connective tissue with a firm, rubbery matrix; avascular and provides flexible support.

Bone

Rigid connective tissue with a solid, crystalline matrix; supports and protects, stores minerals.

Muscle tissue

Tissue specialized for contraction to produce movement and generate heat.

Skeletal muscle

Striated, multi-nucleated muscle attached to bone; under voluntary control.

Cardiac muscle

Striated, branched muscle with a single nucleus and intercalated discs; involuntary rhythm.

Smooth muscle

Non-striated, spindle-shaped muscle with central nuclei; involuntary, slow, sustained contractions.

Nervous tissue

Tissue that transmits and processes information; composed of neurons and glial cells.

Neuron

Nerve cell with cell body, dendrites, and an axon; conducts electrical impulses.

Glial cells

Supportive cells in the nervous system that protect and nourish neurons.

Central nervous system (CNS)

Brain and spinal cord; processes information and coordinates activity.

Peripheral nervous system (PNS)

Nerves outside the CNS; transmits signals between the CNS and the rest of the body.

Cell body (soma)

Neuron region containing the nucleus and most organelles.

Dendrites

Neuron processes that receive signals and convey them to the cell body.

Axon

Neuron process that transmits impulses away from the cell body to other cells.

Presynaptic terminal

Axon ending where neurotransmitters are released into the synapse.

Myelination

Formation of a myelin sheath around axons to increase conduction speed.