General Biology 1: Plant and Animal Tissues

Vocabulary terms and definitions covering animal tissue types, collagen structures, neuron classifications, neurotransmitters, and plant tissue systems from General Biology 1.

Somatic Cells

Major type of animal cells referring to body cells.

Germinal Cells

Major type of animal cells referring to sex cells.

Embryonic Tissue

Any tissue that arises from the fertilization of an ovum and has not become differentiated or specialized.

Embryonic Stem Cells

Tissue in an embryo that produces all tissues during growth.

Adult Stem Cells

Tissue in an adult that produces new tissue cells to replace old and damaged ones.

Permanent Tissue (Animal)

Tissue consisting of four major animal tissue types: epithelial, connective, muscle, and nervous tissue.

Epithelial Tissue

Tissue commonly seen as coverings and linings of organs and cavities, characterized by closely-joined and tightly packed cells.

Simple Squamous Epithelium

Flat epithelial cells with a non-regular outline closely fitted together to form a sheet; prevalent in alveoli, endothelium of blood vessels, and mesothelium of body cavities.

Simple Cuboidal Epithelium

Tissue with a box-shaped structure featuring a brush border in its cell lining, usually found in the kidneys.

Simple Columnar Epithelium

Cylindrical epithelial tissue with a noticeable height that contains goblet cells which secrete mucus; normally found in the stomach.

Stratified Squamous Epithelium

A multilayer of cell groups often found in the skin that protects from bacterial invasion; can be keratinized or non-keratinized.

Stratified Cuboidal Epithelium

Multilayered cube-shaped cells fused together in some glands.

Pseudostratified Columnar Epithelium

A single layer of cells serving as the lining for the respiratory tract.

Muscle Tissue

Tissue composed of long cells called muscle fiber cells that allow the body to move voluntarily or involuntarily.

Skeletal Muscle

Striated and voluntary muscle tissue.

Cardiac Muscle

Striated, involuntary muscle tissue containing intercalated disks for synchronized heart contraction.

Smooth Muscle

Non-striated and involuntary muscle tissue.

Connective Tissue

Group of tissues that maintain the form of the body and its organs, providing cohesion, support, protection, transportation, repair, hematopoiesis, and immunological responses.

Collagen

Key building block protein forming connective fibers in skin, ligaments, cartilage, bones, and teeth, providing support, shape, and bulk to blood vessels, bones, and organs.

Type I Collagen

Collagen type located in bone, skin, dentin, cornea, blood vessels, fibrocartilage, and tendon.

Type II Collagen

Collagen type located in cartilaginous tissues (elastic cartilage) and the vitreous body of the eye.

Type III Collagen

Collagen type located in ligaments, blood vessels, internal organs, and papillary layers of the dermis.

Type IV Collagen

Collagen type located in the basement membrane in various tissues.

Type V Collagen

Collagen type located in blood vessel walls, synovium, corneal stroma, tendon, lung, bone, cartilage, and skeletal muscle.

Fasciae

Collagenous connective tissue containing loose connective tissue.

Tendons

Collagenous connective tissue containing dense, regular connective tissue.

Periosteum

Collagenous connective tissue containing dense, irregular connective tissue.

Reticular Connective Tissues

Connective tissues structurally made of type III collagen, usually found in the supporting structure of hematopoietic and lymphoid organs.

Elastic Connective Tissues

Connective tissues structurally made of type II collagen containing retractile fibers with elastin, usually found in the trachea, bronchi, and blood vessels.

Blood

Connective tissue with special properties made up of plasma matrix, containing erythrocytes, leukocytes, and thrombocytes.

Erythrocytes

Red blood cells (RBC) in blood that carry oxygen.

Leukocytes

White blood cells (WBC) in blood used for defense.

Thrombocytes

Platelets in blood responsible for blood clotting.

Cartilage

Connective tissue with special properties characterized by collagenous fibers embedded in chondroitin sulfate, which functions as a cushion for bones.

Chondrocytes

Cells that secrete collagen and chondroitin sulfate in cartilage.

Bone

Mineralized connective tissue made of osteoblasts depositing collagen combined with calcium, magnesium, and phosphate ions.

Osteoblasts

Bone-forming cells that deposit collagen.

Neurons

Nerve cells in nervous tissue that sense stimuli and transmit electrical signals throughout the animal body.

Glial Cells

Cells in nervous tissue that function as support cells.

Sensory Neuron

Neuron responsible for transmitting signals from the environment or body parts to the Central Nervous System (CNS).

Relay Neuron (Interneuron)

Neuron responsible for the integration and processing of signals.

Motor Neurons

Neurons that command effector organs.

Local Interneurons

Small neurons whose axons are connected within a specific area of the brain.

Projection Interneuron (Excitatory)

Neurons with long axons projecting to distant targets or other brain regions.

Excitatory Neurotransmitters

Chemical messengers that excite neurons and cause them to fire off messages; examples include glutamate, epinephrine, norepinephrine, and dopamine.

Inhibitory Neurotransmitters

Chemical messengers that block or prevent messages from being passed farther; examples include Gamma-aminobutyric acid (GABA), endorphins, and serotonin.

Plant Tissues

Tissues whose primary function is to give structural support to stationary plants.

Meristematic Tissues

Plant tissues consisting of immature, actively dividing cells (meristems) responsible for cell production and increasing plant length and thickness.

Apical Meristem

Meristem present at growing tips of stems and roots responsible for linear, primary growth by increasing length.

Lateral Meristem (Secondary Meristem)

Meristem located beneath the bark that divides mainly in one plane, increasing organ diameter and driving secondary growth.

Intercalary Meristem

Meristem located between permanent tissues (at base of nodes, internodes, and leaf bases) that aids in vertical growth.

Simple Permanent Tissues

Group of non-dividing plant cells similar in origin, structure, and function; includes parenchyma, collenchyma, and sclerenchyma.

Parenchyma

Simple permanent tissue that provides support to plants and stores food.

Chlorenchyma

A type of parenchyma that contains chlorophyll and performs photosynthesis.

Aerenchyma

A type of parenchyma in aquatic plants containing large air cavities to assist floating.

Collenchyma

Simple permanent tissue that provides tensile strength; cells are compactly arranged with little intercellular space and are absent in monocots and roots.

Sclerenchyma

Simple permanent tissue composed of thick-walled, dead cells with thick secondary walls containing uniformly distributed lignin.

Lignin

A complex organic polymer in plant cell walls that makes them rigid and woody.

Complex Permanent Tissues (Vascular Tissues)

Tissues consisting of multiple cell types working as a unit to transport organic material, water, and minerals throughout the plant.

Xylem

Complex vascular tissue containing trachea elements that conveys water and dissolved minerals from roots to the rest of the plant.

Phloem

Complex vascular tissue made of sieve tubes, companion cells, phloem fibers, and phloem parenchyma cells that conducts food from leaves to all other plant parts.

Surface Tissues

The outer-covering tissues of plants, categorized into epidermis and periderm.

Epidermis

Outermost layer of cells of all young plant organs.

Periderm

Multilayered cell structure that replaces the epidermis in mature plants for added protection.