Animal Tissues: Types, Structure, and Function

Comprehensive vocabulary flashcards covering the characteristics, classification, locations, and functions of animal tissues (epithelial, connective, muscular, and nervous).

Cell Differentiation

The process by which cells, initially identical following division by mitosis, specialize in structure to carry out specific functions.

Epithelial Tissue

Tissue arranged tightly with virtually no intercellular spaces that covers internal and external body surfaces and rests on a basal membrane.

Simple Epithelium

An epithelial tissue arrangement consisting of a single layer of cells.

Stratified Epithelium

An epithelial tissue arrangement consisting of more than one layer of cells.

Pseudostratified Epithelium

An epithelial tissue arrangement that appears to comprise multiple cellular layers but actually consists of only a single layer.

Squamous Epithelium

Tissue composed of thin, flat cells tightly packed into a mosaic pattern; lines the internal walls of cavities such as the mouth, heart, and alveoli to protect underlying tissues and permit permeability.

Cuboidal Epithelium

Tissue composed of more or less cube-shaped cells with round, centrally placed nuclei; lines glands to perform secretion and absorption.

Columnar Epithelium

Tissue composed of elongated, column-shaped cells with elongated nuclei situated near their base; lines the alimentary canal for secretion, absorption, and sensation.

Goblet Cell

A specialized cell found within columnar and ciliated epithelium that secretes mucus.

Ciliated Epithelium

Epithelium made of columnar cells bearing fine cilia that perform fast, rhythmical, directional movements to trap and move dust particles, detect stimuli, or move ova in Fallopian tubes.

Connective Tissue

Tissue that binds, supports, or surrounds other tissues and organs, characterized by cells, fibres, and an intercellular non-living matrix that can be fluid, semi-fluid, or solid.

Areolar Connective Tissue

A packing connective tissue containing elastic and collagen fibres in a jelly-like matrix; forms a continuous insulating layer between the skin and underlying muscles to prevent heat loss.

Tendon

A type of dense connective tissue containing a predominant number of white, inelastic fibres that joins muscle to bone to enable movement during contraction and relaxation.

Ligament

A type of dense connective tissue containing a large number of yellow, elastic fibres that joins bone to bone to permit movement in joints.

Chondrin

The tough, rubbery protein matrix found in cartilage tissue.

Lacunae

Fluid-filled spaces within the extracellular matrix of cartilage and bone where chondrocytes or osteocytes reside.

Chondrocytes

Mature cartilage cells located within lacunae.

Perichondrium

The outer membrane that encloses cartilage tissue.

Hyaline Cartilage

An elastic form of cartilage that lines joints, prevents bone-on-bone friction, occurs in the larynx, and gives shape to structures.

Fibrous Cartilage

An intermediate form of cartilage containing many collagen fibres; forms intervertebral discs and prevents friction between tendons and bones.

Elastic Cartilage

A cartilage type characterized by numerous yellow elastic fibres in its matrix; forms permanent structures such as the external ear pinna and the epiglottis.

Osteocyte

A bone cell located inside a lacuna within a hard matrix made of calcium phosphate and calcium carbonate.

Plasma

The liquid matrix of blood making up approximately $55\%$ of whole blood volume; carries dissolved salts, water, blood proteins, nutrients, gases, and organic wastes.

Buffy Coat

The thin intermediate layer formed after centrifuging blood, constituting approximately $1\%$ of whole blood, containing white blood cells (leukocytes) and platelets.

Granulocytes

The subgroup of leukocytes consisting of neutrophils, basophils, and eosinophils.

Agranulocytes

The subgroup of leukocytes consisting of lymphocytes and monocytes.

Skeletal Muscle Tissue

Voluntary, striated muscle tissue attached to bone; composed of long, cylindrical, multinucleated fibres that work in pairs to produce coordinated movement.

Smooth Muscle Tissue

Involuntary, non-striated muscle tissue composed of spindle-shaped cells with a single nucleus; found in organs like the bladder and intestines to drive slow rhythmic peristalsis and blood flow.

Cardiac Muscle Tissue

Involuntary, branched muscle tissue found exclusively in the heart wall, featuring single central nuclei and muscular bridges connecting cells so they function as a unit.

Automatism

The inherent property of cardiac muscle enabling continuous, uninterrupted, involuntary contraction and relaxation.

Neuron

An elongated nerve cell consisting of a central cell body (soma) and cytoplasmic outgrowths specialized for receiving and conducting impulses.

Dendrites

The branched cytoplasmic projections of a neuron that receive impulses and direct them toward the cell body.

Axon

A single elongated cylinder of groundplasm covered by neurilemma and a myelin sheath that conducts nerve impulses away from the cell body.

Nodes of Ranvier

Periodic interruptions or gaps in the myelin sheath along the length of an axon.

Motor Neuron

A neuron that conducts nerve impulses from the central nervous system to effectors, such as muscles.

Sensory Neuron

A neuron that receives impulses from sensory receptors and carries them toward the central nervous system.

Structural Neuron Classification

The categorization of neurons based on morphology: bipolar (two extensions, one axon and one dendrite), unipolar (one process extending from the cell body), and multipolar (many dendrites and a single axon).

Synaptic Transmission

The chemical process whereby a nerve impulse travels across the synaptic gap from the presynaptic axon terminal to neurotransmitter receptors on the postsynaptic neuron via neurotransmitters.