Structural Organisation in Animals Flashcards

Vocabulary flashcards on Structural Organisation in Animals, covering epithelial, connective, muscular, and neural tissues alongside the anatomy and morphology of earthworms, cockroaches, and frogs.

Histology

The study of tissues in organisms.

Simple Squamous Epithelium

A single thin layer of flattened cells with irregular boundaries, also called pavement epithelium due to its tile-like appearance, involved in filtration and diffusion.

Simple Cuboidal Epithelium

A tissue consisting of a single layer of cube-like cells resting on a basement membrane with centrally located nuclei, functioning in secretion, absorption, and excretion.

Simple Columnar Epithelium

A tissue composed of a single layer of tall and slender cells with nuclei located at the base, primarily involved in secretion and absorption.

Ciliated Epithelium

Columnar or cuboidal cells bearing cilia on their free surface that function to move particles or mucus in a specific direction over the epithelium.

Pseudostratified Epithelium

A single layer of irregularly shaped columnar cells that touch the basement membrane but give the appearance of a multi-layered epithelium due to varying cell heights and nuclear levels.

Compound Epithelium

Epithelium formed of two or more cell layers with a limited role in secretion and absorption, primarily functioning to protect against chemical and mechanical stresses.

Transitional Epithelium

A stretchable compound epithelium lacking a basement membrane in which the innermost cube-like cells directly rest on underlying connective tissue.

Tight Junction (Zona occludens)

An occluding junction where plasma membranes of adjacent cells are tightly packed or fused together to prevent substances from leaking across a tissue.

Adhering Junction (Adherens junction)

An anchoring cell junction that performs cementing to hold neighbouring cells together.

Gap Junction

A communication junction connecting the cytoplasm of adjoining cells to allow rapid intercellular communication and transfer of ions, small molecules, and big molecules.

Areolar Tissue

A type of loose connective tissue beneath the skin possessing a transparent, gelatinous, highly vascular matrix containing fibroblasts, macrophages, and mast cells.

Mast Cells

Large, irregular ovoid cells in areolar tissue that secrete histamine (vasodilator), serotonin (vasoconstrictor), and heparin (anticoagulant).

Tendons

Dense regular connective tissues that join muscles to bones.

Ligaments

Dense regular connective tissues that join bone to bone.

Chondroblasts

Active, cartilage-producing cells arranged on the periphery of cartilage.

Chondrocytes

Mature cartilage cells located in vacuole-like spaces within the matrix called lacunae.

Skeletal Muscle Tissue

Voluntary, striated muscle tissue composed of long cylindrical fibres bundled together in a parallel fashion, closely attached to skeletal bones.

Smooth Muscle Tissue

Involuntary, non-striated muscle tissue with fusiform (tapered) fibres located in the walls of internal organs such as blood vessels, stomach, and intestine.

Cardiac Muscle Tissue

Involuntary, striated contractile muscle tissue present only in the heart, featuring intercalated discs that allow cells to contract as a single unit.

Neuroglia

Non-excitable neural system cells that protect and support neurons, constituting more than 50% of the volume of neural tissue.

Prostomium

A sensory lobe at the anterior end of an earthworm that covers the mouth and acts as a wedge to force open soil cracks.

Peristomium

The first body segment of an earthworm containing the mouth.

Clitellum

A prominent dark band of glandular tissue covering segments 14 to 16 in a mature earthworm.

Typhlosole

An internal median fold of the dorsal wall in an earthworm's intestine present after segment 26 that increases effective absorption area.

Vermicomposting

The process of increasing soil fertility using earthworms, which make soil porous by forming burrows.

Sclerites

Hardened chitinous plates (tergites dorsally and sternites ventrally) forming the exoskeleton in each segment of a cockroach.

Arthrodial Membrane

A thin, flexible articular membrane that joins adjacent sclerites in a cockroach.

Hypopharynx

A median flexible lobe acting as a tongue within the cavity enclosed by a cockroach's mouthparts.

Tegmina

Opaque, dark, and leathery mesothoracic forewings of a cockroach that cover the hindwings at rest.

Gizzard (Proventriculus)

A structure in the foregut of a cockroach featuring thick circular muscles and a cuticular lining with six chitinous teeth used for grinding food.

Hepatic Caecae

A ring of 6 to 8 blind tubules at the junction of the foregut and midgut in cockroaches that secretes digestive juice.

Malpighian Tubules

A ring of 100 to 150 yellow-coloured, thin filamentous tubules at the junction of midgut and hindgut in cockroaches that extracts nitrogenous waste from haemolymph.

Ommatidia

Hexagonal visual units (about 2000 per compound eye) in cockroaches that produce mosaic vision.

Paurometabolous Development

Development through a series of nymphal stages where nymphs grow by moulting (about 13 times in Periplaneta americana) to reach the adult form.

Aestivation

Summer sleep taken by cold-blooded animals like frogs in deep burrows to survive extreme heat.

Hibernation

Winter sleep taken by cold-blooded animals like frogs in deep burrows to survive extreme cold.

Mesorchium

A double fold of peritoneum that attaches the testes of a male frog to the upper part of its kidneys.