Anatomical Directional Terms and Biological Concepts

Flashcards covering anatomical directional terms and various biological concepts.

Lateral

Refers to the side of the body, away from the midline.

Medial

Relating to the middle or center; closer to the midline of the body.

Dorsal

Referring to the back side of an organism.

Ventral

Referring to the belly or front side of an organism.

Anterior

The front end or face of an organism.

Posterior

The rear or back end of an organism.

Superior

Above or higher in position.

Inferior

Below or lower in position.

Proximal

Closer to the point of attachment or origin.

Distal

Further away from the point of attachment or origin.

Protostome

An organism in which the mouth develops from the primary embryonic opening.

Deuterostome

An organism in which the anus develops from the primary embryonic opening.

Cephalization

The concentration of sensory organs and nervous system elements at the anterior end of the organism.

Diploblastic

Organisms that develop from two germ layers: ectoderm and endoderm.

Triploblastic

Organisms that develop from three germ layers: ectoderm, mesoderm, and endoderm.

Amorphous (asymmetrical)

Having no specific shape or form; lacking symmetry.

Bilateral symmetry

A body plan that is symmetrical along a central axis.

Radial symmetry

A body plan that is symmetrical around a central axis.

Asexual reproduction

A mode of reproduction that does not involve the fusion of gametes.

Sexual reproduction

A mode of reproduction involving the fusion of male and female gametes.

Hermaphrodite

An organism that has both male and female reproductive organs.

Coelomate (coelom)

An animal that possesses a true body cavity lined with mesoderm.

Acoelomate

An organism that lacks a coelom (body cavity).

Hemocoel

A fluid-filled cavity in certain invertebrates, serving as a secondary body cavity.

Pseudocoelomate (pseudocoelom)

An organism that has a body cavity but it is not completely lined with mesoderm.

Grade vs Clade

Grade refers to a level of organization, while clade refers to a group of organisms that share a common ancestor.

Open circulatory system

A system where blood is not always contained within blood vessels.

Closed circulatory system

A system where blood is contained within blood vessels.

Ventral vs Dorsal nerve cord

Ventral nerve cords are located on the belly side while dorsal nerve cords are on the back side.

Hollow vs Solid nerve cord

Hollow nerve cords have a canal running through, while solid nerve cords do not.

Extra- vs Intracellular digestion

Extracellular digestion occurs outside of cells, intracellular digestion occurs within cells.

Gastrovascular cavity vs Alimentary canal

Gastrovascular cavity is a digestive sac, while alimentary canal is a complete digestive tract.

Hemolymph vs Blood vs Interstitial fluid

Hemolymph is a fluid in open circulatory systems, blood is in closed systems, and interstitial fluid surrounds cells.

Endo- vs Exo- vs Hydrostatic skeleton

Endoskeletons are inside the body, exoskeletons are outside, and hydrostatic skeletons rely on fluid pressure.

Extinct vs Extant

Extinct refers to species that no longer exist, while extant refers to species that are still alive.