Animal Anatomy & Physiology Flashcards

The compound eye of insects produces what type of visual image?

Answer: A mosaic image composed of inputs from many individual ommatidia

Each ommatidium contributes a pixel-like unit to produce a mosaic image; resolution is low but motion detection and wide field of view are exceptional.

Malpighian tubules open into the insect gut at the junction of which two regions?

Answer: Midgut and hindgut

Malpighian tubules empty at the midgut–hindgut junction, depositing waste ions and uric acid for reabsorption or excretion in the rectum.

Which insect hormone triggers molting by stimulating synthesis of new cuticle?

Answer: Ecdysone (20-hydroxyecdysone)

20-hydroxyecdysone (the active form of ecdysone) initiates the molting process by activating genes that produce new cuticle beneath the old.

The tympanal organ in insects such as crickets and moths primarily functions as:

Answer: An auditory organ detecting airborne sound waves

Tympanal organs are thin cuticular membranes backed by air sacs that vibrate in response to airborne sound and are innervated by mechanosensory neurons.

In insects, the dorsal vessel (heart) pumps hemolymph in which direction?

Answer: Anteriorly toward the head

The dorsal vessel pumps hemolymph anteriorly; it then flows freely through body cavities (hemocoel) back toward the abdomen.

Sclerotization of insect cuticle is mediated by cross-linking of proteins using which compound?

Answer: Quinones derived from N-acetyldopamine

Quinone tanning (sclerotization) involves oxidized catecholamines such as N-acetyldopamine cross-linking cuticular proteins, hardening and darkening the exoskeleton.

Which region of the insect midgut is most responsible for nutrient absorption?

Answer: Gastric caeca and the main midgut epithelium

Gastric caeca dramatically increase midgut surface area, and together with the midgut epithelium they are the primary sites of nutrient uptake.