Comprehensive coloured illustrations of the different organs, tissues and structures organised into groups of general function and or purpose. Top left provides the cardio-respiratory system, top right the digestive system and associated vasculature, bottom left the nervous system, focussing on the network and organisation, and the bottom right shows the sensory structures of the peripheral nervous system.
A typical circulatory system of the class Amphibia. Note the three chambered heart (most visible in 4) where oxygenated blood (from capillaries in gills, lungs and/or skin) and de-oxygenated blood from systemic tissues mix in the ventricle before returning to both sets of tissues via a fork in the aorta. The heart is shown in two views looking both at the ventral (2) and dorsal (3) surfaces.
The central nervous system of a stereotypical amphibian. An entire dorsal dissection of a brain (1) shows the cerebral hemispheres (Hem), the optic lobes (C. big), the cerebellum (Crbl) and the medulla oblangata (M. obl) amongst other strutctures. The other views represented are a horizontal longitudinal section (2), a vertical longitudinal section (3), an entire ventral dissection with circulatory and digestive systems pulled to the right side (4), partial ventral dissection of M. obl and C. big with hypothalamus removed (5), a cross section of the spinal cord with associated nerves and ganglia (6) and a representation of a mechanosensory hair cell receptor (7) showing neurons associated with “hairs” contained within a flexible gell cap.
The Cephalochordata are most known for their relation to basal vertebrates. The adult from provides insight in to intermediary structures between invertebrates as they are one step closer to the Vertebrata than the Tunicates. This Chart shows stages through development (1 – 12) with tissue derived from the ectoderm coloured grey, from the endoderm coloured grey-green and the mesoderm coloured yellow. Using the longitudinal section of the adult (14) note the four typical chordate features the pharyngeal gill slits (SF), dorsal, hollow nerve cord (starting at NP), notochord (Ch) and post-anal tail (posterior to A).
Skeletal components of the now obsolete Order of extinct mammals the Amblypoda showing: Coryphodon skulls (1 & 2), feet (3 & 4) and cheek teeth (5 & 6); Dinoceras skulls (7 & 8), feet (9 & 10) and cheek teeth (11 & 12). Note the similar structure of the feet which was incorrectly used to define this obsolete group (ambly – dull or blunt; poda – feet) from fossil evidence.
Initially this group was divided into those that lived solitarily and those that lived colonially. Now considered as a single class the Ascidians are typical tunicates often referred to as sea squirts. Their developmental forms (11 – 13) maintain the four main characteristics of chordates (blue; dorsal hollow nerve chord, gold; notochord, pharyngeal gill slits and post anal tail both not represented here) however as an adult many of these have been reduced or lost to suit their sedentary, filter feeding niche. The large majority of space is taken up by the pharynx (4 & 10) which is used to filter particulate organic matter from water moved through the siphons by cilia. Ascidians have a closed circulatory system (2, red) with a heart that can switch direction. Gametes and feaces are transported from the base of the adult to the outside of the pharynx (10, r & a) where they are carried by water currents out of the ex-current siphon.
Anatomy of members of the Class Thaliacea showing: internal structures through transluscent bodies, variation of individual body plans (1, 3, 4, 6, 7 & 8′) and arrangements of colonies (5 & 10). The general body plan is of seiving structures held within a tubular pharynx where water is funnelled for food, respiration and propulsion. Note the muscle banding used to create water flow and the centralisation of nervous tissue (labelled N) which is indicative of their place within the Chordata.