Comparative Anatomy

Skin is one cell layer with mucus gland

No bones - hydrostatic support

Longitudinal and circular muscles; each segments muscles are independant of the other segments

A pair of nephrida per segment

Through skin

Closed, using hemoglobin as oxygen carriers - aortic arches are pumps

Dorsal brains; ventral nerve cord, with ganglia in each segment

Hormones secreted by nervous system

Male and female parts both present

Mouth, pharynx, esophogus, crop, gizzard, intestine, anus

Gills used for gas exchange

2-chambered heart (no separation of oxygenated and deoxygenated)

Usually externally fertilized

Kidney

Kidney

Nephridia

Two chambered heart

Four chambered heart

Aortic arches

Mostly external

Internal

Hermaphrodites (asexual)

Externally (mostly)

Internally

Externally

Lines most body surfaces, protects tissues from dehydration

Involuntary muscle found in the heart, continuously pulsing to pump blood through the body.

Involuntary muscle that lines the walls of blood vessels and hollow organs

Includes fat, tendons, cartilage, bone, and blood; supports, protects, and insulates the body

In the nerves; triggered by a nerve impulse at an axon terminal of a presynaptic neuron as part of the signal (?)

Filter fluid from the blood, then concentrate the metabolic wastes and excrete them as concentrated urine; also regulate the water content of the body

Oxygen from the air is exchanged with CO2 from the blood

Protects the body from injury, provides the first line of defense against disease, helps regulate body temperature, and prevents the body from drying our through evaporation.

Act as holding places for food, as well as acts as part of the digestion process (?)

Controls blood sugar, modifies amino acids, monitors the production of cholesterol, and detoxifies poisons

Secretes hormones for controlling blood sugar

Pump blood throughout the body

Extracts and absorbs nutrients from food; removes wastes; maintains water and chemical balances

Transport nutrients, wastes, hormones, and gases

Collect extracellular fluid and return it to the blood

Protects and supports the body and organs; interacts with skeletal muscles, produces red blood cells, white blood cells, and platelets

Regulates body temperature, metabolism, development, and reproduction; maintains homeostasis; regulates other organ systems; hormones

Produces gametes and offspring

Protects against injury, infection, and fluid loss; helps regulate body temperature

Moves air into and out of lungs; controls gas exchange between blood and lungs