Question

For spiders,

does it have teeth, tentacles, beak or other structures to eat with?

Is the gut short and straight or convoluted and long?

what structures are used for gas exchange?
how does the animal move air or water to assist gas exchange?

is the vascular system open or closed?

how many hearts?

how many chambers per heart?

does the blood have a pigment?

Are there any similarities in spiders that one sees across other species that are likely related to their functions?

Answer 1

Spiders are arthropods belonging to class Arachnida, with numerous species of around 48,000 distributed globally in nearly every habitat(ecosystem) with few exceptions. The anatomy and physiology of spiders resembles other archanids but also have some other special characteristic features as well.  

Unlike insects, their body is divided into two main parts- (i) prosoma (cephalothorax) (ii) opisthosoma (abdomen)

It is the prosoma or cephalothorax which bears different pair of appendages. Generally, the chelicerae, the pedipalps and four pair of legs are present in this region including the eyes.

Eating mechanism of spiders- The chelicerae and the pedipalps are involed in this action. The pair of chelicerae terminate in fangs, which inject venomous secretions on the prey. Posterior to these chelicareae the pair of pedipalps are present which helps in sensing, grasping or handling the prey. The venomous secretion kills the prey and pre digestion starts at this point, gradually liquidising the food. These liquidized food is then sucked up through the mouth opening located between the chelicerae.   

Digestive tract of the spiders- The digestive tract starts in the prosoma which consists of esophagus, sucking stomach and digestive caecum. Then it goes along to the abdomen starting with intestine, digestive tubules, a sac where excretory organs (the malphigian tubules) open and finally terminates with the anus.

Respiratory organs of the spiders- The book lungs are present in spiders for gas exchange. It is present inside the abdomen. Leaf-like lamellae are projected from the air filled cavities. Blood or haemolymph circulates within these lamellae and gaseous exchange between blood and air occur through their thin walls. In some spiders there are two pairs of book lungs, whereas some possess a single pair of book lungs, the second pair is replaced by tracheal tubes which are divided throughout the body.  

Circulatory system in spiders- The spiders have open circlulatory system. They don't have true blood. The body circulates haemolymph, which is pumped through arteries by a heart. The heart is not divided into chambers.

Yes, the blood i.e. the haemolymph contains a pigment called haemocyanin which contains two copper atoms giving it a slight faint blue color. These haemocyanin resembles haemoglobin in its function.

Yes, there are similarities in spiders with some other species that are likely related to their function. For example, scorpions, opiliones etc.