What does a tick's head look like inside the body? - briefly
Inside the tick, the capitulum (mouthparts) is a compact, hardened structure located at the anterior ventral surface, hidden beneath the dorsal shield. It comprises the hypostome, chelicerae, and pedipalps, forming a cone‑shaped apparatus for attachment and feeding.
What does a tick's head look like inside the body? - in detail
The cephalic region of a feeding arachnid is composed of a compact assembly of mouthparts that penetrate the host’s dermis. The primary structure, the «capitulum», houses the chelicerae, palps, and the hypostome. The chelicerae are short, blade‑like appendages that cut the epidermal surface, creating a small incision. The palps, situated laterally, function as sensory organs and assist in anchoring the organism to the host tissue.
The hypostome projects ventrally from the capitulum and bears numerous backward‑pointing barbs. These barbs embed in the host’s connective tissue, preventing dislodgement during prolonged feeding. When the tick becomes engorged, the capitulum remains visible as a tiny, dark protrusion at the attachment site, usually measuring less than 0.5 mm in length.
Internally, the mouthparts are linked to a series of ducts that deliver saliva and anticoagulant compounds. The salivary glands extend from the opisthosoma into the capitulum, forming a network of tubes that open at the cheliceral bases. This arrangement enables continuous injection of pharmacologically active substances while blood is drawn through the pharyngeal tube, which runs posterior to the hypostome.
During the feeding process, the tick’s musculature contracts rhythmically, creating negative pressure that draws blood into the dilated midgut. The midgut expands dramatically, accommodating volumes up to 100 times the unfed weight, while the head structures remain fixed in place. The visibility of the head after engorgement is limited to the external tip of the capitulum; the remainder of the feeding apparatus is concealed within the host’s tissue.
Key anatomical features observable at the attachment site:
- «Capitulum»: central hub of mouthparts, dark and minute.
- Chelicerae: cutting blades that initiate the lesion.
- Palps: sensory appendages flanking the capitulum.
- Hypostome: barbed anchoring organ, oriented toward the host’s interior.
- Salivary duct openings: minute pores at the cheliceral bases.
Understanding the morphology of these components clarifies how the tick maintains a secure connection and efficiently extracts blood while remaining largely invisible beneath the host’s skin.