Ecological diversity: At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has greater ecosystem diversity than a Scandinavian country like Norway.

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#Id: 5618

#Unit 7. System Physiology – Animal

Proprioceptors relay information about muscle length and tension

Chemoreceptor for taste and smell as well as visceral receptors such as those sensitive to changes in the plasma level of O2 , pH, & Osmolality

Photoreceptors respond to light

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#Id: 5619

#Unit 7. System Physiology – Animal

Touch and pressure are sensed by four types of mechanoreceptors:

Meissner’s corpuscles

Merkel cells

Ruffini corpuscles

Pacinian corpuscles

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#Unit 7. System Physiology – Animal

The sensory nerves from mechanoreceptors are large myelinated Aα and Aβ fibers whose conduction velocities range from ∼70–120 & ∼40–75 m/s, respectively.

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#Id: 5621

#Unit 7. System Physiology – Animal

Impulses from nociceptors are transmitted via two

fiber types:

Thinly myelinated Aδ fibers (2–5 μm in diameter) that conduct at rates of ∼12–35 m/s 

Unmyelinated C fibers (0.4–1.2 μm in diameter) that conduct at low rates of ∼0.5–2 m/s

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#Unit 7. System Physiology – Animal

Activation of Aδ fibers, which release glutamate, is responsible for first pain (also called fast pain or epicritic pain)

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#Id: 5623

#Unit 7. System Physiology – Animal

When a small amount of pressure is applied to the Pacinian corpuscle, a nonpropagated depolarizing potential resembling an excitatory postsynaptic potential (EPSP) is recorded. This is called the generator potential or receptor potential