The primitive streak defines the major body axes of the avian embryo. 

TLS Online TPP Program

#Id: 1193

#Unit 7. System Physiology – Animal

The responses of the bipolar cells are either hyperpolarizing or depolarizing potential

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#Id: 1194

#Unit 7. System Physiology – Animal

The responses of amacrine cells produce depolarizing potential

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#Id: 5617

#Unit 7. System Physiology – Animal

Somatosensory receptors are divided into the major groups of receptors according to specific sensation: 

Mechanoreceptors (for touch and proprioception)

Thermoreceptors (for temperature)

Nociceptors (for pain or noxious stimuli)

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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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#Id: 5620

#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.