Lab 13

structure of neurons

structure of neurons


Kartei Details

Karten 54
Sprache English
Kategorie Biologie
Stufe Universität
Erstellt / Aktualisiert 09.03.2015 / 12.09.2023
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Describe Efferent Nerves

Carry impulses AWAY from the CNS. The ventral roots of the spinal cord are motor nerves.

Describe MIXED NERVES

Carry both afferent and efferent signals - most nerves of the body, including all spinal nerves.

Describe the three tissue shealths of a nerve.

Endoneurium - outter layer of the nerve which insulates it from other neuron processes adjacent to it. Surrounds mylien shealth.

Perineurium - Surrounds groups of axons and is a coarser connective tissue to form bundles of tissue called FASICLES.

Epineurium - Binds all the fasicles together - forming a cordlike nerve.

What are sensory receptors?

Either modified dendritic endings or specialized cells associated with the dendrites that are sensitive to certain environmental stimuli. They react to such stimuli by initiating a nerve impulse.

Name the classifications of sensory receptors by the stimulis they detect.

Exteroceptors, Interoceptors, Proprioceptors.

Describe Exteroceptors -

Respond to stimuli in their external environment and are typically found close to the body surface.

Describe Interoceptors -

Respond to stimuli arising within the body (including the visceral organs).

Describe proprioceptors.

A subclass of interoceptors, are found in skeletal muscles, joints, tendons, and ligaments and report on the degree of stretch in these structures.

Where are cutaneous and proprioceptors located?

Cutaneous - reside in the skin

Proprioceptors - located in skeletal muscles, tendons and join capsules.

What are nonencapsulated free nerve endings?

 

They are endings of sensory neurons which respond chiefly to pain and temperature.

What are tactile epithelial complexs?

Also called merkel discs - they are free nerve endings associated with merkel cells to created merkel discs. Or they entwine in hair follicles to form hair follicle receptors. They generally function as light touch sensors.

Describe the tactile corpuscle

respond to light touch, located in the dermal papillae of hairless skin only.

Describe the Bulbous corpscles.

appear to respond to deep pressure and stretch stimuli.

Describe the lamellar corpsuscles

anatomically more distinctive and lie deepest in the dermis. These receptors respond only when deep pressure is first appplied. Best suited to high-frequency vibrations. Anatomically more distinctive than other receptors.