(E2) 1 - Body Sensation Flashcards
What sensations do human respond to?
External (exteroception) and Internal (interoception)
What is exteroception?
What is interoception?
What are the 4 different structural classifications of neurons and describe them.
Sensory Neurons: Peripheral process/branch contain ____
Specific Receptors
Sensory Neurons: Central Process/Branch project to _____
Central Nervous System
Sensory information from the body is conveyed via ________ neurons with cell bodies located in ________.
- pseudounipolar
- dorsal root (spinal) ganglia
Central processes form ______
Dorsal Roots
Peripheral process courses from _____
receptors
Classification of Sensory Fibers in Peripheral Nerves
(Name the 4 types and their associated cutaneous nerves)
Information can travel faster in what types of axons?
Larger Diameter and Myelinated Axons
Smaller diameter axons convey _______
information
painful
Largest diameter axons convey ______
muscle & joint information for muscle nerves and types of touch for cutaneous nerves
What receptors do humans have?
- Mechanoreceptors
- Chemoreceptors
- Thermoreceptors
Describe Mechanoreceptors.
Describe Thermoreceptors.
Describe Chemoreceptors
What unencapsulated nerve endings?
Free nerve endings
What are encapsulated nerve endings?
How many mechanoreceptors are found on glabrous skin?
Touch receptors are found throughout the skin. Many axons join to form the ________
peripheral nerve bundle
Describe Meissner corpuscle
(fiber type, detection, field size)
Describe Merkel cells.
(fiber type, detection, field size)
Describe Pacinian corpuscle
(fiber type, detection, field size)
Describe Ruffini corpuscle
(fiber type, detection, field size)
Ruddini and Pacinian corpuscles are considered ______ and are found in ________
- deep mechanoreceptors
- dermis, fascia, and periodontium
________ detect muscle length and other contractile properties
Muscle spindles
What are the 2 types of skeletal muscle fibers (and if they have subtypes)
Describe Type Ia fibers (annulospiral)
Describe Type II fibers (secondary ending, flower-spray ending)
What are Golgi Tendon Organs?
Most motor axons terminate at _____ spinal cord
cervical
More_____ matter in cervical region than sacral region
white
Regions of most gray matter corresponds to _____
limbs
Few sensory axons enter the ____ spinal cord
sacral
Fibers are _______ organized throughout the central nervous system
somatotopically
Image - Somatotopic organization of the posterior columns
Pathway: What is the dorsal-column medial lemniscus system?
What is the posterior funiculus?
large region of white matter
- it is divided into two columns
(funiculus - large collection of fibers)
What is this?
Posterior dorsal columns
Describe the dorsal columns and their location in relation to each other
Dorsal-column medial lemniscus system: Where is cell body #1 found?
DRG
Dorsal-column medial lemniscus system: Where is cellbody #2 found?
Characteristics of DC-IML
What axons from mechanoreceptors in the body form the dorsal column?
DC-IML: Peripheral process have ____ receptors
sensory
DC-IML - Central process axons enter ____
spinal cord
DC-IML - Some synapses occur locally in spinal cord but most axons _________
ascend in posterior funiculus as posterior column
DC-IML: Forms _____ fasciculus - more medial
Gracile
DC-IML: 1st neuron is below T6 is coming from ____
lower limb and lower trunk
DC-IML: 1st neuron at T6 and above is coming from ________
upper limb and upper trunk
DC-IML: Forms _____ fasciculus - more lateral
Cuneate
DC-IML: 1st neuron synapses in the ______ on either ________
DC-IML: 2nd neurons are in the ________
Gracile and Cuneate nuclei
DC-IML: Describe the course of axons in the 2 neurons - what are they called?
DC-IML: 2nd neuron axons that are contralateral form _____
Medial Lemniscus
Describe the position of the medial lemniscus in the brainstem
DC-IML: 3rd neuron is located in the ______
DC-IML: 3rd neuron axons pass through _____ to ________
Image - Posterior Limb of Internal Capsule
What is the Spinothalamic Tract and what does it convey?
STT: 1st neuron cell body in ______
DRG
STT: Peripheral process has ____ receptor or ______
STT: Central processes enter spinal cord and synapse _____
within dorsal horn
(different from DC-IML pathway)
_________ fibers are unmyelinated or have little myelin and also ascend or descend 1 or 2 levels before synapsing in dorsal horn
Pain and temperature
Pain and temperature fibers pass through _____
Posterolateral Tract (lissauer’s tract)
Image - Cytoarchitecture of SC - Lamina
STT: 2nd neuron has cell body in ______
Lamina I and V of dorsal horn
STT: 2nd neuron decussates at _______ and forms _______
STT: 3rd neuron has cell body in _______
VPL of thalamus
STT: 3rd neuron axons project through _______ and to _______
Some spinothalamic axons (2nd neuron) project to other areas. What are they?
What is the periaqueductal gray?
