Phys II Flashcards
Contents of the telencephalon
Basal ganglia (nuclei); olfactory lobes and nerves; cerebral hemispheres
Contents of Diencephalon
Epi thalamus; thalamus; hypothalamus and infundibulum
Contents of mesencephalon
Cerebral aquaduct; superior and inferior colliculi; tegmentum
Contents of metencephalon
Cerebellum and pons
Contents of myelencephalon
Medulla oblongata; posterior choroid plexus
Primary motor areas
Direct connections w/ specific muscles
Primary sensory areas
Detect specific sensations
Secondary motor areas
Provide patterns of motor activity
Secondary sensory areas
Analyze meanings of specific sensory signals
Characteristics of tonic receptors
Slow adapting; detect continuous stimulus strength; transmit impulses as long as stimulus is present
Types of tonic receptors
Muscle spindles; Golgi tendon organs; macula and vestibular receptors; baroreceptors; chemoreceptors
What are the neurons that make up the 3-neuron ascending pathways?
Primary sensory neurons: from external receptors; travel through dorsal roots of spinal cord
Secondary neurons: make up tracts in spinal cord and brainstem; neurons typically terminate in thalamus
Tertiary neurons: from thalamus to primary sensory cortex; travel through internal capsule
Anterolateral Spinothalamic Tract
Carries pain and temp; primary fibers ascend or descend 1-2 spinal cord segments before synapses w/ secondary fibers; secondary axons decussate through anterior gray and white commissures; secondary axons make up the lateral Spinothalamic tract traveling in the lateral column of the spinal cord
Medial lemniscuc system
Aka posterior column system; carries sensations for 2-point sensation (fine touch), pressure and vibration; primary fibers ascend entire length of spinal cord and synapse w/ secondary neurons in medulla - fasciculus gracilis and fasciculus cuneatus
Group 1a (type Aalpha) fibers:
Fibers from annulospiral ending of muscle spindles
Group Ib (Aalpha) fibers:
Fibers form Golgi tendon organs
Group II (Abeta, gamma) fibers:
From cutaneous tactile receptor and flower-spray
Group III (Asigma) Fibers:
Carry temp, crude touch, and pricking pain
Group IV (Type C) Fibers:
Carry slow chronic pain, itch, temp, and crude touch
Review Rhodopsin-retinal visual cycle
Slide 9
W Ganglion Cells
Make up about 40% of all ganglion cells; small; transmit signals 8m/sec.; receive most of their excitation from rods transmitted by way of small bipolar cells and amacrine cells; they have broad fields in the peripheral retinal b/c their dendrites spread widely in the inner plexi form layer
X Ganlgion Cells
Make up about 55% of all ganglion cells; medium diameter; transmit signal 14 m/sec; they have small fields - signals represent discrete retinal locations; every X Ganlgion cell receives at input from at least one cone cell; therefore probably responsible for all color vision
Y ganglion cells
Make up about 5% of all ganglion cells; large; transmit signals 50m/sec or faster; respond to rapid changes in visual image; presumably apprise the CNS almost instantaneously when a new visual event occurs anywhere in the field w/o great accuracy w/ respect to location of field `
Hair cells
100 sterorcelia on apical border; longer on the side farther from modiolus; when cilia are bent, a mechanical transduction is created that opens K channels resulting in depolarization of hair cell membrane;
High K concentration in the __________ is related to the resting potential w/I hair cells and generation of action potential
Endolymph
What is the most common cause of congenital deafness?
Inability of the Syria vascular is to conduct K ions into the external fluid
Muscle spindle
3-12 intrafusal fibers - innervated by small gamma motor neurons***; central region has no contractile fibers; functions as a sensory receptor - sensory fibers originate from central region, stretching of central region of intrafusal fiber stimulates sensory fibers; detects changes in muscle length