Autonomic Nervous system Flashcards
Sympathetic effect on Eyes
Pupillary dilation (α1)
Sympathetic effect on Salivary glands
Increased thick, viscous secretions
Sympathetic effect on Bronchioles
Bronchodilation (β2), ↑ secretions
Sympathetic effect on Heart
Tachycardia (β1), ↑ contractility (β1), ↑ AV nodal conduction (β1)
Sympathetic effect on Vascular smooth muscle
Vasoconstriction of cutaneous mucous membrane and splanchnic vessels (α1); vasodilation in skeletal muscle (β2)
Sympathetic effect on Gastrointestinal (GI) tract
↓ Muscle motility and tone (β2), contraction of sphincters (α1)
Sympathetic effect on Male sex organs
Ejaculation (α2)
Sympathetic effect on Uterus
Relaxation (β2), contraction (α1)
Sympathetic effect on Bladder and ureters
Relaxation of detrusor (β2) contraction of trigone and sphincter (α1)
Sympathetic effect on Sweat glands
↑ Secretions (muscarinic)
Sympathetic effect on Kidneys
↑ Renin secretion
Sympathetic effect on Adipocytes
↑ Lipolysis (β1)
Sympathetic effect on Pancreas
↓ Insulin secretion (α2), ↑ insulin secretion (β2)
Parasympathetic effect on Eyes
Pupillary constriction
Parasympathetic effect on Bronchioles
Bronchoconstriction
Parasympathetic effect on Heart
Bradycardia, ↓ contractility, ↓ AV nodal conduction
Parasympathetic effect on GI tract
↑ Motility, relaxation of sphincters
Parasympathetic effect on Male sex organs
Erection
Parasympathetic effect on Bladder and ureters
Contraction of detrusor, relaxation of sphincters and trigone
What type of cholinergic receptor mediates all of the effects of the parasympathetic nervous system?
Muscarinic
What type of motor fiber innervates extrafusal muscle fibers?
A-alpha (A-α)
What type of motor fiber innervates intrafusal muscle fibers?
A-gamma (A-γ)
What is the function of Ia (A-α) fibers
Proprioception, muscle spindles
What is the function of Ib fibers
Proprioception, Golgi tendon organs
What is the function of II (A-β) fibers
Touch, pressure, and vibration; secondary afferents of muscle spindles
What is the function of III (A-δ) fibers
Touch, pressure, fast pain, and temperature
What is the function of IV (c) fibers
Slow pain and temperature (unmyelinated)
What types of sensory fibers have the largest diameter and consequently the fastest conduction velocity?
Ia and Ib
What type of motor fibers have the largest diameter and consequently the fastest conduction velocity?
A-α
What type of sensory fibers have the smallest diameter and consequently the slowest conduction velocity?
C
What is the electrochemical effect of an inward Na+ current on a sensory fiber?
Depolarization
What is the function of the Sensory receptor
Translates environmental stimulus into an electrical impulse
What is the function of the First-order neuron
Carries impulse from sensory receptor into central nervous system (CNS)
What is the function of the Second-order neuron
Carries impulse from primary neuron to the thalamus
What is the function of the Third-order neuron
Carries impulse from second-order neuron to the cerebral cortex
What is the function of the Fourth-order neuron
Carries impulses from third-order neurons to appropriate somatosensory area of cerebral cortex
Onion-like subcutaneous receptors that respond to vibration and tapping
Pacinian corpuscle
Primary receptors of the dermal papillae that mediate two-point tactile discrimination
Meissner corpuscle
Encapsulated receptor that responds to pressure
Ruffini corpuscle
Disc-shaped touch receptor of the deep dermis
Merkel tactile disc
Rods or cones?
Sensitive to low-intensity light
Rods
Rods or cones?
Sensitive to high-intensity light
Cones
Rods or cones?
Receptor used primarily for night vision
Rods
Rods or cones?
Receptor used primarily for day vision
Cones
Rods or cones?
Present in fovea
Cones
Rods or cones?
High visual acuity
Cones
Rods or cones?
Receptor which adjusts to low light conditions most rapidly
Cones
Rods or cones?
Receptor capable of color vision
Cones
Muscle sensor that detects static and dynamic changes in muscle length
Muscle spindles
Muscle sensor that detects muscle tension
Golgi tendon organs
Muscle sensor that detects vibration
Pacinian corpuscles
Muscle sensor that detects pain
Free nerve endings
What type of motoneuron is responsible for ensuring that a muscle will respond appropriately throughout contraction, despite changes in tension?
γ-Motoneurons
What type of muscle reflex, mediated by type Ia afferent fibers, causes muscle contraction in response to muscle stretch?
Stretch or myotatic reflex
What type of muscle reflex, mediated by type Ib afferent fibers, causes muscle relaxation in response to muscle contraction?
Golgi tendon reflex
What type of muscle reflex, mediated by types II, III, and IV afferent fibers, causes ipsilateral flexion and contralateral extension?
Flexor withdrawal reflex
What are the components of the afferent limb of a myotatic reflex arc?
Muscle spindle receptor → Ia fiber → dorsal root ganglion
What comprises the efferent limb of a myotatic reflex arc?
Ventral motor neuron
Muscle group and spinal level of Ankle jerk
Gastrocnemius (S1)
Muscle group and spinal level of Knee jerk
Quadriceps (L2-L4)
Muscle group and spinal level of Biceps jerk Biceps
(C5-C6)
Muscle group and spinal level of Forearm jerk
Brachioradialis (C5-C6)
Muscle group and spinal level of Triceps jerk
Triceps (C7-C8)
What type of posturing is caused by a transecting lesion above the level of the medulla but below the midbrain?
Decerebrate rigidity
What type of posturing is caused by a transecting lesion above the level of the red nucleus (midbrain)?
Decorticate rigidity
What are the three layers of the cerebellar cortex?
- Granular layer (innermost)
- Purkinje layer (middle)
- Molecular layer (outermost)
Which is the major NT of cerebellar Purkinje cells?
γ-Aminobutyric acid (GABA).
Note: The output of Purkinje cells is always inhibitory.
