Nervous system TBL (chapter 5)

Functional anatomy

sensory nervous system

responsible for receiving sensory information from receptors that detect stimuli and transmit to the CNS (afferent)

what are the two types of sensory nerves

somatic sensory and visceral sensory

somatic sensory

detect stimuli we can perceive (proprioception, smell, sight, taste, touch)

visceral sensory

stimuli that we typically do not perceive (chemical composition of blood, stretch of an organ wall)

Motor nervous system

responsible for initiating and transmitting motor output from the CNS to effectors (efferent)

what are the 2 type of motor nerves

somatic and autonomic

somatic motor

initiates and transmits motor output from the CNS to skeletal muscle

autonomic motor

innervates and regulates cardiac muscle, smooth muscle and glands without our control

what are the 2 types of autonomic motors

sympathetic and parasympathetic

what does the CNS consist of

brain and spinal cord

what does the PNS consist of

nerves and ganglia

cerebrum

largest/main portion of the brain.

responsible for the highest level of mental functions.

composed of the R and L cerebral hemispheres and the corpus callosum.

what are the 4 lobes of the hemisphere

frontal

parietal

temporal

occipital

thalamus

relay station for body sensation

location of pain perception

hypothalamus

hormone function and behavior control

basal ganglia

coordination of motor movement

brainstem 3 sections

midbrain, pons, and medulla oblongata

midbrain

center for visual reflexes

pons

bridge/pathway

medulla oblongata

automatic control of respiration and heart rate

cerebellum

control of muscle coordination, tone and posture

spinal cord

continuation of the medulla that runs from the foramen magnum to the conus medullaris

cauda equine

group of nerve roots

vertebral foramen

passageway for the spinal cord

intervertebral foramen

where the spinal nerve root exits the vertebral canal

gray matter

unmyelinated fibers that is in the shape of an “H”

what are the two horns of the grey matter

posterior and anterior

posterior horn

transmits sensory impulses

anterior horn

transmit motor impulses

white matter

myelinated, contains ascending and descending fiber pathways

dorsal columns

transmit sensations of proprioception, pressure, and vibration

lateral corticospinal tract

intervention of skeletal muscle in the extremities

play a key role in skilled motor control

anterior corticospinal tract

intervention of trunk and proximal extremities muscle

upper motor neuron lesions

spasticity

no significant muscle atrophy

no fasciculations or fibrillations present

hyperreflexia

(+) babinski reflex

(+) clonus (phasic stretch response)

lower motor neuron lesions

muscle flaccidity

significant muscle atrophy

fasciculations and fibrillations present

hyporeflexia

no babinski

no clonus present

upper motor neuron

cell body that is housed in the cerebral cortex, cerebral nuclei or the brainstem

lower motor neurons

cell body that is housed in the anterior horn of the spinal cord or within a brainstem cranial nerve nucleus

upper motor neuron disorder

Spinal cord injuries

Multiple sclerosis

Parkinsonism

Cerebral vascular accident (stroke)

Head injuries

lower motor neuron disorders

Muscular dystrophy

Poliomyelitis

Myasthenia gravis

Peripheral nerve injuries

cranial nerves

Extend off of the brain

spinal nerve

extend off of the spinal cord

how many spinal nerves are there

31

how many cervical nerves

8

how many thoracic nerves

12

how many lumbar and sacral nerves (each)

5

how many coccygeal nerves

1

where do the first 7 cervical nerves exit

the vertebral column above the corresponding vertebra

where do the nerves start to exit under the vertebra

C8

where do the spinal nerve join together

when the dorsal (sensory) and ventral (motor) nerve roots join

what is a dermatome

sensory fibers that supply an area on the skin

when will complete anesthesia occur

when at least two spinal nerves have lost function

what is a plexus

when portion of the spinal nerves join together

what are the three main plexuses

cervical- c1-c4

brachial plexus- c5-t1

lumbosacral plexus- l1-s5

what are the terminal nerves of the upper extremities

musculocutaneous, axillary, radial, median, and ulnar nerves

common pathologies of the CNS

spina bifida

hydrocephalus

cerbral palsy

spinal cord injury

spinda bifida

Congenital Defect in which posterior segments of some of the vertebra fail to close during embryonic development

hydrocephalus

Congenital or acquired defect involving CSF production, absorption and flow through the ventricles and subarachnoid space.  Excessive accumulation leads to enlargement of the ventricles and pressure on the brain

cerebral palsy

Non-progressive upper motor neuron disorders of the brain. 

spinal cord injury

Caused by trauma, disease, blood clots

Impairments depend on the injury level and if the injury is complete or incomplete

Can involve sensory, motor or both

common pathologies of the PNS

Diabetic Peripheral Neuropathy

Bell’s Palsy

Scapular winging

Thoracic outlet syndrome

Erb’s palsy

Carpal tunnel syndrome

Sciatica

Erb’s Palsy

paralysis of the arm caused by injury to the brachial plexus, specifically the severing of the upper trunk C5–C6 nerves.

Diabetic Peripheral Neuropathy

A type of nerve damage that can occur if you have diabetes. High blood glucose can injure nerves throughout the body. Nerves in the legs and feet are most commonly affected. 

Diabetic Peripheral Neuropathy symptoms

tingling, burning, numbness and impaired motor function.

how can other neuropathies occur

viral infection or direct pressure to the nerve

(CTS, scapular winging, bell’s palsy, thoracic outlet syndrome)