Nervous System Flashcards
General Function of the Nervous System
- Sensory Input
- Integration Function
- Motor Function
Sensory Input
Input from peripheral receptors (some conscious, some subconscious)
Integration Function
Taking all sensory input and integrating with memory, learning, and grading of response
Motor Function
Similar to #2, but many motor movements are also involuntary (subconscious– i.e. mutliple cerebellar tracts)
What makes up the Peripheral Nervous System?
The peripheral nervous system includes all of the parts of the nervous system that are not encased in the vertebral column or the skull
What makes up the spinal region?
The spinal region includes all parts of the nervous system encased in the vertebral column
What makes up the brain stem?
The brain stem connects the spinal cord with the cerebral region. It also includes the cranial nerves
What makes up the cerebrum?
The diencephalon and cerebral hemispheres
What is the most massive part of the brain?
The most massive part of the brain is the cerebrum
Divisions of the Nervous System
- Central Nervous System
- Brain
- Spinal Cord - Peripheral Nervous System
- Sensory (afferent)
- Motor (efferent)
- Somatic
- Autonomic
- Sympathetic
- Parasympathetic
Nerve roots of the PNS
- 12 pairs of cranial nerves
- 31 pairs of spinal nerves
- 8 Cervical
- 12 Thoracic
- 5 Lumbar
- 5 Sacral
- 1 Coccygeal
Cranial Nerves
see other deck by the same name
Which type of brain matter is inside/outside?
Spinal Cord - Gray matter is inside - White matter is outside Brain - White matter is inside - Gray matter is outside
Spinal Nerves
- Formed by the union of both dorsal (sensory) and ventral (motor) roots/ramii
- Spinal Nerve roots are mixed (motor and sensory)
- Dorsal root ganglion (DRG) on dorsal root where cell bodies of sensory neurons are located
- Communicantes conduct signals between the spinal cord and the sympathetic ganglia
Cervical Spinal Nerves
- First pair leaves between the occipital bone and the atlas (C1)– called the suboccipital nerve
- C2-C7 emerge above the vertebrae for which it is named.
- C8 emerges between C7 and T1
- All others emerge below the vertebrae for which they are named
Plexus Makeup
Cervical plexus - C1 to C4 Brachial plexus - C5 to T1 Lumbar plexus - T12 to L4 Sacral plexus - L4 to S2
Cervical Plexus
- Formed from the ventral rami of the 1st 4 cervical nerves
- Supplies muscles and skin of the neck and upper shoulder
- Partial innervation of the diaphragm (C3-C5)
Brachial Plexus
- Formed from the ventral rami of the last 4 cervical nerves (C5-C8) and the 1st thoracic (T1).
- Can be divided into various roots, trunks, divisions, cords, and nerves
Lumbar Plexus
- Formed from the ventral rami of the first 4 lumbar and some fibers of the last thoracic nerve
- Supplies the lower abdomen and the anterior and medial portions of the lower extremity
Saphenous Nerve
- Largest and longest femoral cutaneous branch.
- Passes deep to the sartorius with femoral artery, in adductor canal
- Accompanies the saphenous vein once it pierces the fascia between the sartorius and gracilis.
- Leaves the adductor canal above the knee (infrapatellar branch) and then continues down the medial lower leg.
Results of Nerve Damage
- Ulnar Nerve –> Claw hand (ulnar nerve entrapment)
- Radial Nerve –> Wrist drop
- Median Nerve –> Ape hand
Tomes
- Dermatome
- Myotome
- Scleratome
Dermatome
Sensory (cutaneous) innervation to skin
Myotome
Innervation to muscles
Scleratome
Innervation to connective tissue and bone
Cutaneous Innervation????
2 different references:
Dermatomes (segmental innervation)
- Representative of a generalized tract that represents a single nerve root
Nerves (helps with sensation over a specific area)
- Are made up of multiple nerve roots and usually innervate a certain area on the body
Key Dermatone Landmarks (Cervical)
- C2: posterior half of the skull cap
- C3: area correlating to a high turtle neck shirt
- C4: area correlating to a low-collar shirt
- C6: (radial nerve) 1st digit (thumb)
- C7: (median nerve) 2nd and 3rd digit
- C8: (ulnar nerve) 4th and 5th digit, also the funny bone
Key Dermatome Landmarks (Thoracic)
- T4: nipples
- T5: Inframammary fold
- T6: xiphoid process
- T10: umbilicus (important for early appendicitis pain)
- T12: pubic bone area
Key Dermatome Landmarks (Lumbosacral)
- L1: inguinal ligament
- L2: On the anterior medial thigh
- L3: At the medial epicondyle of the femur.
- L4: Over the medial malleolus, includes the knee caps
- S2/S3: genitalia
Myotome Levels
- C5: Elbow flexion
- C6: Wrist extension
- C7: Elbow extension
- C8: Flexion- tip of middle finger
- T1: Finger abduction
- L2: Hip flexion
- L3: Knee extension
- L4: Ankle dorsiflexion
- L5: Big toe extension
- S1: Ankle plantar flexion
Sympathetic Division of Autonomic Nervous System
- Thoracolumbar division
- Lateral horns of gray matter of spinal cord from T1-L2
- Prepares for strenuous physical exertion (fight and flight)
Parasympathetic Division of Autonomic Nervous System
- Craniosacral division
- Located in nuclei of cranial nerves
- III– occulomotor
- VII– facial
- IX– glossopharyngeal
- X– vagus
- And in the gray matter of the lateral horns of the 2nd through 4th sacral - Vagus nerve carries 75% of parasympathetic fibers
Effects of Increased Sympathetic Activity on Heart and Blood Pressure
- Increased activity of sympathetic cardiac nerves
- Decreased activity of vagus (parasympathetic nerves)
- Increased heart rate and contractility
- Higher cardiac output
- Increased blood pressure
Effect of Increased Parasympathetic and Decreased Sympathetic Activity on Heart and Blood Pressure
- Increased activity of vagus (parasympathetic) nerve
- Decreased activity of sympathetic cardiac nerves
- Reduction of heart rate
- Lower cardiac output
- Lower blood pressure
