Anatomy Week 2 Flashcards
What do each of the two anatomical divisions of the nervous system consist of?
- CNS = Brain and Spinal Cord
- PNS:
- Cranial/Spinal Nerves
- Ganglia
- Autonomics
- Enteric Plexuses
- Sensory Receptors
Describe the 3 functional levels of Central Nervous System Organization:
- Sensory (Input) = Afferent neurons
- Integrative (Control) = Interneurons
- Motor (Output) = Efferent neurons
Describe the 3 functional levels of Peripheral Nervous System Organization:
- Somatic Nervous System
- Autonomic Nervous System
- Enteric Nervous System
Motor neurons of the SNS are _______ while motor neurons of the ANS are ______.
- Voluntary
2. Involuntary
Sensory neurons of the SNS receive input from _______, while sensory neurons of the ANS receive input from _______.
- Outside the Body
2. The Viscera (Internal Organs)
What are the 2 divisions of the ANS?
- Sympathetic: Fight or Flight
2. Parasympathetic: Rest and Digest
The basic structural unit of the Nervous System is the _______.
Neuron
Describe the 2 main components of a neuron:
- Cell Body:
- Nucleus
- Nissl Bodies: Clusters of rER - Nerve Fibers:
- Dendrites: Input portion
- Axons: Output portion
What cells are responsible for myelination in the Somatic and Peripheral Nervous Systems respectively?
- Oligodendrocytes
2. Schwann Cells
Describe the 3 different structural types of neurons:
- Multipolar Neurons: Multiple dendrites receiving input, one axon providing output
- Unipolar Neurons: One dendrite and one axon (sensory and often somatic in nature)
- Bipolar Neurons: One dendrite and one axon (associated with special senses)
Differentiate between Ganglia and Nuclei:
- BOTH are collection of neuronal cell bodies.
2. Ganglia are located in the PNS while Nuclei are located in the CNS.
Differentiate between Nerves and Tracts:
- BOTH are bundles of neuronal axons.
2. Nerves are located in the PNS while Tracts are located in the CNS.
Differentiate between White Matter and Grey Matter:
White Matter is primarily composed of white, myelinated axons, while Grey Matter is primarily composed of neuronal cell bodies, dendrites, and un-myelinated axons.
Where are white matter and grey matter located, relative to one another, in the brain and spinal cord respectively?
- In the Brain:
- White Matter INSIDE
- Grey Matter OUTSIDE - In the Spinal Cord:
- White Matter OUTSIDE
- Grey Matter INSIDE (butterfly shape)
Describe the protective coverings of the spinal cord:
- The Meninges: (3 layers)
- Dura Mater (Outer layer)
- Arachnoid Mater (Middle layer)
- Pia Mater (Inner layer)
What is the Epidural Space? What is the SubDural Space?
- The space between the Dura Mater of the spinal cord and the wall of the vertebral canal.
- The space between the Dura Mater and the Arachnoid Mater.
The spinal cord meninges are continuous with _____________.
The meninges of the brain
Describe the Subarachnoid Space? What is special about it?
- The space between the Arachnoid Mater and the Pia Mater.
2. It is filled with cerebrospinal fluid (CSF).
CSF acts as a ______ for the spinal cord.
Shock absorber
The spinal cord extends from the _______ to the ______. It gives rise to _____ pairs of spinal nerves.
- Foramen Magnum of the skull
- L-2 vertebrae
- 31
What are MIXED nerves?
Nerves that have both motor and sensory components
The spinal cord is not uniform in diameter. It has an enlarged _____ region which supplies _______, and it has an enlarged _____ region which supplies _______.
- Cervical
- Upper limbs
- Lumbar
- Lower limbs
The inferior end of the spinal cord proper is called the _______, while the origin of the spinal nerves that EXIT from that inferior end is called the _______.
- Conus Medullaris (at L-1 or L-2)
2. Cauda Equina
What is the filum terminale?
The connective tissue that extends from the conus medullaris to the coccyx
The anterior horn of the grey matter in the spinal cord is called the _______, and the posterior horn is called the ______. In the middle of this butterfly-shaped grey matter is the _______.
- Ventral Horn
- Dorsal Horn
- Central Canal
The short, shallow groove on the posterior side of the spinal cord is called the ______.
Posterior Sulcus
The ventral horn contains ________.
Cell bodies of somatic motor neurons
The dorsal horn contains ________.
Axon terminals of sensory neurons that are delivering signals to motor neuron cell bodies in the ventral horn.
Where do sensory neuron cell bodies originate?
The dorsal root ganglion (a collection of sensory neuron cell bodies in the dorsal root, outside of the dorsal horn).
Many ________ come together to form both dorsal and ventral roots. The ventral root and dorsal root come together to form _________.
- Rootlets (Ventral/Dorsal)
2. Spinal Nerves
Spinal nerves branch into ________, in order to _______.
- Rami (plural of Ramus)
2. Have a dorsal ramus supply the posterior of the body and a ventral ramus supply the anterior of the body.
Where are the cell bodies of AUTONOMIC motor neurons found relative to the spinal cord?
In the Lateral Horn of the grey matter (exitting ventrally like the somatic motor neurons)
Where do autonomic motor neuron axons travel to after entering the spinal nerve?
They follow the ventral ramus to the sympathetic chain to interact with sympathetic ganglions.
Besides somatic sensory neuron cell bodies, what else is found in the dorsal root ganglia?
AUTONOMIC sensory neuron cell bodies (both of which gather signals from their targets (body wall/limbs OR viscera) and deliver them into the dorsal horn of the spinal cord grey matter.
What is a nerve plexus?
A network of branching nerves
Describe the 2 main types of plexuses:
- Visceral Plexus: Associated with ANS
- Contain Symp./Parasymp. Nerves - Somatic Plexuses: Associated with SNS
- Cervical, Brachial, Lumbar, and Sacral Plexus
Which vertebrae do nerves extend from to form each of the Somatic Plexuses respectively?
Cervical: C1-C4
Brachial: C5-T1
Lumbar: L1-L4
Sacral: L4/5-S4
Describe the breakdown of structure of Somatic Nerve Plexuses:
- Roots at Ventral Rami of spinal nerves
- Trunks (Superior, middle, inferior)
- Divisions (Anterior and Posterior)
- Cords (Lateral, Medial, Posterior)
- Branches (Terminal)
What are dermatomes?
Regions of the skin that are known to be supplied by a single nerve. This means that they can be tested for sensation to see if that single nerve is functioning properly.
Describe Erb-Duchene Palsy: (3)
- Injury to the Upper Trunk of Brachial Plexus
- Affects: Suprascapular, Musculocutaneous, and Axillary
- Arm cannot raise (abduct), loss of flexion and supination of forearm (arm in “waiter’s tip position”)
Effects of Radial Nerve Injury: (2)
- Loss of function to Extensors of Forearm
- Wrist Drop
Effects of Median Nerve Injury/Palsy: (2)
- Loss of function to Flexors of Forearm and Thumb (Thenar) muscles
- Loss of Thumb abduction and opposition (loose fist)
Effects of Ulnar Nerve Injury/Palsy: (3)
- Loss of function to most Intrinsic muscles of hand
- Loss of function to Flexors or Medial Digits
- Clawing of Hand (casting a spell)
Effects of Long Thoracic Nerve Injury: (2)
- Loss of function to Serratus Anterior Muscle
- Winging of Scapula
How many neurons are associated with the Somatic and Autonomic pathways respectively?
Somatic: ONE Neuron pathway.
i.e. Motor neurons from CNS synapse DIRECTLY with their target effector.
Autonomic: TWO Neuron pathway.
i.e. Preganglionic neuron–> ganglion–> Postganglionic neuron–> Effector.
ALL somatic motor neurons release ________.
ACh
What are the effector targets of the somatic and autonomic motor neurons respectively?
Somatic: Skeletal Muscle (Voluntary Control)
Autonomic: Smooth Muscle, Cardiac Muscle, and Glands (Involuntary Control)
In the ANS, ALL preganglionic neurons release ______, while SYMPATHETIC postganglionic neurons release ________, and PARASYMPATHETIC postganglionic neurons release ________.
- ACh = Pre-ganglionic
- NE = Sympathetic
- ACh = Parasympathetic
The Sympathetic NS is described as _______, because all of the PreGanglionic Neuronal cell bodies are located in the __________.
- Thoracolumbar
2. Thoracic and Lumbar Vertebrae of the Spinal Cord (specifically T1-L2)
Sympathetic Preganglionic neurons lead to the ______ and ______ ganglia.
- Trunk
2. Pre-vertebral
How are the White and Gray Rami involved in the Sympathetic Chain?
Sympathetic Preganglionic neurons enter the chain through White Rami, and Sympathetic Postganglionic neurons exit the chain through the Gray Rami.