Organization of Nervous System Flashcards
Where does the spinal cord extend to and from?
Foramen magnum to L1 vertebral body
How does the spinal cord relate to inputs and outputs?
Spinal nerves that form peripheral nerves, include inputs from sensory receptors and outputs to muscle, glands and smooth muscle
What are the 3 major features of the spinal cord?
- Long and short pathways
- Spinal nerves (dorsal - sensory, ventral - motor)
- Grey matter
What are the 3 types of spinal cord circuits?
- Reflex circuits: feedback inhibition/negative feedback
- Basic motor circuits: postural/locomotor outputs
- Sensory processing
What is the order of portions of the brainstem, caudal to cranial?
Medulla, pons, midbrain (mesencephalon)
What are the key features of the brainstem?
Transition between spinal cord –> brain
- Cranial nerves
- Long pathways (corrticospinal tract)
Which cranial nerves are in the medulla, and what is the function of the medulla?
IX, X, XI and XII
Receive info from: taste structures, skin of head, heart, lungs, major blood vessels and digestive system (digestion + visceral control!)
What are the functions of the nuclei/grey matter in the medulla?
- Regulates body homeostasis: HR, respiration, vasomotor tone, gastric secretion
- Related reflexes: vomiting, coughing, sneezing, swallowing, gagging
What cranial nerves emerge from the pons?
V, VI, VII and VIII
What are the functions of the nuclei of the pons?
Balance
Localizing sound/coordinating eye movements
Facial expression
Reflexes related to: eye movements, jaw jerk
What cranial nerves emerge from the midbrain?
III and IV
What are the functions of the nuclei of the midbrain?
Control orienting to sound, visual reflexes and motor control
What are the projections from the midbrain to the cortex and what is their function?
Substantia nigra, ventral tegmental area
Source of dopamine projections that influence movement and reward
What is the reticular formation?
- Composed of nuclei and neuronal circuits, many of which are the origin of projections to the cortex or spinal cord
- Runs through the core of the brainstem (dorsal side)
What is the reticular activating system? Where does the rostral reticular formation originate and what does it do?
- Pons/midbrain that projects rostrally
- It controls attention, arousal, sleep and wakefulness
What does the caudal reticular formation control and where does it originate?
- Medulla, projects caudally
- Includes centers that control respiratory rhythm, blood pressure, digestion
- reflexes (facial expressions, gag, yawn, swallowing, vomiting)
- Movement: reticulospinal tracts
What is the function of the cerebellum? And by what mechanism?
Functions in motor control, learning, posture, orientation and balance
- Allows feedforward control of movement (as you practice, it builds a model)
How many layers does the cerebellum have in its cortex?
3 layers
What does damage to the cerebellum cause?
ATAXIA (disordered movement)
What is the function of the thalamus? What is its structure?
- Major relay station and integrated center for all inputs to the cortex (e.g. sensory, motor, reticular formation, limbic system)
- Cluster of nuclei which have specific functions
What are the projections to the cortex called?
Thalamocortical radiations
What are the components of the diencephalon?
Thalamus
Hypothalamus
Epithalamus
Subthalamus
Where does sensory information project in the thalamus?
Lateral group
Where does the reticular nuclei in the thalamus receive information from?
Reticular activating system
