Week 6 - finished Flashcards
What is the oldest and most primitive part of the brain?
The brainstem
What is the main function of the brainstem?
Maintenance of homeostasis
CN nuclei are interspersed with the fibers of the reticular formation to form the origins of the CN’s
Contains nuclei which give rise to some of the descending motor pathways
Provides a thoroughfare for fibers passing between the brain, spinal cord and cerebellum
What do cranial nerves do?
They innervate somatic structures of the head and neck with motor and sensory supply
They mediate the special senses
They provide PSNS supply to the viscera, heart, GIT, Resp system and vasculature
Where do each of the CN’s exit the brain?
I - cortex II - diencephalon CN’s III – XII exit the brainstem surface III & IV from the midbrain V & VI from the pons VII & VIII from the pontomedullary junction IX, X, XI & XII from the medulla XI picks up some Cx fibers also
What CN’s tend to exit medially from the brain stem?
Those that have predominantly motor function
What CN’s nuclei sit medially?
Motor nuclei
What is the 4th ventricle continuous with?
The 3rd ventricle above via the cerebral aqueduct
What makes up the core of the brainstem?
The reticular formation
Foramen of Lushka is what?
The end of the lateral recesses there CSF can exit the fourth ventricle and surround the spinal cord
What is larger, the cuneate or gracile tubercle?
The cuneate (as there is more sensation in the upper limbs
What is the reticular formation?
A diffuse network of neurons and glial cells that is interspersed between the CN nuclei and tracts that traverse through the brainstem.
Its function is very poorly understood. Possibly some kind of primitive motor centre.
What are the key functions of the reticular formation?
Coordinates arousal for the adjustment of conscious perception of our environment for sleep & variations in alertness
Controls our habituation to ‘insignificant’ sensory information
Modulation of pain sensation
Regulation of motor function for muscle tone, balance & posture
Relays audiovisual information to the cerebellum for integration into motor control systems
Coordination of autonomic function and rhythmic pattern generation for breathing & swallowing
What art the primary neurotransmitters in the reticular formation nuclei?
Noradrenaline
Serotonin
Dopamine
What is noradrenaline? Where is it made? Where does it usually exert its effects? What does it contribute to?
Largely produced by the locus coeruleus
Exerts its affect on:
- Hippocampus & Amygdala
- Cingulate gyrus & Neocortex
- Thalamus & Hypothalamus
- Striatum
- Cerebellum
- Spinal cord
Contributes to:
- autonomic regulation
- behavioural arousal (to control alertness & vigilance)
- Is a key ‘stress’ hormone
Where is the majority of the bodies serotonin produced and found? How much is found here? What is its function here?
The GIT.
90%
The function is to regulate GIT motility