Mammalian Nervous Systems Flashcards
‘Innervation’
The nerve supply of…
Afferent
Towards
Efferent
Away from
Ipsilateral
The same side
Contralateral
The other side
What does the CNS consist of ?
Brain and spinal chord
What does the peripheral nervous system (PNS) consist of ?
Cranial nerves and spinal nerves
Describe the organisation of the spinal chord
Dorsal horn- sensory
Ventral horn- motor
What is another name for the dorsal column ?
Medial lemniscus
What is the dorsal column ?
It is an ascending sensory pathway, found at the back of the spinal cord.
It processes sensory info.
Neurons decussate at the medulla oblongata- contralateral.
What does decussate mean ?
Cross over
What type of sensory info does the dorsal column process ?
Vibration, fine touch and proprioception
What type of sensory info does spinothalmic process ?
Pain, temp, touch and pressure
What is spinothalamic ?
An ascending pathway, information from the spine up to the thalamus.
It processes sensory info.
It decussates at point of entry (L5)
Lower motor neurons (LMN)
Interneurons connect functionally related LMNs.
Descending pathways are afferent to LMNs.
Important for function of skeletal muscle.
What is another name for the corticospinal tract ?
Pyramidal
What is the corticospinal tract ?
A descending motor pathway, the tract passes through the pyramidal structures of the medulla and decussates.
It has control over lower motor neurons that innervate skeletal muscles.
Purposeful movements.
What is somatotopy ?
The orderly arrangement of the nervous system in relation to the parts of the body
What principles apply to all mammalian brains ?
- Topographic maps show anatomical organisation
- Specific brain regions have specialised functions
- Greater no of neurons means more integration can occur
- Neural circuits are plastic
- Neurogenesis is confined to specific areas
What are the functions of the brainstem ?
- Functional composition of cranial nerves 3-12
- Conveying sensory info to the cortex
- Cerebellar connections
- Regulation of ANS
- Visual and auditory reflexes
What is spina bifida ?
A congenital defect of the spine in which part of the spinal chord and its meninges are exposed through a gap in the backbone
What is hydrocephalus ?
Accumulation of cerebrospinal fluid (CSF) within the brain
Who is Noah Wall ?
He was paralysed from the chest down and had 2% brain function.
He has spina bifida and hydrocephalus.
He has turned 10.
What is the association cortex ?
The cerebral cortex outside the primary areas which is involved in communication, memory, thought etc.
What are gurus ?
Folds on the surface of the brain
What are sulcus ?
Dips between gyri
Examples of inter-hemispheric commissures
Corpus callosum
Anterior commissure
What system is the cerebellum part of ?
Extrapyramidal system, for stereotyped movements
What is the function of the cerebellum ?
Initiating, timing and terminating movements.
Coordinates motor outputs.
What are parts of the brain are grey matter ?
Basal ganglia
Thalamus
Hypothalamus
What is the basal ganglia?
A collection of nuclei which produce regulated movements
What does the thalamus do ?
- Relays sensory pathways to cerebral cortex
- Activating the cerebral cortex
- Coordination of visual and motor activity
What does the hypothalamus do ?
- Responds to physiological, environmental and emotional changes that affect the ANS
- Part of the limbic system- involved in thirst, hunger and appetite
- Maintainence of homeostasis
- Neuroendocrine control
What does the brainstem do ?
Connect the brain to the spinal chord
What is the brainstem composed of ?
- Midbrain
- Pons
- Medulla oblongata
