CNS Lecture 1A Flashcards
What is the Corpus Callosum?
Large group of axons forming a commissural fibre (interhemispheric connection) that provides a link between the left and right hemisphere of the brain
What are the three components of the brain?
Cerebrum, Cerebellum, Brainstem
What is the Brainstem composed of?
Midbrain
Pons
Medulla Oblongata
What are four functions associated with the brainstem?
- Respiration
- locomotion
- cardiovascular functions
- Neurotransmitter Supply
What four lobes make up (one half of) the cerebral cortex
- Frontal Lobe
- Parietal Lobe
- Occipital Lobe
- Temporal Lobe
What functions are associated with the frontal lobe? (3)
- Personality
- Emotions
- Control of movement
The Primary Motor Cortex is located in the frontal lobe (pre-central gyrus)
What functions are associated with the Parietal Lobe? (1)
- Mediates skin and muscle sensation
The Primary Somatosensory Cortex is located here (post-central gyrus)
What function is associated with the Occipital Lobe?
Vision
What are two functions associated with Temporal Lobe?
- Hearing
- Memory
This is where the Primary Auditory Cortex is located
What does the term forebrain refer to?
The cerebrum and diencephalon
What functions are associated with the Cerebellum?
- Voluntary Movement
- Motor Timing
- Scaling
- Coordination and learning
- Balance and gait
- Eye movements
What does the term cerebral Cortex refer to?
Outer gray matter of the cerebrum
(axon cell bodies are clustered = gray matter)
What are four functions associated with the Cerebral Cortex
- Sensory Perception
- Motor Control
- Language
- Cognitive Functions
What are the three nuclei of the Basal Ganglia?
Caudate Nucleus
Putamen
Globus Pallidus
What is the Basal Ganglia important for?
Initiation of movement and inhibition of antagonistic muscles
What is the thalamus?
Sensory “switchboard” which selects and relays sensory signals to the cortex
What is the Hypothalamus?
Part of the brain that maintains homeostasis:
- temperature control, water balance, hunger
- Emotions (fight/fright/flight)
- Autonomic Nervous System
What is the Brainstem Responsible for?
- Autonomic functions of the body (heartrate, rate of respiration (or depth of inspiration/expiration) digestion)
- sleep/wake cycle
- Arousal
- Balance
- Posture
What is the function of the spinal cord?
Locomotor pattern generator
- control timing and sequencing of movements
- mediates simple reflexes
What is the limbic system?
Interconnected group of brain structures that developed earlier than the cortex during evolution
-behavioural and emotional responses
What are four functions associated with the Limbic System?
- Learning
- Emotion
- Appetite
- Sex
- Endocrine integration
What are the “pleasure centres” in the brain?
Septal Nuclei of the Limbic System
-associated with addiction
What are five components of the Limbic System?
- Septal Nuclei
- Olfactory Bulb
- Thalamus
- Hypothalamus
- Hippocampus
What are the three membranes covering the brain and spinal cord known as?
Meninges
What are the three meninge layers from outermost to innermost? Provide a short description of each:
- Dura Mater: tough outer layer
- Arachnoid Mater: Spidery intermediary mesh
- Roof of subarachnoid space (where CSF is stored)
- Pia Mater: Delicate Inner Layer
Infection of the meninges is known as:
Meningitis
What is an important relationship between the production and reabsorption of CSF (cerebral spinal fluid)
The CSF is producedat the same rate that it is reabsorbed into the blood of the venous system
-if this reabsorption is blocked = Hydrocephalus
Where is CSF produced?
What neuroglial cell is associated with CSF production?
In ventricles of the brain
Ependymal Glial Cells
What are two functions of the CSF?
Maintain electrolyte balance around neurons
Bath and support neural tissue
What are the four types of glial cells in the CNS?
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal Cells
Which glial cell forms a “scaffold” that holds neurons together?
Astrocytes
What are 5 functions of Astrocytes?
- Physically support neurons (scaffold)
- Form blood-brain barrier
- Repair: form scar tissue (note: the scar tissue prevents regeneration of severed axons)
- Recycle Neurotransmitters
- Maintain electrolyte balance
What is the function of Oligodendrocytes?
Form myelin sheath around neuronal axons
What is the function of Ependymal Cells?
Produce cerebrospinal fluid
What is a function of microglia?
Microglia are scavengers that ingest bacteria and cellular debris
What is an important note about the relationship between neurons and brain tumors?
Neurons cannot undergo cell-division = brain tumors do not develop from neuronal cells
Brain tumors arise from what kind of cells?
What is the designated term for these tumors?
Glial cells
Gliomas
Tumors that arise in the meninges are called:
Meningiomas
Tumors that arise from glial cells are called:
Gliomas
What is an anatomical difference between the capillaries in the blood-brain barrier and the capillaries in the rest of the body?
Capillaries in the BBB are tightly joined = less porous than capillaries of the rest of the body
What are 2 key functions of the blood-brain barrier (BBB)?
- Protects neurons from chemical fluctuations and large molecules
- Allows oxygen to cross but other molecules (such as Glucose) cannot cross freely and therefore must be aided across via carrier-mediated transport systems
What is a clinical disadvantage caused by the BBB?
Provide an example using Parkinsons
The BBB blocks the transport of beneficial drugs
-must use pre-cursor drugs which are much smaller and can pass through BBB
Parkinson’s: Because dopamine cannot pass the BBB, use the precursor drug L-dopa. L-dopa is converted to dopamine by the affected cells
