Introduction to the Brain Structure and Function (Yvonne Mbaki) Flashcards
3 types of neurons and their roles
Sensory neurons from periphery to CNS
Motor neurons from CNS to periphery
Interneurons work between the two other neurons
What is the role of glial cells and what subtypes are there?
Glial cells are supporting cells that make up the brain, they do not have dendrites or axons.
Astrocytes (at the BBB) support neurons and maintain the BBB.
Micrglia have immune function i.e. in phagocytosis.
Oligodendrocytes provide structural support to the neurons.
Meninges protect the brain from damage (in meningitis they become inflamed).
Subarachnoid space is found between the arachnoid membrane and pia mater.
What is the structural order outwards from the brain?
Pia Mater is directly associated and in contact with the brain
Here there is a Subarachnoid Space before meeting the Arachnoid Membrane (spider web appearance).
The Dura Mater is tough and in between the Arachnoid Membrane and the bone of the skull.
What are brain ventricles?
Ventricles are just cavities within an organ, in the case of the brain they are filled with cerebrospinal fluid (CSF).
How is CSF produced?
Produced by the choroid plexus (group of cells around the ventricles) and circulated through ventricles. CSF is often used for diagnosis.ch
Outline prenatal development of brain
25 days neural tubes form
5 months front/mid/hide of brain has developed
Brain is fully developed at 9 months
Birth defects
Explain what neural tube defects are?
Failure of the neural tube to fold properly can give rise to various birth defects of the brain and spinal cord. Spina bifida (meninges haven't formed properly and can present outside of the spinal column as a deformity. Anencephaly is more severe, parts of the brain are missing, the skull is deformed. Survival is rare.
How are neurons and glial cells formed?
- Stem cell is derived from ectoderm (embryonic tissue)
- Progenitor is produced (a direct ancestor/daughter cell)
- Differentiation takes place, lineage restricted progenitor cells (limited to a particular structure and function).
These cells can differentiate into neurons, ogliodendrocytes or astrocytes.
What is the cerebral cortex?
It is described as the “higher centre” of the brain. It is the largest and most developed region of the brain and is divided into multiple lobes.
What are the four lobes of the cerebral cortex?
- Frontal lobe - prefrontal cortex; intellectual function, emotional behaviour. Executive decision i.e. what you wear!
Motor cortex; contains the premotor/primary motor cortex a.k.a. movement information - Parietal lobe - processes sensory information associated with taste, temperature, touch, knowledge of numbers and orientation.
- Occipital lobe - visual information
- Temporal lobe - primary auditory cortex and some visual cognition
What are Basal Ganglia and what is their role?
Important in movement; filter out unnecessary movement. The Substantia Nigra is associated with the Basal Ganglia.
The basal ganglia inhibits unwanted movement and co-ordinates important movement such as walking.
How is basal ganglia related to Parkinson’s?
In Parkinson’s disease, movement control is disrupted due to the death of basal ganglia neurones.
What is the Limbic system and which parts of the brain are involed?
Emotional Brain
Hippocampus - long term memory, inhibits behaviour, spatial navigation (related to Alzheimer’s). In a lobotomy of the HM there is no long term memory post surgery.
Cingulate gyrus - co-ordinates sensory input with emotions by communicating with the hippocampus and the hypothalamus.
Amygdala - aggression, fear, anger, memory, anxiety, sex drive. Tumours against the amygdala can drastically change a patient’s behaviour i.e. murder of a Marine’s family due to a tumour pressing on the amygdala of the Marine.
Hypothalamus and thalamus - endocrinology functions and emotional function also (see B32RED).
