Neuroanatomy 1 Flashcards
What are the 2 main pathways that the nervous system can be divided into and state what comprises them?
CNS and PNS
- CNS = the brain + the spinal cord
- PNS = 12 pairs of cranial nerves + 31 pairs of spinal nerves and their branches
What are the 5 major embryonic divisions of the brain and what strctures does each of them develop into ?
- Telencephalon - cerebral hemispheres from from this division
- Dienecphalon - thalamus and hypothalamus (collectively these 2 are still referred to as the diencephalon)
- Mesencephalon - Midbrain
- Metencephalon - Pons, cerebellum
- Myelencephalon - medulla oblongata
Think Tyler Dont Make Me Mutilate you
Go over the regions of the brain, also what is the thalamus and hypothalamus collectively known as and what is the midbrain, pons and medulla oblongata (medulla) collectively known as ?
- Thalamus + hypothalamus = diencephalon
- Midbrain, pons and medulla = brainstem
What are the 2 main types of cells found in the CNS?
Neurons
Glial cells - there are 4 different types of glial cells:
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells
What is the function of neurons and describe their structure
They are the ‘communicators’ of the CNS - their function is to receive information mainly via snapses, they then integrate the info & then transmit electrical impulses to another neuron or effector cell.
Most neurons are mutlipolar with many dendrites and one axon (as seen in the pic)
Dendrites are the branched projections of a neuron that receive electrical messages. These messages come in two basic forms: excitatory and inhibitory.
What is the most abudant type of cells in the CNS ?
Glial cells NOT neurons
Describe the function, location and structure of astrocytes
It is often a star shaped with numerous processes
Its function is:
- To support maintraining the blood-brain barrier by working with endothelial cells
- Maintain Ionic, metabolic and nutritional homeostasis,
- The main cell involved in repair and scar formation given the lack of fibroblasts
They are located throughout the CNS, where their processes envelop synaptic plates and wrap around vessels and capillaries within the brain
Pic shows The start burst cell is an astrocyte - this shows it carrying out one of its functions as it extends a ‘foot’ to a blood vessel (the circular thing) and this is how it helps to maintain environmental homeostasis
Note the is NO connective tissue in the CNS hence these different cells performing various functions
Describe the function and structure of oligodendrites
- Function is to produce myelin around different axons in the CNS
- Oligodendrocytes have numerous branches that extend to produce internodes of myelin around different axons. The nodes of myelin as referred to as nodes of Ranvier. They have a round nucleus that is moderately stained in typical preparations.
Note I think I put down in notes that just schwann cells only have nodes of ranvier but this is not true oligodendrocytes do too, they just myelinate longer stretches of axons
Are oligodendrities found in the PNS ?
NO
What is the difference between schwann cells and oligodendrities ?
Schwann cells myelinate axons in the PNS, while Oligodendrocytes myelinate axons in the CNS
Describe the function and structure of microglia cells
- Function is immune monitoring and antigen presentation, and phagocytosis (they have a similar lineage to macrophages)
- . In a resting state they have an elongated nucleus and a number of short, spiny cell processes. When activated, for example by a bacterial infection, they become rounder and take on an appearance similar to a macrophage.
Describe the structure and function of ependmyal cells
They are ciliated cubodial/columnar epithelium that lines the ventricles (they don’t form a barrier between CSF and CNS tho)
What are gyri, sulci and fissures in the brain ?
- Gyrus are ridges between two clefts on the cerebral surface of the brain
- Sulcus are depression/grooves in the cerebral cortex
- Fissures are just deeper sulcus (sulci)
Where is grey matter and white matter situated within the brain and what is contained within each of them?
- Grey matter - located on the outside of the brain (note their are some deep grey mater structures tho). It consists of huge numbers of neurons (not their axons), cell processes, synapses and support cells
- White matter is usually found on the inside of the brain. It is comprised of axons (mostly myelinated and their support cells)
What is the key difference in the location of grey and white matter in the spinal cord compared to the brain ?
White matter is located on the outsdie of the spinal cord and grey matter is located on the inside
Label the structures indicated by the arrows
Label the structure of the brain indicated
Label the indicated structures
- Note the hippocampus sits just below the lentiform nucleus
- Lentiform nucleus is important in movement control
- Hippocampus is important in memory particularly long-term
Label the indicated structures
Label the indicated structures
Describe the location of the frontal lobe
Frontal lobe - located anterior to the central sulcus and superior to the lateral sulcus
Describe the location of the parietal lobe
Located posterior to the central sulcus, superior to the lateral sulcus and anterior to a line drawn from the parieto-occipital sulcus to the preoccipital notch
Describe the location of the occipital lobe
It is located posterior to a line from the parieto-occipital sulcus to the pre-occipital notch
Describe the location of the temporal lobe
Inferior to the lateral sulcus (and a line extending the lateral sulcus posteriorly) and posteriorly by a line from the parieto-occipital sulcus and the preoccipital notch.
Describe the location of the insular lobe/ insula
- It is hidden in the lateral fissure
- Note it plays an important role in the experience of pain
Review the structure of the ventricles of the brain
Note that I’ve drawn this out well in the hand written notes so refer to them
Describe the meninges of the brain and the layers which comprise it
These are the coverings of the brain that lie immediately internal to the cranium
They are composed of 3 membranous connective tissue layers (from outermost to inner):
- Dura mater - tough, thick, external fibrous layer
- Arachnoid mater - thin intermediate layer (has arachnoid granules)
- Pia mater - delicate internal vascular layer which is only a couple of cells thick
