Brain Anatomy Flashcards
How is the nervous system divided into 2?
CNS, PNS
How is the CNS divided (4)
Cerebrum, cerebellum, Brainstem, Spinal cord
How is the PNS divided? (3)
Cranial nerves
Spinal nerves
Visceromotor system
How is the CNS different to the PNS
CNS is encased in bones (skull and spine)
Name the four parts of the spinal cord from rostral to caudal
Cervical cord
Thoracic cord
Lumbar cord
Sacral cord
What name is given to the tract of the descending motor pathway and the ascending sensory pathway
Motor= Corticospinal/ pyramidal tract Sensory= Spinothalamic tract (synapse in thalamus before sensory cortex)
Apart from bone, what else is the CNS enveloped by
The meninges
What does the meninges consist of? (3)
Three membranes that envelop the brain and spinal cord
•Dura mater
•Arachnoid membrane
•Pia mater
What exists between the arachnoid mater and Pia mater?
Cerebrospinal fluid in the subarachnoid space between arachnoid mater and pia mater (Brain floats in CSF)
What is the function of the meninges?
Protection
Name a specialised tissue in the ventricles and the function that it serves
Choroid plexus – specialized tissue in ventricles that secretes CSF
Describe the pathway of the canals to where it ‘finishes’
Cerebrum > brain stem core > subarachnoid space(or spinal cord) > special structures called arachnoid villi absorb CSF
Apart from protection, what other important role does CSF carry out?
Metabolic waste products diffuse rapidly into CSF > removed in bloodstream
Where do the cranial nerves originate and mostly innervate? Also how many?
12 nerves from the brain that mostly innervate the head and neck
Are the cranial nerves sensory or motor?
Can be one one or the other or mixed
Name two completely sensory cranial nerves
olfactory (I) and optic nerve (II) related to Telencephalon and diencephalon (purely sensory)
Which nerves are related to the brain stem?
Cranial nerves III – XII related to the brainstem(more comparable with spinal nerves)
Which cranial nerve forms part of the parasympathetic system?
Vagus(X) forms part of the parasympathetic system
What do the spinal nerves innervate?
Innervate skin, joints, muscles
What do the dorsal root ganglia contain?
contain cell bodies of peripheral sensory neurons
Give another name for the visceral system and describe how it is divided
Visceromotor system; Sympathetic and parasympathetic division
What does the visceral system innervate?
Innervates smooth muscle of internal organs, blood vessels, glands
Where does the sympathetic and parasympathetic system emanate their axons from?
Sympathetic (mid-spinal cord)
Parasympathetic (brainstem (Vagus nerve) and end of spinal cord)
See diagram in notes
Name some effects of the sympathetic system when activated
‘Fight or flight’
Pupil dilation Bronchodilation Cardiac acceleration Inhibition of digestion Piloerection (erection or bristling of hairs) Stimulation of glucose release Systematic vasoconstriction
Name some effects of the parasympathetic system when activated
‘rest or digest’
Pupil constriction Bronchoconstriction Cardiac deceleration Stimulation of digestion Salivation, lacrimation Intestinal vasodilation
What neurotransmitters are released by the sympathetic division?
Acetylcholine from spinal cord, norepinephrine later
What neurotransmitters are released by the parasympathetic division?
Acetylcholine from spinal cord, Acetylcholine later
Apart from movement selection, what other function does the basal ganglia carry out?
How much force or strength you put behind a movement
Where does the basal ganglia get information from and where does it project to?
Gets info from the whole cortex, only projects to motor cortex
What disorders (2) and neurotransmitter is highly related to the basal ganglia?
Dopamine; Parkinson’s and Huntington’s
Describe the lecturerer’s reasoning as to the location on the thalamus, basal ganglia, hypothalamus
Well the basal ganglia goes near the front because it gets information from the whole cortex but only projects to near the front (motor cortex). Behind that would go the thalamus because that’s around the centre and it has inputs and outputs all over the brain/ cortex. Below that would go the hypothalamus because it has a lot of causal connections (i.e the sympathetic and parasympathetic systems) and to the pituitary gland.
The further you go rostral with a coronal cross section, the ______ the basal ganglia become and the ________ the thalamus becomes
smaller the basal ganglia become and the larger
Initially only the basal ganglia is seen
Where has neurulation and differentiation been covered before?
Chpt 7, do the cards it covers most of this lecture “structure of the nervous system”
What are the three primary brain vesicles called?
Prosencephalon (forebrain)
Mesencephalon (Midbrain)
Rhombencephalon (hindbrain)
What neuromodulater is synthesised in the telencephalon vesicle?
Acetylcholine
What neuromodulater is synthesised in the Diencephalon vesicle?
Histamine
What neuromodulater is synthesised in the Diencephalon vesicle?
Dopamine
What neuromodulater is synthesised in the Metencephalon vesicle? (pons and cerebellum)
Noradrenalin
What neuromodulater is synthesised in the Myelencephalon vesicle? (Medulla)
Serotonin (Raphe)
How can the cortex be subdivided?
Neocortex/ Isocortex- 6 layers
Mesocortex- Less layers (+4)
Allocortex- 1 layer of projection cells
What is the oldest type of cortex? Name two types of this cortex
Allocortex; piriform (olfactory) cortex and hippocampus
Which cortex makes up 90% of the human cortex?
Neocortex
Where is the mesocortex situated? Name two mesocortices
Between Neo and allocortex,
Limbic cortex (incl cingulate and entorhinal), insula
Why did the brain not just stay smooth and let us have big heads?
We wouldn’t fit through the birth canal- think of you poor mother
How is the NS axis different in rats and humans
Humans NS axis is curved
How is the SC different in mice, rates and humans
Easily seen from dorsal view in mice, quite covered in rates and completely buried in humans
What is seen as ‘the edge of the cortical plate’?
The limbic cortex- cingulate gyrus and parahippocampal gyrus
How would you describe the location of the hippocampus in any mammal?
The curled up edge of the cortical plate
Is the dentate gyrus in the hippocampus a part of the cortical plate?
Yes but it gets fetched during development
Name two parts of the hippocampus
dentate gyrus; part of the cortical plate but it gets fetched during development
Cornu Ammonis (Ammon’s horn)
See doc for diagram
How is the hippocampus shaped differently in rats and why?
Reaches a lot more dorsal (and caudal) because of the straight axis
Dorsal Hippocampus in rats = ______ hippocampus in humans
Ventral hippocampus in rats = ______ hippocampus in humans
posterior; anterior
At what tip of the hippocampus does the amygdala sit?
Ventral tip in rats, anterior tip in humans
