PHTY209 Lecture Notes - Lecture 9: Basilar Artery, Palpation, Corticobulbar Tract
Brainstem, diencephalon, cranial nerves
• Name the four structures that contribute to the diencephalon and briefly describe its
function, giving focus to the role of the thalamus as a sensory relay and integrative centre
o Diencephalon
• Sits superior to midbrain (brainstem) and between cerebral hemispheres
• The diecephalo cosists of athig with the word thalaus i it
• They are mostly grey matter (nuclei) that have different functions
• Four main structures
▪ Epithalamus
• Pineal gland plus some additional structures
• Function not well defined
• Pineal gland
• Role in sexual function/hormones
• Activity influenced by light – more activity when dark
(secretory product – melatonin)
• Role in circadian rhythms and cognitive/emotional
behaviour
▪ Hypothalamus
• Paired structure either side of 3rd ventricle (narrow mid line slit-
like cavity)
• Controls all autonomic functions for homeostasis
• Small (weighs 4grams)
• Functional roles:
• Control over basic survival strategies – reproduction,
growth, metabolism, hunger, thirst, temperature control,
sleep-wakefulness
• Endocrine functions, emotional and behavioural functions.
▪ Subthalamus
• Associated with basal ganglia
▪ Thalamus
• Bilaterally symmetrical egg-shaped structure
• Either side of the midline third ventricle
• Subdivided into a number of nuclei = functionally related neurons
• Sensory relay nuclei: caudal half of thalamus
• Motor relay nuclei: rostral (e.g. connections with
cerebellum, basal ganglia)
• Three classes of nuclei
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• Described as the gateway to the cerebral cortex/a relay station - it
relas ad processes iforatio/is the receptio desk for the
corte
• All sensory information with the exception of olfaction is relayed
through the thalamus to get access to the cerebral cortex (DCML,
spinothalamic)
• Motor information returning from subcortical areas e.g. basal
ganglia, cerebellum also relayed through the thalamus to the
cortex
• Somatotopic organisation (homunculus)
• Retinotopic organisation – LGN (lateral geniculate nucleus – relay
path vision)
• Tonotopic organisation – MGN (medial geniculate nucleus – relay
path auditory)
• The thalamus is the largest component and can be further subdivided into
nuclei which each with a different task or function
• Function
▪ Relays sensory information between brain regions
▪ Controls many autonomic functions of the PNS
▪ Connects structures of the endocrine system with the nervous system
▪ Works in conjunction with limbic system structures to generate and
manage emotions and memories
• Describe the structure and function of the brainstem and cranial nerves
o The brainstem contains areas crucial to the maintenance of life
o Sits superior to the spinal cord and inferior to the cerebrum. It therefore shares
feature of each
o Contains long pathways travelling through and more localised circuits
o Can be divided into three sections (midbrain, pons and medulla)
o Contains cranial nerve nuclei which are the origin of cranial nerves
o Cranial nerves innervate the skin and muscles of the head and neck
o Brainstem
• Link between the cerebral hemispheres and the spinal cord
▪ Long pathways travel through here
• Diencephalon sits immediately atop
• Cerebellum sits behind (connected by peduncles)
• Gives rise to the cranial nerves
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Brainstem, diencephalon, cranial nerves: name the four structures that contribute to the diencephalon and briefly describe its function, giving focus to the role of the thalamus as a sensory relay and integrative centre, diencephalon. Sits superior to midbrain (brainstem) and between cerebral hemispheres: the die(cid:374)cephalo(cid:374) co(cid:374)sists of a(cid:374)(cid:455)thi(cid:374)g with the word (cid:862)thala(cid:373)us(cid:863) i(cid:374) it, they are mostly grey matter (nuclei) that have different functions. Four main structures: epithalamus, pineal gland plus some additional structures, pineal gland. Functional roles: control over basic survival strategies reproduction, growth, metabolism, hunger, thirst, temperature control, sleep-wakefulness, endocrine functions, emotional and behavioural functions. Subthalamus: associated with basal ganglia, thalamus, bilaterally symmetrical egg-shaped structure, either side of the midline third ventricle. Subdivided into a number of nuclei = functionally related neurons. Link between the cerebral hemispheres and the spinal cord. Long pathways travel through here: diencephalon sits immediately atop, cerebellum sits behind (connected by peduncles, gives rise to the cranial nerves.
