Session 4: Functional Neuroanatomy: Topography of the Brain and Brainstem Flashcards
# Define & appropriately use the descriptive anatomical terms: afferent, efferent, somatic and visceral/autonomic in relation to the organisation and parts of the peripheral nervous system LO (Sem 2 self study)
Q.1. In the spinal cord, the general rule is that dorsal components tend to be concerned with?, and ventral with?
2. How does this contrast with the CNS?
A. 1. afferent (sensory) functions
efferent (motor) functions
2. In the medulla it is as if the two dorsal (sensory) components have been dragged laterally so that sensory components are no longer dorsal but lateral, and motor components now not so much anterior as medial. Higher in the brain stem the pattern becomes less and less obvious, and it has all but disappeared in the diencephalon.
Q. Knowing the info above which part of the PNS are the autonomic nerves located?
A. Dorsal part of the spinal cord if motor / efferent
Q. Define afferent
A. Towards -> towards the spinal cord from a stimulus
Q. Define efferent
A. Away -> from the spinal cord to the effector
Q. Define somatic
A. Voluntary motor control
Q. Define visceral/autonomic
A. Involuntary motor actions/ control
Understand the concept of sensory input from viscera and somatic structures to the CNS and motor output from the CNS to visceral and somatic structures by way of the peripheral nervous system LO
Understand the functional organisation of the nervous system into central and peripheral nervous systems LO
Q. What is the CNS and PNS composed of?
A. CNS: Cerebral hemispheres, brainstem & cerebellum & Spinal cord
PNS: Dorsal and ventral roots, Spinal nerves & Peripheral nerves
Define and appropriately use the descriptive anatomical terms: superior, inferior, ipsilateral, contralateral, proximal, distal, anterior, posterior, deep, superficial, medial, lateral, dorsal, ventral, rostral and caudal LO
Q. Label the diagrams stating which surfaces are the dorsal and ventral surfaces and why
Q. Label the brain with the correct axis
Q. At what location does the axis change?
A. In the medulla, pons and midbrain the ventral aspect of the neural tube is anterior, and the dorsal aspect is posterior, much as in the spinal cord. Above the midbrain, the axis bends forwards so that in the diencephalon, the ventral aspect is inferior and the dorsal surface superior.
Q. What is the meaning of rostral?
A. situated or occurring near the front end of the body (particularly nose region)
Q. What makes up the brainstem and what are their functions?
A. Midbrain (mesencephalon)
• Eye movements and reflex responses
Pons
• Feeding
• Sleep
Medulla medulla for medusa vision motor
• Cardiovascular and respiratory centres
• Contains a major motor pathway to sound and vision (medullary pyramids)
Q. What does decussation mean?
A. Fibres cross from one hemisphere to the other side of the hemisphere
Q. Define Sulci, gyri and fissures
A. Sulcus: a ‘groove or furrow’ in the brain separating adjacent gyri
Gyrus: A ‘ridge or fold’ in the brain
Fissure: A large ‘crack’ or ‘split’ between adjacent large areas of the brain
Label the frontal, temporal, parietal, occipital lobes and cerebellum (lateral aspects of cerebral hemisphere)
Image drawn wrong as lateral sulcus divides both the frontal lobe and parietal lobe above from the temporal lobe below.
The principal external features of the cortex and the primary functional sites for motor, sensory, language, hearing, olfaction and vision. LO
Q. State the function of each of the lobes
A. Frontal lobe: Higher cognition, motor function, speech
Parietal lobe: Sensation, spatial awareness
Temporal lobe: Memory, smell, hearing, olfaction
Occipital lobe: Vision
Cerebellum: Co-ordination and motor learning
Q. State where the Visual, auditory, olfactory centres are located
A. • The visual cortex is in the occipital lobe (posterior)
• The auditory cortex is on the superior surface of the temporal lobe.
• The olfactory cortex is on the under surface of the temporal lobe, principally the uncus.
Q. On the diagram label the central sulcus and the lateral sulcus and state what lobes they separate
Lateral sulcus: Frontal lobe & parietal lobe above from the temporal lobe below
Central sulcus: parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex
Q. What fissure is this image highlighting?
Median saggital fissure
Q. The large fissure between the parietal and temporal lobes is the ?
A. lateral fissure
Q. The median sagittal fissure separates the right and left hemispheres. It contains the?
A. falx cerebri
Q. What are Commissures? Give an e.g.
A. Numerous bundles of fibres (white matter) connect the two sides: these are the commissures, and the largest, deep in the sagittal fissure, is the corpus callosum.
Q. What is anterior and posterior to the central sulcus and what are their functions?
A. Precentral gyrus: the main motor area concerned with the initiation of voluntary movement
Postcentral gyrus: the main sensory area
Q. The inferior aspect of the cerebral hemisphere
- What is the optic chiasm:
- What is the uncus:
- What is the Medullary pyramids:
A. 1. A site where fibres in the visual system cross over desiccation
- Part of the temporal lobe that can herniate, compressing the midbrain (inc in ICP)
- Location of descending motor fibres (each has around 1 million axons!)
Label the optic chiasm, uncus & medullary pyramids on the diagram
Q. The medial aspect of the cerebral hemisphere
- What is the Corpus callosum?
- What is the Thalamus ?
- What is the Hypothalamus ?
A.1. Fibres connecting the two cerebral hemispheres
- Sensory relay station projecting to sensory cortex
- Essential centre for homeostasis
Q. On the diagram showing the medial surface label the white & grey matter, corpus callosum, thalamus, hypothalamus.
Q. The hypothalamus forms the floor of the third ventricle. Its most obvious features when inspecting the brain from below are the pituitary stalk and the mammillary bodies (mammilla = little mamma or breast). The hypothalamus contains the centres regulating appetite (arcuate nuclei) and much autonomic activity (e.g. temperature regulation) as well as controlling the activity of the pituitary gland.
– The posterior pituitary is a component part of the hypothalamus with direct neural connections from the ? nuclei of the hypothalamus. Hormones released by the posterior pituitary (oxytocin, vasopressin) are manufactured in the cell bodies of neurons in these nuclei, and travel down axons to the posterior pituitary where they are released into the bloodstream.
– The anterior pituitary is a separate gland that migrates from the roof of the? The hypothalamus controls it by releasing hormones into the hypophyseal portal system of veins, through which they are transported to the anterior pituitary to act upon its component cells.
A. supraoptic and paraventricular, primitive pharynx Rathkes pouch
Difference & similarities in PNS & CNS
Q. What CN does the hindbrain contain?
A. V–XII (facial sensation, and movements of the upper end of the gut tube for ingestion & phonation)
Q. What CN does the Midbrain contain? It has centres for what reflexes?
A. III and IV and the centres for eye reflexes (e.g. pupillary light reflex) and auditory reflexes.
Q. Forebrain this gives rise to the?
A. Diencephalon (thalamic structures), and the right and left telencephalic derivatives – the cerebral hemispheres (frontal, parietal, occipital and temporal lobes)
Q. Diencephalic derivatives are concerned with
A. motor and sensory coordination, regulation and control, and include the optic vesicles, which give rise to the optic nerves and retinas.
Region for diencephalon:
Q. Cerebral hemispheres are concerned with so-called ‘higher’ functions:
A. Intellectual, reasoning, long-term memory, conscious perception, and voluntary movement. In the cerebral hemispheres, unlike the spinal cord, grey matter is on the external surface, often called the cerebral cortex, or simply the cortex.
Q. It is the caudal part of the forebrain (prosencephalon) that occupies the central region of the brain. The diencephalon is comprised of the:
A.
- Epithalamus (pineal gland)
- Thalamus
- Subthalamus
- Metathalamus
- Hypothalamus
- Hypophysis cerebri
- Posterior pituitary (my input)