W5 Functional Anatomy of the Brain Part 1 and 2 Flashcards
what cranial nerves are associated with the telencephalon?
Olfactory CNI
what cranial nerves are associated with the diencephalon?
optic CNII
what cranial nerves are associated with the mesencephalon?
oculomotor CNIII and trochlear CNIV
what cranial nerves are associated with the metencephalon?
trigeminal CNV
what cranial nerves are associated with the myelencephalon?
CNVI to CNXII
what part of the brain is the cerebrum?
telencephalon
what part of the brain is the cerebellum?
dorsal metencephalon
what parts make up the brainstem?
medulla oblongata (myelencephalon), pons (ventral metencephalon), midbrain (mesencephalon) and diencephalon (thalamus, epithalamus, hypothalamus)
what is the largest part of the brain that carries higher functions?
cerebrum
what is the cerebrum divided into?
two cerebral hemispheres by longitudinal cerebral fissure
what are the ridges and grooves of the brain called?
ridges = gyri
grooves = sulci
what is each hemisphere of the cerebrum composed of?
grey matter superficially (neuronal cell bodies) and central white matter (axons)
what is the cerebral cortex?
the thin superficial layer of the grey matter
what does the cerebrum receive?
inputs from sensory organs to interpret vision and audition, proprioception and general sensations
what does the cerebrum initiate?
voluntary skeletal muscle movements, stores memory, voluntary motor control, behaviour and mental status
what is grey matter and where is it located?
it is made up of neuron cell bodies, located in the cerebral cortex and deep within the hemispheres of the hippocampus, basal nuclei and septal nuclei
what does white matter contain?
myelinated nerve fibres
there is a major neural connection between the right and left cerebral hemispheres known as what?
corpus callosum - the two parts communicate with each other with constant info exchange
what are association fibers?
cell bodies that lie in the cortex and interconnect adjacent gyri, they establish connection between different parts of the cortex within the same hemisphere
what are commissural fibers?
cell bodies that lie in the cortex and connects the two hemispheres (corpus callosum)
what are projection fibers?
they connect the cerebral cortex with other parts of the brain and spinal cord - connects more or less vertically)
is the cerebral cortex acquired late or early in vertebral evolution?
late
from which side of the body does the right cortex receive info from?
the left side of the body (left cortex receives from the right side of the body)
what are the three regions of each cortex?
motor, sensory and association cortexes
what does the motor cortex do?
initiates non-reflex movements, impulses from one hemisphere causes muscle movements elsewhere on the other side of the body (contralateral)
what are the main sensory areas of the brain?
the primary auditory cortex, the primary somatosensory cortex and primary visual cortex
what are the association cortexes?
the sites of complex memory, integration and planning also (in some species) self-awareness, language and personality traits
what lobes is the cerebrum broken into?
frontal, occipital, parietal, temporal and piriform
what does the frontal lobe contain?
parts of the motor cortex associated with voluntary movement and some psychomotor skills
what does the occipital lobe function as?
the visual cortex
what does the parietal lobe function as?
part of the somatosensory cortex, controlling conscious perception and localisation of pain/touch/temp
what does the temporal lobe function as?
the auditory function, behaviour and memory
what is the piriform lobe associated with?
conscious olfaction, receives input from the olfactory bulb
what area of the brain is the smallest and least changed?
the brainstem
what is the brainstem continuous with?
the spinal cord
what does the diencephalon consist of?
paired groups of nuclei separated by the third ventricle
what are the four regions of the diencephalon?
thalamus, hypothalamus, epithalamus and subthalamus
what is the thalamus composed of?
a large number of individual nuclei (grey matter) that communicate with the cerebral cortex
on each side is a large thalamus between what?
the interthalamic adhesion
what does the thalamus do?
all senses except small come here, it interprets awareness of non-localised pain/touch/temp
what are the lateral and ventral walls of the thalamus formed by?
formed by the hypothalamus
what is on the ventral surface of the thalamus?
the optic nerves that form the optic chiasm
caudal to the optic chiasm on the median plane is what?
hypophysis
the mesencephalon connects the lower brain centres and what to the higher brain centres?
spinal cord
what is the mesencephalon divided into?
a dorsal portion (tectum) and a ventral portion
four round swellings characterise the tectum region of the mesencephalon, what are these called?
corpora quadrigemina
the larger what of the mesencephalon is a visual reflex centre?
rostral colliculus
the smaller what of the mesencephalon is an auditory reflex centre?
caudal colliculus
the ventral portion of the mesencephalon includes cerebellar what?
cerebellar peduncles
what nerve arises from cerebral peduncle caudal to the mammillary body?
oculomotor nerve (CNIII)
what nerve arises from slight caudal colliculi of the midbrain?
trochlear nerve (CNIV)
what connects the third and fourth ventricles?
mesencephalic (cerebral) aqueduct-ventricular tube
where is the pons (ventral metencephalon) located?
situated between the medulla oblongata and the mesencephalon?
what are the two portions of the pons?
dorsal portion (tegmentum) and ventral portion
what fibers does the ventral surface of the pons contain?
transverse fibers
what do transverse pontine fibers produce at the surface of the pons?
a prominent bridge
how is the pons connected to the cerebellum?
by cerebellar peduncles
the pons contains the rostral end of the fourth ventricle which gives rise to which nerve?
trigeminal nerve (CNV)
what is the cerebellum and where is it located?
it is the dorsal metencephalon, it lies caudal to the cerebrum, dorsal to the fourth ventricle and brainstem
what separates the cerebellum from the cerebrum?
the transverse cerebral fissure
how many cerebellar peduncles on each side of the fourth ventricle connects the cerebellum to the brainstem?
three on each side
the white matter of the cerebellum is composed of fibers that look like a tree, what is this known as?
arbor vitae
what are the four main functions of the cerebellum?
- maintenance of balance, coordination
- control and adjust body movement
- maintain proper body position in space and coordination of movement
- motor reflex centre in coordinating subconscious and conscious skeletal muscle movements
the cerebellum is ipsilateral - what does this mean?
opposite of cerebral hemispheres - the motor effect is exerted on the same side
what is the difference in cerebellum between flying animals and flightless?
the cerebellum is much larger in flying animals due to the complexity of flight
where does the medulla oblongata extend from?
transverse fibers of the pons to the level of ventral rootlets at the first cervical spinal nerve
abducens nerve and facial nerve lie at what border?
the border between the pons and medulla oblongata
what part of the brain contains most of the fourth ventricle?
the medulla oblongata
bilateral what are present along the ventral surface of the medulla oblongata?
bilateral pyramids
together with the pons, the medulla oblongata contains what pathways?
ascending and descending
what are meninges?
these are the three layers of connective tissue that envelope the brain and spinal cord
what are the names of the three meninges?
dura mater, arachnoid layer and pia mater
describe the dura mater:
thick outer layer of connective tissue that is tough and fibrous
describe the arachnoid layer:
thin middle layer of non-vascularised connective tissue, it has many fine filaments that transverse the subarachnoid space connecting with the pia mater
describe the pia mater:
the innermost vascularised layer of connective tissue that is firmly attached to the underlying nervous tissue
what two meninges layers consist of the leptomeninges?
arachnoid and pia mater (lepto = thin)
in two places the dura mater folds inwards to form double-layered curtains, what are these two called?
falx cerebri and tentorium cerebelli
what is CSF?
cerebrospinal fluid
the subarachnoid space between the pia mater and arachnoid is filled with what?
CSF and a fine network of connective tissue fibers that originate from the arachnoid
where are the ventricles derived from?
the fluid-filled centre of the embryonic neural tube
what are the ventricles?
a series of interconnected cavities in the core of the brain that have an ependymal cell lining and are filled with CSF
how many ventricles are there?
four ventricles that connect to each other and to the central canal (in the spinal cord)
which ventricles are the lateral ventricles, where are they found?
first and second, in the cerebral hemispheres
what do the first and second ventricles connect to the third ventricle of the diencephalon via?
a narrow passage called the interventricular foramen
the aqueduct runs through the midbrain leading to the fourth ventricle which is between what two brain parts?
the medulla oblongata and the cerebellum
what produces the majority of CSF?
small arteries and arterioles in the leptomeninges and choroid plexus in the ventricles
the plexuses consist of tufts of capilaries covered by a layer of what?
ependymal cells
does the CSF flow up or down the pressure gradient from ventricles to the subarachnoid space?
down
where does the CSF pass from the subarachnoid space to?
the venous system
what are the three main routes that CSF drains from?
venules of the subarachnoid space, into the venous sinuses of the brain and by the lymphatic vessels
what is the function of CSF?
it gives the brain buoyancy and support, protecting it from mechanical trauma, provides that brain with nutrients and serves as a medium for diffusion of neuroendocrine and neurotransmitter substances
how many cranial nerves do reptiles birds and mammals have?
12 (I - XII)
what saying is used to remember the type (sensory, motor or both) of each cranial nerve in order?
Some Say Money Matters But My Brother Says Big Brains Matter More
what saying is used to remember the names of the 12 cranial nerves?
On On On They Traveled And Found Voldemort Guarding Very Ancient Horcruxes (olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossophargyngeal, vagus, accessory and hypoglossal)
describe the distribution of the olfactory nerve:
nasal mucosa membrane (smell)
describe the distribution of the optic nerve:
retina of the eye (sight)
describe the distribution of the oculomotor nerve:
most muscles of the eye (parasympathetic to ciliary), muscle of the iris
describe the distribution of the trochlear nerve:
dorsal oblique muscle of the eye
describe the distribution of the trigeminal nerve:
sensory to eye and face and motor to muscles of mastication
describe the distribution of the abducens nerve:
retractor and lateral muscles of the eye
describe the distribution of the facial nerve:
sensory to regions of the ear and taste to cranial 2/3 of tongue, motor to muscles of facial expressions, parasympathetic to mandibular and sublingual salivary glands
describe the distribution of the vestibulocochlear nerve:
cochlea (hearing) and semicircular canals (equilibrium)
describe the distribution of the glossopharyngeal nerve:
sensory to pharynx and taste to caudal 1/3 of tongue, motor to muscles of the pharynx, parasympathetic to parotid salivary glands, blood pressure control by relaying chemoreceptor info to brain from carotid arteries
describe the distribution of the vagus nerve:
sensory to pharynx and larynx, motor to muscles of larynx, parasympathetic to visceral structures of thorax and abdomen
describe the distribution of the accessory nerve:
motor to muscles of the shoulder and neck (arises from brain and spinal cord)
describe the distribution of the hypoglossal nerve:
motor muscles of the tongue
arteries to the cerebrum and cerebellum are branches from where?
the vessels on the ventral surface of the brain
in all species blood is pooled into what before branching into the brain?
cerebral arterial circle (circle of willis)
how many pairs of arteries is arterial blood supply to the brain based around?
5 pairs
which four arteries arise from the cerebral arterial circle?
rostral, middle, caudal cerebral arteries and rostral cerebellar artery
where does the caudal cerebellar artery originate from?
the basilar artery
in the dog, the arterial circle is supplied from how many sources, what are they?
three, paired internal carotid arteries and basilar artery
in dogs, carotid blood reaches most of the cerebral hemispheres except which portion?
the caudal portion
the lumen of which artery becomes occluded in the first few weeks of life in cats?
proximal 2/3 of the internal carotid artery
what supplies the arterial circle in cats?
the anastomosing rami of the maxillary artery via the rete mirabile
what artery supplies the medulla oblongata in cats?
the vertebral artery
what are the two anastomosing branches in the ox?
one from the maxillary artery and one from the vertebral artery both with rete mirabile
in the ox, what supplies the arterial circle?
internal carotid, maxillary, occipital and vertebral arteries
