Vert. Anat. Last Practical Flashcards
Telencephalon
Forebrain; cranial to the notochord
mesencephalon
Midbrain; overlies cranial end of notochord, has a thick dorsal root
Diencephalon
Forebrain; ventral (?) to the otic vesicle
Ganglia
Exist for dorsal cranial nerves 5, 7, 8, 9, 10 - these contain cell bodies of sensory neurons
-Motor neurons (3, 4, 6, 12) do not have ganglia
Tissue lining the coelom surrounding the pericardial cavity
somatic mesoderm
Tissue lining the pericardial cavity
Splanchnic mesoderm
Neural Canal
Space inside the neural tube. In the brain, it is enlarged to form the ventricles
Ependymal layer
Single layer of cells lining the canal.
-All cells of the neural canal are made up by mitosis of these cells
Mantle layer
layer of glial + axon cells surrounding the ependymal layer
Marginal layer
Layer of glial + axon cells surrounding the mantle layer
Endoderm
Lines the pharynx and gut
Infundibulum
the ventral part of the diencephalon, adjacent to the stomodeum.
Forms the posterior pituitary and the hypothalamus.
Sensory Layer
Thick layer of the retina, contains the light-sensing cells (rods & cones)
Archicortex
the dorsal (top) part of the cerebral cortex. Largely functions in memory
Hippocampus
The archicortex of mammals
Paleocortex
the ventral part of the cerebral cortex, functions largely in olfactory
Olfactory bulbs
outpockets of paleocortex
Neocortex
forms between paleocortex and archicortex in later tetrapods
Terminal nerve (0)
contains somatic sensory axons from part of the nasal region
- very thin
- in tetrapods, it incorporates into V
Olfactory nerve (I)
consists of axons from the olfactory epithelium (nasal passages) to the olfactory bulbs
- very shory
- occur where the olfactory bulb comes into contact with olfactory epithelium
Epithalamus
the dorsal roof of the diencephalon
-includes the tela choroidea, plus pineal glans, and parapineal
Tela choroidea
the very thin dorsal roof of the neural canal of parts of the diencephalon, metacephalon, and myelencephalon
-covered by the choroid plexus, a network of blood vessels
Pineal gland
an outpocketing of the epithalamus that excretes melatonin in response to light levels
Parapineal
an accessory light-sensitive organ located cranial to the epiphysis
Thalamus
the lateral wall of the diencephalon
-relaying & filtering input to the telencephalon from other parts of the nervous system
Hypothalamus
ventral part of the diencephalon
-control of visceral motor systems and hormone secretion
Pituitary gland
pulls off when the brain is removed; posterior and anterior
Posterior Pituitary
a ventral outpocketing of the hypothalamus
Anterior Pituitary
a dorsal outpocketing of the stomodeum
Tectum
the dorsal part of the mesencephalon
- the main “decision center”
- Receives sensory input from all parts of the body and initiates somatic motor output via the tegmentum
Tegmentum
the ventral part of the mesencephalon
-control of visceral and somatic motor systmes
Oculomotor nerve (III)
the main nerve of the eye muscles
- focus the eye and adjust the pupil
- innervates the intrinsic muscles plus 4 of the 6 extrinsic muscles that rotate the eye
Trochlear nerve (IV)
supplices motor innervation to the superior oblique muscle (an extrinsic eye muscle)
Cerebellum
a dorsal outpocketing of the metencephalon
-functions as motor coordination and balancing
Medulla oblongata
a general term for the hindbrain (met & my) excluding cerebellum
Nerves V, VIII, IX, X
dorsal cranial nerves
-carry sensory, branchiomeric motor, and visceral motor (parasympathetic) axons
Trigeminal nerve (V)
Dorsal cranial nerve in branchial arch 1
- most anterior of the dorsal cranial nerve
- 3 branches: Superficial opthalmic, Infraorbital, Mandibular
- -upper face, upper jaw, & lower jaw
Nerve VIII
Dorsal cranial nerve in branchial arch 2
Nerve X
Dorsal cranial nerve in branchial arches 4-6 (and 7 if present)
- Parasympathetic to salivary glands & thorax organs (incl. heart)
- run along the side of the met & myel
abducens nerve (VI)
supplies motor innervation to the lateral rectus muscle (an extrinsic eye muscle)
Superficial ophthalmic branch
a branch of nerve V
-sensory from the dorsal part of the snout
Infraorbital branch
a branch of nerve V
-sensory to the ventral part of the snout (overlying the upper jaw)
Mandibular branch
a branch of nerve V
-sensory from the lower jaw, plus motor to the branchiomeric muscles of the 1st branchial arch (mandibular adductor, 1st branchial constrictor, etc)
Hypobranchial nerve
formed by hypaxial rami of spinal nerves at the cranial end of the spinal cord
-in tetrapods this part of the spinal cord is incorporated into the brains, so that the hypobranchial nerve becomes cranial nerve
Metencephalon
located behind the mesencephalon and in front of the myelencephalon
- Cranial to the otic vesicle
- contains nerves V, VII & VIII
Myelencephalon
last part of the hindbrain
-contains nerves IX & X
Ganglion of VII & VIII
located cranial to the otic vesicle
-VII is the sensory from face, mouth, pharynx, taste buds, and ears. Runs along met & myel
Ganglion IX & X
located caudal to the otic vesicle
Meninges
3 layers of connective tissue that surround and protect the brain & spinal cord
Palatoquadrate cartilage
cartilage of the upper 1st arch
Meckel’s cartilage
cartilage of the lower 1st arch
Glossopharyngeal n.
IX
3rd branchial arch
-Branchiomeric motor to facial muscles & larynx
-along met & myel
Facial n.
VIII
2nd branchial arch
-Develops from a branch of VII to the region of the epidermis that forms the otic placode
Vagus n.
X
4th branchial arch
Neuromeres
segments of the hindbrain (met & myel)
gyri
folds of cortex
sulci
grooves between cortex folds
superior and inferior colliculi
make up the tectum in mammals
- unconsciour reflexes such as focusing the eyes, tracking movement, turning head toward sounds
- superior = visual
- inferior = auditory
Descending tracts
collections of axons that carry motor signals down from specific parts of the brain to the spinal cord
-cover the ventral surface of the brain in mammals
Pyramids
Descending tracts that cover the ventral surface of the hindbrain
-in mammals, these tracts connect the motor cortex of the telencephalon directly to somatic motor neurons in the spinal cord
Cerebral peduncles
Descending tracts that cover the ventral surface of the mesencephalon
-the tegmentum is located deep inside
Cranial Nerve XI
Branchiomeric motor to trapezius, sternocleidomastoid, & levator scapulae muscles
-develops from a motor branch of X, in tetrapods only
Cranial Nerve XII
Somatic motor in tongue muscles
- Occurs in tetrapods only
- Corresponds to hypaxial rami of the first few spinal nerves in fist
- Innervates hypobranchial muscles that form the tongue in tetrapods
Corpus callosum
a thick band of white matter than consists of axons connecting the left and right cerebral cortex
Fornix
a tract that carries signals from the hippocamupus to the mammillary body (in the hypothalamus)
-part of the loop of the limbic system
Medulla oblongata
- a general term for most of the metencephalon and myelencephalon, excepts for the pons and cerebellum
- dorsally the tracts relay sensory signals upward from spinal cord to brain
- ventrally the medulla oblongata consists of nuclei involved in motor control of internal organs and tracts that relay motor signals downward from the forebrain and midbrain
Cortical tracts
include association fibers, commissural fiber, and projection fibers that connect different areas of the cerebral cortex
-form a thick layer of white matter that underlies the cerebral cortex
Basal nuclei
develop from the ventral part of the telencephalon
-relay signals from the cerebral cortex to other areas of the cerebral cortex and to motor nuclei of the mid & hindbrain
limbic system
parts of the hippocampus, the hypothalamus (mammillary body) and the thalamus
