Anatomy Lecture 11 - CNS
Describe the structure and functions of the cerebellum.
Located posterior and inferior to the cerebrum, gray and white matter (arbor vitae). Fine motor motions, balance, equilibrium
Which plexus gives rise to the sciatic nerve?
Lumbosacral
What cranial nerve is responsible for controlling eye movements by innervating the superior oblique muscle?
CN IV Trochlear Nerve
What cranial nerve is responsible for innervating the sternocleidomastoid and trapezius muscles?
CN XI Accessory nerve
There are ____ pairs of spinal nerves.
31
Describe the embryonic development of the divisions of the brain.
After the formation of the endoderm, mesoderm, and ectoderm, the neural tube forms the specialized part of the ectoderm called the neural plate by making a neural groove and transversely folds in on itself, forming the neural tube. On the sides of the neural tube are the neural crests, which migrate away from the CNS and will become part of the PNS and craniofacial cartilage/bone and melanocytes AT 25 days, brain/spinal cord begin to form. These are called primary vesicles. First is the prosencephalon (which is the cerebrum), then the mesencephalon (the midbrain), and the rhombencephalon (the hindbrain). Later, the secondary vesicles emerge. The Pros makes the telencephalon (cerebrum) and the diencephalon (thalamus and hypothalamus, eye cups). The mes stays as it and will form the midbrain. The Rhomb becomes the metencephalon (pons/cerebellum), and myelencephalon (medulla)
Differentiate between association, commissural, and projection white matter tracts.
Association - connect gyrus to gyrus and lobe to lobe in same hemisphere (run anterior to posterior) Commissural - connects the two hemispheres (corpus callosum) Projection - connects different brain structures and regions together (thalamus to cerebral cortex or cerebral cortex to spinal cord, usually run superior-inferiorly)
Please label the median nerve.
At the end of the brachial plexus, there's an "M" and the middle branch is the median nerve. (On the diagram in the HW, it's the green nerves, answer D)
You are about to assist a surgeon on a patient who broke the distal end of their left radius. To aid your patient's pain management after they wake up from surgery, a nerve block needs to be performed. What plexus does the anesthesiologist target for your patient?
Brachial
Which of the following is the most likely place for a parasympathetic preganglionic neuron cell body?
Brainstem
Identify the origin, composition, functions and location of cerebrospinal fluid. Identify the brain ventricles where CSF is found. Give the causes and symptoms of hydrocephalus.
CSF is formed by clusters of ependymal cells called choroid plexus in the ventricles. It contains water, small molecules, and electrolytes. It moves from the thalamus/hypothalamus in the 3rd ventricle through the cerebral aqueduct into the 4th ventricle, around the central canal up into the subarachnoid space. It also circles around the cerebellum and the right/left lateral ventricles Hydrocephalus is an excess of CSF in the ventricles of the brain. Can be from overproduction of CSF, a blockage of flow between ventricles, or impaired drainage into dural sinuses. Increased cranial pressure/neurological problems/death
Describe the location and general functions of the following gray matter areas: cerebral cortex, basal nuclei (caudate, putamen, globus pallidus), amygdala, and hippocampus.
Cerebral Cortex - outside gray matter - interneurons that process information and send out motor responses Basal Nuclei: starting, stopping, and monitering movement (caudate, putamen, globus pallidus) Amygdala - creates long-term memory and strong emotional responses (like fear/love) Hippocampus - long-term memory formation/emotional responses
On a longitudinal diagram of the spinal cord, label each of the following structures. Cervical spinal nerves Thoracic spinal nerves Lumbar spinal nerves Sacral spinal nerves Coccygeal spinal nerves Conus medullaris (where is this located in the vertebral canal?) Cauda equina (what is it composed of?)
Cervical Spinal Nerves - C1-C8 Thoracic Spinal Nerves - T1-T12 Lumbar Spinal Nerves - L1-L5 Sacral Spinal Nerves - S1-S5 Coccygeal Spinal Nerves - Co1 (just one) Conus Medullaris is at L1 or L2 Cauda Equina - when the vertebral column grows, the nerves grow with it but are already in the intervertebral foramen, so it ends up as a bunch of nerves going to the conus medullaris (nerve roots and axons)
Describe the location and function of the limbic system.
Cingulate gyrus, parahippocampal gyrus, fornix, hippocampus, amydala (located medially but extends laterally). Controls emotion! memory, and motivation
What structure is indicated by C? (Bulb coming out of the spinal cord on the dorsal root)
Dorsal root ganglion (these are sensory nerve bodies)
Describe the characteristics and functions of the three meninges and the dural septa.
Dura mater - tough, encases and protects CNS and lines cavities Dural Septa - fit into crevices of brain, keep brain and cerebellum in proper position, supports venous sinuses Arachnoid mater - sac-like, spiderweb-y, forms subarachnoid space where trabeculae are found, and is filled with CSF. CSF is filtered here back into the book. Pia mater - tight to the surface of the brain (can't see), holds blood vessels next to the surface of the skin, gentle covering of brain
What portion of the autonomic nervous system is responsible for controlling smooth muscle and glandular tissue in the digestive system?
Enteric nervous system
State the basic functions of each of the cerebral lobes.
Frontal - motor response in precentral gyrus, personality, production of language, decision making, social behaviors Parietal - somatosensation (interpreting the senses on the postcentral gyrus - such as proprioception and kinesthesia, speech, touch, pressure, paid, itch, vibration) Temporal - Audition (hearing) and olfactory sensation, some long term memory Insula - taste Occipital - vision
The parasympathetic nervous system is responsible for:
Increasing digestion (Rest and Digest)
Identify the components of the brainstem and describe their functions.
Midbrain, Pons, Medulla (oblongata) - heart rate, blood pressure, respiration, reflexes like coughing/sneezing/gagging/vomiting, sleep/wake cycles and alertness/arousal, cranial nerves connect to brainstem and provide sensory input
The picture shows which type of reflex?
Monosynaptic reflex
Identify the following areas/structures of the cerebrum. Frontal lobe, parietal lobe, temporal lobe, occipital lobe, insula Longitudinal fissure, central sulcus, lateral sulcus, parietooccipital sulcus Precentral gyrus, postcentral gyrus Corpus callosum
See anatomy textbook for more details
If you were to accidentally place your hand on a hot surface, the withdrawal reflex would ensure that you yanked your hand away quickly. What is the order of the neurons that lead to this reaction?
Sensory neuron; interneuron; motor neuron
Explain how the primary and somatosensory cortices are organized (describe the homunculus).
Somatosensory - touch, vibration, proprioception, temp, pain. Postcentral gyrus (parietal lobe) Homunculus (little man) is the map of the body that starts in the longitudinal fissure with the feet, and moving outward is the rest of the body moving upward. The hands, lower face, and other sensitive areas are much bigger Primary Motor Cortex - Precentral gyrus (Frontal). The homunculus is the same, but is for movements instead of sensation. The greatest space is given to fine, agile muscle movements
Which of the following contains preganglionic neurons and postganglionic neurons?
Sympathetic nervous system
Identify the divisions of the diencephalon and describe their functions.
Thalamus - relay center for sensory info (except olfaction), processes info and decides what's important, influences basal nucl/ Hypothalamus - Limbic system, processes emotion and sensory information to maintain homeostasis (sleep/wake cycle, hunger/thirst, body temp), autonomic nervous system Epithalamus - Pineal gland - secretes hormones and connects limbic system to other parts of brain Subthalamus - connects to globus pallidus and excites it (don't really need to know this...)
Parasympathetic neurons leave the spinal cord at the level of the brainstem and sacral spinal cord. Where do sympathetic neurons exit the spinal cord?
Thoracic and lumbar levels
When you visit your grandmother, she kisses you on the cheek. Which cranial nerve is responsible for directing this touch sensation from your cheek to your central nervous system?
V (Trigeminal nerve V)
The hypoglossal nerve is cranial nerve number ________ and is responsible for ________.
XII; tongue movement
Sensory neurons found within spinal nerves connect with the skin in a topographically organized manner, illustrated as ________ .
dermatomes
The _______ plexus contains the phrenic nerve. The phrenic nerve innervates the _______.
cervical; diaphragm
#2 is a _____ neuron and its neural impulse is _____. (red neuron on quizlet diagram)
motor / efferent
Motor neuron cell bodies are found in the ___________ and their axons are found in the ___________.
ventral horn; ventral root
