Anatomy and physiology 102 chapter 13 objectives

What are the parts of the brain stem (3)?

- Midbrain - Pons - Medulla oblongata

What is the Circle of Willis? What structures form the Circle of Willis? What structure does it surround?

1.) Anterior Cerebral 2.) Anterior communicating 3.) Internal carotid 4.) posterior communicating 5.) Posterior Cerebral

What are the three (3) layers of the cranial meninges?

1.) Dura Mater 2.) Arachnoid mater 3.) Pia Mater

Cranial Nerves

12 pairs of nerves that carry messages to and from the brain

What are the different motor functions of the oculomotor (III) nerve? (Iris, ciliary muscles, somatic muscles, etc.)

4 eye muscles (super rectus) (inferior rectus) (medial rectus) (superior oblique) Somatic motor functions and parasymphatic motor functions

What specialization of the dura (dural folds) separates the two cerebral hemispheres? The cortex from the cerebellum? The two cerebellar hemispheres?

A bundle of white matter commissural tracts called the corpus callosum connects the right and left hemispheres of the cerebrum.

Be able to describe the production and structures CSF travels through until it leaves the brain.

A midsagittal section identifies the sites where cerebrospinal fluid (CSF) is formed and the pathway of its circulation toward the arachnoid villi. CSF flows out from the arachnoid villi into the dural venous sinuses.

What are the dural folds? What structures form them?

Adds support and protection 1.) Falx Cerebri- which is located between the left and right hemisphere . 2.) Falx Cerebelli- between both hemispheres of the cerebellum 3.) Tentorium Cerebelli- tent between the cerebrum and cerebellum.

What are the main structures associated with the telencephalon? (E.g. corpus callosum, cerebral cortex, olfactory nerve, etc.)

Also known as the cerebrum. The structures that comprise it: the cerebral cortex, the hippocampus, the amygdala, the olfactory bulb, and the basal ganglia.

What structures contain CSF?

Cerebrospinal fluid is a clear liquid produced within spaces in the brain called ventricles. Like saliva it is a filtrate of blood. It is also found inside the subarachnoid space of the meninges which surrounds both the brain and the spinal cord.

Brain stem

Connects the brain and spinal cord

What cranial nerve innervates the cornea? What cranial nerve innervates the retina?What type of information do these nerves transmit?

Cranial nerve IV (the trochlear nerve_ innervates the superior oblique muscles, which moves the eye downward and outward. Cranial nerve VI (the abducens nerve) innervates the lateral rectus muscles, which abducts the eyes.

What are the dural sinuses? What are the choroid plexuses? Where are they located?

Dural venous sinuses- tributaries that drain blood from the head and neck. Choroid plexuses- The choroid plexus helps produce cerebrospinal fluid. A coronal brain section shows the choroid plexus in lateral ventricles. The choroid plexus is composed of ependymal cells and capillaries within the pia mater. It forms CSF from the blood plasma and ependymal cells, and then the CSF enters the ventricle.

What are the names of the fibers that connect the cortical lobes/gyri of the same hemisphere? Those that connect each hemisphere? Those that connect the cortex to subcortical structures?

Fissure - deep groove separating hemispheres Gyrus - grey matter of the cerebrum Sulcus - shallow depressions or grooves separating gyri

What are the major functions of the hypothalamus? How many regions does the hypothalamus have?

Homeostasis ANS control Food and water intake Control emotional behavior master control of endocrine system. 2 regions posterior and anterior pituitary glands.

What would you expect to happen if you fracture the Frontal bone? Occipital? Temporal? Parietal?

If a fracture were to occur to the frontal bone it would push the bone into the brain and it could allow for infections to occur easily because the barrier has been broken. This can go for all of the lobes and could disrupt the normal functions of the body.

Where is the pineal gland located? What hormone does it produce?

In the Epithalamus Melatonin helps regulate sleep-wake cycle

What substances can pass easily through the BBB? Which substances hydrophobic or hydrophilic have difficulty passing through the BBB?

Lipophilic or lipid soluble substances can cross the blood-brain barrier by the process of simple, passive diffusion. The cell membranes of the endothelial cells which form the blood-brain barrier are formed by of lipid bilayers. Lipid bilayers are made up of molecules that have a polar (hydrophilic) and a non-polar (hydrophobic) group. The non-polar groups face the centre of the bilayer, while the polar groups face the surrounding medium. Now, for any water-soluble substance, entering the non-polar, hydrophobic centre of the lipid bilayer is really difficult, as it is energetically unfavorable. As a result, such molecules are stopped at the membrane, and can not cross the barrier. Lipid soluble substances, on the other hand, are usually hydrophobic and non-polar in nature themselves, and can easily pass through the bilayers, allowing them to freely cross the blood-brain barrier.

Where is the decussation of the pyramids located? What type of nerve fiber travels through the pyramids? Where do these fibers originate? Where do they terminate?

Medulla

In which brain stem structure is the substantia nigra located? Where are the superior and inferior colliculi located? Where is the cerebral aqueduct located?

Midbrain

What areas of the body does the vagus (X) nerve innervate?

Special Sensory (Afferent) Taste from epiglottis Proprioceptors from throat Monitor BP & CO2/O2

Which cranial nerve innervates the sternocleidomastoid muscle and trapezius?

The Accessory Nerve (CN XI) The accessory nerve is the eleventh paired cranial nerve. It has a purely somatic motor function, innervating the sternocleidomastoid and trapezius muscles.

What is the Blood-brain-barrier? What property is important in allowing the transfer of substances across the barrier? What substances are transported through the BBB?

The BBB protects brain cells from harmful substances and pathogens by serving as a selective barrier to prevent passage of many substances from the blood into the brain. Lipophilic substances such as oxygen, and carbon dioxide readily pass through the BBB.

What is the basilar artery? How is it formed? After it travels along the pons, what two arterial branches does it form?

The basilar artery lies at the front of the brainstem in the midline and is formed from the union of the two vertebral arteries. The basilar artery terminates by splitting into the left and right posterior cerebral arteries.

What artery connects the two anterior cerebral arteries?

The anterior cerebral artery (ACA) is one of a pair of arteries on the brain that supplies oxygenated blood to most midline portions of the frontal lobes and superior medial parietal lobes. The two anterior cerebral arteries arise from the internal carotid artery and are part of the circle of Willis.

A continuous supply of what substances are required for brain cell metabolism?

The brain utilizes about 20% of the body's oxygen supply Any interruption of the oxygen supply can result in weakening, permanent damage, or death of brain cells.

What is the main function of the cerebellum? What sensory signals (3) are sent to the cerebellum to maintain balance? What part of the 4th ventricle is formed by the cerebellum? How many pairs of peduncles connect the cerebellum to the brain stem? Can you name them?

The cerebellum functions in the coordination of skeletal muscle contractions. Maintenance of normal muscle tone, posture, and balance. Receives sensory information from eyes, vestibular apparatus (from inner ear) and proprioception (body position receptors in the muscles, tendons,

Which statement best describes the location of the cerebellum?

The cerebellum occupies the inferior and posterior aspects of the cranial cavity. Consists of 2 hemispheres (4 lobes separated by the primary fissure) and a central vermis with surface folds (folia). 3 internal regions, cerebellar cortex, arbor vitae, deep cerebellar nuclei. 3 Cerebellar peduncles connect to the three regions of the brainstem. The cerebellum functions in the coordination of skeletal muscle contractions. Maintenance of normal muscle tone, posture, and balance. Receives sensory information from eyes, vestibular apparatus (from inner ear) and proprioception (body position receptors in the muscles, tendons, and joints).

What is the main function of the basal nuclei? What are it main structures? What structure supplies dopamine to the basal nuclei? Where are these structures located and can you identify them on a schematic?

The cerebral nuclei are paired, irregular masses of gray matter buried deep within the central white matter in the basal (deepest) region of the cerebral hemispheres inferior to the floor of the lateral ventricle. In general, the basal nuclei primarily help regulate motor output initiated by the cerebral cortex, to help inhibit unwanted movements. Diseases that affect the cerebral nuclei (such as Parkinson disease and Huntington disease often are associated with jerky, involuntary movements.

Where is cerebral spinal fluid synthesized?

The choroid plexus helps form the CSF. It forms CSF from the blood plasma and ependymal cells, and then the CSF enters the ventricle.

What structure produces CSF? Where are these structures located?

The choroid plexus is located in the ventricular system. This series of connecting hollow spaces house and circulate cerebrospinal fluid. Choroid plexus structures are found in certain locations within both lateral ventricles, as well as within the third ventricle and fourth ventricle of the brain.

Which cranial nerves are associated with the autonomic/parasympathetic nervous system?

The cranial nerves involved in the parasympathetic nervous system are the oculomotor, facial, glossopharyngeal, and vagus nerves.

What structure drains venous blood from the brain and delivers it to the jugular vein?

The dural venous sinuses are spaces between the periosteal and meningeal layers of dura mater, which are lined by endothelial cells. They collect venous blood from the veins that drain the brain and bony skull, and ultimately drain into the internal jugular vein

What type of junctions join the ependymal cells?

The ependymal cells in the ventricles are loosely joined together by special intercellular adhesion sites called desmosomes, which enable the cells to form a nearly continuous epithelial sheet over the surface of the ventricles and spinal canal.

What muscle(s) do/does the abducens (VI), Trochlear (IV) and Oculomotor (III) nerves innervate? Where do these nerves exit the brain stem? What modality are these nerves?

The eye muscle Oculomotor (CN III) Somatic motor (superior rectus, inferior rectus, medial rectus, and inferior oblique) Special motor (autonomic) Accommodation (ciliary muscle) Constriction of pupil (iris of the eye) Trochlear (CN IV) Somatic motor (superior oblique) Only CN that emerges from dorsal surface of the brainstem Abducens (CN VI) Somatic motor (lateral

What is the lumbar cistern? Where is it located? What does it contain?

The lumbar cistern is part of the lumbar spinal cord and it is located in L3 and it contains Cerebrospinal fluid.

What structure contains the cauda equina?

The spinal cord contains the Cauda Equina(a.k.a horse tail)

What senses relay through the thalamus? Which sensory modality does not? What type of information is registered in the thalamus? What happens to sensory input during sleep? What two motor support systems feed into the thalamus before the information goes to the premotor cortex?

The thalamus is the principal and final relay point for incoming sensory information that is processed and then projected to the appropriate lobe of the cerebral cortex. Only a relatively small portion of the sensory information that arrives at the thalamus is forwarded to the cerebrum because the thalamus acts as an information filter. For example, the thalamus is responsible for filtering out the sounds and sights in a crowded cafeteria when you are trying to study. Everything shuts off except the olfactory senses.

What is the Wernicke's area? Broca's area? Where are they located? What are their functions?

Wernicke's area(area 22) located only in left hemisphere and deals with sensory speech or language comprehension Broca's area(area 44-45) deals with motor speech or speech delivery they are both linked by association fibers as both part of your language system.

Brain

a complex organ that is composed of 4 subdivisions.

What are the functions associated with the Hypothalamus? Cerebellum? Thalamus? Medulla?

[\]Hypothalamus-Master control of the autonomic nervous system. Master control of the endocrine system. Regulation of body temperature. . Control of food intake. Control of water intake. Regulation of sleep-wake (circadian) rhythms. Control of emotional behavior. {|}Cerebellum- The cerebellum functions in the coordination of skeletal muscle contractions. Maintenance of normal muscle tone, posture, and balance. Receives sensory information from eyes, vestibular apparatus (from inner ear) and proprioception (body position receptors in the muscles, tendons, and joints). {+}Thalamus- is the principal and final relay point for incoming sensory information that is processed and then projected to the appropriate lobe of the cerebral cortex. {=}Medulla- connects the brain to the spinal cord. The medulla contains several NUCLEI. Autonomic nuclei (cardiovascular center, Medullary respiratory center) Nuclei associated with sensory input from proprioceptors relayed to the cerebellum (inferior olivary nucleus), and Nuclei associated with somatic sensory input (nucleus cuneatus, nucleus gracilis)

What are the fingerlike projections found in the dural venous sinuses reabsorb cerebral spinal fluid?

arachnoid villi

What cranial nerve innervates the taste buds of the posterior 1/3 part of the tongue? Anterior 2/3?

facial nerve (VII)

What color is CSF? Why? What substances in CSF is required to maintain neurons & neuroglia?

it is clear and colorless like distilled water. This is so that it can provide support and protection for the brain both from chemical and physical injuries. The choroid plexus is composed of ependymal cells and capillaries within the pia mater. It forms CSF from the blood plasma and ependymal cells, and then the CSF enters the ventricle.

Are they general senses or special senses?

olfactory nerve (CNI)

Which cranial nerve (s) attaches to the pons?

optic nerve

What are the structures of the diencephalon?

thalamus, hypothalamus, epithalamus

What are the arteries that supply the brain? What is the major vein draining blood away from the brain?

the internal carotid and vertebral arteries that supply the brain. internal jugular vein

What nerve innervates the muscles of mastication? (temporalis and masseter)

trigeminal

In a diagram, identify the central sulcus, precentral gyrus, postcentral gyrus. Occipital lobe, temporal lobe, parietal lobe. What are the major functions associated with these areas?

{}The primary somatosensory cortex is housed within the postcentral gyrus of the parietal lobes. {}The primary visual cortex is located within the occipital lobe, where it receives and processes incoming visual information. {}The primary auditory cortex is located within the temporal lobe, where it receives and processes auditory information.The primary olfactory cortex is also located within the temporal lobe and provides conscious awareness of smells. {}The primary motor cortex is located in the precentral gyrus and deals with voluntary skeletal muscle activity .