Flashcards in 15CHAPTER 14: BRAIN AND CRANIAL NERVES Deck (57):
What is rostral?
toward the nose (forehead)
What is caudal?
toward the tail (spinal cord)
What are gyri?
What are sulci?
What does that longitudinal fissure do?
divides r/l hemispheres
What does the corpus callosum do?
What is grey matter composed of?
cell bodies, dendrites, proximal axons
What does grey matter form?
-Forms cortex over cerebrum and cerebellum
-Forms nuclei deep within brain (within white matter)
What is white matter composed of?
Composed of tracts (bundles of axons) that connect parts of brain
What are the different kinds of meninges?
Dura mater, arachnoid mater, pia mater
What are the two layers of dura mater and where are they?
Periosteal layer- outer, against skull, no epidural space
Meningeal layer- inner, extends to form dura mater around spinal cord
Where can you find dural sinuses and what do they collect?
-occur between the two dura layers
-collect blood that has circulated through the brain
-drain blood into internal jugular veins of the neck
What are the 2 types of dural sinuses?
Superior sagittal sinus & transverse sinus
What separates meningeal dura from arachnoid?
What separates arachnoid from pia mater?
What is the subarachnoid space filled with?
What are the ventricles lined with?
Ependymal cells (glial cells)
What do ependymal cells (glial cells) produce?
Each ventricle contains a ______________.
What is a choroid plexus and what does it produce?
Network of capillaries, produces CSF
What is the choroid plexuses covered with?
What is CSF’s functions?
-Floats brain so it is neutrally buoyant -Buoyancy
-Cushions brain from hitting inside of skull -protection
-Chemical stability -- rinses away wastes –chemical stability
How much CSF does the body produce and absorb in a day?
What are the 7 locations of circulation of CSF?
1. 2 lateral ventricles (chamber within all 4 lobes of cerebrum
2. Interventricular foramen
3. 3rd ventricle (midsagittal, between thalami)
4. Cerebral aqueduct (midsagittal)
5. 4th ventricle (midsagittal between cerebellum and pons
6. Out to subarachnoid space via 2 lateral and 1 medial aperturesbathes external brain and spinal cord
7. Reabsorbed by arachnoid ville and released into superior sagittal sinus transverse sinus mixes with blood --> internal jugular vein
When does brain damage occur?
4 minutes without blood
What does the brain barrier system regulate?
Passage of solutes from blood into tissue fluid of the brain
What are the points of entry of the brain barrier system?
1. Blood capillaries throughout brain tissue (Blood-brain barrier)
2. Capillaries of choroid plexuses in the ventricles (Blood-CSF barrier)
What is the brain barrier system highly permeable to?
Highly permeable to: H2O, O2, glucose, small lipids, caffeine, alcohol, nicotine, anesthetics, CO2
Where is the blood-CSF barrier?
At the choroid plexus lining ventricles
What do the ependymal cells join in blood-CSF barriers?
What do astrocytes do in the blood-brain barrier?
Astrocytes reach out with perivascular feet and contact capillaries à stimulate endothelial cells to form tight junctions à seal capillaries so substances leaving blood pass through cells and do not escape between them
What does the medulla conduct?
Signals up and down brainstem and between brainstem and cerebellum
What are the 2 types of signals the medulla conducts?
-Ascending tracts carry sensory information; found on the dorsal surface
-Descending tracts carry motor information; found on the ventral surface
What does the medulla contain and what crainal nerve arise from it?
Contains nuclei involved in vasomotin, respiration, swallowing, vomiting, head movements.
Nerve IX and XII
What do pons conduct?
Conduct signals up and down brainstem
What do pons contain and what nerves arise from it?
Contains nuclei involved in sleep, hearing, equilibrium, taste, eye movements, respiration, swallowing, Cranial nerve V
Where does the cerebellum get input?
From cortex (what do you want me to do?)
From vestibular system (where am I?)
And proprioception (what are my muscles doing right now?)
Where does the cerebellum get output?
Up to control centres in motor cortex via thalamus for fine adjustment
What is the function of the cerebellum?
Motor coordination, posture, balance, motor learning, some emotion
What does the midbrain do?
Connects hindbrain and forebrain
What does the midbrain conduct?
Signals up and down to brainstem
What does the midbrain contain and what nerves arise from it?
Contains nuclei involved in motor control, pain, visual attention, auditory reflexes
Gives rise to cranial nerves III and IV
What is the reticular formation?
Web of gray matter (nuclei) running vertically thru all levels of the brainstem
What are the functions of the reticular formation?
-Somatic motor control (reticulospinal tract regulates balance and posture)
-Sleep and consciousness
What is cranial nerve I? Is it sensory, motor or mixed functions and what is its function?
Olfactory – S – Smell
What is cranial nerve II? Is it sensory, motor or mixed functions and what is its function?
Optic – S – Vision
What is cranial nerve III? Is it sensory, motor or mixed functions and what is its function?
Oculomotor – M – Muscles of eye and Pupil constriction
What is cranial nerve IV? Is it sensory, motor or mixed functions and what is its function?
Trochlear – M – muscles of the eye
What is cranial nerve V? Is it sensory, motor or mixed functions and what is its function?
Trigeminal – M –chewing/ S – Facial sensation
What is cranial nerve VI? Is it sensory, motor or mixed functions and what is its function?
Abducens – M – Muscles in eye
What is cranial nerve VII? Is it sensory, motor or mixed functions and what is its function?
Facial – S –taste/ M –Muscles of facial expression
What is cranial nerve VIII? Is it sensory, motor or mixed functions and what is its function?
Vestibulo-cochlear – S – equilibrium
What is cranial nerve IX? Is it sensory, motor or mixed functions and what is its function?
Glosso- Pharyngeal – S –taste/ M –swallowing
What is cranial nerve X? Is it sensory, motor or mixed functions and what is its function?
Vagus – S – Cardiovascular regulation/ M –GI regulation and swallowing
What is cranial nerve XI? Is it sensory, motor or mixed functions and what is its function?
Accessory – M – Muscles of head, neck
What is cranial nerve XII? Is it sensory, motor or mixed functions and what is its function?
Hypoglossal – M – Tongue