Brain and Cranial Nerves Flashcards
Name the protective covering of the brain
-Meninges (dura mater, arachnoid, pia mater)
Name and locate the brain ventricles (what are they)
- Ventricles are cavities in the brain.
- The cerebrum has the lateral ventricles
- the diencephalon has the third ventricles
- the brainstem Cerebellum has the fourth ventricle
Describe how these ventricles interconnect
the lateral and third ventricles connect through the interventricular foramen, the third and fourth ventricles connect through the cerebral aqueduct.
Explain the formation of CSF and describe its circulation (Cerebrospinal Fluid)
- formed in the blood of Choroid Plexus (makes and reabsorbs CSF) especially in the lateral ventricles
- used for transport and cushion
- circulates in the ventricles then in the subarachnoid space of brain & spinal cord
Describe the function of CSF
Cushion, nourishment and transport of nutrients/waste
Name the 4 main parts of the brain
- Medulla Oblongatta
- Pons
- Diencephalon
- cerebum
Name the 3 parts of the brain stem and describe their locations
- Madulla Oblongatta- most inferier
- Pons- Just superior to medulla oblongata
- Mesencaphalon (midbrain)- between pons and diecephalon
Which cranial nerves originates from the brain stem
3-7
Explain why the right cerebrum controls left muscular movement of the body
At the pyramids the pathways (both motor and sensory) cross to the other side of the body. (in the medulla oblangata
Describe the functions of the medulla oblongata
- All ascending/ descending tracts between brain and spinal cord (pyramidal motor tracts)
- all vital reflexes (cardiac, breathing, vasomotor, smooth muscle, and mis. control center)
- Reticular formation (RAS)- conscious and conscious
- coordinates other reflexes such as swallowing, vomiting
Describe the function of the Reticular Formations (Reticular Activating System)
- located in (mostly) medulla, pons, mesenecphalon and diecephalon
- activation leads to arousal inactivation leads to sleep (the conscious and unconscious) knocked out if punched in the face
Describe the function of the pons
- Bridges cerebrum, cerebellum and spinal cord
- aids in respiration control (deep and shallow)
Describe the function of all the parts of the mesencephalon (midbrain)
- located between pons and diencephalon
- cerebral peduncles- main descending pathways
- connects upper/ lower brain and spinal cord
- Corpora Quadrigemina
- Superior colliculi- Visual reflexes
- Inferior colliculi- Auditory reflexes
Name the 2 main components of the diencephalon. Describe their locations and functions
- Thalamus (barbell weight)
- Sensory rely- filters what goes on to cerebrum and filters what is unimportant infor out.
- except for olfaction
- Hypothalamus(below)
- Homeostasis
- regulates ANS fight or flight, release and produces hormones, receives sensory information on internal environment, regulates temp, water balance, appetite, sexual activity, mid over body emotions.
- Homeostasis
Name the largest portion of the human brain
Cerebrum
Define cerebral cortex
-Gray matter (outer) cerebrum
Define Gyrus or Convolution (to Cerebrum)
-convolutions or folds
Define Sulcus (to Cerebrum)
-groves (little dips)
Define Fissure (to Cerebrum)
-Deep groves
Name the four lobes of the cerebrum
- Temporal
- Frontal
- Occipital
- Parietal
Name the 3 fiber tracts in the white matter of the Cerebrum, Describe their general functions
- Projection Fibers
- Carries descending motor information from cerebral cortex, carries ascending sensory information from lower brain to cerebral cortex
- Association Fibers
- Connects ipsilateral areas of the cerebral cortex
- Commissural Fibers
- from one hemisphere to the other (corpus Callosum)
Name the furrow that divides the cerebrum into left and right hemispheres. how are these hemispheres internally connected.
- Longitudinal Fissure
- They are internally connected by the corpus callosum
Name the surface layer of gray matter of the cerebrum. Name the gray matter just deep to this.
- Cerebral cortex
- Basal nuclei which “fine tunes” motor activity
Name the 9 functional areas of the cerebral cortex. Describe the basic functions of each area and their general location.
- Motor area (frontal)
- Premotor area (frontal)
- Motor Speech area (frontal)
- General sensory area (parietal)
- Taste area (parietal)
- Visual area (occipital)
- Olfactory area (temporal)
- Auditory area (temporal) -words into coherent thoughts)
- Association area (all loves)
- iq, foresight, judgement, process sensory info for motor response.
Describe the general function of the basal nuclei
- Controls skeletal muscles, inhibits some muscles to allow precise control of movements.
- to assure smooth motor activity
Describe the location and function of the limbic system.
- emotional aspects of behavior related to survival as finding sex pleasurable relates to the survival of humans.
- hippocampus-organizes experiences for memory
- Amygdala- mediates emotional responses based on senses
- located in the cerebrum and diencephalon
Contrast functions of the left vs right hemispheres of the brain.
- Generally, left brain controls right hand, speech and analytical skills; math science, sequencing, speech and language
- right brain controls artistic abilities, thinking in 3-D, visual patterns, imagination, emotion and left hand.
Describe the location and function of the cerebellum. Name the furrow that divides the cerebellum from the cerebrum
- located in the 4th ventricle, inferior & posterior brain
- it is control of coordination and equilibrium.
- transverse fissure separates it from cerebrum.
Define cranial and mixed nerve
- Nerve going to or from brain, mixed contains both sensory and motor info.
- They are all mixed except I, II, VIII
Name the cranial nerves, their functions, whether they re mixed and through which foramen each travels
- Olfactory nerve-1
- Optic Nerve-2
- Oculomotor nerve-3
- Trochlear nerve-4
- Trigeminal nerve-5
- Abducens Nerve-6
- Facial Nerve-7
- Acoustic Nerve-8
- Glossopharyngeal Nerve-9
- Vagus Nerve-10
- Accessory nerve-11
- hypoglossal nerve-12
Describe sensory pathways to the brain
-Ascending and crosses to the other side at the pyramids.
Describe the motor pathways away from the brain
- Descending. If it goes through the pyramids, it crosses to the other side of the body and consists of two neurons, the UMN in the CNS and then the neuron going to the effector in the PNS, the LMN.
- This pathway is known as the corticospinal pathway.
- If it does not go through the pyramids, it is an ipsilateral polysynaptic pathway involved more with posture, rather than voluntary movement.
Define UMN (upper motor neuron) and LMN (lower motor neuron)
-UMN is motor neuron in CNS and LMN is motor neuron in PNS
Describe some possible mechanism of memory
-anatomical changes, synapse changes, more synaptic pathways, more neurotransmitter.
I. Olfactory nerve
- enters from the cerebrum
- exits through the olfactory foramina in the cribriform plate of the ethmoid
- Function: sensory only, sense of smell (does not go though the thalamus, goes straight to temporal lobe)
II. Optic Nerve
- Enters from diencephalon
- Exits through optic canal of sphneoid
- Function sensory only vision. (goes thru thalamus to occipital lobe)
III. Oculomotor nerve (eye Movement)
- Enters brain stem
- Exits through superior orbital fissure f sphenoid
- Function: Motor: Intrinsic and extrinsic eye muscle, Sensory: proprioception
IV.Trochlear nerve
- Enters-brain stem
- Exits superior orbital fissure of sphenoid
- Function Motor: Extrinsic eye muscle Sensory: Proprioception
V. Trigeminal nerve
- Enters from brain stem
- Exits
1) ophthalmic branch exits thru superior orbital fissura (sensory to eye)
2) Maxillary branch exits thru foreman rotundum of sphenoid
3) Mandibular branch exit thru foramen ovale of shenoid - Function: Motor: Chewing Sensory: face scalp tear glands mucous membrane
VI. Abducens Nerve
- Enters from brain stem
- Exits through superior orbital fissure
- Function motor: extrinsic eye Sensory: proprioception
VII. Facial Nerve
- Enters brain stem
- Exits thru the stylomastoid foramen of temporal bone
- Function Motor: Facial expression, salivation, lacrimation. Sensory: Taste
VIII. Acoustic Nerve (Vestibulocochlear nerve)
- Enters Brain stem
- Exits the internal auditory meatus of temporal bone
- Function: Sensory only. Vestibular brance for equilibrium, cochlear branch sensory for hearing
IX. Glossopharyngeal Nerve (tongue throat)
- Enters brain stem
- Exits the juglar foramen of temporal bone
- Function Motor: Swallowing salivation Sensory Taste
X. Vagus Nerve
-Most important cranial nerve as it goes to the viscera of the thorax and abdomen
-Enters Brain stem
-Exits juglar foramen
-Function: ANS (the parasympathetic Nervous system- rest and Digest)
Motor: visera of thorax sensory: proprioception
XI. Accessory nerve
- Enters (2 nerves) one from brain stem, one from cervical spinal cord
- Exits- juglar foamen
- Function- motor pharynex and larynx and head movement and swallowing, sensory proprioception
XII. hypoglossal nerve
- Enters- brain stem
- Exits- hypoglossal canal of occipital bone
- Function- Motor tongue sensory of tongue proprioception
