Lectures 24-25: Part 1 Flashcards
Nervous System contains…
- CNS
- Brain
- Spinal Cord
Peripheral Nervous System contains…
- Nerves
- Ganglia
Rostral
Toward the front of the head
Cephalic
Toward the head
Caudal
Toward the tail
Ipsilateral
Same side
Contralateral
Opposite side
CNS Development - 1st week following conception
Development of neural plate
CNS Development - 2nd week following conception
Neural plate invaginates to form neural groove
CNS Development - 3rd week following conception
- Neural groove closes to form the neural tube
- Neural crest cells form the dorsal root ganglia
- Notochord forms the nucleus pulposus
Primary brain vesicles
- Forebrain (prosencephalon)
- Midbrain (mesencephalon)
- Hindbrain (rhombencephalon)
(auxiliary) Brain vesicles - rostral to caudal
- Cerebrum (telencephalon)
- Thalamus & hypothalamus (diencephalon)
- Midbrain (mesencephalon)
- Cerebellum & pons (metencephalon)
- Medulla (myelencephalon)
Brainstem consists of…
- Midbrain (mesencephalon)
- Pons (metencephalon)
- Medulla (myelencephalon)
- Fourth ventricle
The brainstem is connected to the cerebellum via…
3 cerebellar peduncles
- superior
- middle
- inferior
Parts of the medulla
- Pyramids (decussation)
- Hypoglossal nerve
- Olivary eminance
- Spinal Accessory Nerve
- Vagus Nerve
- Glossophayngeal Nerve
- Cuneate tubercle
- Clava (gracile tubercule)
The Pyramids…
- located on ventral side of medulla
- contain corticospinal fibers
Parts of cerebellum
- Anterior lobe
- Posterior lobe
- Vermis
- Tonsils
Cerebellum: anterior lobe
Receives input from spine
Cerebellum: posterior lobe
Receives input from cerebral cortex
Cerebellum: vermis
- Formed first
- Equilibrium and balance
Cerebellum: tonsils
Squeeze brainstem during swelling, causing circulation to brainstem to stop
<p>Brainstem Reticular Formation</p>
<p>- drive respiratory mechanism - help integrate cardiovascular reflexes - govern muscle tone, consciousness, and awareness</p>
Brainstem Reticular Foramen: Ascending
- Ascends up to Cerebral Cortex
- Consciousness cells cycle (on/off)
- can be altered by drugs, caffeine, and anesthesia
Brainstem Reticular Foramen: Descending
- Respiration cells cycle (on/off)
Cerebellar lesions: Ataxia
gross lack of coordination and muscle movements
- Truncal: trouble holding trunk upright
- Gait: trouble walking
Cerebellar lesions: Dysynergia
inability to coordinate voluntary muscle movements
- intention tremor: tremor when trying to do something
Cerebellar lesions: Dysmetria
lack of coordination by overshoot or undershoot of limb
- past pointing
Diencephalan consists of…
- thalamus
- hypothalamus
- subthalamus
- epithalamus
Third ventricle is located…
- between the thalamic lobes
- hypothalamus as floor
- corpus collosum as roof
Thalamus
- largest portion of diencephalan
- acts as a “relay station” for information to cerebral cortex
Internal Medullary Lamina
Band of fibers seen in the thalamus that helps to separate the three different functional nuclear groups (relay, diffuse, association)
Thalamus nuclear group: relay
carry general or special sensation from incoming systems to cerebral cortex; most specific
Thalamus nuclear group: diffuse
carry information from the reticular formation to the relay nuclei (and hence to cerebral cortex); help to screen out excess info
Thalamus nuclear group: association
- interconnect various portions of the cerebral cortex with each other
- helps you to know what incoming info is
- 90% of nuclei are association nuclei; performs independently of the other two
Massa intermedia
Gray matter bridging the third ventricle and connects two lobes of thalamus
Hypothalamus
Integrating center for the autonomic nervous system
- Anterior hypothalamus (parasympathetic responses)
- Posterior hypothalamus (sympathetic responses)
Hypothalamic Sulcus
Separates thalamus from hypothalamus
Optic chiasm
Where optic nerve crosses
Diaphragma Sellae
Dura Mater that covers pituitary gland as it passes through hypophyseal fossa
Pituitary Gland: two parts
- Anterior Pituitary (adenhypophysis)
- Posterior Pituitary (neurohypophysis)
Anterior Pituitary
- Hormone production and release regulated by hypothalamus
- Thyroid Stimulating Hormone (TSH), Adrenocorticotropic hormone (ACTH), Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH)
Posterior Pituitary
- Releases hormones produced by hypothalamus
- Oxytocin and vasopressin/antidiuretic hormone (ADH)
Epithalamus
- posterior to thalamus
- houses pineal gland/body (secretes melatonin)
- Regulates sleep/wake cycle, but calcifies in adolescence
Subthalamus
- houses subthalamic nucleus (refines voluntary movement)
- prevents dyskinesia
Dyskinesia
- “bad movement”
- Hemiballismus
- Parkinson’s disease (caused by degeneration of Substantia Nigra (SN))
Where do the corticospinal fibers of the medulla cross?
at the pyramid decussation (so right brain can control left, and vice versa)
