Nervous System Connections CNS: Brain & Spinal cord PNS: - PowerPoint PPT Presentation

Nervous System Connections CNS: Brain & Spinal cord PNS: Ascending & descending nerves

• CNS – Brain, spinal cord – Processing center – Nuclei • PNS – Spinal & cranial nerves – Information relay system – ganglia

Cranial nerves • I – Olfactory S • II – Optic S • III – Oculomotor M • VI – Trochlear M • V – Trigeminal SM • VI – Abducens M • VII – Facial SM • VIII – Auditory (Vestibulocochlear) S • IX – Glossopharyngeal SM • X – Vagus SM • XI – Spinal Accesory M • XII – Hypoglossal M

Divisions of PNS • Somatic – Voluntary • Autonomic – Visceral (involuntary)

• CNS – Brain, spinal cord – Processing center – Nuclei • PNS – Spinal and cranial nerves – Information relay system – ganglia

Divisions of PNS Unconscious Conscious control control

Basic regulatory & reflex functions in brainstem

Support and Protection • Meninges encase brain & SC • Three layers: • Dura mater • Arachnoid • Pia mater • Between layers: • Cerebrospinal fluid (CSF; airbag for brain)

Ventricles

Meninges (spinal cord) • Dura mater: outer layer – Subdural space; Serous fluid (lubricant) • Arachnoid mater: – Subarachnoid space (between arachnoid and pia) filled with CSF & blood vessels • Pia Mater: inner layer – Shrink wrapped to spinal cord & brain

Spinal cord anatomy • Gray matter: cell bodies & unmyelinated axons • White matter: Myelinated axons

Major Features of Brain

Vertebrate Brain • Hindbrain – Medulla oblongata – Pons – Cerebellum • Midbrain • Diencephalon – Thalamus – Hypothalamus • Telencephalon – Cerebral cortex, (white & gray matter)

Vertebrate brain • Mesencephalon : Visual and Auditory reflex centers (head-turning) • Pons : Relay station for sensory info. • Medulla oblongata : Regulate cardio, respiratory, digestive activities

Medulla Oblongata • Regulatory Nuclei: – heart & respiratory rate, blood pressure, coughing, sneezing, vomiting, swallowing, balance, coordination, digestion, sleep • Pyramids: – Descending motor nerves; conscious control of skeletal muscle

Pons • Ascending & descending nerve tracts • Regulatory nuclei: – Chewing & salivation; respiration – Initiates sleep • Relay nuclei: – Reticular Formation : Share info between cerebrum & cerebellum

Reticular Formation • Filters out the humdrum • Relays the novel & exciting

Midbrain • Reflex nuclei – Visual reflex; startle & tracking – Auditory reflex & nerve tracts • Regulatory nuclei – Lens shape, pupil diameter – Initiates & terminates body movements – Initiates arousal

Diencephalon • Thalamus – Ascending sensory neurons synapse here; project to cerebrum • Epithalamus – Emotional & visceral response to odors; pineal body regulates long-term cycles • Hypothalamus – Maintaining homeostasis via hormone release

Cerebellum • Gray and white matter • Balance; maintains muscle tone; coordinates fine muscle movement • Comparator : integrates proposed movements with current body position to produce smooth, exact movement • Involved in learning new balance-intensive activities – Riding a bike, yoga, climbing

Movement & Body position

Cerebrum & its Regions Complex info. Processing • Conscious thought • Reasoning • Memory creation & storage

Cerebral Space

Axons connect CNS - CNS and CNS -PNS Association, commissural, projection

Axons connect CNS - CNS and CNS -PNS