Human Physiology The Central Nervous System ▪Thing to be covered ▸ Anatomy of the CNS ▸ The...

Human PhysiologyThe Central Nervous System

▪Thing to be covered▸Anatomy of the CNS▸The Spinal Cord▸The Brain

Human PhysiologyThe Central Nervous System

▪Anatomy of the CNS▸The Skull or Cranium (for brain)

▸The Vetebral Column (for spinal cord)

▸Meninges –Dura mater (outermost layer)

–Arachnoid membrane ( middle layer)

–Pia mater (innermost layer)

Human PhysiologyThe Central Nervous System

▪Cerebrospinal Fluid (CSF)▸Cranial vault - 1.4L; cells - 1.0L; blood - 0.1-

0.15L; CSF - 0.2-0.3L▸Colorless, salty solution▸Continuously secreted from specialized cells

(ependymal cells) in the choroid plexus in ventricles▸Ependyma actively transport Na+ and solutes into

ventricles▸Functions: Physical and chemical protection

▸Contains little protein and lower K+, Ca++, HCO3-,

and glucose

Human PhysiologyThe Central Nervous System

▪Path of CerebroSpinal Fluid

Human PhysiologyThe Central Nervous System

▪Three-dimensional view of the ventricles of the Brain

Human PhysiologyThe Central Nervous System

▪The Blood-Brain Barrier (BBB)▸Function - protection▸Brain capillaries much less permeable than others▸Protects the brain from blood composition

fluctuations▸Can transport nutrients into the ISF▸Exceptions - posterior pituitary and vomiting center

Human PhysiologyThe Central Nervous System

▪Divisions of the CNS▸Gray matter▸Nuclei▸White matter▸Tracts - ascending and descending▸Spinal cord

–Dorsal root (afferent, sensory)

–Ventral root (efferent, motor)

–Dorsal horns

–Ventral horns

–Dorsal root ganglion

Human PhysiologyThe Central Nervous System

Human PhysiologyThe Central Nervous System

▪Organization of the grey matter of the spinal cord

Major ascending and descending pathways

of the spinal cord

Human PhysiologyThe Central Nervous System

▪The Brain▸Cerebrum▸Brain stem▸Cerebellum

▸Forebrain - cerebrum and diencephalon▸Brain stem - midbrain, pons, medulla

Human PhysiologyThe Central Nervous System

▪The Brain Stem▸Contains the third and fourth ventricles▸9 cranial nerves emerge (know tables 9-1 & 2 )▸Medulla oblongata contains vital centers▸Pyramids▸Midbrain or mesencephalon controls eye and ear

functions▸Reticular formation - arousal and sleep

Human PhysiologyThe Central Nervous System

▪The Cranial Nerves (Know Table 9-1)▸I Olfactory▸II Optic▸III Oculomotor▸IV Trochlear▸V Trigeminal▸VI Abducens▸VII Facial▸VIII Vestibulocochlear▸IX Glossopharyngeal▸X Vagus▸XI Accessory▸XII Hypoglossal

Human PhysiologyThe Central Nervous System

▪The Cerebellum▸Process sensory information▸Coordinates muscle activity▸Involves cordinating balance and equilibrium

▪The Diencephalon▸Composed of thalamus and the hypothalamus▸Also contains the pineal gland▸Thalamus has several nuclei and is described as a

relay station for signals on their way to the cerebral cortex▸The hypothalamus contains centers for behaviorial

drives and homeostasis (See Table 9-2 for more info)▸It controls both endocrine and autonomic functions▸Receives information from various sources

Human PhysiologyThe Central Nervous System

▪The Cerebrum: Lobes and Fissures of the Cerebral Hemispheres: Lateral Left

Human PhysiologyThe Central Nervous System

▪The Cerebrum: Lobes and Fissures of the Cerebral Hemispheres: Medial surface

Lobes:

1. Frontal

2. Parietal

3. Occipital

4. Temporal

5. Limbic

Human PhysiologyThe Central Nervous System

▪Major Regions of the Cerebral Hemipheres

Human PhysiologyThe Central Nervous System

▪Functional Area of the Cerebrum

Human PhysiologyThe Central Nervous System

▪Motor and Sensory Areas of the Cerebrum

Human PhysiologyThe Central Nervous System