Set 12: Lecture 12 - Nervous System

CNS components

Brain and spinal cord

PNS components

Cranial nerves (12 pairs), spinal nerves (31 pairs), ganglia

Somatic nervous system

Voluntary control of skeletal muscle

Autonomic nervous system

Involuntary control of internal organs (sympathetic: fight/flight; parasympathetic: rest/digest)

Brain divisions

Cerebrum, Diencephalon, Midbrain, Cerebellum, Pons, Medulla oblongata

Cerebrum lobes

Frontal, Parietal, Temporal, Occipital, Insula

Frontal lobe functions

Primary motor cortex, higher intellectual functions, behavior

Parietal lobe functions

Somatosensory cortex, spatial orientation, reading/writing/math

Temporal lobe functions

Auditory cortex, olfactory cortex, language, memory with emotions

Occipital lobe functions

Primary visual cortex

Insula lobe functions

Visceral perception, gustatory cortex, emotional awareness

Left hemisphere functions

Controls right body, language, logic, analytical, verbal

Right hemisphere functions

Controls left body, non-verbal, visual/spatial, artistic, holistic

Corpus callosum

Connects cerebral hemispheres with 200-300 million axons

Limbic system components

Cingulate gyrus, Hippocampus, Amygdala (emotional brain)

Hippocampus

Major role in learning, memory, spatial processing; damaged by chronic stress

Amygdala

Processes fear, threatening stimuli, activates sympathetic ANS

Thalamus

"Gateway" to cerebral cortex; organizes, amplifies, tones down signals

Hypothalamus functions

Controls ANS, regulates temperature/hunger/thirst, controls endocrine system

Pineal gland

Secretes melatonin for sleep-wake cycles

Midbrain structures

Substantia nigra (dopamine, Parkinson's if damaged), Corpora quadrigemina (vision/auditory reflexes)

Cerebellum functions

Balance, coordination, postural reflexes, skilled movement learning

Pons functions

Regulates respiratory system depth and rhythm

Medulla oblongata vital centers

Cardiac center (heart rate), Vasomotor center (blood pressure), Respiratory center (breathing)

Cranial nerves originating from pons

Trigeminal (V), Abducens (VI), Facial (VII), Vestibulocochlear (VIII)

Cranial nerves from medulla

Glossopharyngeal (IX), Vagus (X), Accessory (XI), Hypoglossal (XII)

Phrenic nerve origin

C3-C5; motor to diaphragm for breathing

Spinal nerve count

31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Brachial plexus nerves

Axillary, Radial, Musculocutaneous, Ulnar, Median

Sciatic nerve

Largest nerve in body (L4-S3) splitting into tibial and common peroneal

Spinal cord termination

L1-L2 vertebrae

Spinal cord gray matter components

Dorsal horn (sensory), Ventral horn (motor), Lateral horn (autonomic)

Meninges layers from superficial to deep

Dura mater, Arachnoid mater, Pia mater

CSF functions

Cushions nervous tissue, provides buoyancy, exchanges nutrients/wastes

CSF production

By choroid plexuses in ventricles; ~500 mL/day, replaced 3-4x daily

Ventricles of brain

Lateral (2), Third, Fourth

Hydrocephalus

Abnormal CSF accumulation; treated with shunts (VP or VA)