Nervous System Structures Nervous Systems Spinal Chord Connects

Nervous System Structures

Nervous Systems

Spinal Chord • Connects the brain and body. Also controls reflexes independently of the brain.

Brain • Embryros contain a forebrain, midbrain, and hindbrain that differentiate into the major brain parts.

Brain Stem • Brain stem – (mid brain) homeostasis, movement and conduction of information. • Medulla oblongata and Pons Transfers info from the PNS to the brain. Medulla coordinates large scale movements (running)per instruction from the upper regions and controls autonomic functions.

Brain Stem • Reticular formation – a network of neurons that filters information before it gets to the brain. • It determines whether or not you pay attention to incoming data. • Sleep is also controlled by the brain stem. Believed to help process learning and memory.

Cerebellum • Cerebellum – (hindbrain) controls movements and balance. Helps learn motor skills. • Double checks motor commands from the cerebrum. (hand eye coordination) • Receives hearing and visual input

Diencephalon • Diencephalon –(forebrain) epithalamus (pineal gland), thalamus, and hypothalamus • Thalamus – stores all information from the senses before sending them the cerebrum • Epithalamus – rhythms (sleep) • Hypothalamus – homeostasis (body temp)

Cerebrum • Cerebrum – main center of information processing • Cerebral cortex – outer layer of gray matter. Receives and processes info from the senses and somatosensory organs (pain, pressure, temp, muscles).

Cerebrum • Left and Right brain Hemepheres- each controls the opposite side of the body • Connected by axon called corpus callosum. • Lateralization – differences in the left and right • Left – better at math and logic • Right – better at recognition, patterns, and nonverbal thinking (creativity).

Cerebrum • • • Cerebral Cortex is separated into four lobes Frontal lobe – plans actions and movements Occipital lobe – visual processing Temporal lobe – Hearing and smelling Parietal lobe – speech, taste, reading

Neural plasticity • Neural plasticity – ability of the brain to change. • Synapses can be strengthened or weakened by frequency of use. • This leads to memory.

Sense receptors • Mechanoreceptors –pressure, touch, sound • Chemoreceptors – taste, smell, solute concentration • Electromagnetic receptors – light, electricity, magnetism • Thermoreceptors – detect hot and cold • Pain receptors – detects harmful conditions and solicits a reaction to minimize damage

Hearing and Equilibrium • Sound waves travel in the ear and vibrates the tympanic membrane which vibrates a bone called a stapes. • The stapes causes fluid in the cochlear duct to vibrate thus moving hairs in the cochlear duct. • The hairs sends signals to auditory nerves • Fluid in semicircular canal move hairs in response to gravity or out head tilting for equilibrium.

Taste Smell • Taste occurs when a receptor protein binds to a molecule and begin a transduction pathway that stimulates a taste nerve (chemoreceptor). • Smell (olfactory) – is all nerve cells that bind to a molecule and sends signals directly to the brain. (linning of the nose, mucus needed)

Vision • Light comes in the cornea (a fixed lens). The iris can dilate the pupil to control the amount of light that hits the flexible lens of your eye. • The retina contains photoreceptors that detect color in cones and black and white in rods (night vision). • The optic nerve carries visual input to the brain.