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.