Nervous System Delia Ocampo P.2
Major functions of the nervous system
Internal process of physiology
Movement
Thinking
Major subdivisions and divisions
Central nervous system:comprised of the brain and spinal cord
Peripheral nervous system:connects the CNS to the rest of the body.
CNS has seven basic parts:spinal cord,medulla,the pons,cerebellum,midbrain,diencephalon and cerebral hemisphere
The PNS is subdivided into nerves,autonomic system and the somatic system.
Tissues
Nervous tissue: consists of cells called neuron and neuroglia
Nerve cells:sends motor commands to our muscles
There are four types of neuroglia cells found in the CNS called astrocytes,microglial cells,ependymal and oligodendrocytes. And then 2 types found in PNS called satellite and Schwann cells. The main function of the cells is to maintain homeostatic control and immune surveillance in the nervous system.
Classification of neurons
Sensory Neurons: they fire and send off signals to the rest of the nervous system.
Motor neurons: transmit impulses from the spinal cord to skeletal and smooth muscles directly control all of our muscle movement.
Interneurons: connects spinal motor and sensory neurons.
Connective Tissue Coverings
Epineurium-outer covering of a nerve
Perineurium-covering around fascicles of nerve fibers
Endoneurium-covering around individual nerve fibers
Major parts and functions of brain
Cerebrum:largest portion;associated with higher mental functions and sensory and motor functions.
Diencephalon-processes sensory input and controls many homeostatic process.
Cerebellum--coordinates muscular activity
Brainstem-coordinates and regulates visceral activity and connects different parts of the nervous system.
Major parts of spinal cord
Cervical-neck
Thoracic-chest
Lumbar-lower back and it's a thick region near the bottom of spinal cord.
Cuada-Known as horse tail and it is formed where spinal cord tapers to a point inferiorly.
Action Potential & Nerve Impulse
Action Potential:It occurs when a neuron sends information down an axon away from a cell body.
Nerve impulse: An electrical signal that travels along a nerve fiber in response to a stimulus and serves to transmit a record of sensation.
Cranial nerves
Olfactory nerve-transmits sensory information to your brain regarding smells that you encounter.
2:Optic nerve-sensory nerve that involves vision
3.Oculomotor nerve-Has 2 different motor functions muscle functions and pupil response.
4.Trochlear nerve-Controls Superior oblique muscle which that muscle is responsible for downward,upward and inward eye movements.
5.Trigeminal nerve-Largest cranial nerve and has 3 divisions which are ophthalmic,maxillary and mandibular.
6.Abdunces nerve- Controls another muscle that is associated with eye movement called lateral rectus muscle.
7.Facial nerve- moving muscles used for facial expressions,providing a sense of taste for most of the tongue and communicating sensations from the outer ear.
8.Vestibulocochlear- sensory functions involving hearing and balance it has 2 parts cochlear and vestibular.
9.Glossopharyngeal- sending sensory information from sinus
Vagus- A very diverse nerve
Accessory- Motor nerve that controls the muscles in your neck.
Hypoglossal- Movement of most of muscles in the tounge
Spinal nerves
-8 cervical
-12 thoracic
-5 lumbar
-5 sacral
-1 coccygeal
Neurotransmitters
Acetylcholine- Controls skeletal muscle actions
Norepinephrine-creates a sense of feeling good and low levels may lead to depression.
Dopamine-Creates sense of good feeling in some areas of the brain and associated with Parkinson disease.
Serotonin- Leads to sleepiness
Histamine-Release in hypothalamus promotes alertness
Autonomic nervous system
The difference between somatic and autonomic is that somatic system causes contraction of skeletal muscles and the other one controls cardiac and smooth muscle as well as glandular tissue.
Reflex Arc
Sensory receptor-detects changes
Sensory neuron- carries the information from a receptor toward CNS.
Interneuron-reflex center
Motor neuron- carries command to effectors
Effector- muscle or gland that carries out the reflex that responds to the initial change.