Nervous System Flashcards
Nervous System has three interconnected functions:
sensory input (the conduction of signals from the sensory receptors to the brain and spinal cord
integration-the interpretation of the sensory signals
Motor output-the conduction of signals from a processing center to effector cells that actually perform the work
Nervous system is composed of two classes of cells:
Supporting cells
neurons
Central nervous system
consists of the brain and spinal cord
Peripheral nervous system
consists of nerves and receptors
Nerves
ropelike bundles of neurons that carry signals into and out of the CNS
Receptors
receives the stimulus
Peripheral nervous system [detailed]
Divided into two parts
Sensory-senses information from both internal and external environment. One set of neuron brings information about the outside environment (from the eyes, ears, and other external sense organs
The other set of neuron supplies the CNS with information about the body itself, for example, information about the acidity of the blood from sensors in the arteries.
Motor division-part of the nervous system that performs work
Motor division
Subdivided into autonomic and somatic nervous system
Somatic nervous system is under voluntary control. It carry signals to skeletal muscles, mainly in response to external stimuli
Autonomic nervous system (self-governing) is under involuntary control
Subdivided into sympathetic and parasympathetic nervous system
These divisions will have antagonistic or opposite effects because the have different sets of neurons and they respond to different neurotransmitters
Sympathetic nervous system
prepares the body for intense, energy consuming activities [FLIGHT OR FIGHT SYNDROME]
Activities of the sympathetic nervous system
Dilation of pupil, inhibition of saliva production, increased production of epinephrine and norephinephrine, stimulation of glucose release, inhibition of activities of the stomach, intestines and pancreas
Parasympathetic nervous system
primes the body for digesting food and for resting-activities that gain and conserve energy.
Activities of the parasympathetic nervous system include
Constricting the pupil, stimulating saliva production, stimulating stomach, pancreas and intestine activities
The neurons of the sympathetic system
emerge from the middle region of the spinal cord. They produce their effects by releasing norepinephrine.
Non-myelinated (gray matter)
Functions: integration
Makes thousands to million of connections with other neurons
Myelinated neurons (white matter)
Function: transmission
2 types: motor and sensory
Motor neurons
effector neurons. They perform work
Sensory neurons
affector neurons. They perceive the stimuli
Types of synapses
Inhibitory- block the propagation of the nerve impulse.
Excitatory-stimulate the propagation of the nerve impulse.
neurotransmitters
Chemicals which are released from the axonal bulb. They can either excite or inhibit the next neuron
Excitatory -stimulates the next neuron
Example: acetylcholine
Inhibitory neurotransmitters
chemicals which inhibit the passage of the message from one neuron to the next.
Examples: dopamine and serotonin
neuromodulators
Chemicals which changes the action of neurotransmitters. Examples: alcohol
Nerve impulse resting state
all neurons have an excitable membrane. At resting potential, there is a passive movement of Na+. K+, and Cl- ions. The membrane is now polarized.
Nerve impulse excited state
Channels open up in the membrane and there is an influx of ions into the axon. Sodium ions rush in and chlorine ions rush out. This results in a net negative charge inside the membrane and a net positive charge outside the membrane.
Central nervous system
Composed of the brain and spinal cord
Parts of the brain
rhombencephalon, mesencephalon, prosencephalon
Rhombencephalon
(hind brain)
Pon
reflex center, regulates respiration
Medulla oblongata
controls respiration
Cerebellum
coordinates muscle activity, and balance
Mesencephalon
midbrain
Tegmentum
contains the reticular formation involved in the fight or flight syndrome
Tectum
contains the superior and inferior colliculi-involved in vision and sound
Prosencephalon
forebrain Divided into two parts: diencephalon and telencephalon
Thalamus
recognize pain, temp, and touch. relays sensory information to the cerebrum, responsible for emotional responses and contains the reticular formation.
Divided into two parts: diencephalon and telencephalon
Hypothalamus
Links the nervous and endocrine system. Regulates and coordinates autonomic activities, regulates appetite and thirst, controls hormone production, controls homeostasis and contains the limbic system (links the psyche with physical)
Telencephalon
Cerebral cortex-which is divided into two hemispheres which are connected by the corpus callosum
Major lobes of the cerebrum
Frontal lobe-primary motor area, insight and personality
Parieral lobe-general memory, taste, touch, pressure, temperature
Temporal lobe -hearing, vision, auditory memory
Occipital lobe-smell, visual memory
Cerebral cortex
which is divided into two hemispheres which are connected by the corpus callosum
Major lobes of the cerebrum
Frontal lobe-primary motor area, insight and personality
Parieral lobe-general memory, taste, touch, pressure, temperature
Temporal lobe -hearing, vision, auditory memory
Occipital lobe-smell, visual memory
Frontal lobe
primary motor area, insight and personality
Parieral lobe
general memory, taste, touch, pressure, temperature
Temporal lobe
hearing, vision, auditory memory
Occipital lobe
smell, visual memory
