Nervous System Flashcards
What are the 2 main regions of the nervous system?
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
What are the components of the CNS
- Brain
- Spinal Cord
What are the components of the PNS?
- Sensory Structure
- Spinal Nerves
- Cranial Nerves
- Neuroglia
What are the sensory parts of the Peripheral Nervous System
- Somatic and Special sensory receptors (SNS)
- Autonomic sensory receptors and neurons (ANS)
- GI tract and entric plexus Sensory receptors and neutrons (ENS)
What are the motor parts of PNS
- somatic motor neurons (voluntary)
- Autonomic motor neurons (involuntary)
- Enteric motor neurons (involuntary)
What are the 2 divisions of the autonomic motor neurons?
- Parasympathetic
- Sympathetic
What are the effectors?
- Skeletal Muscle
- Smooth Muscle,
- cardiac muscle,
- gland
- enteric and endocrine cells of GI tract
what is nervous tissue composed of
- Neuroglia
- Neurons
what is another name for neuroglia cells?
-Glia cells
what are neuroglia cells
support cells within the nervous system
What is the function of neuroglia?
- mechanical support
- nutrient supply to neurons
- immunity
What are Schwann cells?
specialized neuroglia cells
What do Schwann cells do?
lay down a myelin sheath around axons
What is the function of the myelin sheath
acts as an electrical insulator which speeds up nerve impulse transmission along the axon
What are nerve cells (neurons)
- main functional unit of nervous system
- turn stimulus (chemical, mechanical, light) into electrical signal known as an action potential
- communicate between other nerve cells and send impulses to muscle or glands
- composed of a cell body, dendrites, and axon
What are the types of neurons?
- sensory neuron (afferent)
- Motor neuron (efferent)
- Association neuron (interneurons)
Describe Sensory Neurons
-carry nerve impulses from sensory structures and touch receptors to central nervous system
Describe motor neurons
- Carry nerve stimuli from CNS to PNS
- synapse with muscle cells to produce a contraction or with a gland to cause a secretion
Describe association neurons
-receive information from sensory or other associated neurons, process it and pass it on to another association neuron or motor neuron
What is the most prevalent type of neuron in the body?
- Association neurons
- accounts for 99% of neurons in body
What are the types of structures of neurons?
- Multipolar neuron
- Bipolar neuron
- unipolar neuron
What is the order of function as an impulse moves towards the CNS?
- Sensory Receptor
- spinal cord
- thalmus
- cerebrum
What is the order of function as an impulse moves away from the CNS?
- Cerebrum
- upper motor neuron
- spinal cord
- lower motor neuron
- skeletal muscle
Describe Grey matter
- consist mainly of cell bodies of neurons
- found on the surface of the brain
- internal, butterfly shape of spinal cord
Describe White matter where is it located?
- consists of myelinated axons
- centralized in the brain to form tracts
- peripheral with spinal cord
What are mennings
a special connective tissue layers found in the brain and spinal cord
what is the function of mennings
- protect the brain
- anchor it within the skull
- location for blood vessels
What are the major regions of the brain
- Cerebrum
- Pituitary Gland
- hypothalamus
- cerebellum
- brain stem
what are the regions of the cerebrum
- Cerebral Cortex
- basal ganglia
- limbic system
What is the structure of the cerebral cortex?
- outer grey matter (cell bodies, dendrites, unmyelinated axons, neuroglia
- expands and envelops the midbrain
- highly folded to accommodate an increased number of interneurons
- left and right hemispheres each divide into specialized lobes
What are the lobes of the cerebral cortex?
- Frontal
- Parietal
- Temporal
- Occipital
- Insula (deep to the other lobes laterally)
what are the functional areas of the cerebral cortex?
- Sensory Areas-Interpret sensory input
- Motor Areas - store and determine motor output
- Association Areas-emotions, intelligence, language
What is the basal ganglia
-involved in control of large, automatic muscle movements and muscle tone
what is the limbic system?
- “emotional brain”
- pain, pleasure, anger, fear
What is the pituitary gland?
- Release hormones (human growth hormone)
- subdivided into anterior and posterior pituitary each releasing different hormones
what is the Hypothalamus
communication centre between the endocrine and nervous system
What does the hypothalamus regulate
- release of hormones from the pituitary glands
- hunger, thirst, sexual response, and pleasure
- contains bodies thermostat
- relaxation state of body vs stress reaction
what is the relaxation state of the body called?
-parasympathetic nervous system
What is the flight or fight state of the body called?
-sympathetic nervous system
What is the cerebellum
- involved in unconscious regulation of balance and some locomotion movements
- hand eye coordination
What components make up the brainstem?
- medulla oblongata
- midbrain
- pons
what is the role of the brainstem?
- connects spinal cord inferiorly
- connects to the cerebellum, hypothalamus, and cerebrum
what is the characteristics of the medulla oblongata
-thickened stalk at the base of the brain
What is the function of the medulla oblongata
- controls subconscious activities
- ie respiration and heart rate
What is the spinal cord composed of?
- outer white matter
- inner grey matter
what is grey matter composed of?
-cell bodies of motor and sensory neurons associated with spinal nerves
What is white matter composed of?
- groups of myelinated axons
- sensory or afferent axons to the brain
- motor or efferent away from the brain
What is the spinal cord protected by?
- mennings
- bone
What is the function of the spinal cord?
- relay info to and from brain
- integrate simple responses to certain stimuli
- controls aspects of body through reflexes
What are reflexes?
-fast, automatic preprogrammed responses to internal or external stimuli
What are common reflex stimuli?
- receptors -located in skin viscera, blood vessel, muscles
- sensory or afferent neurons
- integration centres -grey matter of spinal cord segment
- motor or efferent neurons
- effector - muscle or gland
What are examples of reflexes
-withdrawing hand due to painful stimuli
-breathing rate
-heart rate
-secreting from sweat gland
blinking
What does the peripheral nervous system consist of
- 31 pairs of spinal nerves which travel the spinal cord and exit at each intervertebral space
- 12 pair of cranial nerves - exit at brain
What are nerves
bundles of axons surrounded by connective tissue coverings
What are plexuses
Spinal nerves branch when they leave the spinal cord
Define Rami
networks between nerve branches
Define Plexus
Rami that from the final nerves that supply skeletal muscles and glands
What are the 4 principle plexuses?
- Cervical (neck)
- Brachial (arms)
- Lumbar (legs)
- Sacral (legs)
what is the sensory system of the somatic peripheral nervous system?
-Sensory neurons from receptors to the CNS
What is the motor system of the somatic peripheral nervous system?
-Motor neurons form the CNS to effectors (muscle and glands)
Describe the somatic nervous system
- motor neurons controlling skeletal muscles for locomotion, feeding, speech, etc
- voluntary, consciously control this system
Describe automatic nervous system
- motor neurons are involuntary
- controls HR, digestion, excretion, glandular organs, smooth muscle of blood vessels
What are 2 divisions of the autonomic nervous system
- Sympathetic
- Parasympathetic
Describe the sympathetic nervous system
- involved in the expenditure of energy as well as flight and fight response
- increases metabolic rates
- increases Heart rate
- decreases activity of the stomach and intestines
Describe the parasympathetic nervous system
- conserves energy or (SLUDD)
- decreases metabolic rate
- decreases heart rate
- increases activity of the stomach and intestines
What does SLUDD stand for
- Salvation
- Lacrimation
- Urination
- Digestion
- Defication
