Introduction to CNS and PNS Flashcards
What are the main functions of the nervous system (NS)?
Detects changes in external and internal environments and brings about responses in muscles, organs, and glands.
What higher functions have evolved in the nervous system?
Learning, memory, cognition, self-awareness, intellect, and personality.
What are the two main components of the nervous system?
CNS: Brain and spinal cord; PNS: Links CNS to body, receives sensory info, and sends controlling impulses.
What is the CNS, and what are its characteristics?
Brain and spinal cord protected by cranium and vertebral column; harbors most nerve cell bodies and synapses.
What is the PNS, and what are its characteristics?
Connects CNS to peripheral body; includes cranial and spinal nerves, forming brachial and lumbar plexuses.
What is the structure of a neuron?
Cell body with dendrites (receptors) and axon (sends impulses), ending in terminal boutons for synaptic transfer.
How is information passed between neurons?
Through synapses, where adjacent cell membranes closely interact for signal transfer.
What are afferent neurons and their function?
Carry information from peripheral receptors to the CNS; sensory if conscious level is reached.
What are efferent neurons and their function?
Carry impulses away from the CNS; motor neurons if innervating skeletal muscles.
What are interneurons?
Neurons entirely within CNS, acting as cortical afferents or efferents depending on direction.
What is the function of neurons?
Receive, integrate, and transmit information to other neurons or effector organs.
What are neuroglia, and what roles do they play?
Support neurons; types include oligodendrocytes, astrocytes, and microglia.
How does nerve conduction occur in neurons?
Through changes in electrical energy (action potentials), driven by ion movement across cell membranes.
What is an action potential?
Brief polarity reversal due to ion exchange, propagated along the axon, leading to neurotransmitter release.
What are the divisions of the autonomic nervous system (ANS)?
Sympathetic: Fight or flight response; Parasympathetic: Rest and digest functions.
What does the ANS control?
Smooth muscle, cardiac muscle, and secretory glands; regulates homeostasis.
What is the difference between grey and white matter?
Grey matter: Nerve cell bodies; White matter: Myelinated nerve processes.
What are nuclei and tracts in the CNS?
Nuclei: Groups of related nerve cell bodies; Tracts: Nerve processes following shared pathways.
Why do sensory and motor pathways decussate in the CNS?
To ensure each cerebral hemisphere controls the contralateral side of the body.
What protects the CNS?
Skull, vertebral column, and meninges (dura mater, arachnoid mater, pia mater).
What are the functions of cerebrospinal fluid (CSF)?
Provides protection, buoyancy, and chemical stability for the CNS.
What are the four ventricles in the brain, and their roles?
Lateral, third, and fourth ventricles: Produce, circulate, and remove CSF.
What are the major landmarks of the brainstem?
Medulla oblongata, pons, and midbrain; control vital functions like respiration and cardiovascular activity.
What is the cerebellum’s function?
Coordinates balance, movement, and unconscious voluntary actions.
What is the frontal lobe responsible for?
Emotion, personality, motor function, memory, language understanding, and attention regulation.
What are the functions of the temporal lobe?
Auditory processing, memory encoding, emotion regulation, and language understanding.
What is the role of the parietal lobe?
Integrates sensory information, constructs spatial coordination, and assists cognition.
What is the primary role of the occipital lobe?
Visual processing center with the primary visual cortex in Brodmann Area 17.
