Lecture 2 - Nervous System Flashcards
Nervous System
Respond quickly to stimuli but short-lived, using action potentials and neurotransmitters.
Endocrine System
Respond slowly but long-lasting, by secreting hormones into the circulatory system that travel to the target tissue.
Central Nervous System (CNS)
Brain and spinal cord.
Receives sensory input via PNS sensory nerves.
Processes/interprets sensory input (interneurons).
Sends response to effectors (muscles, gland) via motor nerves.
Peripheral Nervous System (PNS)
Cranial and spinal nerves extending from brain and spinal cord.
Connects CNS to entire body.
Autonomic nervous system (ANS)
Cranial and spinal nerves connecting CNS to heart, stomach, intestine, and gland.
Control unconscious activities.
Somatic nervous system (SNS)
Cranial and spinal nerves connecting CNS to skin and skeletal muscle.
Oversees conscious activities.
Sympathetic nervous system
Increases heart rate, bronchiole dilation, blood glucose, blood to skeletal muscle, bladder.
Decreases digestion, pupil size, urinary output.
Fight or flight.
Parasympathetic nervous system
Decreases heart rate, bronchiole dilation, blood glucose, blood to skeletal muscle, bladder.
Increases digestion, pupil size, urinary output.
Rest and digest.
Brain
Control center of the body
Spinal Cord
Most caudal, receives sensory information from the body, sends efferent to muscles and glands.
Medulla (oblongata)
Rostral to spinal cord
Pons
Integration point from spinal cord, medulla to cerebral cortex and cerebellum.
Cerebellum
Functions for smooth coordinated movements.
Function of Sensory Cortex?
Pain, heat, and other sensations.
Function of Parietal Lobe?
Comprehension of language.
Function of Temporal Lobe?
Hearing, intellectual and emotional functions.
Function of Occipital Lobe?
Primary visual area.
Function of Wernicke’s area?
Speech comprehension
Function of Cerebellum?
Coordination
Function of Brain stem?
Swallowing, breathing, heartbeat, wakefulness center and other involuntary functions.
Function of Frontal Lobe?
Smell.
Judgement, foresight, and voluntary movement.
Function of Broca’s Area?
Speech
Function of Motor Cortex?
Movement
What nervous system is responsible for homeostasis?
Autonomic nervous system (ANS)
Except for skeletal muscle, innervation to all other organs is supplied by the autonomic nervous system.
The sympathetic nervous system comes out of the CNS via _______
the thoracic through lumbar regions of the spinal cord.
“thoracolumber”
The parasympathetic nervous system exits the CNS via ______
the cranial nerves and nerves existing the spinal cord at the sacral level.
“craniosacral”
Sensory nerves
carry messages from body to brain (pain pressure, temperature, etc.)
Motor nerves
carry messages from brain to body to respond.
Neuron
Structural and functional unit of the nervous system.
Dendrites
Fibers that receive messages from other neurons.
Cell body (with nucleus)
Where signal integration and impulse generation takes place.
Axon
Fibers that send messages to other neurons.
Neurons are _____
amitotic; they do not divide. They have a very high metabolic rate.
Nuclei
Clusters of cell bodies in the CNS.
What are the most numerous cell in the CNS?
Glial cells.
Synapse
Gap between neuron cells.
Messages are sent across the synapses by special chemicals called ______.
Neurotransmitters.
Multipolar
Many processes arising from cell body.
Brain and spinal cord.
Bipolar
2 processes (1 from each end of cell body)
Ear, eyes, noses
Unipolar
Single process extends from cell body.
Outside of brain & spinal cord
Sensory neurons (afferent)
Have specialized receptor ends that sense stimuli and then carry impulses from peripheral body parts to brain or spinal cord. Can be unipolar or bipolar.
Interneurons
Lie entirely within the brain or spinal cord.
Direct incoming sensory impulses to appropriate parts for processing and interpreting.
Multipolar.
Motor neurons (efferent)
Carry impulses out of the brain or spinal cord to effectors (muscles, glands)
Multipolar.
Glial cells
Supporting cells of the nervous system.
Make up half the volume of the vertebrate brain and outnumber neurons by 10:1
Astrocytes
Provide support between neurons and capillaries.
Microglial cells
CNS phagocytic cell, macrophage-like.
Oligodendrocytes
CNS, produce myelin sheaths in CNS.
Ependymal cells
Line cavities in CNS, produce and help circulate CSF (cerebral spinal fluid)
Schwann cells
Create the myelin sheaths in PNS.
Myelin sheath
Covering of lipid material often found on axons, insulates axons and speeds nerve impulse transmission.
Produced in the CNS by oligodendrocytes, in the PNS by schwann cells.
Nodes of Ranvier
Gaps between schwann cells, important in nerve impulse conduction.
Fibrous astrocytes
contain many filaments, found in white matter, help maintain structural integrity of the brain.
Protoplasmic astrocytes
found in grey matter & have granular cytoplasm.
Saltatory conduction
Myelin sheaths permit for faster nerve impulse transmission
