Chapter 11 Flashcards
a nerve cell that is capable of conducting nerve impulses
neuron
the reception, transmission, and integration of nerve impulses by neurons, and the response to these impulses
neural signalling
a neuron that carries impulses from sensory receptors to the central nervous system; also called a sensory neuron
afferent neuron
a local circuit neuron of the central nervous system that relays impulses between afferent (sensory) and efferent (motor) neurons
interneuron
a neuron that carries impulses from the central nervous system to skeletal muscles; also known as a motor neuron
efferent neuron
a projection of cytosol that carries signals toward the nerve cell body
dendrite
an extension of cytosol that carries nerve signals away from the nerve cell body
axon
a non-conducting cell that is important for the structural support and metabolism of nerve cells
glial cell
an insulated covering over the axon of a nerve cell
myelin sheath
a regularly occurring gap between sections of myelin sheath along the axon
node of Ranvier
the body’s coordinating centre for mechanical and chemical actions; made up of the brain and spinal cord
central nervous system (CNS)
all parts of the nervous system, excluding the brain and spinal cord; relays information between the central nervous system and other parts of the body
peripheral nervous system (PNS)
the component of the peripheral nervous system that receives input through receptors and transmits the input to the central nervous system
afferent system
the component of the peripheral nervous system that carries signals away to the effectors (muscles and glands)
efferent system
a subdivision of the efferent system (within the PNS); composed of efferent (motor) neurons that carry signals to skeletal muscles in response to external stimuli
somatic system
a subdivision of the efferent system (within the PNS); regulates the internal environment
autonomic system
one of two subdivisions of the autonomic nervous system; increases energy consumption and prepares the body for action
sympathetic division
one of two subdivisions of the autonomic nervous system; stimulates body activities that acquire and conserve energy
parasympathetic division
the coordination of the receptor, afferent neuron, interneuron, efferent neuron, and effector in response to a stimulus
neural circuit
a neural circuit that travels through the spinal cord but does not require the coordination of the brain; allows for reflex actions
reflex arc
a functional connection between neurons or between neurons and effectors
synapse
a synapse in which a neurotransmitter moves from a presynaptic cell to a postsynaptic cell through the synaptic cleft
chemical synapse
a chemical that is released from vesicles into synapses to facilitate nerve signal transmission
neurotransmitter
the tiny gap between presynaptic and postsynaptic cells in a chemical synapse, across which the neurotransmitter diffuses
synaptic cleft
a synapse in which the presynaptic cell makes direct contact with the postsynaptic cell, allowing current to flow via gap junctions between the cells
electrical synapse
the electrical potential of a membrane, which is caused by an imbalance of charges on either side of the membrane
membrane potential
a protein embedded in the plasma membrane that allows ions to pass through it
ion channel
the voltage difference across a nerve cell membrane of an unstimulated neuron; usually negative
resting potential
the voltage difference across a nerve cell membrane when the nerve is excited
action potential
the potential at which an action potential is generated by a neuron
threshold potential
the period of time during which the threshold required for the generation of an action potential is much higher than normal
refractory period
three layers of connective tissue that surround and protect the brain and spinal cord
meninges
circulating fluid that surrounds the membranes of the brain and spinal cord; provides neural connection to the endocrine system
cerebrospinal fluid
the tissue of the brain and spinal cord, where the cell bodies and dendrites of neurons are located
grey matter
the tissue of the brain and spinal cord, composed primarily of axons of neurons; in the spinal cord, it surrounds the grey matter
white matter
the hindbrain region that connects the spinal cord to the cerebellum; important in autonomic nerve control
medulla oblongata
the hindbrain region that is involved in muscle movement and balance
cerebellum
the brain region that transfers nerve signals between the cerebellum and the medulla
pons
the brain region that is involved in motor activities and sensory information; the largest and most developed region of the brain
cerebrum
the outermost layer of the cerebral hemispheres
cerebral cortex
the brain region that interprets sensory input and signals the cerebrum
thalamus
a barrier formed by tight junctions between endothelial cells in the capillaries in the brain that blocks the movement of most substances into the brain via the bloodstream
blood-brain barrier
the 31 pairs of nerves within the somatic system that transmit motor, sensory, and autonomic signals between the spinal cord and the rest of the body
spinal nerves
the 12 pairs of nerves within the parasympathetic division of the autonomic system, which emerge directly from the brain and serve the head, neck, and body trunk
cranial nerves
a band of grey matter in the spinal cord that, when stimulated, produces a neurotransmitter that communicates with an injured region of the body; a simultaneous signal to the brain results in the perception of pain
substantia gelatinosa (SG)
the tendency for some sensory receptors to become less sensitive when stimulated repeatedly
sensory adaptation
a negative feedback mechanism that attempts to maintain blood pressure
renin-angiotensin-aldosterone pathway
