Chapter 11 Biology Terms Flashcards
Neuron
A nerve cell that is capable of conducting nerve impulses.
Neural signaling
The reception, transmission, and integration of nerve impulses by neurons, and the response to these impulses.
Afferent Neuron
A neuron that carries impulses from sensory receptors to the central nervous system; also called a sensory neuron.
Interneuron
A local circuit neuron of the central nervous system that relays impulses between afferent (sensory) and efferent (motor) neurons.
Efferent neuron
A neuron that carries impulses from the central nervous system to skeletal muscles; also known as a motor neuron.
Dendrite
A projection of cytosol that carries signals toward the nerve cell body.
Axon
An extension of cytosol that carries nerve signals away from the nerve cell body.
Glial cell
Is a non-conducting cell that is important for the structural support of and metabolism of nerve cells.
Myelin Sheath
An insulated covering over the axon of a nerve cells
Node of Ranvier
A regularly occurring gap between sections of myelin sheath along the axon.
Central nervous System (CNS)
The body’s coordinating center for mechanical and chemical actions; made up of the brain and spinal cord.
Peripheral Nervous System (PNS)
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.
Afferent System
The component of the peripheral nervous system that receives input through receptors and transmits the input to the central nervous system.
Efferent System
The component of the peripheral nervous system that carries signals away to the effectors (muscle and glands).
Somatic system
A subdivision of the efferent system (within the PNS); composed of efferent (motor) neurons that carry signals to the skeletal muscles in response to external stimuli.
Autonomic system
A subdivision of the efferent system (within the PNS); regulates the internal environment.
Sympathetic Division
One of two subdivisions of the autonomic nervous system; increases energy consumption and prepares the body for action.
Parasympathetic Division
One of two subdivisions of the autonomic nervous system; stimulates body activities that acquire and conserve energy.
Neural circuit
The coordination of the receptor, afferent neuron, interneuron, efferent neuron, and effector in response to a stimulus.
Reflex Arc
A neural circuit that travels through the spinal cord but does not require the coordination of the brain; allows for reflex actions.
Synapse
A functional connection between neurons or between neurons and effectors
Chemical Synapse
A synapse in which a neurotransmitter moves from a presynaptic cell to a postsynaptic cell through the synaptic cleft.
Neurotransmitters
A chemical that is released from vesicles into synapse to facilitate nerve signal transmission.
Synaptic cleft
The tiny gap between presynaptic and postsynaptic cells in a chemical synapse, across which the neurotransmitter diffuses.
Electrical synapse
Electrical synapse- a synapse in which the presynaptic cell makes direct contact with the postsynaptic cell, allowing current to flow via gap junctions between the cells.
Membrane potential
The electrical potential of a membrane, which is caused by an imbalance of charges on either side of the membrane.
Ion channel
A protein embedded in the plasma membrane that allows ions to pass through it.
Resting potential
The voltage difference across a nerve cell membrane of an unstimulated neuron; usually negative.
Action potential
The voltage difference across a nerve cell membrane when the nerve is excited.
Threshold potential
The potential at which an action potential is generated by a neuron.
Refractory period
The period of time during which the threshold required for the generation of an action potential is much higher than normal.
Meninges
Three layers of connective tissues that surround and protect the brain and spinal cord.
Cerebrospinal fluid
Circulating fluid that surrounds the membranes of the brain and spinal cord; provides neural connection to the endocrine system.
Grey matter
The tissue of the brain and spinal cord where the cell bodies and dendrites of neurons are located.
White matter
The tissue of the brain and spinal cord, composed primarily of axons of neurons; in the spinal cord, it surrounds the grey matter.
Medulla oblongata
The hindbrain region that connects the spinal cord to the cerebellum; important in autonomic nerve control.
Cerebellum
The hindbrain region that is involved in muscle movement and balance.
Pons
The brain region that transfers nerve signals between the cerebellum and the medulla.
Cerebrum
The brain region that is involved in motor activities and sensory information; the largest and most developed region of the brain.
Cerebral cortex
The outermost layer of the cerebral hemispheres.
Thalamus
The brain region that interprets sensory input and signals the cerebrum.
Blood brain barrier
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.
Spinal nerves
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.
Cranial 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.
Substantia Gelatinosa (SG)
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.
Sensory adaptation
The tendency for some sensory receptors to become less sensitive when stimulated repeatedly
Renin-angiotensin-aldosterone pathway
A negative feedback mechanism that attempts to maintain blood pressure.
